u blox 1EHQ37NN UMTS/GSM//LTE Data Module User Manual TOBY L4 series
u-blox AG UMTS/GSM//LTE Data Module TOBY L4 series
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Contents
- 1. TempConfidential_TOBY-L4_SysIntegrManual_UBX-16024839
- 2. TempConfidential_TOBY-L4_SysIntegrManual_UBX-16024839_rev1
TempConfidential_TOBY-L4_SysIntegrManual_UBX-16024839
![TOBY-L4 series LTE Advanced (Cat 6) modules with 3G and 2G fallback System Integration Manual Abstract This document describes the features and the system integration of TOBY-L4 series multi-mode cellular modules. The modules are a complete and cost efficient LTE-FDD, LTE-TDD, DC-HSPA+, (E)GPRS multi-mode and multi-band solution with uCPU embedded Linux programming capability. The modules offer up to 301.5 Mb/s download and up to 51.0 Mb/s upload data rates with Category 6 LTE-Advanced carrier aggregation technology in the compact TOBY form factor. www.u-blox.com UBX-16024839 - R04](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-1.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Page 2 of 143 Document Information Title TOBY-L4 series Subtitle LTE Advanced (Cat 6) modules with 3G and 2G fallback Document type System Integration Manual Document number UBX-16024839 Revision, date R04 08-Feb-2018 Disclosure restriction Product Status Corresponding content status Functional Sample Draft For functional testing. Revised and supplementary data will be published later. In Development / Prototype Objective Specification Target values. Revised and supplementary data will be published later. Engineering Sample Advance Information Data based on early testing. Revised and supplementary data will be published later. Initial Production Early Prod. Information Data from product verification. Revised and supplementary data may be published later. Mass Production / End of Life Production Information Final product specification. This document applies to the following products: Name Type number Modem version Application version PCN reference Product status TOBY-L4006 TOBY-L4006-00A-00 TBD TBD TBD Functional Sample TOBY-L4006-50A-00 40.24 A00.02 UBX-18007908 Engineering Sample TOBY-L4106 TOBY-L4106-00A-00 TBD TBD TBD Functional Sample TOBY-L4106-50A-00 40.24 A00.02 UBX-18007908 Engineering Sample TOBY-L4206 TOBY-L4206-00A-00 TBD TBD TBD Functional Sample TOBY-L4206-50A-00 TBD TBD TBD Functional Sample TOBY-L4906 TOBY-L4906-00A-00 TBD TBD TBD Functional Sample TOBY-L4906-50A-00 40.19 A00.02 UBX-17058711 Engineering Sample u-blox reserves all rights to this document and the information contained herein. Products, names, logos and designs described herein may in whole or in part be subject to intellectual property rights. Reproduction, use, modification or disclosure to third parties of this document or any part thereof without the express permission of u-blox is strictly prohibited. The information contained herein is provided “as is” and u-blox assumes no liability for the use of the information. No warranty, either express or implied, is given, including but not limited, with respect to the accuracy, correctness, reliability and fitness for a particular purpose of the information. This document may be revised by u-blox at any time. For most recent documents, please visit www.u-blox.com. Copyright © 2018, u-blox AG u-blox® is a registered trademark of u-blox Holding AG in the EU and other countries. Microsoft and Windows are either registered trademarks or trademarks of Microsoft Corporation in the United States and/or other countries. All other registered trademarks or trademarks mentioned in this document are property of their respective owners.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-2.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Preface Page 3 of 143 Preface u-blox Technical Documentation As part of our commitment to customer support, u-blox maintains an extensive volume of technical documentation for our products. In addition to our product-specific technical data sheets, the following manuals are available to assist u-blox customers in product design and development. AT Commands Manual: This document provides the description of the AT commands supported by the u-blox cellular modules. System Integration Manual: This document provides the description of u-blox cellular modules’ system from the hardware and the software point of view, it provides hardware design guidelines for the optimal integration of the cellular modules in the application device and it provides information on how to set up production and final product tests on application devices integrating the cellular modules. Application Note: These documents provide guidelines and information on specific hardware and/or software topics on u-blox cellular modules. See Related documents for a list of Application Notes related to your Cellular Module. How to use this Manual The TOBY-L4 series System Integration Manual provides the necessary information to successfully design and configure the u-blox cellular modules. This manual has a modular structure. It is not necessary to read it from the beginning to the end. The following symbols are used to highlight important information within the manual: An index finger points out key information pertaining to module integration and performance. A warning symbol indicates actions that could negatively impact or damage the module. Questions If you have any questions about u-blox Cellular Integration: Read this manual carefully. Contact our information service on the homepage http://www.u-blox.com/ Technical Support Worldwide Web Our website (http://www.u-blox.com/) is a rich pool of information. Product information, technical documents can be accessed 24h a day. By E-mail Contact the closest Technical Support office by email. Use our service pool email addresses rather than any personal email address of our staff. This makes sure that your request is processed as soon as possible. You will find the contact details at the end of the document. Helpful Information when Contacting Technical Support When contacting Technical Support, have the following information ready: Module type (TOBY-L4106) and firmware version Module configuration Clear description of your question or the problem A short description of the application Your complete contact details](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-3.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Contents Page 4 of 143 Contents Preface ................................................................................................................................ 3 Contents .............................................................................................................................. 4 1 System description ....................................................................................................... 7 1.1 Overview .............................................................................................................................................. 7 1.2 Architecture ........................................................................................................................................ 10 1.3 Pin-out ............................................................................................................................................... 12 1.4 Operating modes ................................................................................................................................ 20 1.5 Supply interfaces ................................................................................................................................ 22 1.5.1 Module supply input (VCC) ......................................................................................................... 22 1.5.2 RTC back-up supply (V_BCKP) ..................................................................................................... 30 1.5.3 Generic digital interfaces supply output (V_INT) ........................................................................... 30 1.6 System function interfaces .................................................................................................................. 31 1.6.1 Module power-on ....................................................................................................................... 31 1.6.2 Module power-off ....................................................................................................................... 33 1.6.3 Module reset ............................................................................................................................... 35 1.6.4 Module / host configuration selection ......................................................................................... 35 1.7 Antenna interfaces ............................................................................................................................. 36 1.7.1 Antenna RF interfaces (ANT1 / ANT2) .......................................................................................... 36 1.7.2 Antenna detection interface (ANT_DET) ...................................................................................... 38 1.8 SIM interfaces ..................................................................................................................................... 38 1.8.1 SIM interfaces.............................................................................................................................. 38 1.8.2 SIM detection interface ............................................................................................................... 38 1.9 Data communication interfaces .......................................................................................................... 39 1.9.1 USB interface............................................................................................................................... 40 1.9.2 UART interfaces ........................................................................................................................... 41 1.9.3 SPI interfaces ............................................................................................................................... 44 1.9.4 DDC (I2C) interfaces ..................................................................................................................... 45 1.9.5 SDIO interface ............................................................................................................................. 45 1.9.6 RGMII interface ........................................................................................................................... 46 1.10 eMMC interface .............................................................................................................................. 47 1.11 Audio interfaces .............................................................................................................................. 48 1.11.1 Analog audio interfaces ............................................................................................................... 48 1.11.2 Digital audio interface ................................................................................................................. 49 1.12 ADC interfaces ................................................................................................................................ 50 1.13 General Purpose Input/Output ........................................................................................................ 50 1.14 Reserved pins (RSVD) ...................................................................................................................... 51 2 Design-in ..................................................................................................................... 52 2.1 Overview ............................................................................................................................................ 52 2.2 Supply interfaces ................................................................................................................................ 53](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-4.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Contents Page 5 of 143 2.2.1 Module supply (VCC) .................................................................................................................. 53 2.2.2 RTC back-up supply (V_BCKP) ..................................................................................................... 66 2.2.3 Generic digital interfaces supply output (V_INT) ........................................................................... 67 2.3 System functions interfaces ................................................................................................................ 68 2.3.1 Module power-on (PWR_ON) ...................................................................................................... 68 2.3.2 Module reset (RESET_N) .............................................................................................................. 69 2.3.3 Module / host configuration selection ......................................................................................... 70 2.4 Antenna interface ............................................................................................................................... 71 2.4.1 Antenna RF interfaces (ANT1 / ANT2) .......................................................................................... 71 2.4.2 Antenna detection interface (ANT_DET) ...................................................................................... 77 2.5 SIM interfaces ..................................................................................................................................... 79 2.5.1 Guidelines for SIM circuit design.................................................................................................. 79 2.5.2 Guidelines for SIM layout design ................................................................................................. 85 2.6 Data communication interfaces .......................................................................................................... 86 2.6.1 USB interface............................................................................................................................... 86 2.6.2 UART interfaces ........................................................................................................................... 89 2.6.3 SPI interfaces ............................................................................................................................... 93 2.6.4 DDC (I2C) interfaces ..................................................................................................................... 94 2.6.5 SDIO interface ............................................................................................................................. 98 2.6.6 RGMII interface ......................................................................................................................... 100 2.7 eMMC interface ............................................................................................................................... 101 2.8 Audio interface ................................................................................................................................. 102 2.8.1 Analog audio interface .............................................................................................................. 102 2.8.2 Digital audio interface ............................................................................................................... 111 2.9 ADC interfaces ................................................................................................................................. 113 2.10 General Purpose Input/Output ...................................................................................................... 114 2.11 Reserved pins (RSVD) .................................................................................................................... 115 2.12 Module placement ........................................................................................................................ 115 2.13 Module footprint and paste mask ................................................................................................. 116 2.14 Thermal guidelines ........................................................................................................................ 117 2.15 Design-in checklist ........................................................................................................................ 118 2.15.1 Schematic checklist ................................................................................................................... 118 2.15.2 Layout checklist ......................................................................................................................... 119 2.15.3 Antenna checklist ...................................................................................................................... 119 3 Handling and soldering ........................................................................................... 120 3.1 Packaging, shipping, storage and moisture preconditioning ............................................................. 120 3.2 Handling ........................................................................................................................................... 120 3.3 Soldering .......................................................................................................................................... 121 3.3.1 Soldering paste.......................................................................................................................... 121 3.3.2 Reflow soldering ....................................................................................................................... 121 3.3.3 Optical inspection ...................................................................................................................... 122 3.3.4 Cleaning .................................................................................................................................... 122 3.3.5 Repeated reflow soldering ......................................................................................................... 123](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-5.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Contents Page 6 of 143 3.3.6 Wave soldering.......................................................................................................................... 123 3.3.7 Hand soldering .......................................................................................................................... 123 3.3.8 Rework ...................................................................................................................................... 123 3.3.9 Conformal coating .................................................................................................................... 123 3.3.10 Casting ...................................................................................................................................... 123 3.3.11 Grounding metal covers ............................................................................................................ 123 3.3.12 Use of ultrasonic processes ........................................................................................................ 123 4 Approvals .................................................................................................................. 124 4.1 Product certification approval overview ............................................................................................. 124 4.2 US Federal Communications Commission notice ............................................................................... 125 4.2.1 Safety warnings review the structure ......................................................................................... 125 4.2.2 Declaration of conformity .......................................................................................................... 125 4.2.3 Modifications ............................................................................................................................ 126 4.3 Innovation, Science and Economic Development Canada notice ....................................................... 127 4.3.1 Declaration of Conformity ......................................................................................................... 127 4.3.2 Modifications ............................................................................................................................ 128 4.4 European Conformance CE mark ...................................................................................................... 130 4.5 Chinese CCC and SRRC certifications ............................................................................................... 131 5 Product testing ......................................................................................................... 132 5.1 u-blox in-series production test ......................................................................................................... 132 5.2 Test parameters for OEM manufacturers........................................................................................... 133 5.2.1 “Go/No go” tests for integrated devices .................................................................................... 133 5.2.2 RF functional tests ..................................................................................................................... 133 Appendix ........................................................................................................................ 135 A Migration between TOBY-L2 and TOBY-L4 ............................................................ 135 A.1 Overview .......................................................................................................................................... 135 A.2 Pin-out comparison between TOBY-L2 and TOBY-L4 ........................................................................ 137 B Glossary .................................................................................................................... 139 Related documents......................................................................................................... 141 Revision history .............................................................................................................. 142 Contact ............................................................................................................................ 143](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-6.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 System description Page 7 of 143 1 System description 1.1 Overview The TOBY-L4 series modules support multi-band LTE-FDD, LTE-TDD, DC-HSPA+, and (E)GPRS radio access technologies (see Table 1) in the very small TOBY 248-pin LGA form-factor (35.6 x 24.8 mm), which is easy to integrate in compact designs. TOBY-L4 series modules are form-factor compatible with the other u-blox cellular module families (including SARA, LISA, LARA, and TOBY form-factors): this allows customers to take maximum advantage of their hardware and software investments, and provides very short time-to-market. With LTE-Advanced carrier aggregation category 6 data rates up to 301.5 Mbit/s (downlink) / 51.0 Mbit/s (uplink), the modules are ideal for applications requiring the highest data-rates and high-speed internet access. Reduced cost variants supporting LTE Cat 4 or LTE Cat 1 will be available for lower speed or “pure” telematics devices. TOBY-L4 series include the following LTE Cat 6 modules with 3G and 2G fallback: TOBY-L4006 modules, mainly designed for operation in North America TOBY-L4106 modules, mainly designed for operation in Europe TOBY-L4206 modules, mainly designed for operation in Asia-Pacific and South America TOBY-L4906 modules, mainly designed for operation in China TOBY-L4 series modules include the following product versions: The “00” product versions, integrating the u-blox uCPU on-chip processor to allow customers to run their dedicated applications on an embedded Linux distribution based on Yocto, with RIL-Core connectivity APIs The “50” product versions, which can be controlled by an external application processor through standard and u-blox proprietary AT commands described in the u-blox AT Commands Manual [2] TOBY-L4 series modules are the ideal product for the development of all kinds of automotive devices, such as smart antennas and in-dash telematics / infotainment devices, supporting a comprehensive set of HW interfaces (including RGMII/RMII for Ethernet and analog audio) over a very extended temperature range that allow the establishment of an emergency call up to +95 °C, complemented by a set of state-of-the art security features. TOBY-L4 series modules are also the perfect choice for consumer fixed-wireless terminals, mobile routers and gateways, applications requiring video streaming and many other industrial (M2M) applications. TOBY-L4 series modules are manufactured in ISO/TS 16949 certified sites, with the highest production standards and the highest quality and reliability. Each module is fully tested and inspected during production. The modules are qualified according to the automotive requirements as for systems installed in vehicles.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-7.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 System description Page 8 of 143 Table 1 summarizes the main features and interfaces of the TOBY-L4 series modules. Model Region Bands Interfaces Features Grade LTE FDD bands LTE TDD bands UMTS FDD bands GSM bands UART USB 2.0 device/host* USB 3.0 device** SPI RGMII / RMII eMMC SDIO DDC (I2C) SIM GPIO ADC Antenna supervisor CA / MIMO / Rx Diversity Analog audio Digital Audio uCPU for customer applications GNSS via modem Wi-Fi via modem Network indication Jamming detection Embedded TCP/UDP stack Embedded HTTP, FTP, SSL FOTA Dual stack IPv4/IPv6 Standard Professional Automotive TOBY-L4006-00 North America 2,4,5 7,12 13,29 2 4,5 850 1900 4 1 1 2 1 1 1 2 2 14 2 ● ● ● ● ● ● ● ● ● ● ● ● ● TOBY-L4006-50 North America 2,4,5 7,12 13,29 2 4,5 850 1900 1 1 2 9 ● ● ● ● ● ● ● TOBY-L4106-00 EMEA 1,3 7,8 20 38 1,8 900 1800 4 1 1 2 1 1 1 2 2 14 2 ● ● ● ● ● ● ● ● ● ● ● ● ● TOBY-L4106-50 EMEA 1,3 7,8 20 38 1,8 900 1800 1 1 2 9 ● ● ● ● ● ● ● TOBY-L4206-00 APAC, South America 1,3,5 7,8,9 19,28 1 5,8 Quad 4 1 1 2 1 1 1 2 2 14 2 ● ● ● ● ● ● ● ● ● ● ● ● ● TOBY-L4206-50 APAC, South America 1,3,5 7,8,9 19,28 1 5,8 Quad 1 1 2 9 ● ● ● ● ● ● ● TOBY-L4906-00 China 1,3 39 40,41 1,8 900 1800 4 1 1 2 1 1 1 2 2 14 2 ● ● ● ● ● ● ● ● ● ● ● ● ● TOBY-L4906-50 China 1,3 39 40,41 1,8 900 1800 1 1 2 9 ● ● ● ● ● ● ● * USB 2.0 host role not supported by the "50" product versions ** USB 3.0 interface supported by future firmware versions Table 1: TOBY-L4 series main features summary](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-8.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 System description Page 9 of 143 TOBY-L4 series modules provide multi-band 4G / 3G / 2G multi-mode radio access technologies, based on the 3GPP Release 10 protocol stack, with the main characteristics summarized in Table 2 and Table 3. LTE 3G 2G LTE-Advanced Carrier Aggregation Frequency Division Duplex (LTE FDD) Time Division Duplex (LTE TDD) Down-Link CA / MIMO / Rx diversity Dual-Cell High Speed Packet Access Frequency Division Duplex (UMTS FDD) Down-Link Rx diversity Enhanced Data rate GSM Evolution (EDGE) Time Division Multiple Access (TDMA) DL Advanced Rx Performance Phase 1 LTE FDD Power Class Class 3 (23 dBm) LTE TDD Power Class Class 3 (23 dBm) UMTS FDD Power Class Class 3 (24 dBm) GMSK Power Class Class 4 (33 dBm) for GSM/E-GSM bands Class 1 (30 dBm) for DCS/PCS bands 8-PSK Power Class Class E2 (27 dBm) for GSM/E-GSM bands Class E2 (26 dBm) for DCS/PCS bands Data rate LTE category 6: up to 301.5 Mbit/s DL up to 51.0 Mbit/s UL Data rate FDD UE categories: DL cat.24, up to 42.2 Mbit/s UL cat.6, up to 5.76 Mbit/s Data rate GPRS multi-slot class 33, CS1-CS4: up to 107.0 kbit/s DL up to 85.6 kbit/s UL EDGE multi-slot class 33, MCS1-MCS9 up to 296.0 kbit/s DL up to 236.8 kbit/s UL Table 2: TOBY-L4 series LTE, 3G and 2G characteristics summary Module Region LTE FDD bands LTE TDD bands LTE CA UMTS FDD bands GSM bands TOBY-L4006 North America 12 (700 MHz) 17 (700 MHz) 29 (700 MHz) 13 (750 MHz) 5 (850 MHz) 4 (1700 MHz) 2 (1900 MHz) 7 (2600 MHz) 4 + 17 2 + 13 2 + 17 2 + 29 4 + 5 4 + 4 4 + 13 4 + 29 5 (850 MHz) 4 (1700 MHz) 2 (1900 MHz) GSM 850 PCS 1900 TOBY-L4106 EMEA, APAC 20 (800 MHz) 8 (900 MHz) 3 (1800 MHz) 1 (2100 MHz) 7 (2600 MHz) 38 (2600 MHz) 3 + 20 7 + 20 3 + 3 3 + 7 8 (900 MHz) 1 (2100 MHz) E-GSM 900 DCS 1800 TOBY-L4206 APAC, South America 28 (750 MHz) 19 (850 MHz) 5 (850 MHz) 8 (900 MHz) 9 (1800 MHz) 3 (1800 MHz) 1 (2100 MHz) 7 (2600 MHz) 3 + 28 3 + 7 7 + 28 3 + 3 1 + 8 3 + 19 1 + 19 5 (850 MHz) 8 (900 MHz) 1 (2100 MHz) GSM 850 E-GSM 900 DCS 1800 PCS 1900 TOBY-L4906 China 3 (1800 MHz) 1 (2100 MHz) 39 (1900 MHz) 40 (2300 MHz) 41 (2500 MHz) 3 + 3 40 + 40 41 + 41 39 + 41 8 (900 MHz)1 1 (2100 MHz) E-GSM 900 DCS 1800 Table 3: TOBY-L4 series supported bands2 and Carrier Aggregation combinations summary 1 Down-Link Rx diversity not supported on this band 2 TOBY-L4 series modules support all the E-UTRA channel bandwidths for each operating band according to 3GPP TS 36.521-1 [13].](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-9.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 System description Page 10 of 143 1.2 Architecture Figure 1 summarizes the internal architecture of the TOBY-L4 series modules. CellularBase-bandProcessorMemoryPower Management Unit26 MHz32.768 kHzANT1RF TransceiverANT2V_INT (I/O)V_BCKP (RTC)VCC (Supply)2 x SIMUSB 2.0 / 3.02 x ADCPower onExternal resetPAsLNAs FiltersFiltersDuplexerFiltersPAsLNAs FiltersFiltersDuplexerFiltersLNAs FiltersFiltersLNAs FiltersFiltersSwitchSwitch2 x DDC (I2C)SDIO4 x UARTAnalog audioAntenna detectionHost Select2 x SPIRGMIIeMCC2 x Digital audio (I2S)GPIOs Figure 1: TOBY-L4 series modules simplified block diagram TOBY-L4 series modules internally consist of the RF, Baseband and Power Management sections described herein with more details than the simplified block diagrams of Figure 1. RF section The RF section is composed of an RF transceiver, PAs, LNAs, crystal oscillator, filters, duplexers and RF switches. The Tx signal is pre-amplified by the RF transceiver, then output to the primary antenna input/output port (ANT1) of the module via power amplifier (PA), SAW band pass filters band, specific duplexer and antenna switch. Dual receiving paths are implemented according to Carrier Aggregation, MIMO, and Receiver Diversity radio technologies supported by the modules as LTE category 6 and HSDPA category 24 User Equipments: incoming signals are received through the primary (ANT1) and the secondary (ANT2) antenna input ports which are connected to the RF transceiver via specific antenna switch, diplexer, duplexer, LNA, SAW band pass filters. RF transceiver performs modulation, up-conversion of the baseband I/O signals for Tx, down-conversion and demodulation of the dual RF signals for Rx. The RF transceiver contains: Single chain high linearity receivers with integrated LNAs for multi-band multi-mode CA operation, Highly linear RF demodulator / modulator capable GMSK, 8-PSK, QPSK, 16-QAM, 64-QAM RF synthesizer, VCO. Power Amplifiers (PA) amplify the Tx signal modulated by the RF transceiver RF switches connect the primary (ANT1) and secondary (ANT2) antenna ports to the suitable Tx / Rx path SAW duplexers and band pass filters separate the Tx and Rx signal paths and provide RF filtering 26 MHz voltage-controlled temperature-controlled crystal oscillator (VC-TCXO) generates the clock reference in active mode or connected mode.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-10.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 System description Page 11 of 143 Baseband and power management section The Baseband and Power Management section is composed of the following main elements: A mixed signal ASIC, which integrates o Microprocessor for control functions o DSP core for cellular Layer 1 and digital processing of Rx and Tx signal paths o Memory interface controller o Dedicated peripheral blocks for control of the USB, SIM and generic digital interfaces o Interfaces to the RF transceiver ASIC Memory system, which includes NAND flash and LPDDR2 RAM Voltage regulators to derive all the subsystem supply voltages from the module supply input VCC Voltage source for external use: V_INT Hardware power on Hardware reset Low power idle mode support 32.768 kHz crystal oscillator to provide the clock reference in the low power idle mode, which can be set by enabling the power saving configuration.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-11.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 System description Page 12 of 143 1.3 Pin-out Table 4 lists the pin-out of the TOBY-L4 series modules, with pins grouped by function. Function Pin Name Pin No I/O Description Remarks Power VCC 70,71,72 I Module supply input VCC supply circuit affects the RF performance and compliance of the device integrating the module with applicable required certification schemes. See section 1.5.1 for functional description / requirements. See section 2.2.1 for external circuit design-in. GND 2, 30, 32, 44, 46, 69, 73, 74, 76, 78, 79, 80, 82, 83, 85, 86, 88-90, 92-152, 209, 219, 226, 229, 232, 235, 238, 241 N/A Ground GND pins are internally connected each other. External ground connection affects the RF and thermal performance of the device. See section 1.5.1 for functional description. See section 2.2.1 for external circuit design-in. V_BCKP 3 I/O RTC back-up supply If the VCC voltage is below the operating range, the RTC block can be externally supplied through the V_BCKP pin. See section 1.5.2 for functional description. See section 2.2.2 for external circuit design-in. V_INT 5 O Generic digital interfaces supply output V_INT = 1.8 V (typical) generated by internal DC/DC regulator when the module is switched on. Test-Point for diagnostic access is recommended. See section 1.5.3 for functional description. See section 2.2.3 for external circuit design-in. System PWR_ON 20 I Power-on input Internal 35 k pull-up resistor to internal 1.3 V supply rail. Test-Point for diagnostic access is recommended. See section 1.6.1 for functional description. See section 2.3.1 for external circuit design-in. RESET_N 23 I External reset input Internal 100 k pull-up resistor to V_INT. Test-Point for diagnostic access is recommended. See section 1.6.3 for functional description. See section 2.3.2 for external circuit design-in. HOST_SELECT0 26 I/O / I GPIO / External Interrupt 1.8 V GPIO or External Interrupt configurable by uCPU API. See sections 1.6.4, 1.13 for functional description. See sections 2.3.3, 2.10 for external circuit design-in. HOST_SELECT1 62 I/O / I GPIO / External Interrupt 1.8 V GPIO or External Interrupt configurable by uCPU API. See sections 1.6.4, 1.13 for functional description. See sections 2.3.3, 2.10 for external circuit design-in. Antennas ANT1 81 I/O Primary antenna Main Tx / Rx antenna interface. 50 nominal characteristic impedance. Antenna circuit affects the RF performance and application device compliance with required certification schemes. See section 1.7.1 for functional description / requirements. See section 2.4 for external circuit design-in. ANT2 87 I Secondary antenna Rx only for Down-Link CA, MIMO and Rx diversity. 50 nominal characteristic impedance. Antenna circuit affects the RF performance and application device compliance with required certification schemes. See section 1.7.1 for functional description / requirements. See section 2.4 for external circuit design-in. ANT_DET 75 I Antenna detection ADC for antenna presence detection function. See section 1.7.2 for functional description. See section 2.4.2 for external circuit design-in.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-12.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 System description Page 13 of 143 Function Pin Name Pin No I/O Description Remarks SIM0 VSIM 59 O SIM0 supply output VSIM = 1.8 V / 3 V output as per the connected SIM type. See section 1.8 for functional description. See section 2.5 for external circuit design-in. SIM_IO 57 I/O SIM0 data Data input/output for 1.8 V / 3 V SIM. Internal 4.7 k pull-up to VSIM. See section 1.8 for functional description. See section 2.5 for external circuit design-in. SIM_CLK 56 O SIM0 clock 3.9 MHz clock output for 1.8 V / 3 V SIM. See section 1.8 for functional description. See section 2.5 for external circuit design-in. SIM_RST 58 O SIM0 reset Reset output for 1.8 V / 3 V SIM. See section 1.8 for functional description. See section 2.5 for external circuit design-in. SIM1 VSIM1 172 O SIM1 supply output VSIM1 = 1.8 V / 3 V output as per the connected SIM type. See section 1.8 for functional description. See section 2.5 for external circuit design-in. SIM1_IO 178 I/O SIM1 data Data input/output for 1.8 V / 3 V SIM. Internal 4.7 k pull-up to VSIM1. See section 1.8 for functional description. See section 2.5 for external circuit design-in. SIM1_CLK 182 O SIM1 clock 3.9 MHz clock output for 1.8 V / 3 V SIM. See section 1.8 for functional description. See section 2.5 for external circuit design-in. SIM1_RST 177 O SIM1 reset Reset output for 1.8 V / 3 V SIM. See section 1.8 for functional description. See section 2.5 for external circuit design-in. USB VUSB_DET 4 I USB detect input VBUS (5 V typical) generated by the host must be connected to this pin to enable the module USB device interface. Test-Point for diagnostic / FW update access is recommended. See section 1.9.1 for functional description. See section 2.6.1 for external circuit design-in. USB_D– 27 I/O USB High-Speed 2.0 diff. transceiver (–) 90 nominal differential impedance (Z0). 30 nominal common mode impedance (ZCM). Pull-up or pull-down resistors and external series resistors as required by the USB 2.0 specifications [3] are part of the USB pin driver and need not be provided externally. Test-Point for diagnostic / FW update access is recommended. See section 1.9.1 for functional description. See section 2.6.1 for external circuit design-in. USB_D+ 28 I/O USB High-Speed 2.0 diff. transceiver (+) 90 nominal differential impedance (Z0). 30 nominal common mode impedance (ZCM). Pull-up or pull-down resistors and external series resistors as required by the USB 2.0 specifications [3] are part of the USB pin driver and need not be provided externally. Test-Point for diagnostic / FW update access is recommended. See section 1.9.1 for functional description. See section 2.6.1 for external circuit design-in. USB_ID 168 I USB device identification Pin for ID resistance measurement. See section 1.9.1 for functional description. See section 2.6.1 for external circuit design-in.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-13.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 System description Page 14 of 143 Function Pin Name Pin No I/O Description Remarks USB_SSTX+ 175 O USB Super-Speed 3.0 diff. transmitter (+) 90 nominal differential characteristic impedance. Internal series 100 nF capacitor for AC coupling. Compliant with USB Revision 3.0 specification [4]. See section 1.9.1 for functional description. See section 2.6.1 for external circuit design-in. USB_SSTX– 176 O USB Super-Speed 3.0 diff. transmitter (–) 90 nominal differential characteristic impedance. Internal series 100 nF capacitor for AC coupling. Compliant with USB Revision 3.0 specification [4]. See section 1.9.1 for functional description. See section 2.6.1 for external circuit design-in. USB_SSRX+ 170 I USB Super-Speed 3.0 diff. receiver (+) 90 nominal differential characteristic impedance. Compliant with USB Revision 3.0 specification [4]. See section 1.9.1 for functional description. See section 2.6.1 for external circuit design-in. USB_SSRX– 171 I USB Super-Speed 3.0 diff. receiver (–) 90 nominal differential characteristic impedance. Compliant with USB Revision 3.0 specification [4]. See section 1.9.1 for functional description. See section 2.6.1 for external circuit design-in. UART0 RXD 17 O UART0 data output 1.8 V output, Circuit 104 (RXD) in ITU-T V.24. Test-Point for diagnostic access recommended. See section 1.9.2 for functional description. See section 2.6.2 for external circuit design-in. TXD 16 I UART0 data input 1.8 V input, Circuit 103 (TXD) in ITU-T V.24. Internal active pull-up to V_INT. Test-Point for diagnostic access recommended. See section 1.9.2 for functional description. See section 2.6.2 for external circuit design-in. CTS 15 O UART0 clear to send output 1.8 V output, Circuit 106 (CTS) in ITU-T V.24. See section 1.9.2 for functional description. See section 2.6.2 for external circuit design-in. RTS 14 I UART0 ready to send input 1.8 V input, Circuit 105 (RTS) in ITU-T V.24. Internal active pull-up to V_INT. See section 1.9.2 for functional description. See section 2.6.2 for external circuit design-in. DSR 10 I/O / I GPIO / External Interrupt 1.8 V GPIO or External Interrupt configurable by uCPU API. See sections 1.9.2, 1.13 for functional description. See sections 2.6.1, 2.10 for external circuit design-in. RI 11 O / I/O / I UART0 ring indicator / GPIO / External Interrupt 1.8 V output, Circuit 125 (RI) in ITU-T V.24. Configurable as GPIO or External Interrupt. See sections 1.9.2, 1.13 for functional description. See sections 2.6.1, 2.10 for external circuit design-in. DTR 13 I/O / I GPIO / External Interrupt 1.8 V GPIO or External Interrupt configurable by uCPU API. See sections 1.9.2, 1.13 for functional description. See sections 2.6.1, 2.10 for external circuit design-in. DCD 12 I/O / I GPIO / External Interrupt 1.8 V GPIO or External Interrupt configurable by uCPU API. See sections 1.9.2, 1.13 for functional description. See sections 2.6.1, 2.10 for external circuit design-in.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-14.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 System description Page 15 of 143 Function Pin Name Pin No I/O Description Remarks UART1 RXD1 160 O / O UART1 data output / SPI1 MOSI 1.8 V output, Circuit 104 (RXD) in ITU-T V.24, alternatively configurable as SPI1 MOSI by uCPU API. See section 1.9.2 / 1.9.3 for functional description. See section 2.6.2 / 2.6.3 for external circuit design-in. TXD1 159 I / I UART1 data input / SPI1 MISO 1.8 V input, Circuit 103 (TXD) in ITU-T V.24, alternatively configurable as SPI1 MISO by uCPU API. Internal pull-up to V_INT enabled when UART1 data input. See section 1.9.2 / 1.9.3 for functional description. See section 2.6.2 / 2.6.3 for external circuit design-in. CTS1 195 O / O UART1 CTS output / SPI1 Chip Select 1.8 V output, Circuit 106 (CTS) in ITU-T V.24, alternatively configurable as SPI1 Chip Select by uCPU API. See section 1.9.2 / 1.9.3 for functional description. See section 2.6.2 / 2.6.3 for external circuit design-in. RTS1 193 I / O UART1 RTS input / SPI1 Clock 1.8 V input, Circuit 105 (RTS) in ITU-T V.24, alternatively configurable as SPI1 Clock by uCPU API. Internal pull-up to V_INT enabled when UART1 RTS input. See section 1.9.2 / 1.9.3 for functional description. See section 2.6.2 / 2.6.3 for external circuit design-in. UART2 RXD2 162 O UART2 data output 1.8 V output, Circuit 104 (RXD) in ITU-T V.24. See section 1.9.2 for functional description. See section 2.6.2 for external circuit design-in. TXD2 161 I UART2 data input 1.8 V input, Circuit 103 (TXD) in ITU-T V.24. Internal active pull-up to V_INT. See section 1.9.2 for functional description. See section 2.6.2 for external circuit design-in. UART3 RXD3 19 O UART3 data output 1.8 V output, Circuit 104 (RXD) in ITU-T V.24. See section 1.9.2 for functional description. See section 2.6.2 for external circuit design-in. TXD3 18 I UART3 data input 1.8 V input, Circuit 103 (TXD) in ITU-T V.24. Internal active pull-up to V_INT. See section 1.9.2 for functional description. See section 2.6.2 for external circuit design-in. SPI0 SPI_MOSI 174 O SPI0 Master Output Slave Input 1.8 V, SPI0 data output. See section 1.9.3 for functional description. See section 2.6.3 for external circuit design-in. SPI_MISO 169 I SPI0 Master Input Slave Output 1.8 V, SPI0 data input. See section 1.9.3 for functional description. See section 2.6.3 for external circuit design-in. SPI_SCLK 179 O SPI0 Shift Clock 1.8 V, SPI0 clock. See section 1.9.3 for functional description. See section 2.6.3 for external circuit design-in. SPI_CS 173 O SPI0 Chip Select 0 1.8 V, SPI0 chip select 0. See section 1.9.3 for functional description. See section 2.6.3 for external circuit design-in. I2C0 SCL 54 O I2C0 clock 1.8 V open drain. External pull-up required. See section 1.9.4 for functional description. See section 2.6.4 for external circuit design-in. SDA 55 I/O I2C0 data 1.8 V open drain. External pull-up required. See section 1.9.4 for functional description. See section 2.6.4 for external circuit design-in.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-15.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 System description Page 16 of 143 Function Pin Name Pin No I/O Description Remarks I2C1 SCL1 54 O I2C1 clock 1.8 V open drain. External pull-up required. See section 1.9.4 for functional description. See section 2.6.4 for external circuit design-in. SDA1 55 I/O I2C1 data 1.8 V open drain. External pull-up required. See section 1.9.4 for functional description. See section 2.6.4 for external circuit design-in. SDIO SDIO_D0 66 I/O SDIO serial data [0] SDIO interface for communication with Wi-Fi / Bluetooth. See section 1.9.5 for functional description. See section 2.6.5 for external circuit design-in. SDIO_D1 68 I/O SDIO serial data [1] SDIO interface for communication with Wi-Fi / Bluetooth. See section 1.9.5 for functional description. See section 2.6.5 for external circuit design-in. SDIO_D2 63 I/O SDIO serial data [2] SDIO interface for communication with Wi-Fi / Bluetooth. See section 1.9.5 for functional description. See section 2.6.5 for external circuit design-in. SDIO_D3 67 I/O SDIO serial data [3] SDIO interface for communication with Wi-Fi / Bluetooth. See section 1.9.5 for functional description. See section 2.6.5 for external circuit design-in. SDIO_CLK 64 O SDIO serial clock SDIO interface for communication with Wi-Fi / Bluetooth. See section 1.9.5 for functional description. See section 2.6.5 for external circuit design-in. SDIO_CMD 65 I/O SDIO command SDIO interface for communication with Wi-Fi / Bluetooth. See section 1.9.5 for functional description. See section 2.6.5 for external circuit design-in. Ethernet V_ETH 221 O Ethernet Interface supply output Ethernet (RGMII / RMII) interface supply output. See section 1.9.6 for functional description. See section 2.6.6 for external circuit design-in. ETH_TX_CLK 29 O Ethernet Transmission Clock RGMII: Transmit reference clock (TXC). RMII: Reference clock (REF_CLK). See section 1.9.6 for functional description. See section 2.6.6 for external circuit design-in. ETH_TX_CTL 33 O Ethernet Transmit Control RGMII: Control signal for the transmit data (TXEN on TXC rising edge; TXEN xor TXER on TXC falling edge). RMII: Control signal for the transmit data (TX_EN). See section 1.9.6 for functional description. See section 2.6.6 for external circuit design-in. ETH_TXD0 37 O Ethernet Transmit Data [0] RGMII: Tx data bit 0 / 4 on TXC rising / falling edges. RMII: Tx data bit 0 in sync with REF_CLK. See section 1.9.6 for functional description. See section 2.6.6 for external circuit design-in. ETH_TXD1 36 O Ethernet Transmit Data [1] RGMII: Tx data bit 1 / 5 on TXC rising / falling edges. RMII: Tx data bit 1 in sync with REF_CLK. See section 1.9.6 for functional description. See section 2.6.6 for external circuit design-in. ETH_TXD2 35 O Ethernet Transmit Data [2] RGMII: Tx data bit 2 / 6 on TXC rising / falling edges. RMII: Not used. See section 1.9.6 for functional description. See section 2.6.6 for external circuit design-in. ETH_TXD3 34 O Ethernet Transmit Data [3] RGMII: Tx data bit 3 / 7 on TXC rising / falling edges. RMII: Not used. See section 1.9.6 for functional description. See section 2.6.6 for external circuit design-in.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-16.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 System description Page 17 of 143 Function Pin Name Pin No I/O Description Remarks ETH_RX_CLK 43 I Ethernet Receive Clock RGMII: Receive reference clock (RXC). RMII: Not used. See section 1.9.6 for functional description. See section 2.6.6 for external circuit design-in. ETH_RX_CTL 42 I Ethernet Receive Control RGMII: Control signal for receive data (RXDV on RXC rising edge; RXDV xor RXER on RXC falling edge). RMII: Control signal for receive data, contains carrier sense (CRS) and data valid (RX_DV) information. See section 1.9.6 for functional description. See section 2.6.6 for external circuit design-in. ETH_RXD0 38 I Ethernet Receive Data [0] RGMII: Rx data bit 0 / 4 on RXC rising / falling edges. RMII: Rx data bit 0 in sync with REF_CLK. See section 1.9.6 for functional description. See section 2.6.6 for external circuit design-in. ETH_RXD1 39 I Ethernet Receive Data [1] RGMII: Rx data bit 1 / 5 on RXC rising / falling edges. RMII: Rx data bit 1 in sync with REF_CLK. See section 1.9.6 for functional description. See section 2.6.6 for external circuit design-in. ETH_RXD2 40 I Ethernet Receive Data [2] RGMII: Rx data bit 2 / 6 on RXC rising / falling edges. RMII: Not used. See section 1.9.6 for functional description. See section 2.6.6 for external circuit design-in. ETH_RXD3 41 I Ethernet Receive Data [3] RGMII: Rx data bit 3 / 7 on RXC rising / falling edges. RMII: Not used. See section 1.9.6 for functional description. See section 2.6.6 for external circuit design-in. ETH_INTR 220 I Ethernet Interrupt Input Input for the detection of an interrupt event in the PHY. See section 1.9.6 for functional description. See section 2.6.6 for external circuit design-in. ETH_MDIO 222 I/O Ethernet Management Data Input Output Ethernet management data input / output. See section 1.9.6 for functional description. See section 2.6.6 for external circuit design-in. ETH_MDC 223 O Ethernet Management Data Clock Ethernet management data clock output. See section 1.9.6 for functional description. See section 2.6.6 for external circuit design-in. eMMC V_MMC 210 O Multi-Media Card Interface supply output Embedded Multi-Media / SD Card memory supply. See section 1.10 for functional description. See section 2.7 for external circuit design-in. MMC_D0 214 I/O Multi-Media Card Data [0] Embedded Multi-Media / SD Card memory data [0]. See section 1.10 for functional description. See section 2.7 for external circuit design-in. MMC_D1 212 I/O Multi-Media Card Data [1] Embedded Multi-Media / SD Card memory data [1]. See section 1.10 for functional description. See section 2.7 for external circuit design-in. MMC_D2 217 I/O Multi-Media Card Data [2] Embedded Multi-Media / SD Card memory data [2]. See section 1.10 for functional description. See section 2.7 for external circuit design-in. MMC_D3 213 I/O Multi-Media Card Data [3] Embedded Multi-Media / SD Card memory data [3]. See section 1.10 for functional description. See section 2.7 for external circuit design-in. MMC_CMD 215 I/O Multi-Media Card Command Embedded Multi-Media / SD Card memory command. See section 1.10 for functional description. See section 2.7 for external circuit design-in. MMC_CLK 216 O Multi-Media Card Clock Embedded Multi-Media / SD Card memory clock. See section 1.10 for functional description. See section 2.7 for external circuit design-in.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-17.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 System description Page 18 of 143 Function Pin Name Pin No I/O Description Remarks MMC_RST_N 211 O Multi-Media Card Reset Embedded Multi-Media / SD Card memory reset. See section 1.10 for functional description. See section 2.7 for external circuit design-in. MMC_CD_N 218 I Multi-Media Card Detect Embedded Multi-Media / SD Card detect. See section 1.10 for functional description. See section 2.7 for external circuit design-in. I2S0 I2S_TXD 51 O I2S0 transmit data I2S transmit data output. See sections 1.11 for functional description. See sections 2.8 for external circuit design-in. I2S_RXD 53 I I2S0 receive data I2S receive data input. See sections 1.11 for functional description. See sections 2.8 for external circuit design-in. I2S_CLK 52 I/O I2S0 clock I2S serial clock. See sections 1.11 for functional description. See sections 2.8 for external circuit design-in. I2S_WA 50 I/O I2S0 word alignment I2S word alignment. See sections 1.11 for functional description. See sections 2.8 for external circuit design-in. I2S1 I2S1_TXD 206 O I2S1 transmit data I2S transmit data output. See sections 1.11 for functional description. See sections 2.8 for external circuit design-in. I2S1_RXD 207 I I2S1 receive data I2S receive data input. See sections 1.11 for functional description. See sections 2.8 for external circuit design-in. I2S1_CLK 208 I/O I2S1 clock I2S serial clock. See sections 1.11 for functional description. See sections 2.8 for external circuit design-in. I2S1_WA 205 I/O I2S1 word alignment I2S word alignment. See sections 1.11 for functional description. See sections 2.8 for external circuit design-in. Analog audio MIC_BIAS 231 O Microphone supply output Supply output for external microphones. See sections 1.11 for functional description. See sections 2.8 for external circuit design-in. MIC_GND 230 I Microphone analog reference Local ground for the external microphone. See sections 1.11 for functional description. See sections 2.8 for external circuit design-in. MIC1_P 237 I MIC1 differential analog audio input (+) MIC1 differential analog audio signal input (positive). See sections 1.11 for functional description. See sections 2.8 for external circuit design-in. MIC1_N 236 I MIC1 differential analog audio input (–) MIC1 differential analog audio signal input (negative). See sections 1.11 for functional description. See sections 2.8 for external circuit design-in. MIC2_P 234 I MIC2 differential analog audio input (+) MIC2 differential analog audio signal input (positive). See sections 1.11 for functional description. See sections 2.8 for external circuit design-in. MIC2_N 233 I MIC2 differential analog audio input (–) MIC2 differential analog audio signal input (negative). See sections 1.11 for functional description. See sections 2.8 for external circuit design-in.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-18.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 System description Page 19 of 143 Function Pin Name Pin No I/O Description Remarks SPK_P 227 O Differential analog audio output (+) Differential analog audio signal output (positive). See sections 1.11 for functional description. See sections 2.8 for external circuit design-in. SPK_N 228 O Differential analog audio output (–) Differential analog audio signal output (negative). See sections 1.11 for functional description. See sections 2.8 for external circuit design-in. ADC ADC1 240 I ADC input See section 1.12 for functional description. See section 2.9 for external circuit design-in. ADC2 239 I ADC input See section 1.12 for functional description. See section 2.9 for external circuit design-in. GPIO GPIO1 21 I/O GPIO 1.8 V GPIO with alternatively configurable functions. See section 1.13 for functional description. See section 2.10 for external circuit design-in. GPIO2 22 I/O GPIO 1.8 V GPIO with alternatively configurable functions. See section 1.13 for functional description. See section 2.10 for external circuit design-in. GPIO3 24 I/O GPIO 1.8 V GPIO with alternatively configurable functions. Configurable as External Interrupt by uCPU API. See section 1.13 for functional description. See section 2.10 for external circuit design-in. GPIO4 25 I/O GPIO 1.8 V GPIO with alternatively configurable functions. Configurable as SPI0 Chip Select 1 by uCPU API. See sections 1.13, 1.9.3 for functional description. See sections 2.10, 2.6.3 for external circuit design-in. GPIO5 60 I/O GPIO 1.8 V GPIO with alternatively configurable functions. See section 1.13 for functional description. See section 2.10 for external circuit design-in. GPIO6 61 I/O GPIO 1.8 V GPIO with alternatively configurable functions. See section 1.13 for functional description. See section 2.10 for external circuit design-in. GPIO7 248 I/O GPIO 1.8 V GPIO with alternatively configurable functions. See section 1.13 for functional description. See section 2.10 for external circuit design-in. GPIO8 247 I/O GPIO 1.8 V GPIO with alternatively configurable functions. See section 1.13 for functional description. See section 2.10 for external circuit design-in. Reserved RSVD 6 N/A Reserved pin This pin must be connected to ground. See sections 1.14 and 2.11 RSVD 1, 7-9, 31, 45, 47-49, 77, 84, 91, 153-158, 163-167, 180, 181, 183-192, 194, 196-202, 224, 225, 242, 243, 244-246 N/A Reserved pin Leave unconnected. See sections 1.14 and 2.11 Table 4: TOBY-L4 series module pin definition, grouped by function](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-19.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 System description Page 20 of 143 1.4 Operating modes TOBY-L4 series modules have several operating modes. The operating modes are defined in Table 5 and described in detail in Table 6, providing general guidelines for operation. General Status Operating Mode Definition Power-down Not-powered mode VCC supply not present or below operating range: module is switched off. Power-off mode VCC supply within operating range and module is switched off. Normal Operation Idle mode Module processor core runs with 32 kHz reference generated by the internal oscillator. Active mode Module processor core runs with 26 MHz reference generated by the internal oscillator. Connected mode RF Tx/Rx data connection enabled and processor core runs with 26 MHz reference. Table 5: TOBY-L4 series modules operating modes definition Mode Description Transition between operating modes Not-powered Module is switched off. Application interfaces are not accessible. When VCC supply is removed, the modules enter not-powered mode. When in not-powered mode, the modules do not switch on by applying VCC supply, or by using the PWR_ON pin. When in not-powered mode, the modules go to power-off mode by applying VCC supply. Power-off Module is switched off: normal shutdown by an appropriate power-off event (see 1.6.2). Application interfaces are not accessible. When the modules are switched off by an appropriate power-off event (see 1.6.2), the modules enter power-off mode from active mode. When in power-off mode, the modules can be switched on by means of the PWR_ON pin (see 1.6.1). When in power-off mode, the modules enter not-powered mode by removing VCC supply. Idle Module is switched on with application interfaces temporarily disabled or suspended to reduce the current consumption (see 1.5.1.5) due to power saving configuration enabled by AT+UPSV command or uCPU API The modules automatically switch from the active mode to low power idle mode whenever possible if power saving is enabled. The modules wake up from low power idle mode to active mode due to any necessary network related activity, external wake-up through the operating interfaces, or wake-up by means of dedicated uCPU API. Active Module is switched on with application interfaces enabled or not suspended: the module is ready to communicate with an external device by means of the application interfaces unless power saving configuration is enabled by AT+UPSV command or uCPU API. When the modules are switched on by an appropriate power-on event (see 1.6.1), the module enter active mode from power-off mode. If power saving configuration is enabled by the AT+UPSV command or uCPU API, the module automatically switches from active to idle mode whenever possible and the module wakes up from idle to active mode in the events listed above (see idle mode to active mode transition description above). When a RF Tx/Rx data or voice connection is initiated or when RF Tx/Rx is required due to a connection previously initiated, the module switches from active to connected mode. Connected RF Tx/Rx data connection is in progress. The module is prepared to accept data signals from an external device unless power saving configuration is enabled by AT+UPSV command or uCPU API. When a data or voice connection is initiated, the module enters connected mode from active mode. Connected mode is suspended if Tx/Rx data or voice is not in progress. In such case, the module automatically switches from connected to active mode and then, if power saving configuration is enabled by the AT+UPSV command or uCPU API, the module automatically switches to idle mode whenever possible. Vice-versa, the module wakes up from idle to active mode and then connected mode if RF Tx/Rx is necessary. When a data connection is terminated, the module returns to the active mode. Table 6: TOBY-L4 series modules operating modes descriptions](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-20.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 System description Page 21 of 143 Figure 2 describes the transition between the various operating modes. If power saving is enabled and there is no activity for a defined time intervalAny wake up event described in the module operating modes summary table aboveIncoming/outgoing call or other dedicated device network communicationNo RF Tx/Rx in progress, Call terminated, Communication droppedRemove VCCSwitch ON:•PWR_ONNot poweredPower offActiveConnected IdleSwitch OFF:•AT+CPWROFF•uCPU API•PWR_ONApply VCC Figure 2: TOBY-L4 series modules operating modes transitions](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-21.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 System description Page 22 of 143 1.5 Supply interfaces 1.5.1 Module supply input (VCC) The modules must be supplied via the three VCC pins that represent the module power supply input. The VCC pins are internally connected to the RF power amplifier and to the integrated Power Management Unit: all supply voltages needed by the module are generated from the VCC supply by integrated voltage regulators, including the Real Time Clock supply, V_INT generic digital interfaces supply, VSIM SIM card supply, V_ETH RGMII interface supply, V_MMC eMMC interface supply, and any other internal rail. During operation, the current drawn by the TOBY-L4 series modules through the VCC pins can vary by several orders of magnitude. This ranges from the pulse of current consumption during GSM transmitting bursts at maximum power level in connected mode (as described in section 1.5.1.2) to the low current consumption during low power idle mode with power saving enabled (as described in section 1.5.1.5). Figure 3 provides a simplified block diagram of the TOBY-L4 series modules’ internal VCC supply routing. 72VCC71VCC70VCCTOBY-L4 seriesPower ManagementUnitMemoryBaseband ProcessorTransceiverRF PMUCellular Power Amplifiers Figure 3: TOBY-L4 series modules’ internal VCC supply routing simplified block diagram](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-22.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 System description Page 23 of 143 1.5.1.1 VCC supply requirements Table 7 summarizes the requirements for the VCC modules supply. See section 2.2.1 for suggestions on how to properly design a VCC supply circuit compliant with the requirements listed in Table 7. The supply circuit affects the RF compliance of the device integrating TOBY-L4 series modules with applicable required certification schemes as well as antenna circuit design. Compliance is guaranteed if the requirements summarized in Table 7 are fulfilled. Item Requirement Remark VCC nominal voltage Within VCC normal operating range: 3.40 V min. / 4.40 V max. RF performance is guaranteed when VCC PA voltage is inside the normal operating range limits. RF performance may be affected when VCC PA voltage is outside the normal operating range limits, though the module is still fully functional until the VCC voltage is inside the extended operating range limits. VCC voltage during normal operation Within VCC extended operating range: 3.00 V min. / 4.50 V max. VCC voltage must be above the extended operating range minimum limit to switch-on the module. The module may switch-off when the VCC voltage drops below the extended operating range minimum limit. Operation above VCC extended operating range is not recommended and may affect device reliability. VCC average current Support with adequate margin the highest averaged VCC current consumption value in connected mode conditions The maximum average current consumption can be greater than the specified value according to the actual antenna mismatching, temperature and supply voltage. Sections 1.5.1.2, 1.5.1.3 and 1.5.1.4 describe the current consumption profiles in 2G, 3G and LTE connected modes. VCC peak current Support with margin the highest peak VCC current consumption value in connected mode conditions The specified maximum peak of current consumption occurs during the GSM single transmit slot in 850/900 MHz connected mode, in case of a mismatched antenna. Section 1.5.1.2 describes 2G Tx peak/pulse current. VCC voltage drop during 2G Tx slots Lower than 400 mV Supply voltage drop values greater than recommended during 2G TDMA transmission slots directly affect the RF compliance with the applicable certification schemes. Figure 5 describes supply voltage drop during 2G Tx slots. VCC voltage ripple during 2G/3G/LTE Tx Noise in the supply must be minimized High supply voltage ripple values during LTE/3G/2G RF transmissions in connected mode directly affect the RF compliance with applicable certification schemes. Figure 5 describes supply voltage ripple during RF Tx. VCC under/over-shoot at start/end of Tx slots Absent or at least minimized Supply voltage under-shoot or over-shoot at the start or the end of 2G TDMA transmission slots directly affect the RF compliance with the applicable certification schemes. Figure 5 describes supply voltage under/over-shoot Table 7: Summary of VCC modules supply requirements](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-23.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 System description Page 24 of 143 1.5.1.2 VCC current consumption in 2G connected mode When a GSM call is established, the VCC module current consumption is determined by the current consumption profile typical of the GSM transmitting and receiving bursts. The peak of current consumption during a transmission slot is strictly dependent on the RF transmitted power, which is regulated by the network (the current base station). The transmitted power in the transmit slot is also the more relevant factor for determining the average current consumption. If the module is transmitting in 2G single-slot mode in the 850 or 900 MHz bands, at the maximum RF power level (approximately 2 W or 33 dBm in the allocated transmit slot/burst) the current consumption can reach an upper peak for 576.9 µs (width of the transmit slot/burst) with a periodicity of 4.615 ms (width of 1 frame = 8 slots/burst), so with a 1/8 duty cycle according to GSM TDMA (Time Division Multiple Access). If the module is transmitting in 2G single-slot mode in the 1800 or 1900 MHz bands, the current consumption figures are considerably lower than the one in the low bands, due to the 3GPP transmitter output power specifications. During a GSM call, current consumption is not so significantly high in receiving or in monitor bursts and is low in the inactive unused bursts. Figure 4 shows an example of the module current consumption profile versus time in 2G single-slot mode. Time [ms]RX slotunused slotunused slotTX slotunused slotunused slotMON slotunused slotRX slotunused slotunused slotTX slotunused slotunused slotMON slotunused slotGSM frame 4.615 ms (1 frame = 8 slots)Current [A]200 mA60-120 mA1900 mAPeak current depends on TX power and actual antenna loadGSM frame 4.615 ms (1 frame = 8 slots)60-120 mA10-40 mA0.01.51.00.52.02.5 Figure 4: VCC current consumption profile versus time during a 2G single-slot call (1 TX slot, 1 RX slot) Figure 5 illustrates VCC voltage profile versus time during a 2G single-slot call, according to the relative VCC current consumption profile illustrated in Figure 4. Time [ms]undershootovershootrippledropVoltage [mV]3.8 V (typ)RX slotunused slotunused slotTX slotunused slotunused slotMON slotunused slotRX slotunused slotunused slotTX slotunused slotunused slotMON slotunused slotGSM frame 4.615 ms (1 frame = 8 slots)GSM frame 4.615 ms (1 frame = 8 slots) Figure 5: VCC voltage profile versus time during a 2G single-slot call (1 TX slot, 1 RX slot)](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-24.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 System description Page 25 of 143 When a GPRS connection is established, more than one slot can be used to transmit and/or more than one slot can be used to receive. The transmitted power depends on the network conditions, which set the peak current consumption, but following the 3GPP specifications, the maximum Tx RF power is reduced if more than one slot is used to transmit, so the maximum peak of current is not as high as can be the case with a 2G single-slot call. If the module transmits in GPRS class 12 in the 850 or 900 MHz bands, at the maximum RF power control level, the current consumption can reach a quite high peak but lower than the one achievable in 2G single-slot mode. This happens for 2.307 ms (width of the 4 transmit slots/bursts) with a periodicity of 4.615 ms (width of 1 frame = 8 slots/bursts), so with a 1/2 duty cycle, according to 2G TDMA. If the module is in GPRS connected mode in the 1800 or 1900 MHz bands, the current consumption figures are quite less high than the one in the low bands, due to 3GPP transmitter output power specifications. Figure 6 reports the current consumption profiles in GPRS class 12 connected mode, in the 850 or 900 MHz bands, with 4 slots used to transmit and 1 slot used to receive. It must be noted that the actual current consumption of the module in 2G connected mode depends also on the specific concurrent activities performed by the integrated CPU, beside the actual Tx power and antenna load. Time [ms]RX slotunused slotTX slotTX slotTX slotTX slotMON slotunused slotRX slotunused slotTX slotTX slotTX slotTX slotMON slotunused slotGSM frame 4.615 ms (1 frame = 8 slots)Current [A]200mA60-130mAPeak current depends on TX power and actual antenna loadGSM frame 4.615 ms (1 frame = 8 slots)1600 mA0.01.51.00.52.02.5 Figure 6: VCC current consumption profile during a 2G GPRS/EDGE multi-slot connection (4 TX slots, 1 RX slot) For EDGE connections, the VCC current consumption profile is very similar to the GPRS current profile, so the image shown in Figure 6, representing the current consumption profile in GPRS class 12 connected mode, is valid for the EDGE class 12 connected mode as well.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-25.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 System description Page 26 of 143 1.5.1.3 VCC current consumption in 3G connected mode During a 3G connection, the module can transmit and receive continuously due to the Frequency Division Duplex (FDD) mode of operation with the Wideband Code Division Multiple Access (WCDMA). The current consumption depends on output RF power, which is always regulated by the network (the current base station) sending power control commands to the module. These power control commands are logically divided into a slot of 666 µs, so the rate of power change can reach a maximum rate of 1.5 kHz. There are no high current peaks as in the 2G connection, since transmission and reception are continuously enabled due to FDD WCDMA implemented in the 3G that differs from the TDMA implemented in the 2G case. In the worst case scenario, corresponding to a continuous transmission and reception at maximum output power (approximately 250 mW or 24 dBm), the average current drawn by the module at the VCC pins is considerable. At the lowest output RF power (approximately 0.01 µW or –50 dBm), the current drawn by the internal power amplifier is strongly reduced. The total current drawn by the module at the VCC pins is due to baseband processing and transceiver activity. Figure 7 shows an example of the current consumption profile of the module in 3G WCDMA/DC-HSPA+ continuous transmission mode. It must be noted that the actual current consumption of the module in 3G connected mode depends also on the specific concurrent activities performed by the integrated CPU, beside the actual Tx power and antenna load. Time [ms]3G frame 10 ms (1 frame = 15 slots)Current [mA]Current consumption value depends on TX power and actual antenna load170 mA1 slot 666 µs850 mA0300200100500400600700 Figure 7: VCC current consumption profile versus time during a 3G connection (TX and RX continuously enabled)](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-26.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 System description Page 27 of 143 1.5.1.4 VCC current consumption in LTE connected mode During an LTE connection, the module can transmit and receive continuously due to the Frequency Division Duplex (FDD) mode of operation used in LTE radio access technology. The current consumption depends on output RF power, which is always regulated by the network (the current base station) sending power control commands to the module. These power control commands are logically divided into a slot of 0.5 ms (time length of one Resource Block), thus the rate of power change can reach a maximum rate of 2 kHz. The current consumption profile is similar to that in 3G radio access technology. Unlike the 2G connection mode, which uses the TDMA mode of operation, there are no high current peaks since transmission and reception are continuously enabled in FDD. In the worst case scenario, corresponding to a continuous transmission and reception at maximum output power (approximately 250 mW or 24 dBm), the average current drawn by the module at the VCC pins is considerable. At the lowest output RF power (approximately 0.1 µW or –40 dBm), the current drawn by the internal power amplifier is greatly reduced and the total current drawn by the module at the VCC pins is due to baseband processing and transceiver activity. Figure 8 shows an example of the module current consumption profile versus time in LTE connected mode. It must be noted that the actual current consumption of the module in LTE connected mode depends also on the specific concurrent activities performed by the integrated CPU, beside the actual Tx power and antenna load. Time [ms]Current [mA]Current consumption value depends on TX power and actual antenna load1 Slot1 Resource Block (0.5 ms) 1 LTE Radio Frame (10 ms)0300200100500400600700800900 Figure 8: VCC current consumption profile versus time during LTE connection (TX and RX continuously enabled)](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-27.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 System description Page 28 of 143 1.5.1.5 VCC current consumption in cyclic idle/active mode (power saving enabled) The power saving configuration is disabled by default, but it can be enabled using the AT+UPSV command (see the u-blox AT Commands Manual [2]) or the dedicated uCPU API. When power saving is enabled, the module automatically enters the low power idle mode whenever possible, reducing current consumption. During low power idle mode, the module processor runs with 32 kHz reference clock frequency. When the power saving configuration is enabled and the module is registered or attached to a network, the module automatically enters the low power idle mode whenever possible, but it must periodically monitor the paging channel of the current base station (paging block reception), in accordance with the 2G/3G/LTE system requirements, even if connected mode is not enabled by the application. When the module monitors the paging channel, it wakes up to the active mode to enable the reception of the paging block. In between, the module switches to low power idle mode. This is known as discontinuous reception (DRX). The module processor core is activated during the paging block reception, and automatically switches its reference clock frequency from 32 kHz to the 26 MHz used in active mode. The time period between two paging block receptions is defined by the network. This is the paging period parameter, fixed by the base station through the broadcast channel sent to all users on the same serving cell: For 2G radio access technology, the paging period can vary from 470.8 ms (DRX = 2, length of 2 x 51 2G frames = 2 x 51 x 4.615 ms) up to 2118.4 ms (DRX = 9, length of 9 x 51 2G frames = 9 x 51 x 4.615 ms) For 3G radio access technology, the paging period can vary from 640 ms (DRX = 6, i.e. length of 26 3G frames = 64 x 10 ms) up to 5120 ms (DRX = 9, length of 29 3G frames = 512 x 10 ms). For LTE radio access technology, the paging period can vary from 320 ms (DRX = 5, i.e. length of 25 LTE frames = 32 x 10 ms) up to 2560 ms (DRX = 8, length of 28 LTE frames = 256 x 10 ms). Figure 9 illustrates a typical example of the module current consumption profile when power saving is enabled. The module is registered with the network, automatically enters the low power idle mode and periodically wakes up to active mode to monitor the paging channel for the paging block reception. ~50 msIDLE MODE ACTIVE MODE IDLE MODEActive Mode EnabledIdle Mode Enabled2G case: 0.44-2.09 s 3G case: 0.61-5.09 s LTE case: 0.27-2.51 sIDLE MODE~50 msACTIVE MODETime [s]Current [mA]Time [ms]Current [mA]RX Enabled01000100 Figure 9: VCC current consumption profile with power saving enabled and module registered with the network: the module is in low-power idle mode and periodically wakes up to active mode to monitor the paging channel for paging block reception](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-28.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 System description Page 29 of 143 1.5.1.6 VCC current consumption in fixed active mode (power saving disabled) When power saving is disabled, the module does not automatically enter the low power idle mode whenever possible: the module remains in active mode. Power saving configuration is by default disabled. It can also be disabled using the AT+UPSV command (see the u-blox AT Commands Manual [2]) or the dedicated uCPU API. The module processor core is activated during idle mode, and the 26 MHz reference clock frequency is used. It would draw more current during the paging period than that in the power saving mode. Figure 10 illustrates a typical example of the module current consumption profile when power saving is disabled. In such a case, the module is registered with the network and while active mode is maintained, the receiver is periodically activated to monitor the paging channel for paging block reception. It must be noted that the actual current consumption of the module in active mode depends on the specific concurrent activities performed by the integrated CPU. ACTIVE MODE2G case: 0.44-2.09 s 3G case: 0.61-5.09 sLTE case: 0.32-2.56 sPaging periodTime [s]Current [mA]Time [ms]Current [mA]RX Enabled01000100 Figure 10: VCC current consumption profile with power saving disabled and module registered with the network: active mode is always held and the receiver is periodically activated to monitor the paging channel for paging block reception](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-29.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 System description Page 30 of 143 1.5.2 RTC back-up supply (V_BCKP) When the VCC module supply input voltage is within the valid operating range, the internal Power Management Unit (PMU) supplies the Real Time Clock (RTC) through the rail available at the V_BCKP pin. The RTC provides the module time reference (date and time) that is used to set the wake-up interval during the low power idle mode periods, and is able to make the programmable alarm functions available. If the VCC module supply input voltage is under the minimum operating limit (e.g. during the not powered mode), the RTC can be externally supplied through the V_BCKP pin. This lets the time reference (date and time) run until the V_BCKP voltage is within its valid range, even when the main supply is not provided to the module. Consider that the module cannot switch on if a valid voltage is not present on VCC even when the RTC is supplied through V_BCKP (meaning that VCC is mandatory to switch on the module). The RTC has a very low current consumption, but is highly temperature dependent. If V_BCKP is left unconnected and the module main supply is not applied to the VCC pins, the RTC is supplied from a small bypass capacitor mounted inside the module. However, this small capacitor is not able to provide a long buffering time: within a few milliseconds the voltage on V_BCKP will drop below the valid range. This has no impact on cellular connectivity, as all the module functionalities do not rely on date and time settings. 1.5.3 Generic digital interfaces supply output (V_INT) The V_INT output pin of the TOBY-L4 series modules is connected to an internal 1.8 V supply. This supply is internally generated by a switching step-down regulator integrated in the Power Management Unit and it is internally used to source the generic digital I/O interfaces of the cellular module, as illustrated in Figure 11. The output of this regulator is enabled when the module is switched on and it is disabled when the module is switched off. Baseband Processor70VCC71VCC72VCC5V_INTSwitchingStep-DownPower ManagementTOBY-L4 seriesDigital I/O Figure 11: TOBY-L4 series generic digital interfaces supply output (V_INT) simplified block diagram The switching regulator operates in Pulse Width Modulation (PWM) mode for greater efficiency at high output loads and it automatically switches to Pulse Frequency Modulation (PFM) power save mode for greater efficiency at low output loads.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-30.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 System description Page 31 of 143 1.6 System function interfaces 1.6.1 Module power-on TOBY-L4 series modules can be switched on in the following way: Low pulse on the PWR_ON pin, which is normally set high by an internal pull-up, for a valid time period, when the applied VCC voltage is stable at its nominal value within the valid operating range. As illustrated in Figure 12, the TOBY-L4 series PWR_ON input is equipped with an internal active pull-up resistor to an internal 1.3 V supply rail: the PWR_ON input voltage thresholds are different from the other generic digital interfaces, and the line should be driven by an open drain, by an open collector or by a contact switch, without an external pull-up resistor. Detailed electrical characteristics and specifications are described in TOBY-L4 series Data Sheet [1]. Baseband Processor20PWR_ONTOBY-L4 seriesPower-onPower ManagementPower-on35k1.3 V Figure 12: TOBY-L4 series PWR_ON input description TOBY-L4 series modules do not switch on by applying the VCC supply only: a low pulse must be forced on the PWR_ON pin when the VCC voltage is stable at its nominal value within the valid operating range.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-31.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 System description Page 32 of 143 Figure 13 shows the module power-on sequence, describing the following phases: The VCC module supply is stable at its nominal value within the normal operating range The PWR_ON input pin is set low for a valid time period, representing the switch-on event. All the generic digital pins of the modules are tri-stated until the switch-on of their supply source (V_INT): any external signal connected to the generic digital pins must be tri-stated or set low at least until the activation of the V_INT supply output to avoid latch-up of circuits and allow a clean boot of the module. The V_INT generic digital interfaces supply output is enabled by the integrated power management unit. The RESET_N line rises suddenly to the high logic level due to internal pull-up to V_INT. The internal reset signal is held low by the integrated power management unit: the baseband processor core and all the digital pins of the modules are held in reset state. When the internal reset signal is released, any digital pin is set in the correct sequence from the reset state to the default operational configured state. The duration of this pins’ configuration phase differs within the generic digital interfaces and the USB interface due to host / device enumeration timings (see section 1.9.1). The module is fully ready to operate after all interfaces are configured. VCCPWR_ONV_INTRESET_NInternal ResetSystem StateDigital Pins StateInternal Reset → Operational OperationalTristate / Floating OFFONInternal Reset0 ms~35 ms~3 sStart of interface configurationModule interfaces are configuredThe module starts the switch-on routine Figure 13: TOBY-L4 series power-on sequence description The Internal Reset signal is not available on a module pin, but the host application can monitor the V_INT pin to sense the start of the TOBY-L4 series module power-on sequence. Before the switch-on of the generic digital interface supply source (V_INT) of the module, no voltage driven by an external application should be applied to any generic digital interface of the module. Before the TOBY-L4 series module is fully ready to operate, the host application processor should not send any AT command over the AT communication interface (USB) of the module. The duration of the TOBY-L4 series modules’ switch-on routine can vary depending on the application / network settings and any concurrent module activities.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-32.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 System description Page 33 of 143 1.6.2 Module power-off TOBY-L4 series can be properly switched off by: AT+CPWROFF command3 (see the u-blox AT Commands Manual [2]) uCPU application4 Low pulse on the PWR_ON pin, which is normally set high by an internal pull-up, for a valid time period (see the TOBY-L4 series Data Sheet [1]), module normal switch-off: the internal switch-off sequence of the module starts when the external application releases the PWR_ON line from the low logic level, after that it has been set low for an appropriate time period. The methods listed above represent the appropriate normal switch-off events, triggering an appropriate normal switch-off procedure of the module: the current parameter settings are saved in the module’s non-volatile memory and a clean network detach is performed. An abrupt under-voltage shutdown occurs on TOBY-L4 series modules when the VCC module supply is removed. If this occurs, it is not possible to perform the storing of the current parameter settings in the module’s non-volatile memory or to perform a clean network detach. It is highly recommended to avoid an abrupt removal of the VCC supply during TOBY-L4 series modules normal operations: the switch-off procedure must be started by an appropriate switch-off event (see above), and then a suitable VCC supply must be held at least until the end of the modules’ internal switch-off sequence, which occurs when the generic digital interfaces supply output (V_INT) is switched off by the module. An abrupt emergency shutdown procedure is triggered on TOBY-L4 series modules when a long enough low pulse is set at the PWR_ON input pin (see the TOBY-L4 series Data Sheet [1], module emergency switch-off). In this case, storage of the current parameter settings in the module’s non-volatile memory and the clean network detach are not performed. This abrupt emergency shutdown procedure is intended only for use for emergency, e.g. if the module does not provide a reply to a specific AT command after a time period longer than the one defined in the u-blox AT Commands Manual [2], or if shutdown via a normal switch-off procedure fails. An over-temperature shutdown occurs on TOBY-L4 series modules when the temperature measured within the cellular module reaches a critical range. 3 Not supported by "00" product version 4 Not supported by "50" product version](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-33.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 System description Page 34 of 143 Figure 14 describes the TOBY-L4 series modules’ switch-off sequence started by means of the PWR_ON input pin, allowing storage of current parameter settings in the module’s non-volatile memory and a clean network detach, with the following phases A low pulse with the appropriate time duration is applied at the PWR_ON input pin, which is normally set high by an internal pull-up: the module starts the switch-off routine when the PWR_ON signal is released from the low logical level. At the end of the switch-off routine, all the digital pins are tri-stated and all the internal voltage regulators are turned off, including the generic digital interfaces supply (V_INT). Then, the module remains in power-off mode as long as a switch-on event does not occur (i.e. applying a suitable low level pulse to the PWR_ON input pin), and enters not-powered mode if the supply is removed from the VCC pins. VCC PWR_ONRESET_N V_INTInternal ResetSystem StateBB Pads StateOFFTristate / FloatingONOperational -> TristateOperational0 s~2.5 s~5 sThe module starts the switch-off routineVCC can be removed Figure 14: TOBY-L4 series power-off sequence description The Internal Reset signal is not available on a module pin, but the application can monitor the V_INT pin to sense the end of the power-off sequence. The VCC supply can be removed only after the end of the module internal switch-off routine, i.e. only after that the V_INT voltage level has gone low. The duration of each phase in the TOBY-L4 series modules’ switch-off routines can largely vary depending on the application / network settings and the concurrent module activities.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-34.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 System description Page 35 of 143 1.6.3 Module reset TOBY-L4 series modules can be properly reset (rebooted) by: AT+CFUN command5 (see the u-blox AT Commands Manual [2]) uCPU application6 The methods listed above represent appropriate reset (reboot) events, triggering an appropriate “internal” or “software” reset of the module: the current parameter settings are saved in the module’s non-volatile memory and a clean network detach is performed. An abrupt hardware reset occurs on TOBY-L4 series modules when a low level is applied on the RESET_N input pin. In this case, the current parameter settings are not saved in the module’s non-volatile memory and a clean network detach is not performed. It is highly recommended to avoid an abrupt hardware reset of the module by forcing a low level on the RESET_N input during modules normal operation: the RESET_N line should be set low only if reset via AT commands or if the uCPU application fails. As illustrated in Figure 15, the RESET_N input pins are equipped with an internal pull-up to the V_INT supply. Baseband Processor23RESET_NTOBY-L4 series5V_INTReset100k Figure 15: TOBY-L4 series RESET_N input equivalent circuit description 1.6.4 Module / host configuration selection Host Select pins are not supported by the "50" product version. TOBY-L4 series modules include two 1.8 V digital pins (HOST_SELECT0, HOST_SELECT1), which can be configured for External Interrupt detection or as GPIO by means of the uCPU API. 5 Not supported by "00" product version 6 Not supported by "50" product version](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-35.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 System description Page 36 of 143 1.7 Antenna interfaces 1.7.1 Antenna RF interfaces (ANT1 / ANT2) TOBY-L4 series modules provide two RF interfaces for connecting the external antennas: The ANT1 represents the primary RF input/output for transmission and reception of LTE/3G/2G RF signals. The ANT1 pin has a nominal characteristic impedance of 50 and must be connected to the primary Tx / Rx antenna through a 50 transmission line to allow clean RF transmission and reception. The ANT2 represents the secondary RF input for the reception of the RF signals for CA, MIMO and Rx diversity configurations supported by TOBY-L4 series modules as a required feature for LTE category 6 UEs. The ANT2 pin has a nominal characteristic impedance of 50 and must be connected to the secondary Rx antenna through a 50 transmission line to allow for clean RF reception. 1.7.1.1 Antenna RF interfaces requirements Table 8, Table 9 and Table 10 summarize the requirements for the antennas’ RF interfaces (ANT1 / ANT2). See section 2.4.1 for suggestions on how to correctly design antennas circuits which are compliant with these requirements. The antenna circuits affect the RF compliance of the device integrating TOBY-L4 series modules with the applicable required certification schemes (for more details see section 4). Compliance is guaranteed if the antenna RF interfaces (ANT1 / ANT2) requirements summarized in Table 8, Table 9 and Table 10 are fulfilled. Item Requirements Remarks Impedance 50 nominal characteristic impedance The impedance of the antenna RF connection must match the 50 impedance of the ANT1 port. Frequency Range See the TOBY-L4 series Data Sheet [1] The required frequency range of the antenna connected to the ANT1 port depends on the operating bands of the used cellular module and the used mobile network. Return Loss S11 < -10 dB (VSWR < 2:1) recommended S11 < -6 dB (VSWR < 3:1) acceptable The Return loss or the S11, as the VSWR, refers to the amount of reflected power, measuring how well the antenna RF connection matches the 50 characteristic impedance of the ANT1 port. The impedance of the antenna termination must match as much as possible the 50 nominal impedance of the ANT1 port over the operating frequency range, reducing as much as possible the amount of reflected power. Efficiency > -1.5 dB ( > 70% ) recommended > -3.0 dB ( > 50% ) acceptable The radiation efficiency is the ratio of the radiated power to the power delivered to antenna input: the efficiency is a measure of how well an antenna receives or transmits. The radiation efficiency of the antenna connected to the ANT1 port needs to be enough high over the operating frequency range to comply with the Over-The-Air (OTA) radiated performance requirements, as Total Radiated Power (TRP) and the Total Isotropic Sensitivity (TIS), specified by applicable related certification schemes. Maximum Gain According to radiation exposure limits The power gain of an antenna is the radiation efficiency multiplied by the directivity: the gain describes how much power is transmitted in the direction of peak radiation to that of an isotropic source. The maximum gain of the antenna connected to ANT1 port must not exceed the herein stated value to comply with regulatory agencies’ radiation exposure limits. Input Power > 33 dBm ( > 2 W ) The antenna connected to the ANT1 port must support with adequate margin the maximum power transmitted by the modules. Table 8: Summary of primary Tx/Rx antenna RF interface (ANT1) requirements](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-36.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 System description Page 37 of 143 Item Requirements Remarks Impedance 50 nominal characteristic impedance The impedance of the antenna RF connection must match the 50 impedance of the ANT2 port. Frequency Range See the TOBY-L4 series Data Sheet [1] The required frequency range of the antennas connected to ANT2 port depends on the operating bands of the used cellular module and the used mobile network. Return Loss S11 < -10 dB (VSWR < 2:1) recommended S11 < -6 dB (VSWR < 3:1) acceptable The Return loss or the S11, as the VSWR, refers to the amount of reflected power, measuring how well the antenna RF connection matches the 50 characteristic impedance of the ANT2 port. The impedance of the antenna termination must match as much as possible the 50 nominal impedance of the ANT2 port over the operating frequency range, reducing as much as possible the amount of reflected power. Efficiency > -1.5 dB ( > 70% ) recommended > -3.0 dB ( > 50% ) acceptable The radiation efficiency is the ratio of the radiated power to the power delivered to antenna input: the efficiency is a measure of how well an antenna receives or transmits. The radiation efficiency of the antenna connected to the ANT2 port needs to be enough high over the operating frequency range to comply with the Over-The-Air (OTA) radiated performance requirements, as the TIS, specified by applicable related certification schemes. Table 9: Summary of secondary Rx antenna RF interface (ANT2) requirements Item Requirements Remarks Efficiency imbalance < 0.5 dB recommended < 1.0 dB acceptable The radiation efficiency imbalance is the ratio of the primary (ANT1) antenna efficiency to the secondary (ANT2) antenna efficiency: the efficiency imbalance is a measure of how much better an antenna receives or transmits compared to the other antenna. The radiation efficiency of the secondary antenna needs to be roughly the same as the radiation efficiency of the primary antenna for good RF performance. Envelope Correlation Coefficient < 0.4 recommended < 0.5 acceptable The Envelope Correlation Coefficient (ECC) between the primary (ANT1) and the secondary (ANT2) antenna is an indicator of 3D radiation pattern similarity between the two antennas: low ECC results from antenna patterns with radiation lobes in different directions. The ECC between the primary and secondary antennas needs to be low enough to comply with the radiated performance requirements specified by related certification schemes. Isolation > 15 dB recommended > 10 dB acceptable The antenna to antenna isolation is the loss between the primary (ANT1) and the secondary (ANT2) antenna: high isolation results from low coupled antennas. The isolation between primary and secondary antenna needs to be high for good RF performance. Table 10: Summary of primary (ANT1) and secondary (ANT2) antennas relationship requirements](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-37.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 System description Page 38 of 143 1.7.2 Antenna detection interface (ANT_DET) The antenna detection is based on ADC measurement. The ANT_DET pin is an Analog to Digital Converter (ADC) provided to sense the antenna presence. The antenna detection function provided by ANT_DET pin is an optional feature that can be implemented if the application requires it. The ANT_DET pin generates a DC current and measures the resulting DC voltage, thus determining the resistance from the antenna connector provided on the application board to GND. So the requirements to achieve antenna detection functionality are the following: an RF antenna assembly with a built-in resistor (diagnostic circuit) must be used an antenna detection circuit must be implemented on the application board See section 2.4.2 for the antenna detection circuit on the application board and the diagnostic circuit in the antenna assembly design-in guidelines. 1.8 SIM interfaces 1.8.1 SIM interfaces TOBY-L4 series modules provide two SIM interfaces for the direct connection of two external SIM cards/chips, which can be used alternatively (only one SIM at a time can be used for network access): SIM0 interface (VSIM, SIM_IO, SIM_CLK, SIM_RST pins), which is enabled by default SIM1 interface (VSIM1, SIM1_IO, SIM1_CLK, SIM1_RST pins), which can be alternatively enabled by dedicated AT command7 (see the u-blox AT Commands Manual [2]), or by means of the uCPU application8. Both 1.8 V and 3 V SIM types are supported by the SIM interfaces. Activation and deactivation with an automatic voltage switch from 1.8 V to 3 V is implemented according to ISO-IEC 7816-3 specifications. High-speed SIM/ME interface and the PPS procedure for baud-rate selection is implemented according to the values proposed by the SIM card/chip. Both the VSIM supply output and the VSIM1 supply output provide internal short circuit protection to limit the start-up current and protect the SIM from short circuits. 1.8.2 SIM detection interface The GPIO5 pin of TOBY-L4 series modules can be configured to detect the mechanical / physical presence of an external SIM card connected to the SIM0 interface. The pin can sense SIM card presence as intended to be properly connected to the mechanical switch of a SIM card holder as described in section 2.5: Low logic level at GPIO5 input pin is recognized as SIM card not present High logic level at GPIO5 input pin is recognized as SIM card present The SIM card detection function provided by GPIO5 pin is an optional feature that can be implemented / used or not according to the application requirements: an Unsolicited Result Code (URC) is generated each time that there is a change of status. The optional function “SIM card hot insertion/removal” can be additionally configured on the GPIO5 pin, in order to enable / disable the SIM0 interface upon detection of external SIM card physical insertion / removal. 7 Not supported by the "00" product version 8 Not supported by the "50" product version](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-38.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 System description Page 39 of 143 1.9 Data communication interfaces TOBY-L4 series modules provide the following serial communication interfaces: USB interface (see section 1.9.1): USB Super-Speed 3.0 compliant interface9, with the module acting as a USB device: USB High-Speed 2.0 compliant interface, with the module acting as a USB device or host11, providing: AT command10 Data communication Ethernet-over-USB virtual channel (CDC-NCM) FW upgrades Trace log capture (diagnostic purposes) Auxiliary channel to tune internal audio parameters using a dedicated external tool Linux console for uCPU API development and debug11 Communication with external processor / device by means of uCPU API11 Up to four UART interfaces (see section 1.9.2): UART0 interface, providing: Communication with external serial devices by means of uCPU API11 Trace log capture (diagnostic purposes) Ring Indicator functionality UART1 interface12, providing: Communication with external serial devices by means of uCPU API11 UART2 interface, providing: Communication with external serial devices by means of uCPU API11 UART3 interface, providing: Linux console for uCPU API development and debug11 Up to two SPI interfaces11 (see section 1.9.3): SPI0 interface, with the module acting as SPI master, providing: Communication with external SPI slave devices by means of uCPU API SPI1 interface12, with the module acting as SPI master, providing: Communication with external SPI slave devices by means of uCPU API Two DDC I2C bus compatible interfaces11 (see section 1.9.4): I2C0 interface, with the module acting as I2C master, providing: Communication with u-blox GNSS positioning chips / modules Communication with external I2C slave devices by means of uCPU API I2C1 interface, with the module acting as I2C master, providing: Communication with external I2C slave devices by means of uCPU API SDIO interface11, with the module acting as SDIO host, providing (see section 1.9.5): Communication with compatible u-blox short range radio modules by means of uCPU API Communication with external SDIO devices by means of uCPU API RGMII / RMII interface11, with the module acting as Ethernet MAC, providing (see section 1.9.6): Ethernet connection enabled by means of uCPU API, through the external Ethernet PHY 9 Supported by future FW versions 10 Not supported by the "00" product version 11 Not supported by the "50" product version 12 UART1 and SPI1 interfaces can be used alternatively, in mutually exclusive way, by means of uCPU API](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-39.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 System description Page 40 of 143 1.9.1 USB interface The USB Super-Speed 3.0 compliant interface will be supported by future firmware versions. The USB High-Speed 2.0 host role is not supported by the "50" product versions. TOBY-L4 series modules include a USB Super-Speed 3.0 compliant interface, supporting up to 5 Gbit/s data rate, and also including a USB High-Speed 2.0 compliant interface, supporting up to 480 Mbit/s data rate. The USB High-Speed 2.0 compliant interface consists of the following pins: USB_D+/USB_D–, USB High-Speed differential transceiver data lines as per USB 2.0 specification [3] VUSB_DET input pin, which senses the VBUS USB supply presence (nominally 5 V at the source) to detect the host connection and enable the USB 2.0 interface with the module acting as a USB device. Neither the USB interface, nor the whole module is supplied by the VUSB_DET input pin, which senses the VBUS USB supply voltage presence and absorbs few microamperes. USB_ID pin, available for USB ID resistance measurement: if the USB_ID pin is externally connected to GND, then the module acts as a USB host if the USB_ID pin is externally left unconnected (floating), then the module acts as a USB device The USB High-Speed 2.0 compliant interface, with the module acting as a USB device, provides: AT command13 Data communication Ethernet-over-USB virtual channel Trace log capture (diagnostic purposes) Auxiliary channel to tune internal audio parameters using a dedicated external tool Linux console for uCPU applications development and debug14 FW upgrades The module, acting as a USB device, identifies itself by its VID (Vendor ID) and PID (Product ID) combination, included in the USB device descriptor according to the USB 2.0 specifications [3]. If the module, acting as a USB device, is connected to the USB host before the module is switched on, or if the module is reset (rebooted) with the USB connected to the host, the VID and PID are automatically updated during the boot of the module. First, the VID and PID are the following: VID = 0x8087 PID = 0x0801 This VID and PID combination identifies a USB profile where no USB function described above is available: the AT commands must not be sent to the module over the USB profile identified by this VID and PID combination. Then, after a time period (depending on the host / device enumeration timings), the VID and PID are updated to the one where the normal operative functions (AT, Data, Ethernet-over-USB, Trace, Linux console) are available. VID and PID for normal operative functions are the following: VID = 0x1546 PID = 0x1010 The USB High-Speed 2.0 compliant interface, with the module acting as USB host (OTG), provides: Communication with external device by means of the uCPU application 13 Not supported by the "00" product version 14 Not supported by the "50" product version](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-40.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 System description Page 41 of 143 The USB Super-Speed 3.0 compliant interface as per USB 3.0 specifications [4], with the module acting as a USB device, consists of the following additional pins: USB_SSTX+/USB_SSTX–, USB Super-Speed differential transmitter data lines USB_SSRX+/USB_SSRX–, USB Super-Speed differential receiver data lines USB drivers are available for Windows operating system platforms. TOBY-L4 series modules are compatible with standard Linux/Android USB kernel drivers. 1.9.2 UART interfaces UART interfaces are not supported by the "50" product version, except for trace logging (diagnostic purposes) and Ring Indicator functionality over the UART0 interface. 1.9.2.1 UART0 interface The UART0 Universal Asynchronous Receiver/Transmitter serial interface has CMOS compatible signal levels (0 V for ON / active state and 1.8 V for OFF / idle state), providing: Communication with external devices by means of the uCPU API, over the following pins: o RXD module output and TXD module input data lines o CTS module output and RTS module input hardware flow control lines Trace logging (diagnostic purpose), over the following pins: o RXD module output and TXD module input data lines Ring Indicator functionality, over the following pin: o RI module output line The UART0 interface can operate at 9.6 kbit/s, 19.2 kbit/s, 38.4 kbit/s, 57.6 kbit/s, 115.2 kbit/s, 230.4 kbit/s, 460.8 kbit/s, 921.6 kbit/s, 3 Mbit/s, 3.25 Mbit/s and 6.5 Mbit/s baud rates, with 8N1 frame format (illustrated in Figure 16), and with hardware flow control output (CTS line) driven to the OFF state when the module is not prepared to accept data by the UART0 interface. D0 D1 D2 D3 D4 D5 D6 D7Start of 1-BytetransferStart Bit(Always 0)Possible Start ofnext transferStop Bit(Always 1)tbit = 1/(Baudrate)Normal Transfer, 8N1 Figure 16: Description of UART 8N1 frame format (8 data bits, no parity, 1 stop bit)](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-41.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 System description Page 42 of 143 The RI line can notify an incoming call: the RI line is switched from the OFF state to the ON state with a 4:1 duty cycle and a 5 s period (ON for 1 s, OFF for 4 s, see Figure 17), until the DTE attached to the module sends the ATA string and the module accepts the incoming data call. The RING string sent by the module (DCE) to the serial port at constant time intervals is not correlated with the switch of the RI line to the ON state. Figure 17: RI behavior during an incoming call The RI output line can notify an SMS arrival. When the SMS arrives, the RI line switches from OFF to ON for 1 s (see Figure 18), if the feature is enabled by the AT+CNMI command (see the u-blox AT Commands Manual [2]). Figure 18: RI behavior at SMS arrival This behavior allows the DTE to stay in power saving mode until the DCE related event requests service. For SMS arrival, if several events coincidently occur or in quick succession, each event independently triggers the RI line, although the line will not be deactivated between each event. As a result, the RI line may stay to ON for more than 1 s, if an incoming call is answered within less than 1 s (with ATA or if auto-answering is set to ATS0=1) then the RI line is set to OFF earlier, so that: RI line monitoring cannot be used by the DTE to determine the number of received SMSs. For multiple events (incoming call plus SMS received), the RI line cannot be used to discriminate the two events, but the DTE must rely on subsequent URCs and interrogate the DCE with the suitable commands. The RI line can additionally notify URCs and/or incoming data, if the feature is enabled by the specific AT+URING command (for more details, see the u-blox AT Commands Manual [2]): the RI line is asserted when one of the configured events occur and it remains asserted for 1 s unless another configured event will happen, with the same behavior illustrated in Figure 18. The DTR, DSR, DCD and RI pins can be alternatively configured for External Interrupt detection or as GPIO by means of the uCPU API. The RI pin can be alternatively configured as GPIO by an AT command. SMS arrives time [s] 0 RI ON RI OFF 1s time [s] 0 RI ON RI OFF 1s 1stime [s]151050RI ONRI OFFCall incomes1stime [s]151050RI ONRI OFFCall incomes](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-42.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 System description Page 43 of 143 1.9.2.2 UART1 interface The UART1 Universal Asynchronous Receiver/Transmitter serial interface, with CMOS compatible signal levels (0 V for ON / active state and 1.8 V for OFF / idle state), can operate as a serial interface for communication with external devices by means of the uCPU API, with the following pins: o RXD1 module output and TXD1 module input data lines o CTS1 module output and RTS1 module input hardware flow control lines The UART1 interface can operate at 9.6 kbit/s, 19.2 kbit/s, 38.4 kbit/s, 57.6 kbit/s, 115.2 kbit/s, 230.4 kbit/s, 460.8 kbit/s, 921.6 kbit/s, 3 Mbit/s, 3.25 Mbit/s and 6.5 Mbit/s baud rates, with 8N1 frame format (illustrated in Figure 16), and with hardware flow control output (CTS1 line) driven to the OFF state when the module is not prepared to accept data by the UART1 interface. The UART1 interface can be alternatively, in mutually exclusive way, configured as SPI1 interface by means of the uCPU API, for communication with external devices with the following pins: o RXD1 pin, alternatively configured as SPI1 Master Output Slave Input (module output) o TXD1 pin, alternatively configured as SPI1 Master Input Slave Output (module input) o CTS1 pin, alternatively configured as SPI1 Chip Select (module output) o RTS1 pin, alternatively configured as SPI1 Clock (module output) 1.9.2.3 UART2 interface The UART2 Universal Asynchronous Receiver/Transmitter serial interface, with CMOS compatible signal levels (0 V for ON / active state and 1.8 V for OFF / idle state), can operate as a serial interface for communication with external devices by means of the uCPU API, with the following pins: o RXD2 module output and TXD2 module input data lines The UART2 interface can operate at 9.6 kbit/s, 19.2 kbit/s, 38.4 kbit/s, 57.6 kbit/s, 115.2 kbit/s, 230.4 kbit/s, 460.8 kbit/s, 921.6 kbit/s, 3 Mbit/s, 3.25 Mbit/s and 6.5 Mbit/s baud rates, with 8N1 frame format (illustrated in Figure 16). 1.9.2.4 UART3 interface The UART3 Universal Asynchronous Receiver/Transmitter serial interface, with CMOS compatible signal levels (0 V for ON / active state and 1.8 V for OFF / idle state), can operate as Linux console for uCPU API development and debug, with the following pins: o RXD3 module output and TXD3 module input data lines The UART3 interface can operate at 9.6 kbit/s, 19.2 kbit/s, 38.4 kbit/s, 57.6 kbit/s, 115.2 kbit/s, 230.4 kbit/s, 460.8 kbit/s, 921.6 kbit/s, 3 Mbit/s, 3.25 Mbit/s and 6.5 Mbit/s baud rates, with 8N1 frame format (illustrated in Figure 16).](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-43.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 System description Page 44 of 143 1.9.3 SPI interfaces SPI interfaces are not supported by the "50" product version. 1.9.3.1 SPI0 interface The SPI0 1.8 V Serial Peripheral Interface supports communication with an external SPI slave devices, with the module acting as SPI master, by means of the uCPU API, with the following pins: SPI_MOSI pin, SPI0 Master Output Slave Input (module output) SPI_MISO pin, SPI0 Master Input Slave Output (module input) SPI_SCLK pin, SPI0 Serial Clock (module output) SPI_CS pin, SPI0 Chip Select 0 (module output) GPIO4 pin, alternatively configured as SPI0 Chip Select 1 (module output) The SPI0 Serial Clock signal can be configured to different operating frequencies: 26 MHz (maximum frequency), and 26 / n MHz, where n is 2, 3, 4, etc. 1.9.3.2 SPI1 interface The SPI1 1.8 V Serial Peripheral Interface supports communication with an external SPI slave devices, with the module acting as SPI master, by means of the uCPU API, with the following UART1 pins configured as alternative functions, in a mutually exclusive way: RXD1 pin, alternatively configured as SPI1 Master Output Slave Input (module output) TXD1 pin, alternatively configured as SPI1 Master Input Slave Output (module input) RTS1 pin, alternatively configured as SPI1 Serial Clock (module output) CTS1 pin, alternatively configured as SPI1 Chip Select (module output) The SPI1 Serial Clock signal can be configured at various operating frequencies: 26 MHz (maximum frequency), and 26 / n MHz, where n is 2, 3, 4, etc.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-44.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 System description Page 45 of 143 1.9.4 DDC (I2C) interfaces DDC (I2C) interfaces are not supported by the "50" product version. 1.9.4.1 I2C0 interface The SDA and SCL pins represent the I2C0 1.8 V I2C bus compatible Display Data Channel (DDC) interface, with the module acting as I2C master, available for communication with u-blox GNSS chips / modules communication with other external I2C devices by means of the uCPU API The I2C0 interface pins of the module are open drain outputs conforming to the I2C bus specifications [6], supporting up to 100 kbit/s data rate in Standard mode, and up to 400 kbit/s data rate in Fast mode. External pull-up resistors to suitable 1.8 V supply (e.g. V_INT) are required for operations. u-blox has implemented special features to ease the design effort required for the integration of a u-blox cellular module with a u-blox GNSS receiver. Combining a u-blox cellular module with a u-blox GNSS receiver allows designers to have full access to the positioning receiver directly via the cellular module: it relays control messages to the GNSS receiver via a dedicated DDC (I2C) interface. An interface connected to the positioning receiver is not necessary: the cellular module allows full control of the GNSS receiver. The modules provide embedded GNSS aiding that is a set of specific features developed by u-blox to improve the cellular / GNSS system power consumption and the GNSS performance, decreasing the Time-To-First-Fix (TTFF), thus allowing to calculate the position in a shorter time with higher accuracy. 1.9.4.2 I2C1 interface The SDA and SCL pins represent the I2C1 I2C bus compatible Display Data Channel (DDC) interface, with the module acting as the I2C master, available for communication with other external I2C devices by means of uCPU API The I2C1 interface pins of the module are open drain outputs conforming to the I2C bus specifications [6], supporting up to 100 kbit/s data rate in Standard mode, and up to 400 kbit/s data rate in Fast mode. External pull-up resistors to a suitable 1.8 V supply (e.g. V_INT) are required for operations. 1.9.5 SDIO interface SDIO interface is not supported by the "50" product version. TOBY-L4 series modules include a 4-bit Secure Digital Input Output interface (SDIO_D0, SDIO_D1, SDIO_D2, SDIO_D3, SDIO_CLK, SDIO_CMD), where the module acts as an SDIO host controller designed to communicate with compatible u-blox short range radio communication modules by means of the uCPU API communicate with external SDIO devices by means of the uCPU API The SDIO interface supports up to 832 Mbit/s data rate with SD 3.0 SDR104 mode at 208 MHz clock frequency. Combining a u-blox cellular module with a u-blox short range communication module gives designers full access to the Wi-Fi module directly via the cellular module, so that a second interface connected to the Wi-Fi module is not necessary. The cellular module allows a full control of the Wi-Fi module, because Wi-Fi control messages are relayed to the Wi-Fi module via the dedicated SDIO interface. u-blox has implemented special features in the cellular modules to ease the design effort for the integration of a u-blox cellular module with a u-blox short range Wi-Fi module to provide Router functionality.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-45.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 System description Page 46 of 143 1.9.6 RGMII interface RGMII interface is not supported by the "50" product version. TOBY-L4 series modules include an Ethernet Media Access Control (MAC) block supporting up to 1 Gbit/s data rate via a Reduced Gigabit Media-Independent Interface compliant with the RGMII Version 1.3 specification [7] and the RMII Revision 1.2 specification [8]. The module represents an Ethernet MAC controller, which can be connected to an external Ethernet physical transceiver (PHY) chip for communication with a remote processor over Ethernet. The following signals are provided for communication and management of an external Ethernet PHY: V_ETH Interface supply output ETH_TX_CLK RGMII Transmit reference Clock (TXC) output RMII Reference Clock (REF_CLK) output ETH_TX_CTL RGMII Transmit Control output, driven on both edges of the Transmit clock (TXC) RMII Transmit Enable (TXEN) output, synchronous with Reference Clock (REF_CLK) ETH_TXD0 RGMII / RMII Transmit Data [0], from MAC to PHY (module output) ETH_TXD1 RGMII / RMII Transmit Data [1], from MAC to PHY (module output) ETH_TXD2 RGMII Transmit Data [2], from MAC to PHY (module output) ETH_TXD3 RGMII Transmit Data [3], from MAC to PHY (module output) ETH_RX_CLK RGMII Receive reference Clock (RXC) input ETH_RX_CTL RGMII Receive Control input, sampled on both edges of the Receive clock (RXC) RMII Carrier Sense (CRS) / Receive Data Valid (RX_DV) input ETH_RXD0 RGMII / RMII Receive Data [0], from PHY to MAC (module input) ETH_RXD1 RGMII / RMII Receive Data [1], from PHY to MAC (module input) ETH_RXD2 RGMII Receive Data [2], from PHY to MAC (module input) ETH_RXD3 RGMII Receive Data [3], from PHY to MAC (module input) ETH_INTR Ethernet Interrupt Input, from PHY to MAC (module input) When this signal is high, it indicates an interrupt event in the PHY ETH_MDIO Management Data Input Output, bidirectional signal (module input/output) ETH_MDC Management Data Clock, from MAC to PHY (module output)](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-46.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 System description Page 47 of 143 1.10 eMMC interface The eMMC interface is not supported by the "50" product version. TOBY-L4 series modules include a 4-bit embedded Multi-Media Card interface compliant with the JESD84-B451 Embedded Multimedia Card (eMMC) Electrical Standard 4.51 [9]. The following signals are provided for connection and management of an external eMMC / SD memory by means of the uCPU API: V_MMC Interface supply output (module output) MMC_D0 Multi-Media Card Data [0], bidirectional signal (module input/output) MMC_D1 Multi-Media Card Data [1], bidirectional signal (module input/output) MMC_D2 Multi-Media Card Data [2], bidirectional signal (module input/output) MMC_D3 Multi-Media Card Data [3], bidirectional signal (module input/output) MMC_CMD Multi-Media Card Command, bidirectional signal (module input/output) MMC_CLK Multi-Media Card Clock (module output) MMC_RST_N Multi-Media Card Reset (module output) MMC_CD_N Multi-Media Card Detect (module input)](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-47.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 System description Page 48 of 143 1.11 Audio interfaces 1.11.1 Analog audio interfaces TOBY-L4 series modules provide the following analog audio interfaces: Analog audio inputs (analog audio uplink path)15: First differential analog audio input (MIC1_P, MIC1_N), which can be connected to the output of an external analog audio device, or an external microphone for voice call or eCall purposes. The MIC1_P / MIC1_N pins are internally directly connected to a differential input (positive/negative) of the Audio Front-End, consisting of a Low Noise Amplifier integrated in a dedicated IC, without any internal series capacitor for DC blocking. The LNA is internally followed by an integrated sigma-delta ADC connecting the analog Audio Front-End to the digital audio processing system. Second differential analog audio input (MIC2_P, MIC2_N), which can be connected to the output of an external analog audio device, or an external microphone for voice call or eCall purposes. The MIC2_P / MIC2_N pins are internally directly connected to a differential input (positive/negative) of the Audio Front-End, consisting of a Low Noise Amplifier integrated in a dedicated IC, without any internal series capacitor for DC blocking. The LNA is internally followed by an integrated sigma-delta ADC connecting the analog Audio Front-End to the digital audio processing system. Supply output for external microphones (MIC_BIAS), which can provide the bias / supply for external microphones by means of a simple circuit implemented on the application board. The MIC_BIAS pin is internally connected to the output of a low noise LDO linear regulator integrated in a dedicated IC, with appropriate internal bypass capacitor provided to guarantee stable operation of the linear regulator. Local ground for the external microphone (MIC_GND) The MIC_GND pin is internally connected to ground as a sense line, representing a clean ground reference for the analog audio input. Analog audio output (analog audio downlink path): Differential analog audio output (SPK_P, SPK_N), which can be connected to the input of an external analog audio device, or an external speaker. The SPK_P / SPK_N pins are internally directly connected to a differential output (positive/negative) of the Audio Front-End, consisting of a low power audio amplifier integrated in a dedicated IC, without any internal series capacitor for DC blocking. The low power audio amplifier is internally preceded by an integrated DAC connecting the analog Audio Front-End to the digital audio processing system. 15 The first differential analog audio input (MIC1_P, MIC1_N) and the second differential analog audio input (MIC2_P, MIC2_N) interfaces can be used alternatively, in mutually exclusive way.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-48.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 System description Page 49 of 143 1.11.2 Digital audio interface TOBY-L4 series modules include two 4-wire I2S digital audio interfaces: I2S0 digital audio interface, consisting of the following pins: I2S_TXD data output I2S_RXD data input I2S_CLK bit clock input/output I2S_WA world alignment / synchronization signal input/output I2S1 digital audio interface consisting of the following pins: I2S1_TXD data output I2S1_RXD data input I2S1_CLK bit clock input/output I2S1_WA world alignment / synchronization signal input/output The second digital audio interface (I2S1) will be supported by future firmware versions. Both I2S0 and I2S1 digital audio interfaces are suitable to transfer digital audio data with an external compatible digital audio device, as an audio codec or as an audio digital signal processor. The I2S interfaces can be alternatively set in different modes: PCM mode (short synchronization signal): I2S word alignment signal is set high for 1 or 2 clock cycles for the synchronization, and then is set low for 16 clock cycles according to the 17 or 18 clock cycles frame length. Normal I2S mode (long synchronization signal): I2S word alignment is set high / low with a 50% duty cycle (high for 16 clock cycles / low for 16 clock cycles, according to the 32 clock cycles frame length). The I2S interface can be alternatively set in 2 different roles: Master mode Slave mode The sample rate of transmitted/received words, which corresponds to the I2S word alignment / synchronization signal frequency (<I2S_sample_rate>), can be alternatively set to: 8 kHz 11.025 kHz 12 kHz 16 kHz 22.05 kHz 24 kHz 32 kHz 44.1 kHz 48 kHz 96 kHz 192 kHz The modules support I2S transmit and I2S receive data 16-bit words long, linear. Data is transmitted and read in 2’s complement notation. The MSB is transmitted and read first. I2S clock signal frequency depends on the frame length, the sample rate and the selected mode of operation: 17 x <I2S_sample_rate> or 18 x <I2S_sample_rate> in PCM mode (short synchronization signal) 16 x 2 x <I2S_sample_rate> in Normal I2S mode (long synchronization signal)](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-49.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 System description Page 50 of 143 1.12 ADC interfaces The ADC pins are not supported by the "50" product version. TOBY-L4 series modules include Analog to Digital Converter inputs (ADC1, ADC2), which can be handled by means of the dedicated uCPU API. 1.13 General Purpose Input/Output TOBY-L4 series modules "00" product versions include 14 pins (GPIO1, GPIO2, GPIO3, GPIO4, GPIO5, GPIO6, GPIO7, GPIO8, HOST_SELECT0, HOST_SELECT1, DTR, DSR, DCD, and RI) that can be configured by the uCPU application as general purpose input/output or to provide custom functions as summarized in Table 11. Function Description Configurable GPIOs External Interrupt External Interrupt detection (module input) GPIO3, HOST_SELECT0, HOST_SELECT1, DTR, DSR, DCD, RI SPI Chip Select SPI0 Chip Select 1 (module output) GPIO4 GNSS supply enable Enable/disable the supply of u-blox GNSS receiver connected to the cellular module over the I2C0 interface GPIO2 GNSS data ready Sense when u-blox GNSS receiver connected to the module is ready for sending data over the I2C0 interface GPIO3 GNSS RTC sharing RTC synchronization signal to the u-blox GNSS receiver connected to the cellular module over the I2C0 interface GPIO4 SIM card detection External SIM card physical presence detection GPIO5 SIM card hot insertion/removal Enable / disable SIM interface upon detection of external SIM card physical insertion / removal GPIO5 Wi-Fi enable Switch-on/off the external u-blox Wi-Fi module connected to the cellular module over the SDIO interface GPIO1 Wake-up Wake-up the module from Suspend to RAM state GPIO3 Core dump Indicates core dump sent over Ethernet RGMII / RMII interface GPIO8 Input Input to sense high or low digital level GPIO1, GPIO2, GPIO3, GPIO4, GPIO5, GPIO6, GPIO7, GPIO8, HOST_SELECT0, HOST_SELECT1, DTR, DSR, DCD, RI Output Output to set the high or the low digital level GPIO1, GPIO2, GPIO3, GPIO4, GPIO5, GPIO6, GPIO7, GPIO8, HOST_SELECT0, HOST_SELECT1, DTR, DSR, DCD, RI Pin disabled Output tri-stated with an internal active pull-down enabled GPIO1, GPIO2, GPIO3, GPIO4, GPIO5, GPIO6, GPIO7, GPIO8, HOST_SELECT0, HOST_SELECT1, DTR, DSR, DCD, RI Table 11: TOBY-L4 series modules "00" product versions GPIO custom functions summary](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-50.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 System description Page 51 of 143 TOBY-L4 series modules "50" product versions include 9 pins (GPIO1, GPIO2, GPIO3, GPIO4, GPIO5, GPIO6, GPIO7, GPIO8, and RI) that can be configured by AT commands as general purpose input/output or to provide custom functions as summarized in Table 12. Function Description Configurable GPIOs Ring Indicator UART0 Ring Indicator functionality (Circuit 125 in ITU-T V.24) RI SIM card detection External SIM card physical presence detection GPIO5 SIM card hot insertion/removal Enable / disable SIM interface upon detection of external SIM card physical insertion / removal GPIO5 Input Input to sense high or low digital level GPIO1, GPIO2, GPIO3, GPIO4, GPIO5, GPIO6, GPIO7, GPIO8, RI Output Output to set the high or the low digital level GPIO1, GPIO2, GPIO3, GPIO4, GPIO5, GPIO6, GPIO7, GPIO8, RI Pin disabled Output tri-stated with an internal active pull-down enabled GPIO1, GPIO2, GPIO3, GPIO4, GPIO5, GPIO6, GPIO7, GPIO8, RI Table 12: TOBY-L4 series modules "50" product versions GPIO custom functions summary 1.14 Reserved pins (RSVD) TOBY-L4 series modules have pins reserved for future use, marked as RSVD: they can all be left unconnected on the application board, except the RSVD pin number 6 that must be externally connected to ground](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-51.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 52 of 143 2 Design-in 2.1 Overview For optimal integration of the modules in the application PCB, follow the design guidelines stated in this section. Every application circuit must be properly designed to guarantee the correct functionality of the relative interface, but a number of points require greater attention during the design of the application device. The following list provides a rank of importance in the application design, starting with the most significant: 1. Module antenna connection: Antenna circuit directly affects the RF compliance of the device integrating a TOBY-L4 series module with applicable certification schemes. Very carefully follow the suggestions provided in section 2.4 for the schematic and layout design. 2. Module supply: The supply circuit affects the RF compliance of the device integrating a TOBY-L4 series module with applicable required certification schemes as well as the antenna circuit design. Very carefully follow the suggestions provided in section 2.2.1 for the schematic and layout design. 3. USB interface: Accurate design is required to guarantee USB functionality. Carefully follow the suggestions provided in section 2.6.1 for the schematic and layout design. 4. SIM interface: Accurate design is required to guarantee SIM card functionality reducing the risk of RF coupling. Carefully follow the suggestions provided in section 2.5 for the schematic and layout design. 5. System functions: Accurate design is required to guarantee well defined voltage level during operation at Reset and Power-on inputs. Carefully follow the suggestions provided in section 2.3 for the schematic and layout design. 6. Analog audio: Accurate design is required to obtain clear and high quality audio reducing the risk of noise from audio lines due to both supply burst noise coupling and RF detection. Carefully follow the suggestions provided in section 2.8.1 for the schematic and layout design. 7. SDIO, RGMII, eMMC interfaces: Accurate design is required to guarantee SDIO, RGMII, eMMC interfaces functionality. Carefully follow the suggestions provided in section 2.6.5, 2.6.6, 2.7 for the schematic and layout design. 8. ADC interfaces: Accurate design is required to guarantee ADC interfaces functionality. Carefully follow the suggestions provided in section 2.9 for the schematic and layout design. 9. Other digital interfaces: (UART, SPI, I2C, I2S, Host Select, GPIOs, and Reserved pins). Accurate design is required to guarantee correct functionality and reduce the risk of digital data frequency harmonics coupling. Follow the suggestions provided in sections 2.6.1, 2.6.3, 2.6.4, 2.8.2, 2.3.3, 2.10, 2.11. 10. Other supplies: V_BCKP RTC supply and V_INT generic digital interfaces supply. Correct design is required to guarantee functionality. Follow the suggestions provided in 2.2.2 and 2.2.3. It is recommended to also follow the specific design guidelines provided by each manufacturer of any external part selected for the application board that integrates the u-blox cellular modules.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-52.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 53 of 143 2.2 Supply interfaces 2.2.1 Module supply (VCC) 2.2.1.1 General guidelines for VCC supply circuit selection and design All the available VCC pins must be connected to the external supply minimizing the power loss due to series resistance. GND pins are internally connected. Application design shall connect all the available pads to solid ground on the application board, since a good (low impedance) connection to external ground can minimize power loss and improve RF and thermal performance. TOBY-L4 series modules must be sourced through the VCC pins with a suitable DC power supply that should meet the following prerequisites to comply with the modules’ VCC requirements summarized in Table 7. The suitable DC power supply can be selected according to the application requirements (see Figure 19) between the different possible supply sources types, which most common ones are the following: Switching regulator Low Drop-Out (LDO) linear regulator Rechargeable Lithium-ion (Li-Ion) or Lithium-ion polymer (Li-Pol) battery Primary (disposable) battery Main Supply Available?BatteryLi-Ion 3.7 VLinear LDO RegulatorMain Supply Voltage > 5V?Switching Step-Down RegulatorNo, portable deviceNo, less than 5 VYes, greater than 5 VYes, always available Figure 19: VCC supply concept selection The switching step-down regulator is the typical choice when the available primary supply source has a nominal voltage much higher (e.g. greater than 5 V) than the operating supply voltage of TOBY-L4 series. The use of switching step-down provides the best power efficiency for the overall application and minimizes current drawn from the main supply source. See sections 2.2.1.2, 2.2.1.6, 2.2.1.10, 2.2.1.11 for specific design-in. The use of an LDO linear regulator becomes convenient for a primary supply with a relatively low voltage (e.g. less or equal than 5 V). In this case the typical 90% efficiency of the switching regulator diminishes the benefit of voltage step-down and no true advantage is gained in input current savings. On the opposite side, linear regulators are not recommended for high voltage step-down as they dissipate a considerable amount of energy in thermal power. See sections 2.2.1.3, 2.2.1.6, 2.2.1.10, 2.2.1.11 for specific design-in. If TOBY-L4 series modules are deployed in a mobile unit where no permanent primary supply source is available, then a battery will be required to provide VCC. A standard 3-cell Li-Ion or Li-Pol battery pack directly connected to VCC is the usual choice for battery-powered devices. During charging, batteries with Ni-MH chemistry typically reach a maximum voltage that is above the maximum rating for VCC, and should therefore be avoided. See sections 2.2.1.4, 2.2.1.6, 2.2.1.10, 2.2.1.11 for specific design-in. Keep in mind that the use of rechargeable batteries requires the implementation of a suitable charger circuit which is not included in the modules. The charger circuit must be designed to prevent over-voltage on VCC pins, and it should be selected according to the application requirements: a DC/DC switching charger is the typical choice when the charging source has an high nominal voltage (e.g. ~12 V), whereas a linear charger is the](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-53.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 54 of 143 typical choice when the charging source has a relatively low nominal voltage (~5 V). If both a permanent primary supply / charging source (e.g. ~12 V) and a rechargeable back-up battery (e.g. 3.7 V Li-Pol) are available at the same time as possible supply source, then a suitable charger / regulator with integrated power path management function can be selected to supply the module while simultaneously and independently charging the battery. See sections 2.2.1.7, 2.2.1.8, and 2.2.1.4, 2.2.1.6, 2.2.1.10, 2.2.1.11 for specific design-in. An appropriate primary (not rechargeable) battery can be selected taking into account the maximum current specified in the TOBY-L4 series Data Sheet [1] during connected mode, considering that primary cells might have weak power capability. See sections 2.2.1.5, and 2.2.1.6, 2.2.1.10, 2.2.1.11 for specific design-in. The usage of more than one DC supply at the same time should be evaluated carefully: depending on the supply source characteristics, different DC supply systems can result as mutually exclusive. The usage of a regulator or a battery not able to support the highest peak of VCC current consumption specified in the TOBY-L4 series Data Sheet [1] is generally not recommended. However, if the selected regulator or battery is not able to support the highest peak current of the module, it must be able to support with adequate margin at least the highest averaged current consumption value specified in the TOBY-L4 series Data Sheet [1]. The additional energy required by the module during a 2G Tx slot can be provided by an appropriate bypass tank capacitor or a super-capacitor with very large capacitance and very low ESR placed close to the module VCC pins. Depending on the actual capability of the selected regulator or battery, the required capacitance can be considerably larger than 1 mF and the required ESR can be in the range of few tens of m. Carefully evaluate the super-capacitor characteristics since aging and temperature may affect the actual characteristics. The following sections highlight some design aspects for each of the supplies listed above providing application circuit design-in compliant with the module VCC requirements summarized in Table 7. 2.2.1.2 Guidelines for VCC supply circuit design using a switching regulator The use of a switching regulator is suggested when the difference from the available supply rail source to the VCC value is high, since switching regulators provide good efficiency transforming a 12 V or greater voltage supply to the typical 3.8 V value of the VCC supply. The characteristics of the switching regulator connected to VCC pins should meet the following prerequisites to comply with the module VCC requirements summarized in Table 7: Power capability: the switching regulator with its output circuit must be capable of providing a voltage value to the VCC pins within the specified operating range and must be capable of delivering to VCC pins the maximum peak / pulse current consumption during Tx burst at maximum Tx power specified in the TOBY-L4 series Data Sheet [1]. Low output ripple: the switching regulator together with its output circuit must be capable of providing a clean (low noise) VCC voltage profile. High switching frequency: for best performance and for smaller applications it is recommended to select a switching frequency ≥ 600 kHz (since L-C output filter is typically smaller for high switching frequency). The use of a switching regulator with a variable switching frequency or with a switching frequency lower than 600 kHz must be evaluated carefully since this can produce noise in the VCC voltage profile and therefore negatively impact LTE/3G/2G modulation spectrum performance. An additional L-C low-pass filter between the switching regulator output to VCC supply pins can mitigate the ripple at the input of the module, but adds extra voltage drop due to resistive losses on series inductors. PWM mode operation: it is preferable to select regulators with Pulse Width Modulation (PWM) mode. While in connected mode, the Pulse Frequency Modulation (PFM) mode and PFM/PWM modes transitions must be avoided to reduce noise on VCC voltage profile. Switching regulators can be used that are able to switch between low ripple PWM mode and high ripple PFM mode, provided that the mode transition occurs when the module changes status from the idle/active modes to connected mode. It is permissible to use a regulator that switches from the PWM mode to the burst or PFM mode at an appropriate current threshold.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-54.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 55 of 143 Figure 20 and Table 13 show an example of a high reliability power supply circuit, where the module VCC input is supplied by a step-down switching regulator capable of delivering maximum current with low output ripple and with fixed switching frequency in PWM mode operation greater than 1 MHz. 12VC5R3C4R2C2C1R1VINRUNVCRTPGSYNCBDBOOSTSWFBGND671095C61238114C7 C8D1 R4R5L1C3U1TOBY-L4 series71 VCC72 VCC70 VCCGND Figure 20: Example of high reliability VCC supply application circuit using a step-down regulator Reference Description Part Number - Manufacturer C1 10 µF Capacitor Ceramic X7R 5750 15% 50 V C5750X7R1H106MB - TDK C2 10 nF Capacitor Ceramic X7R 0402 10% 16 V GRM155R71C103KA01 - Murata C3 680 pF Capacitor Ceramic X7R 0402 10% 16 V GRM155R71H681KA01 - Murata C4 22 pF Capacitor Ceramic C0G 0402 5% 25 V GRM1555C1H220JZ01 - Murata C5 10 nF Capacitor Ceramic X7R 0402 10% 16 V GRM155R71C103KA01 - Murata C6 470 nF Capacitor Ceramic X7R 0603 10% 25 V GRM188R71E474KA12 - Murata C7 22 µF Capacitor Ceramic X5R 1210 10% 25 V GRM32ER61E226KE15 - Murata C8 330 µF Capacitor Tantalum D_SIZE 6.3 V 45 m T520D337M006ATE045 - KEMET D1 Schottky Diode 40 V 3 A MBRA340T3G - ON Semiconductor L1 10 µH Inductor 744066100 30% 3.6 A 744066100 - Wurth Electronics R1 470 k Resistor 0402 5% 0.1 W 2322-705-87474-L - Yageo R2 15 k Resistor 0402 5% 0.1 W 2322-705-87153-L - Yageo R3 22 k Resistor 0402 5% 0.1 W 2322-705-87223-L - Yageo R4 390 k Resistor 0402 1% 0.063 W RC0402FR-07390KL - Yageo R5 100 k Resistor 0402 5% 0.1 W 2322-705-70104-L - Yageo U1 Step-Down Regulator MSOP10 3.5 A 2.4 MHz LT3972IMSE#PBF - Linear Technology Table 13: Components for high reliability VCC supply application circuit using a step-down regulator](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-55.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 56 of 143 Figure 21 and the components listed in Table 14 show an example of a low-cost power supply circuit, where the VCC module supply is provided by a step-down switching regulator capable of delivering to VCC pins the specified maximum peak / pulse current, transforming a 12 V supply input. TOBY-L4 series12VR5C6C1VCCINHFSWSYNCOUTGND263178C3C2D1 R1R2L1U1GNDFBCOMP54R3C4R4C571 VCC72 VCC70 VCC Figure 21: Example of low cost VCC supply application circuit using a step-down regulator Reference Description Part Number - Manufacturer C1 22 µF Capacitor Ceramic X5R 1210 10% 25 V GRM32ER61E226KE15 – Murata C2 100 µF Capacitor Tantalum B_SIZE 20% 6.3V 15m T520B107M006ATE015 – Kemet C3 5.6 nF Capacitor Ceramic X7R 0402 10% 50 V GRM155R71H562KA88 – Murata C4 6.8 nF Capacitor Ceramic X7R 0402 10% 50 V GRM155R71H682KA88 – Murata C5 56 pF Capacitor Ceramic C0G 0402 5% 50 V GRM1555C1H560JA01 – Murata C6 220 nF Capacitor Ceramic X7R 0603 10% 25 V GRM188R71E224KA88 – Murata D1 Schottky Diode 25V 2 A STPS2L25 – STMicroelectronics L1 5.2 µH Inductor 30% 5.28A 22 m MSS1038-522NL – Coilcraft R1 4.7 k Resistor 0402 1% 0.063 W RC0402FR-074K7L – Yageo R2 910 Resistor 0402 1% 0.063 W RC0402FR-07910RL – Yageo R3 82 Resistor 0402 5% 0.063 W RC0402JR-0782RL – Yageo R4 8.2 k Resistor 0402 5% 0.063 W RC0402JR-078K2L – Yageo R5 39 k Resistor 0402 5% 0.063 W RC0402JR-0739KL – Yageo U1 Step-Down Regulator 8-VFQFPN 3 A 1 MHz L5987TR – ST Microelectronics Table 14: Components for low cost VCC supply application circuit using a step-down regulator](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-56.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 57 of 143 2.2.1.3 Guidelines for VCC supply circuit design using a Low Drop-Out linear regulator The use of a linear regulator is suggested when the difference from the available supply rail source and the VCC value is low. The linear regulators provide high efficiency when transforming a 5 VDC supply to a voltage value within the module VCC normal operating range. The characteristics of the Low Drop-Out (LDO) linear regulator connected to the VCC pins should meet the following prerequisites to comply with the module VCC requirements summarized in Table 7: Power capabilities: the LDO linear regulator with its output circuit must be capable of providing a voltage value to the VCC pins within the specified operating range and must be capable of delivering to the VCC pins the maximum peak / pulse current consumption during Tx burst at maximum Tx power specified in the TOBY-L4 series Data Sheet [1]. Power dissipation: the power handling capability of the LDO linear regulator must be checked to limit its junction temperature to the maximum rated operating range (i.e. check the voltage drop from the maximum input voltage to the minimum output voltage to evaluate the power dissipation of the regulator). Figure 22 and the components listed in Table 15 show an example of a power supply circuit where the VCC module supply is provided by an LDO linear regulator capable of delivering the required current with a suitable power handling capability. It is recommended to configure the LDO linear regulator to generate a voltage supply value slightly below the maximum limit of the module VCC normal operating range (e.g. ~4.1 V for the VCC, as in the circuits illustrated in Figure 22 and Table 15). This reduces the power on the linear regulator and improves the thermal design of the circuit. 5VC1 R1IN OUTADJGND12453C2R2R3U1SHDNTOBY-L4 series71 VCC72 VCC70 VCCGNDC3 Figure 22: Example of high reliability VCC supply application circuit using an LDO linear regulator Reference Description Part Number - Manufacturer C1, C2 10 µF Capacitor Ceramic X5R 0603 20% 6.3 V GRM188R60J106ME47 - Murata C3 330 µF Capacitor Tantalum D_SIZE 6.3 V 45 m T520D337M006ATE045 - KEMET R1 47 k Resistor 0402 5% 0.1 W RC0402JR-0747KL - Yageo Phycomp R2 9.1 k Resistor 0402 5% 0.1 W RC0402JR-079K1L - Yageo Phycomp R3 3.9 k Resistor 0402 5% 0.1 W RC0402JR-073K9L - Yageo Phycomp U1 LDO Linear Regulator ADJ 3.0 A LT1764AEQ#PBF - Linear Technology Table 15: Components for high reliability VCC supply application circuit using an LDO linear regulator](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-57.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 58 of 143 Figure 23 and the components listed in Table 16 show an example of a low-cost power supply circuit, where the VCC module supply is provided by an LDO linear regulator capable of delivering the specified highest peak / pulse current, with suitable power handling capability. The regulator illustrated in this example supports a limited input voltage range and it includes internal circuitry for current and thermal protection. It is recommended to configure the LDO linear regulator to generate a voltage supply value slightly below the maximum limit of the module’s VCC normal operating range (e.g. ~4.1 V as in the circuit illustrated in Figure 23 and Table 16). This reduces the power on the linear regulator and improves the whole thermal design of the supply circuit. 5VC1IN OUTADJGND12453C2R1R2U1ENTOBY-L4 series71 VCC72 VCC70 VCCGNDC3 Figure 23: Example of a low cost VCC supply application circuit using an LDO linear regulator Reference Description Part Number - Manufacturer C1, C2 10 µF Capacitor Ceramic X5R 0603 20% 6.3 V GRM188R60J106ME47 - Murata C3 330 µF Capacitor Tantalum D_SIZE 6.3 V 45 m T520D337M006ATE045 - KEMET R1 27 k Resistor 0402 5% 0.1 W RC0402JR-0727KL - Yageo Phycomp R2 4.7 k Resistor 0402 5% 0.1 W RC0402JR-074K7L - Yageo Phycomp U1 LDO Linear Regulator ADJ 3.0 A LP38501ATJ-ADJ/NOPB - Texas Instrument Table 16: Components for a low cost VCC supply application circuit using an LDO linear regulator](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-58.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 59 of 143 2.2.1.4 Guidelines for VCC supply circuit design using a rechargeable Li-Ion or Li-Pol battery Rechargeable Li-Ion or Li-Pol batteries connected to the VCC pins should meet the following prerequisites to comply with the module’s VCC requirements as summarized in Table 7: Maximum pulse and DC discharge current: the rechargeable Li-Ion battery with its related output circuit connected to the VCC pins must be capable of delivering a pulse current as the maximum peak / pulse current consumption during Tx burst at the maximum Tx power specified in the TOBY-L4 series Data Sheet [1] and must be capable of extensively delivering a DC current as the maximum average current consumption as specified in the TOBY-L4 series Data Sheet [1]. The maximum discharge current is not always reported in the data sheets of batteries, but the maximum DC discharge current is typically almost equal to the battery capacity in Amp-hours divided by 1 hour. DC series resistance: the rechargeable Li-Ion battery with its output circuit must be capable of avoiding a VCC voltage drop below the operating range summarized in Table 7 during transmit bursts. 2.2.1.5 Guidelines for VCC supply circuit design using a primary (disposable) battery The characteristics of a primary (non-rechargeable) battery connected to the VCC pins should meet the following prerequisites to comply with the module’s VCC requirements as summarized in Table 7: Maximum pulse and DC discharge current: the non-rechargeable battery with its related output circuit connected to the VCC pins must be capable of delivering a pulse current as the maximum peak current consumption during Tx burst at the maximum Tx power specified in the TOBY-L4 series Data Sheet [1] and must be capable of extensively delivering a DC current as the maximum average current consumption as specified in the TOBY-L4 series Data Sheet [1]. The maximum discharge current is not always reported in the data sheets of batteries, but the maximum DC discharge current is typically almost equal to the battery capacity in Amp-hours divided by 1 hour. DC series resistance: the non-rechargeable battery with its output circuit must be capable of avoiding a VCC voltage drop below the operating range as summarized in Table 7 during transmit bursts.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-59.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 60 of 143 2.2.1.6 Additional guidelines for VCC supply circuit design To reduce voltage drops, use a low impedance power source. The series resistance of the power supply lines (connected to the modules’ VCC and GND pins) on the application board and battery pack should also be considered and minimized: cabling and routing must be as short as possible to minimize power losses. Three pins are allocated to the VCC supply. Several pins are designated for GND connection. It is recommended to correctly connect all of them to supply the module to minimize series resistance losses. For modules supporting 2G radio access technology, to avoid voltage drop undershoot and overshoot at the start and end of a transmit burst during a GSM call (when current consumption on the VCC supply can rise up as specified in the TOBY-L4 series Data Sheet [1]), place a bypass capacitor with large capacitance (at least 100 µF) and low ESR near the VCC pins, for example: 330 µF capacitance, 45 m ESR (e.g. KEMET T520D337M006ATE045, Tantalum Capacitor) To reduce voltage ripple and noise, improving RF performance especially if the application device integrates an internal antenna, place the following bypass capacitors near the VCC pins: 68 pF capacitor with Self-Resonant Frequency in the 800/900 MHz range (e.g. Murata GRM1555C1H680J) 15 pF capacitor with Self-Resonant Frequency in 1800/1900 MHz range (e.g. Murata GRM1555C1E150J) 8.2 pF capacitor with Self-Resonant Frequency in 2500/2600 MHz range (e.g. Murata GRM1555C1H8R2D) 10 nF capacitor (e.g. Murata GRM155R71C103K) to filter digital logic noise from clocks and data sources 100 nF capacitor (e.g. Murata GRM155R61C104K) to filter digital logic noise from clocks and data sources A suitable series ferrite bead can be correctly placed on the VCC line for additional noise filtering if required by the specific application according to the whole application board design. C2GNDC3 C4TOBY-L4 series71VCC72VCC70VCCC1 C5 C63V8+ Figure 24: Suggested schematic for the VCC bypass capacitors to reduce ripple / noise on the supply voltage profile Reference Description Part Number - Manufacturer C1 8.2 pF Capacitor Ceramic C0G 0402 5% 50 V GRM1555C1H8R2DZ01 - Murata C2 15 pF Capacitor Ceramic C0G 0402 5% 50 V GRM1555C1H150JA01 - Murata C3 68 pF Capacitor Ceramic C0G 0402 5% 50 V GRM1555C1H680JA01 - Murata C4 10 nF Capacitor Ceramic X7R 0402 10% 16 V GRM155R71C103KA01 - Murata C5 100 nF Capacitor Ceramic X7R 0402 10% 16 V GRM155R71C104KA01 - Murata C6 330 µF Capacitor Tantalum D_SIZE 6.3 V 45 m T520D337M006ATE045 - KEMET Table 17: Suggested components to reduce ripple / noise on the VCC The necessity of each part depends on the specific design, but it is recommended to provide all the bypass capacitors illustrated in Figure 24 / Table 17 if the application device integrates an internal antenna. The ESD sensitivity rating of the VCC supply pins is 1 kV (HBM as per JESD22-A114). A higher protection level can be required if the line is externally accessible on the application board, e.g. if the accessible battery connector is directly connected to the supply pins. A higher protection level can be achieved by mounting an ESD protection (e.g. EPCOS CA05P4S14THSG varistor) close to the accessible point.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-60.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 61 of 143 2.2.1.7 Guidelines for the external battery charging circuit TOBY-L4 series modules do not have an on-board charging circuit. Figure 25 provides an example of a battery charger design which is suitable for applications that are battery powered with a Li-Ion (or Li-Polymer) cell. In the application circuit, a rechargeable Li-Ion (or Li-Polymer) battery cell, that features the correct pulse and DC discharge current capabilities and the correct DC series resistance, is directly connected to the VCC supply input of the module. Battery charging is completely managed by the STMicroelectronics L6924U Battery Charger IC that, from a USB power source (5.0 V typ.), charges the battery as a linear charger, in three phases: Pre-charge constant current (active when the battery is deeply discharged): the battery is charged with a low current, set to 10% of the fast-charge current. Fast-charge constant current: the battery is charged with the maximum current, configured by the value of an external resistor to a value suitable for USB power source (~500 mA). Constant voltage: when the battery voltage reaches the regulated output voltage (4.2 V), the L6924U starts to reduce the current until the charge termination is done. The charging process ends when the charging current reaches the value configured by an external resistor to ~15 mA or when the charging timer reaches the value configured by an external capacitor to ~9800 s. Using a battery pack with an internal NTC resistor, the L6924U can monitor the battery temperature to protect the battery from operating under unsafe thermal conditions. The L6924U, as a linear charger, is more suitable for applications where the charging source has a relatively low nominal voltage (~5 V), so that a switching charger is suggested for applications where the charging source has a relatively high nominal voltage (e.g. ~12 V, see the following section 2.2.1.8 for the specific design-in). C5 C8C7C6 C9GNDTOBY-L4 series71 VCC72 VCC70 VCC+USB SupplyC3 R4θU1IUSBIACIENDTPRGSDVINVINSNSMODEISELC2C15V0THGNDVOUTVOSNSVREFR1R2R3Li-Ion/Li-Pol Battery PackD1B1C4Li-Ion/Li-Polymer Battery Charger ICD2 Figure 25: Li-Ion (or Li-Polymer) battery charging application circuit Reference Description Part Number - Manufacturer B1 Li-Ion (or Li-Polymer) battery pack with 470 NTC Various manufacturer C1, C4 1 µF Capacitor Ceramic X7R 0603 10% 16 V GRM188R71C105KA12 - Murata C2, C6 10 nF Capacitor Ceramic X7R 0402 10% 16 V GRM155R71C103KA01 - Murata C3 1 nF Capacitor Ceramic X7R 0402 10% 50 V GRM155R71H102KA01 - Murata C5 330 µF Capacitor Tantalum D_SIZE 6.3 V 45 m T520D337M006ATE045 - KEMET C7 100 nF Capacitor Ceramic X7R 0402 10% 16 V GRM155R61A104KA01 - Murata C8 68 pF Capacitor Ceramic C0G 0402 5% 50 V GRM1555C1H680JA01 - Murata C9 15 pF Capacitor Ceramic C0G 0402 5% 50 V GRM1555C1H150JA01 - Murata D1, D2 Low Capacitance ESD Protection CG0402MLE-18G - Bourns R1, R2 24 k Resistor 0402 5% 0.1 W RC0402JR-0724KL - Yageo Phycomp R3 3.3 k Resistor 0402 5% 0.1 W RC0402JR-073K3L - Yageo Phycomp R4 1.0 k Resistor 0402 5% 0.1 W RC0402JR-071K0L - Yageo Phycomp U1 Single Cell Li-Ion (or Li-Polymer) Battery Charger IC L6924U - STMicroelectronics Table 18: Suggested components for Li-Ion (or Li-Polymer) battery charging application circuit](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-61.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 62 of 143 2.2.1.8 Guidelines for external battery charging and power path management circuit Application devices where both a permanent primary supply / charging source (e.g. ~12 V) and a rechargeable back-up battery (e.g. 3.7 V Li-Pol) are available at the same time as possible supply source should implement a suitable charger / regulator with integrated power path management function to supply the module and the whole device while simultaneously and independently charging the battery. Figure 26 reports a simplified block diagram circuit showing the working principle of a charger / regulator with an integrated power path management function. This component allows the system to be powered by a permanent primary supply source (e.g. ~12 V) using the integrated regulator which simultaneously and independently recharges the battery (e.g. 3.7 V Li-Pol) that represents the back-up supply source of the system: the power path management feature permits the battery to supplement the system current requirements when the primary supply source is not available or cannot deliver the peak system current. A power management IC should meet the following prerequisites to comply with the module’s VCC requirements as summarized in Table 7: High efficiency internal step down converter, compliant with the performances specified in section 2.2.1.2 Low internal resistance in the active path Vout – Vbat, typically lower than 50 m High efficiency switch mode charger with separate power path control GNDPower path management ICVoutVinθLi-Ion/Li-Pol Battery PackGNDSystem12 V Primary SourceCharge controllerDC/DC converter and battery FET control logicVbat Figure 26: Charger / regulator with integrated power path management circuit block diagram Figure 27 and the components listed in Table 19 provide an application circuit example where the MPS MP2617 switching charger / regulator with integrated power path management function provides the supply to the cellular module while concurrently and autonomously charging a suitable Li-Ion (or Li-Polymer) battery with the correct pulse and DC discharge current capabilities and the correct DC series resistance according to the rechargeable battery recommendations as described in section 2.2.1.4. The MP2617 IC constantly monitors the battery voltage and selects whether to use the external main primary supply / charging source or the battery as the supply source for the module, and starts a charging phase accordingly. The MP2617 IC normally provides a supply voltage to the module regulated from the external main primary source allowing immediate system operation even under missing or deeply discharged battery: the integrated switching step-down regulator is capable to provide up to 3 A output current with low output ripple and fixed 1.6 MHz switching frequency in PWM mode operation. The module load is satisfied in priority, then the integrated switching charger will take the remaining current to charge the battery. Additionally, the power path control allows an internal connection from the battery to the module with a low series internal ON resistance (40 m typical), in order to supplement additional power to the module when the current demand increases over the external main primary source or when this external source is removed.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-62.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 63 of 143 Battery charging is managed in three phases: Pre-charge constant current (active when the battery is deeply discharged): the battery is charged with a low current, set to 10% of the fast-charge current. Fast-charge constant current: the battery is charged with the maximum current, configured by the value of an external resistor to a value suitable for the application. Constant voltage: when the battery voltage reaches the regulated output voltage (4.2 V), the current is progressively reduced until the charge termination is done. The charging process ends when the charging current reaches 10% of the fast-charge current or when the charging timer reaches the value configured by an external capacitor. Using a battery pack with an internal NTC resistor, the MP2617 can monitor the battery temperature to protect the battery from operating under unsafe thermal conditions. Several parameters, such as the charging current, the charging timings, the input current limit, the input voltage limit, and the system output voltage, can be easily set according to the specific application requirements to the actual electrical characteristics of the battery and the external supply / charging source: suitable resistors or capacitors must be accordingly connected to the related pins of the IC. C10 C13GNDC12C11 C14TOBY-L4 series71 VCC72 VCC70 VCC+Primary SourceR3U1ENILIMISETTMRAGNDVINC2C112VNTCPGNDSWSYSBATC4R1R2D1θLi-Ion/Li-Pol Battery PackB1C5Li-Ion/Li-Polymer Battery Charger / Regulator with Power Path ManagmentVCCC3 C6L1BSTD2VLIMR4R5C7 C8 Figure 27: Li-Ion (or Li-Polymer) battery charging and power path management application circuit Reference Description Part Number - Manufacturer B1 Li-Ion (or Li-Polymer) battery pack with 10 k NTC Various manufacturer C1, C5, C6 22 µF Capacitor Ceramic X5R 1210 10% 25 V GRM32ER61E226KE15 - Murata C2, C4, C11 100 nF Capacitor Ceramic X7R 0402 10% 16 V GRM155R61A104KA01 - Murata C3 1 µF Capacitor Ceramic X7R 0603 10% 25 V GRM188R71E105KA12 - Murata C7, C13 68 pF Capacitor Ceramic C0G 0402 5% 50 V GRM1555C1H680JA01 - Murata C8, C14 15 pF Capacitor Ceramic C0G 0402 5% 25 V GRM1555C1E150JA01 - Murata C10 330 µF Capacitor Tantalum D_SIZE 6.3 V 45 m T520D337M006ATE045 - KEMET C12 10 nF Capacitor Ceramic X7R 0402 10% 16 V GRM155R71C103KA01 - Murata D1, D2 Low Capacitance ESD Protection CG0402MLE-18G - Bourns R1, R3, R5 10 k Resistor 0402 5% 1/16 W RC0402JR-0710KL - Yageo Phycomp R2 1.0 k Resistor 0402 5% 0.1 W RC0402JR-071K0L - Yageo Phycomp R4 22 k Resistor 0402 5% 1/16 W RC0402JR-0722KL - Yageo Phycomp L1 1.2 µH Inductor 6 A 21 m 20% 7447745012 - Wurth U1 Li-Ion/Li-Polymer Battery DC/DC Charger / Regulator with integrated Power Path Management function MP2617 - Monolithic Power Systems (MPS) Table 19: Suggested components for a Li-Ion (or Li-Polymer) battery charging and power path management application circuit](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-63.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 64 of 143 2.2.1.9 Guidelines for removing VCC supply As described in section 1.6.2 and Figure 14, the VCC supply can be removed after the end of the TOBY-L4 series module’s internal power-off sequence, which must be properly started as described in section 1.6.2. Removing the VCC power can be useful in order to minimize the current consumption when the TOBY-L4 series modules are switched off. Then, the modules can be switched on again by re-applying the VCC supply. If the VCC supply is generated by a switching or an LDO regulator, the application processor may control the input pin of the regulator which is provided to enable / disable the output of the regulator (as for example, the RUN input pin for the regulator illustrated in Figure 20, the INH input pin for the regulator illustrated in Figure 21, the SHDNn input pin for the regulator illustrated in Figure 22, or the EN input pin for the regulator illustrated in Figure 23), in order to apply / remove the VCC supply. If the regulator that generates the VCC supply does not provide an on / off pin, or for other applications such as the battery-powered ones, the VCC supply can be switched off using an appropriate external p-channel MOSFET controlled by the application processor by means of a suitable inverting transistor as shown in Figure 28, given that the external p-channel MOSFET has provided: Very low RDS(ON) (for example, less than 50 m), to minimize voltage drops Adequate maximum Drain current (see the TOBY-L4 series Data Sheet [1] for module consumption figures) Low leakage current, to minimize the current consumption C3GNDC2C1 C4TOBY-L4 series71 VCC72 VCC70 VCC+VCC Supply SourceGNDGPIO C5R1R3R2T2T1Application Processor Figure 28: Example of application circuit for VCC supply removal Reference Description Part Number - Manufacturer R1 47 k Resistor 0402 5% 0.1 W RC0402JR-0747KL - Yageo Phycomp R2 10 k Resistor 0402 5% 0.1 W RC0402JR-0710KL - Yageo Phycomp R3 100 k Resistor 0402 5% 0.1 W RC0402JR-07100KL - Yageo Phycomp T1 P-Channel MOSFET Low On-Resistance AO3415 - Alpha & Omega Semiconductor Inc. T2 NPN BJT Transistor BC847 - Infineon C1 330 µF Capacitor Tantalum D_SIZE 6.3 V 45 m T520D337M006ATE045 - KEMET C2 10 nF Capacitor Ceramic X7R 0402 10% 16 V GRM155R71C103KA01 - Murata C3 100 nF Capacitor Ceramic X7R 0402 10% 16 V GRM155R61A104KA01 - Murata C4 56 pF Capacitor Ceramic C0G 0402 5% 25 V GRM1555C1E560JA01 - Murata C5 15 pF Capacitor Ceramic C0G 0402 5% 25 V GRM1555C1E150JA01 - Murata Table 20: Components for VCC supply removal application circuit It is highly recommended to avoid an abrupt removal of the VCC supply during the TOBY-L4 series module’s normal operations: the power off procedure must be started as described in section 1.6.2, and then a suitable VCC supply must be held at least until the end of the modules’ internal power off sequence, which occurs when the generic digital interfaces supply output (V_INT) is switched off by the module.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-64.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 65 of 143 2.2.1.10 Guidelines for VCC supply layout design A clean connection of the module VCC pins with a DC supply source is required for correct RF performance. Guidelines are summarized in the following list: All the available VCC pins must be connected to the DC source. VCC connection must be as wide as possible and as short as possible. Any series component with Equivalent Series Resistance (ESR) greater than few milliohms must be avoided. VCC connection must be routed through a PCB area separated from RF lines / parts, sensitive analog signals and sensitive functional units: it is good practice to interpose at least one layer of PCB ground between the VCC track and other signal routing. Coupling between VCC and digital lines, especially USB, must be avoided. The tank bypass capacitor with low ESR for current spikes smoothing described in section 2.2.1.6 should be placed close to the VCC pins. If the main DC source is a switching DC-DC converter, place the large capacitor close to the DC-DC output and minimize the VCC track length. Otherwise consider using separate capacitors for the DC-DC converter and module tank capacitor. The bypass capacitors in the pF range illustrated in Figure 24 and Table 17 should be placed as close as possible to the VCC pins, where the VCC line narrows close to the module input pins, improving the RF noise rejection in the band centered on the Self-Resonant Frequency of the pF capacitors. This is highly recommended if the application device integrates an internal antenna. Since VCC input provides the supply to the RF Power Amplifiers, any voltage ripple at high frequency may result in unwanted spurious modulation of the transmitter RF signal. This is more likely to happen with switching DC-DC converters, in which case it is better to select the highest operating frequency for the switcher and add a large L-C filter before connecting to the TOBY-L4 series modules in the worst case. Shielding of switching DC-DC converter circuit, or at least the use of shielded inductors for the switching DC-DC converter, may be considered since all switching power supplies may potentially generate interfering signals as a result of high-frequency high-power switching. If the VCC is protected by a transient voltage suppressor to ensure that the voltage maximum ratings are not exceeded, place the protecting device along the path from the DC source toward the module, preferably closer to the DC source (otherwise protection functionality may be compromised). 2.2.1.11 Guidelines for grounding layout design A clean connection of the module GND pins with the application board solid ground layer is required for correct RF performance. It significantly reduces EMC issues and provides a thermal heat sink for the module. Connect each GND pin with the application board solid GND layer. It is strongly recommended that each GND pad surrounding the VCC pins has one or more dedicated via down to the application board solid ground layer. The VCC supply current flows back to the main DC source through GND as the ground current: provide an adequate return path with a suitable uninterrupted ground plane to the main DC source. It is recommended to implement one layer of the application board as a ground plane as wide as possible. If the application board is a multilayer PCB, then all the board layers should be filled with GND plane as much as possible and each GND area should be connected together with a complete via stack down to the main ground layer of the board. If the whole application device is composed of more than one PCB, then it is required to provide a good and solid ground connection between the GND areas of all the multiple PCBs. Good grounding of the GND pads also ensures the thermal heat sink. This is critical during connection, when the real network commands the module to transmit at maximum power: correct grounding helps prevent module overheating.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-65.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 66 of 143 2.2.2 RTC back-up supply (V_BCKP) 2.2.2.1 Guidelines for V_BCKP circuit design TOBY-L4 series modules provide the V_BCKP pin, which can be used to: power the Real Time Clock (RTC) only when the voltage value at VCC main module supply input is too low The RTC can be supplied from an external back-up battery or capacitor through the V_BCKP pin, when the main module voltage supply is not applied to the VCC pins. This lets the time reference (date and time) run as long as the V_BCKP voltage is within its valid range, even when the main supply is not provided to the module. Figure 29 and Table 21 describe possible application circuits for V_BCKP Real Time Clock (RTC) back-up supply: a. 100 µF capacitor, to let the RTC run for ~1 minute after the VCC removal b. 70 mF super-capacitor with a 4.7 k series resistor, to let the RTC run for ~1 hour after the VCC removal c. Coin non-rechargeable battery with series diode, to let the RTC run for days after the VCC removal TOBY-L4 seriesC1a.3V_BCKPR2TOBY-L4 seriesC2(SuperCap)b.3V_BCKPD3TOBY-L4 seriesB3c.3V_BCKP Figure 29: RTC back-up supply (V_BCKP) application circuits using a capacitor, a super-capacitor, or a non-rechargeable battery Reference Description Part Number - Manufacturer C1 100 µF Tantalum Capacitor GRM43SR60J107M - Murata R2 4.7 k Resistor 0402 5% 0.1 W RC0402JR-074K7L - Yageo Phycomp C2 70 mF Capacitor XH414H-IV01E - Seiko Instruments Table 21: Example of components for RTC back-up supply (V_BCKP) The V_BCKP supply output pin provides internal short circuit protection to limit the start-up current and protect the device in short circuit situations. No additional external short circuit protection is required. The V_BCKP pin can be left unconnected if the RTC timing is not required when the VCC supply is removed. The internal regulator for V_BCKP is optimized for low leakage current and very light loads. Do not apply loads which might exceed the limit for the maximum available current from V_BCKP supply, as this can cause malfunctions in the module. The TOBY-L4 series Data Sheet [1] describes the detailed electrical characteristics. The ESD sensitivity rating of the V_BCKP supply pin is 1 kV (HBM according to JESD22-A114). A higher protection level can be required if the line is externally accessible on the application board, e.g. if an accessible back-up battery connector is directly connected to the V_BCKP pin, and it can be achieved by mounting an ESD protection (e.g. EPCOS CA05P4S14THSG varistor array) close to the accessible point. 2.2.2.2 Guidelines for V_BCKP layout design The V_BCKP supply requires careful layout: avoid injecting noise on this voltage domain, as it may affect the stability of the internal circuitry.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-66.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 67 of 143 2.2.3 Generic digital interfaces supply output (V_INT) 2.2.3.1 Guidelines for V_INT circuit design TOBY-L4 series provide the V_INT generic digital interfaces 1.8 V supply output, which can be mainly used to: Indicate when the module is switched on (as described in sections 1.6.1, 1.6.2) Pull-up SIM detection signal (see section 2.5 for more details) Supply voltage translators to connect 1.8 V module generic digital interfaces to 3.0 V devices (e.g. see 2.6.1) Pull-up DDC (I2C) interface signals (see section 2.6.4 for more details) Supply a 1.8 V u-blox GNSS receiver (see section 2.6.4 for more details) Supply an external device as an external 1.8 V audio codec (see section 2.8.2 for more details) The V_INT supply output pin provides internal short circuit protection to limit the start-up current and protect the device in short circuit situations. No additional external short circuit protection is required. Do not apply loads which might exceed the limit for the maximum available current from V_INT supply as this can cause malfunctions in the internal circuitry. Since the V_INT supply is generated by an internal switching step-down regulator, it is not recommended to supply sensitive analog circuitry without adequate filtering for digital noise. V_INT can only be used as an output: do not connect any external supply source on V_INT. The ESD sensitivity rating of the V_INT supply pin is 1 kV (Human Body Model according to JESD22-A114). A higher protection level could be required if the line is externally accessible and it can be achieved by mounting an ESD protection (e.g. EPCOS CA05P4S14THSG varistor array) close to the accessible point. It is recommended to monitor the V_INT pin to sense the end of the internal switch-off sequence of TOBY-L4 series modules: the VCC supply can be removed only after V_INT goes low It is recommended to provide direct access to the V_INT pin on the application board by means of an accessible test point directly connected to the V_INT pin, for diagnostic purposes. 2.2.3.2 Guidelines for V_INT layout design The V_INT supply output is generated by an integrated switching step-down converter. Because of this, it can be a source of noise: avoid coupling with sensitive signals.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-67.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 68 of 143 2.3 System functions interfaces 2.3.1 Module power-on (PWR_ON) 2.3.1.1 Guidelines for PWR_ON circuit design TOBY-L4 series PWR_ON input is equipped with an internal active pull-up resistor to an internal 1.3 V supply rail as illustrated in Figure 30: an external pull-up resistor is not required and should not be provided. If connecting the PWR_ON input to a push button, the pin will be externally accessible on the application device. According to EMC/ESD requirements of the application, an additional ESD protection should be provided close to the accessible point, as illustrated in Figure 30 and Table 22. The ESD sensitivity rating of the PWR_ON pin is 1 kV (Human Body Model according to JESD22-A114). A higher protection level can be required if the line is externally accessible on the application board, e.g. if an accessible push button is directly connected to the PWR_ON pin, and it can be achieved by mounting an ESD protection (e.g. EPCOS CA05P4S14THSG varistor) close to the accessible point. An open drain or open collector output is suitable to drive the PWR_ON input from an application processor, as the pin is equipped with an internal active pull-up resistor, as illustrated in Figure 30. TOBY-L4 series20 PWR_ONPower-on push buttonESDOpen Drain OutputApplication ProcessorTOBY-L4 series35 k1.3 V20 PWR_ONTP TP35 k1.3 V Figure 30: PWR_ON application circuits using a push button and an open drain output of an application processor Reference Description Remarks ESD CT0402S14AHSG - EPCOS Varistor array for ESD protection Table 22: Example ESD protection component for the PWR_ON application circuit It is recommended to provide direct access to the PWR_ON pin on the application board by means of an accessible test point directly connected to the PWR_ON pin, for diagnostic purposes. 2.3.1.2 Guidelines for PWR_ON layout design The power-on circuit (PWR_ON) requires careful layout since it is the sensitive input available to switch on the TOBY-L4 series modules. It is required to ensure that the voltage level is well defined during operation and no transient noise is coupled on this line, otherwise the module might detect a spurious power-on request.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-68.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 69 of 143 2.3.2 Module reset (RESET_N) 2.3.2.1 Guidelines for RESET_N circuit design TOBY-L4 series RESET_N line is equipped with an internal pull-up to the V_INT supply as illustrated in Figure 31. An external pull-up resistor is not required. If connecting the RESET_N input to a push button, the pin will be externally accessible on the application device. According to the EMC/ESD requirements of the application, an additional ESD protection device (e.g. the EPCOS CA05P4S14THSG varistor) should be provided close to the accessible point on the line connected to this pin, as illustrated in Figure 31 and Table 23. The ESD sensitivity rating of the RESET_N pin is 1 kV (HBM according to JESD22-A114). A higher protection level can be required if the line is externally accessible on the application board, e.g. if an accessible push button is directly connected to the RESET_N pin, and it can be achieved by mounting an ESD protection (e.g. EPCOS CA05P4S14THSG varistor) close to the accessible point. An open drain output is suitable to drive the RESET_N input from an application processor as it is equipped with an internal pull-up to V_INT supply, as illustrated in Figure 31. A compatible push-pull output of an application processor can also be used. In any case, take care to set the correct level in all the possible scenarios to avoid an inappropriate module reset. TOBY-L4 series5V_INT23 RESET_NPower-on push buttonESDOpen Drain OutputApplication ProcessorTOBY-L4 series5V_INT23 RESET_NTP TP100 k100 k Figure 31: RESET_N application circuits using a push button and an open drain output of an application processor Reference Description Remarks ESD Varistor for ESD protection CT0402S14AHSG - EPCOS Table 23: Example of ESD protection component for the RESET_N application circuits If the external reset function is not required by the customer application, the RESET_N input pin can be left unconnected to external components, but it is recommended to provide direct access on the application board by means of an accessible test point directly connected to the RESET_N pin. 2.3.2.2 Guidelines for RESET_N layout design The RESET_N circuit requires careful layout due to the pin function: ensure that the voltage level is well defined during operation and no transient noise is coupled on this line, otherwise the module might detect a spurious reset request. It is recommended to keep the connection line to the RESET_N pin as short as possible.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-69.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 70 of 143 2.3.3 Module / host configuration selection Host Select pins are not supported by the "50" product version. 2.3.3.1 Guidelines for HOST_SELECTx circuit design TOBY-L4 series modules include two 1.8 V digital pins (HOST_SELECT0, HOST_SELECT1), which can be configured for External Interrupt detection or as GPIO by means of the uCPU API: the pins can be connected to external devices following the guidelines provided in section 2.10. Do not apply voltage to the HOST_SELECT0 and HOST_SELECT1 pins before the switch-on of their supply source (V_INT), to avoid latch-up of circuits and allow a correct boot of the module. The ESD sensitivity rating of the HOST_SELECT0 and HOST_SELECT1 pins is 1 kV (HBM as per JESD22-A114). A higher protection level could be required if the lines are externally accessible and it can be achieved by mounting an ESD protection (e.g. EPCOS CA05P4S14THSG varistor array) close to the accessible points. If the functionality of the HOST_SELECT0 and HOST_SELECT1 pins is not required, the pins can be left unconnected on the application board. 2.3.3.2 Guidelines for HOST_SELECTx layout design The design for the HOST_SELECT0 and HOST_SELECT1 pins functions is generally not critical for layout.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-70.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 71 of 143 2.4 Antenna interface TOBY-L4 series modules provide two RF interfaces for connecting the external antennas: The ANT1 pin represents the primary RF input/output for LTE/3G/2G RF signals transmission and reception. The ANT2 pin represents the secondary RF input for MIMO and Rx diversity RF signals reception. Both the ANT1 and the ANT2 pins have a nominal characteristic impedance of 50 and must be connected to the related antenna through a 50 transmission line to allow correct transmission / reception of RF signals. Two antennas (one connected to ANT1 pin and one connected to ANT2 pin) must be used to support the CA, MIMO and Rx diversity configurations. This is a required feature for LTE category 6 User Equipments (up to 301.5 Mbit/s Down-Link data rate) according to the 3GPP specifications. 2.4.1 Antenna RF interfaces (ANT1 / ANT2) 2.4.1.1 General guidelines for antenna selection and design The antenna is the most critical component to be evaluated. Designers must take care of the antennas from all perspectives at the very start of the design phase when the physical dimensions of the application board are under analysis/decision, since the RF compliance of the device integrating TOBY-L4 series modules with all the applicable required certification schemes depends on the antenna radiating performance. LTE/3G/2G antennas are typically available in the types of linear monopole or PCB antennas such as patches or ceramic SMT elements. External antennas (e.g. linear monopole) o External antennas basically do not imply a physical restriction to the design of the PCB where the TOBY-L4 series module is mounted. o The radiation performance mainly depends on the antennas. It is required to select antennas with optimal radiating performance in the operating bands. o RF cables should be carefully selected to have minimum insertion losses. Additional insertion loss will be introduced by low quality or long cable. Large insertion loss reduces both transmit and receive radiation performance. o A high quality 50 RF connector provides suitable PCB-to-RF-cable transition. It is recommended to strictly follow the layout and cable termination guidelines provided by the connector manufacturer. Integrated antennas (e.g. patch-like antennas): o Internal integrated antennas imply a physical restriction to the design of the PCB: An integrated antenna excites RF currents on its counterpoise, typically the PCB ground plane of the device that becomes part of the antenna: its dimension defines the minimum frequency that can be radiated. Therefore, the ground plane can be reduced down to a minimum size that should be similar to the quarter of the wavelength of the minimum frequency that must be radiated, given that the orientation of the ground plane relative to the antenna element must be considered. The isolation between the primary and the secondary antennas must be as high as possible and the correlation between the 3D radiation patterns of the two antennas must be as low as possible. In general, a separation of at least a quarter wavelength between the two antennas is required to achieve a good isolation and low pattern correlation. As a numerical example, the physical restriction to the PCB design can be considered as following: Frequency = 750 MHz Wavelength = 40 cm Minimum GND plane size = 10 cm](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-71.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 72 of 143 o Radiation performance depends on the whole PCB and antenna system design, including product mechanical design and usage. Antennas should be selected with optimal radiating performance in the operating bands according to the mechanical specifications of the PCB and the whole product. o It is recommended to select a pair of custom antennas designed by an antennas’ manufacturer if the required ground plane dimensions are very small (e.g. less than 6.5 cm long and 4 cm wide). The antenna design process should begin at the start of the whole product design process. o It is highly recommended to strictly follow the detailed and specific guidelines provided by the antenna manufacturer regarding correct installation and deployment of the antenna system, including PCB layout and matching circuitry. o Further to the custom PCB and product restrictions, antennas may require tuning to obtain the required performance for compliance with all the applicable required certification schemes. It is recommended to consult the antenna manufacturer for the design-in guidelines for antenna matching relative to the custom application. In both cases, selecting external or internal antennas, these recommendations should be observed: Select antennas providing optimal return loss (or VSWR) figures over all the operating frequencies. Select antennas providing optimal efficiency figures over all the operating frequencies. Select antennas providing similar efficiency for both the primary (ANT1) and the secondary (ANT2) antenna. Select antennas providing appropriate gain figures (i.e. combined antenna directivity and efficiency figures) so that the electromagnetic field radiation intensity does not exceed the regulatory limits specified in certain countries (e.g. by the FCC in the United States). Select antennas capable of providing a low Envelope Correlation Coefficient between the primary (ANT1) and the secondary (ANT2) antenna: the 3D antenna radiation patterns should have lobes in different directions. 2.4.1.2 Guidelines for antenna RF interface design Guidelines for ANT1 / ANT2 pins RF connection design Correct transition between the ANT1 / ANT2 pads and the application board PCB must be provided, implementing the following design-in guidelines for the application PCB layout close to the ANT1 / ANT2 pads: On a multilayer board, the whole layer stack below the RF connection should be free of digital lines. Increase GND keep-out (i.e. clearance, a void area) around the ANT1 / ANT2 pads, on the top layer of the application PCB, to at least 250 µm up to the adjacent pads metal definition and up to 400 µm on the area below the module, to reduce parasitic capacitance to ground, as illustrated in the left example of Figure 32. Add GND keep-out (i.e. clearance, a void area) on the buried metal layer below the ANT1 / ANT2 pads if the top-layer to buried layer dielectric thickness is below 200 µm, to reduce parasitic capacitance to ground, as illustrated in the right example of Figure 32. Min. 250 µmMin. 400 µm GNDANT1GND clearance on very close buried layerbelow ANT1 padGND clearance on top layer around ANT1 padMin. 250 µmMin. 400 µmGNDANT2GND clearance on very close buried layerbelow ANT2 padGND clearance on top layer around ANT2 pad Figure 32: GND keep-out area on top layer around ANT1 / ANT2 pads and on very close buried layer below ANT1 / ANT2 pads](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-72.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 73 of 143 Guidelines for RF transmission line design Any RF transmission line, such as the ones from the ANT1 and ANT2 pads up to the related antenna connector or up to the related internal antenna pad, must be designed so that the characteristic impedance is as close as possible to 50 . RF transmission lines can be designed as a micro strip (consists of a conducting strip separated from a ground plane by a dielectric material) or a strip line (consists of a flat strip of metal which is sandwiched between two parallel ground planes within a dielectric material). The micro strip, implemented as a coplanar waveguide, is the most common configuration for printed circuit boards. Figure 33 and Figure 34 provide two examples of suitable 50 coplanar waveguide designs. The first example of an RF transmission line can be implemented for a 4-layer PCB stack-up herein illustrated, and the second example of an RF transmission line can be implemented for a 2-layer PCB stack-up herein illustrated. 35 µm35 µm35 µm35 µm270 µm270 µm760 µmL1 CopperL3 CopperL2 CopperL4 CopperFR-4 dielectricFR-4 dielectricFR-4 dielectric380 µm 500 µm500 µm Figure 33: Example of a 50 coplanar waveguide transmission line design for the described 4-layer board layup 35 µm35 µm1510 µmL2 CopperL1 CopperFR-4 dielectric1200 µm 400 µm400 µm Figure 34: Example of a 50 coplanar waveguide transmission line design for the described 2-layer board layup If the two examples do not match the application PCB stack-up, the 50 characteristic impedance calculation can be made using the HFSS commercial finite element method solver for electromagnetic structures from Ansys Corporation, or using freeware tools like AppCAD from Agilent (www.agilent.com) or TXLine from Applied Wave Research (www.mwoffice.com), taking care of the approximation formulas used by the tools for the impedance computation. To achieve a 50 characteristic impedance, the width of the transmission line must be chosen depending on: the thickness of the transmission line itself (e.g. 35 µm in the examples of Figure 33 and Figure 34) the thickness of the dielectric material between the top layer (where the transmission line is routed) and the inner closer layer implementing the ground plane (e.g. 270 µm in Figure 33, 1510 µm in Figure 34)](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-73.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 74 of 143 the dielectric constant of the dielectric material (e.g. dielectric constant of the FR-4 dielectric material in Figure 33 and Figure 34) the gap from the transmission line to the adjacent ground plane on the same layer of the transmission line (e.g. 500 µm in Figure 33, 400 µm in Figure 34) If the distance between the transmission line and the adjacent GND area (on the same layer) does not exceed 5 times the track width of the micro strip, use the “Coplanar Waveguide” model for the 50 calculation. Additionally to the 50 impedance, the following guidelines are recommended for transmission line design: Minimize the transmission line length: the insertion loss should be minimized as much as possible, in the order of a few tenths of a dB. Add GND keep-out (i.e. clearance, a void area) on buried metal layers below any pad of a component present on the RF transmission lines, if the top-layer to buried layer dielectric thickness is below 200 µm, to reduce parasitic capacitance to ground. The transmission lines width and spacing to GND must be uniform and routed as smoothly as possible: avoid abrupt changes of width and spacing to GND. Add GND stitching vias around the transmission lines, as illustrated in Figure 35. Ensure a solid metal connection of the adjacent metal layer on the PCB stack-up to the main ground layer, providing enough vias on the adjacent metal layer, as illustrated in Figure 35. Route RF transmission lines far from any noise source (as switching supplies and digital lines) and from any sensitive circuit (as USB). Avoid stubs on the transmission lines. Avoid signal routing in parallel to the transmission lines or crossing the transmission lines on a buried metal layer. Do not route the microstrip lines below discrete components or other mechanics placed on the top layer. An example of a suitable RF circuit design is illustrated in Figure 35. In this case, the ANT1 and ANT2 pins are directly connected to SMA connectors by means of suitable 50 transmission lines, designed with a suitable layout. SMA Connector Primary AntennaSMA Connector Secondary AntennaTOBY-L4 Figure 35: Example of the circuit and layout for antenna RF circuits on the application board](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-74.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 75 of 143 Guidelines for RF termination design RF terminations must provide a characteristic impedance of 50 as well as the RF transmission lines up to the RF terminations themselves, to match the characteristic impedance of the ANT1 / ANT2 ports of the modules. However, real antennas do not have a perfect 50 load on all the supported frequency bands. Therefore, to reduce as much as possible any performance degradation due to antennas mismatch, the RF terminations must provide optimal return loss (or VSWR) figures over all the operating frequencies, as summarized in Table 8 and Table 9. If external antennas are used, the antenna connectors represent the RF termination on the PCB: Use suitable 50 connectors providing a correct PCB-to-RF-cable transition. Strictly follow the connector manufacturer’s recommended layout, for example: o SMA Pin-Through-Hole connectors require GND keep-out (i.e. clearance, a void area) on all the layers around the central pin up to the annular pads of the four GND posts, as shown in Figure 35. o U.FL surface-mounted connectors require no conductive traces (i.e. clearance, a void area) in the area below the connector between the GND land pads. Cut out the GND layer under RF connectors and close to buried vias, in order to remove stray capacitance and thus keep the RF line 50 , e.g. the active pad of U.FL connectors needs to have a GND keep-out (i.e. clearance, a void area) at least on the first inner layer to reduce parasitic capacitance to ground. If integrated antennas are used, the RF terminations are represented by the integrated antennas themselves. The following guidelines should be followed: Use antennas designed by an antenna manufacturer, providing the best possible return loss (or VSWR). Provide a ground plane large enough according to the relative integrated antenna requirements. The ground plane of the application PCB can be reduced down to a minimum size that must be similar to one quarter of a wavelength of the minimum frequency that must be radiated. As a numerical example, Frequency = 750 MHz Wavelength = 40 cm Minimum GND plane size = 10 cm It is highly recommended to strictly follow the detailed and specific guidelines provided by the antenna manufacturer regarding correct installation and deployment of the antenna system, including PCB layout and matching circuitry. Further to the custom PCB and product restrictions, antennas may require a tuning to comply with all the applicable required certification schemes. It is recommended to consult the antenna manufacturer for the design-in guidelines for the antenna matching relative to the custom application. Additionally, these recommendations regarding the antenna system placement must be followed: Do not place antennas within a closed metal case. Do not place the antennas in close vicinity to the end user since the emitted radiation in human tissue is limited by regulatory requirements. Place the antennas far from sensitive analog systems or employ countermeasures to reduce EMC issues. Take care of interaction between co-located RF systems since the LTE/3G/2G transmitted power may interact or disturb the performance of companion systems. Place the two LTE antennas providing low Envelope Correlation Coefficient (ECC) between the primary (ANT1) and secondary (ANT2) antenna: the antenna 3D radiation patterns should have lobes in different directions. The ECC between the primary and secondary antennas needs to be low enough to comply with the radiated performance requirements specified by related certification schemes, as indicated in Table 10. Place the two LTE antennas providing enough high isolation (see Table 10) between the primary (ANT1) and secondary (ANT2) antennas. The isolation depends on the distance between antennas (separation of at least a quarter wavelength required for good isolation), antenna type (using antennas with different polarization improves isolation), and the antenna 3D radiation patterns (uncorrelated patterns improve isolation).](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-75.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 76 of 143 Examples of antennas Table 24 lists some examples of possible internal on-board surface-mount antennas. Manufacturer Part Number Product Name Description Taoglas PA.710.A Warrior GSM / WCDMA / LTE SMD Antenna 698..960 MHz, 1710..2170 MHz, 2300..2400 MHz, 2490..2690 MHz 40.0 x 6.0 x 5.0 mm Taoglas PA.711.A Warrior II GSM / WCDMA / LTE SMD Antenna Pairs with the Taoglas PA.710.A Warrior for LTE MIMO applications 698..960 MHz, 1710..2170 MHz, 2300..2400 MHz, 2490..2690 MHz 40.0 x 6.0 x 5.0 mm Antenova SR4L002 Lucida GSM / WCDMA / LTE SMD Antenna 698..960 MHz, 1710..2170 MHz, 2300..2400 MHz, 2490..2690 MHz 35.0 x 8.5 x 3.2 mm Table 24: Examples of internal surface-mount antennas Table 25 lists some examples of possible internal off-board PCB-type antennas with cable and connector. Manufacturer Part Number Product Name Description Taoglas FXUB66.07.0150C Maximus GSM / WCDMA / LTE PCB Antenna with cable and U.FL 698..960 MHz, 1390..1435 MHz, 1575.42 MHz, 1710..2170 MHz, 2300..2700 MHz, 3400..3600 MHz, 4800..6000 MHz 120.2 x 50.4 mm Ethertronics 5001537 Prestta GSM / WCDMA / LTE PCB Antenna with cable 704..960 MHz, 1710..2170 MHz, 2300..2400 MHz, 2500..2690 MHz 80.0 x 18.0 mm Table 25: Examples of internal antennas with cable and connector Table 26 lists some examples of possible external antennas. Manufacturer Part Number Product Name Description Taoglas GSA.8827.A.101111 Phoenix GSM / WCDMA / LTE adhesive-mount antenna with cable and SMA(M) 698..960 MHz, 1575.42 MHz, 1710..2700 MHz 105 x 30 x 7.7 mm Taoglas MA241.BI.001 Genesis GSM / WCDMA / LTE MIMO 2-in-1 adhesive-mount combination antenna waterproof IP67 rated with cable and SMA(M) 698..960 MHz, 1710..2690 MHz 205.8 x 58 x 12.4 mm Laird Tech. TRA6927M3PW-001 GSM / WCDMA / LTE screw-mount antenna with N-type(F) 698..960 MHz, 1710..2170 MHz, 2300..2700 MHz 83.8 x Ø 36.5 mm Laird Tech. OC69271-FNM GSM / WCDMA / LTE pole-mount antenna with N-type(M) 698..960 MHz, 1710..2690 MHz 248 x Ø 24.5 mm Laird Tech. CMD69273-30NM GSM / WCDMA / LTE ceiling-mount MIMO antenna with cables & N-type(M) 698..960 MHz, 1710..2700 MHz 43.5 x Ø 218.7 mm Pulse Electronics WA700/2700SMA GSM / WCDMA / LTE clip-mount MIMO antenna with cables and SMA(M) 698..960 MHz,1710..2700 MHz 149 x 127 x 5.1 mm Table 26: Examples of external antennas](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-76.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 77 of 143 2.4.2 Antenna detection interface (ANT_DET) 2.4.2.1 Guidelines for ANT_DET circuit design Figure 36 and Table 27 describe the recommended schematic / components for the antennas detection circuit that must be provided on the application board and for the diagnostic circuit that must be provided on the antennas’ assembly to achieve primary and secondary antenna detection functionality. Application BoardAntenna CableTOBY-L4 series81ANT175ANT_DET R1C1 D1C2 J1Z0= 50 ohm Z0= 50 ohm Z0= 50 ohmPrimary Antenna AssemblyR2C4L3Radiating ElementDiagnostic CircuitL2L1Antenna Cable87ANT2C3 J2Z0= 50 ohm Z0= 50 ohm Z0= 50 ohmSecondary Antenna AssemblyR3C5L4Radiating ElementDiagnostic Circuit Figure 36: Suggested schematic for the antenna detection circuit on the application board and the diagnostic circuit on the antennas assembly Reference Description Part Number - Manufacturer C1 27 pF Capacitor Ceramic C0G 0402 5% 50 V GRM1555C1H270J - Murata C2, C3 33 pF Capacitor Ceramic C0G 0402 5% 50 V GRM1555C1H330J - Murata D1 Very Low Capacitance ESD Protection PESD0402-140 - Tyco Electronics L1, L2 68 nH Multilayer Inductor 0402 (SRF ~1 GHz) LQG15HS68NJ02 - Murata R1 10 k Resistor 0402 1% 0.063 W RK73H1ETTP1002F - KOA Speer J1, J2 SMA Connector 50 Through Hole Jack SMA6251A1-3GT50G-50 - Amphenol C4, C5 22 pF Capacitor Ceramic C0G 0402 5% 25 V GRM1555C1H220J - Murata L3, L4 68 nH Multilayer Inductor 0402 (SRF ~1 GHz) LQG15HS68NJ02 - Murata R2, R3 15 k Resistor for Diagnostic Various Manufacturers Table 27: Suggested components for the antenna detection circuit on the application board and the diagnostic circuit on the antennas assembly The antenna detection circuit and diagnostic circuit suggested in Figure 36 and Table 27 are explained here: When antenna detection is forced by the AT+UANTR command, ANT_DET generates a DC current measuring the resistance (R2 // R3) from the antenna connectors (J1, J2) provided on the application board to GND. DC blocking capacitors are needed at the ANT1 / ANT2 pins (C2, C3) and at the antenna radiating element (C4, C5) to decouple the DC current generated by the ANT_DET pin. Choke inductors with a Self Resonance Frequency (SRF) in the range of 1 GHz are needed in series at the ANT_DET pin (L1, L2) and in series at the diagnostic resistor (L3, L4), to avoid a reduction of the RF performance of the system, improving the RF isolation of the load resistor. Additional components (R1, C1 and D1 in Figure 36) are needed at the ANT_DET pin as ESD protection. The ANT1 / ANT2 pins must be connected to the antenna connector by means of a transmission line with a nominal characteristic impedance as close as possible to 50 .](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-77.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 78 of 143 The DC impedance at the RF port for some antennas may be a DC open (e.g. linear monopole) or a DC short to reference GND (e.g. PIFA antenna). For those antennas without the diagnostic circuit of Figure 36, the measured DC resistance is always at the limits of the measurement range (respectively open or short), and there is no means to distinguish between a defect on the antenna path with similar characteristics (respectively: removal of linear antenna or RF cable shorted to GND for a PIFA antenna). Furthermore, any other DC signal injected to the RF connection from an ANT connector to a radiating element will alter the measurement and produce invalid results for antenna detection. It is recommended to use an antenna with a built-in diagnostic resistor in the range from 5 k to 30 k to assure good antenna detection functionality and avoid a reduction of module RF performance. The choke inductor should exhibit a parallel Self Resonance Frequency (SRF) in the range of 1 GHz to improve the RF isolation of the load resistor. For example: Consider an antenna with a built-in DC load resistor of 15 k. Using the +UANTR AT command, the module reports the resistance value evaluated from the antenna connector provided on the application board to GND: Reported values close to the used diagnostic resistor nominal value (i.e. values from 13 k to 17 k if a 15 k diagnostic resistor is used) indicate that the antenna is properly connected. Values close to the measurement range maximum limit (approximately 50 k) or an open-circuit “over range” report (see the u-blox AT Commands Manual [2]) means that that the antenna is not connected or the RF cable is broken. Reported values below the measurement range minimum limit (1 k) indicate a short to GND at the antenna or along the RF cable. Measurement inside the valid measurement range and outside the expected range may indicate an incorrect connection, damaged antenna or wrong value of antenna load resistor for diagnostics. The reported value could differ from the real resistance value of the diagnostic resistor mounted inside the antenna assembly due to the antenna cable length, the antenna cable capacity or the measurement method used. If the primary / secondary antenna detection function is not required by the customer application, the ANT_DET pin can be left unconnected and the ANT1 / ANT2 pins can be directly connected to the related antenna connector by means of a 50 transmission line as illustrated in Figure 35. 2.4.2.2 Guidelines for ANT_DET layout design The recommended layout for the primary antenna detection circuit to be provided on the application board to achieve the primary antenna detection functionality, implementing the recommended schematic illustrated in Figure 36 and Table 27, is explained here: The ANT1 / ANT2 pins must be connected to the antenna connector by means of a 50 transmission line, implementing the design guidelines described in section 2.4.1 and the recommendations of the SMA connector manufacturer. DC blocking capacitor at ANT1 / ANT2 pins (C2, C3) must be placed in series to the 50 RF line. The ANT_DET pin must be connected to the 50 transmission line by means of a sense line. Choke inductors in series at the ANT_DET pin (L1, L2) must be placed so that one pad is on the 50 transmission line and the other pad represents the start of the sense line to the ANT_DET pin. The additional components (R1, C1 and D1) on the ANT_DET line must be placed as ESD protection.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-78.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 79 of 143 2.5 SIM interfaces 2.5.1 Guidelines for SIM circuit design Guidelines for SIM cards, SIM connectors and SIM chips selection TOBY-L4 series modules provide two SIM interfaces for the direct connection of two external SIM cards/chips, which can be used alternatively (only one SIM at a time can be used for network access): SIM0 interface (VSIM, SIM_IO, SIM_CLK, SIM_RST pins), enabled by default SIM1 interface (VSIM1, SIM1_IO, SIM1_CLK, SIM1_RST pins), alternatively enabled The ISO/IEC 7816, the ETSI TS 102 221 and the ETSI TS 102 671 specifications define the physical, electrical and functional characteristics of Universal Integrated Circuit Cards (UICC), which contains the Subscriber Identification Module (SIM) integrated circuit that securely stores all the information needed to identify and authenticate subscribers over the LTE/3G/2G network. Removable UICC / SIM card contact mapping is defined by ISO/IEC 7816 and ETSI TS 102 221 as follows: Contact C1 = VCC (Supply) It must be connected to VSIM / VSIM1 Contact C2 = RST (Reset) It must be connected to SIM_RST / SIM1_RST Contact C3 = CLK (Clock) It must be connected to SIM_CLK / SIM1_CLK Contact C4 = AUX1 (Auxiliary contact) It must be left not connected Contact C5 = GND (Ground) It must be connected to GND Contact C6 = VPP (Programming supply) It can be left not connected Contact C7 = I/O (Data input/output) It must be connected to SIM_IO / SIM1_IO Contact C8 = AUX2 (Auxiliary contact) It must be left not connected A removable SIM card can have 6 contacts (C1, C2, C3, C5, C6, C7) or 8 contacts, also including the auxiliary contacts C4 and C8. Only 6 contacts are required and must be connected to the module SIM interface. Removable SIM cards are suitable for applications requiring a change of SIM card during the product’s lifetime. A SIM card holder can have 6 or 8 positions if a mechanical card presence detector is not provided, or it can have 6+2 or 8+2 positions if two additional pins relative to the normally-open mechanical switch integrated in the SIM connector for the mechanical card presence detection are provided. Select a SIM connector providing 6+2 or 8+2 positions if the optional SIM detection feature is required by the custom application, otherwise a connector without an integrated mechanical presence switch can be selected. Solderable UICC / SIM chip contact mapping (M2M UICC Form Factor) is defined by ETSI TS 102 671 as: Case Pin 8 = UICC Contact C1 = VCC (Supply) It must be connected to VSIM / VSIM1 Case Pin 7 = UICC Contact C2 = RST (Reset) It must be connected to SIM_RST / SIM1_RST Case Pin 6 = UICC Contact C3 = CLK (Clock) It must be connected to SIM_CLK / SIM1_CLK Case Pin 5 = UICC Contact C4 = AUX1 (Aux.contact) It must be left not connected Case Pin 1 = UICC Contact C5 = GND (Ground) It must be connected to GND Case Pin 2 = UICC Contact C6 = VPP (Progr. supply) It can be left not connected Case Pin 3 = UICC Contact C7 = I/O (Data I/O) It must be connected to SIM_IO / SIM1_IO Case Pin 4 = UICC Contact C8 = AUX2 (Aux. contact) It must be left not connected A solderable SIM chip has 8 contacts and can also include the auxiliary contacts C4 and C8 for other uses, but only 6 contacts are required and must be connected to the module SIM card interface as described above. Solderable SIM chips are suitable for M2M applications where it is not required to change the SIM once installed.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-79.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 80 of 143 Guidelines for single SIM card connection without detection A removable SIM card placed in a SIM card holder must be connected to the SIM0 or the SIM1 interface of TOBY-L4 series modules as illustrated in Figure 37, where the optional SIM detection feature is not implemented. Follow these guidelines to connect the module to a SIM connector without SIM presence detection: Connect the UICC / SIM contact C1 (VCC) to the VSIM or the VSIM1 pin of the module. Connect the UICC / SIM contact C7 (I/O) to the SIM_IO or the SIM1_IO pin of the module. Connect the UICC / SIM contact C3 (CLK) to the SIM_CLK or the SIM1_CLK pin of the module. Connect the UICC / SIM contact C2 (RST) to the SIM_RST or the SIM1_RST pin of the module. Connect the UICC / SIM contact C5 (GND) to ground. Provide a 100 nF bypass capacitor (e.g. Murata GRM155R71C104K) on SIM supply line, close to the relative pad of the SIM connector, to prevent digital noise. Provide a bypass capacitor of about 22 pF to 47 pF (e.g. Murata GRM1555C1H470J) on each SIM line, very close to each related pad of the SIM connector, to prevent RF coupling especially when the RF antenna is placed closer than 10 - 30 cm from the SIM card holder. Provide a very low capacitance (i.e. less than 10 pF) ESD protection (e.g. Tyco PESD0402-140) on each externally accessible SIM line, close to each relative pad of the SIM connector. The ESD sensitivity rating of the SIM interface pins is 1 kV (HBM). So that, according to EMC/ESD requirements of the custom application, a higher protection level can be required if the lines are externally accessible on the application device. Limit the capacitance and series resistance on each SIM signal to match the SIM requirements (27.7 ns is the maximum allowed rise time on the clock line, 1.0 µs is the maximum allowed rise time on the data and reset lines). TOBY-L4 seriesVSIMxSIMx_IOSIMx_CLKSIMx_RSTSIM CARD HOLDERC5C6C7C1C2C3SIM Card Bottom View (contacts side)C1VPP (C6)VCC (C1)IO (C7)CLK (C3)RST (C2)GND (C5)C2 C3 C5J1C4 D1 D2 D3 D4C8C4 Figure 37: Application circuits for the connection to a single removable SIM card, with SIM detection not implemented Reference Description Part Number - Manufacturer C1, C2, C3, C4 47 pF Capacitor Ceramic C0G 0402 5% 50 V GRM1555C1H470JA01 - Murata C5 100 nF Capacitor Ceramic X7R 0402 10% 16 V GRM155R71C104KA01 - Murata D1, D2, D3, D4 Very Low Capacitance ESD Protection PESD0402-140 - Tyco Electronics J1 SIM Card Holder, 6 p, without card presence switch Various manufacturers, as C707 10M006 136 2 - Amphenol Table 28: Example of components for the connection to a single removable SIM card, with SIM detection not implemented](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-80.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 81 of 143 Guidelines for single SIM chip connection A solderable SIM chip (M2M UICC Form Factor) must be connected the SIM0 / SIM1 interface of TOBY-L4 series modules as illustrated in Figure 38. Follow these guidelines to connect the module to a solderable SIM chip without SIM presence detection: Connect the UICC / SIM contact C1 (VCC) to the VSIM or the VSIM1 pin of the module. Connect the UICC / SIM contact C7 (I/O) to the SIM_IO or the SIM1_IO pin of the module. Connect the UICC / SIM contact C3 (CLK) to the SIM_CLK or the SIM1_CLK pin of the module. Connect the UICC / SIM contact C2 (RST) to the SIM_RST or the SIM1_RST pin of the module. Connect the UICC / SIM contact C5 (GND) to ground. Provide a 100 nF bypass capacitor (e.g. Murata GRM155R71C104K) at the SIM supply line close to the relative pad of the SIM chip, to prevent digital noise. Provide a bypass capacitor of about 22 pF to 47 pF (e.g. Murata GRM1555C1H470J) on each SIM line, to prevent RF coupling especially when the RF antenna is placed closer than 10 - 30 cm from the SIM lines. Limit the capacitance and series resistance on each SIM signal to match the SIM requirements (20.5 ns is the maximum rise time on the clock line, 1.0 µs is the maximum rise time on the data and reset lines). TOBY-L4 seriesVSIMxSIMx_IOSIMx_CLKSIMx_RSTSIM CHIPSIM ChipBottom View (contacts side)C1VPP (C6)VCC (C1)IO (C7)CLK (C3)RST (C2)GND (C5)C2 C3 C5U1C4283671C1 C5C2 C6C3 C7C4 C887651234 Figure 38: Application circuits for the connection to a single solderable SIM chip, with SIM detection not implemented Reference Description Part Number - Manufacturer C1, C2, C3, C4 47 pF Capacitor Ceramic C0G 0402 5% 50 V GRM1555C1H470JA01 - Murata C5 100 nF Capacitor Ceramic X7R 0402 10% 16 V GRM155R71C104KA01 - Murata U1 SIM chip (M2M UICC Form Factor) Various Manufacturers Table 29: Example of components for the connection to a single solderable SIM chip, with SIM detection not implemented](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-81.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 82 of 143 Guidelines for single SIM card connection with detection If the optional SIM card detection feature is required by the application, then a removable SIM card placed in a SIM card holder must be connected to the SIM0 interface of TOBY-L4 series modules as illustrated in Figure 39: Follow these guidelines to connect the module to a SIM connector implementing SIM presence detection: Connect the UICC / SIM contact C1 (VCC) to the VSIM pin of the module. Connect the UICC / SIM contact C7 (I/O) to the SIM_IO pin of the module. Connect the UICC / SIM contact C3 (CLK) to the SIM_CLK pin of the module. Connect the UICC / SIM contact C2 (RST) to the SIM_RST pin of the module. Connect the UICC / SIM contact C5 (GND) to ground. Connect one pin of the normally-open mechanical switch integrated in the SIM connector (e.g. the SW2 pin as illustrated in Figure 39) to the GPIO5 input pin of the module. Connect the other pin of the normally-open mechanical switch integrated in the SIM connector (e.g. the SW1 pin as illustrated in Figure 39) to the V_INT 1.8 V supply output of the module by means of a strong (e.g. 1 k) pull-up resistor, as the R1 resistor in Figure 39. Provide a weak (e.g. 470 k) pull-down resistor at the SIM detection line, as the R2 resistor in Figure 39. Provide a 100 nF bypass capacitor (e.g. Murata GRM155R71C104K) at the SIM supply line, close to the related pad of the SIM connector, to prevent digital noise. Provide a bypass capacitor of about 22 pF to 47 pF (e.g. Murata GRM1555C1H470J) on each SIM line, very close to each related pad of the SIM connector, to prevent RF coupling especially when the RF antenna is placed closer than 10 - 30 cm from the SIM card holder. Provide a very low capacitance (i.e. less than 10 pF) ESD protection (e.g. Tyco PESD0402-140) on each externally accessible SIM line, close to each related pad of the SIM connector: ESD sensitivity rating of the SIM interface pins is 1 kV (HBM), so that, according to the EMC/ESD requirements of the custom application, a higher protection level can be required if the lines are externally accessible on the application device. Limit the capacitance and series resistance on each SIM signal to match the SIM requirements (20.5 ns is the maximum rise time on the clock line, 1.0 µs is the maximum rise time on the data and reset lines). TOBY-L4 series5V_INT60GPIO5SIM CARD HOLDERC5C6C7C1C2C3SIM Card Bottom View (contacts side)C1VPP (C6)VCC (C1)IO (C7)CLK (C3)RST (C2)GND (C5)C2 C3 C5J1C4SW1SW2D1 D2 D3 D4 D5 D6R2R1C8C4TP59VSIM57SIM_IO56SIM_CLK58SIM_RST Figure 39: Application circuit for the connection to a single removable SIM card, with SIM detection implemented Reference Description Part Number - Manufacturer C1, C2, C3, C4 47 pF Capacitor Ceramic C0G 0402 5% 50 V GRM1555C1H470JA01 - Murata C5 100 nF Capacitor Ceramic X7R 0402 10% 16 V GRM155R71C104KA01 - Murata D1, … , D6 Very Low Capacitance ESD Protection PESD0402-140 - Tyco Electronics R1 1 k Resistor 0402 5% 0.1 W RC0402JR-071KL - Yageo Phycomp R2 470 k Resistor 0402 5% 0.1 W RC0402JR-07470KL- Yageo Phycomp J1 SIM Card Holder, 6 + 2 p, with card presence switch Various manufacturers, as CCM03-3013LFT R102 - C&K Table 30: Example of components for the connection to a single removable SIM card, with SIM detection implemented](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-82.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 83 of 143 Guidelines for dual SIM card / chip connection Two SIM cards / chips can be connected to the SIM interfaces of TOBY-L4 modules as illustrated in Figure 40. TOBY-L4 series modules do not support the usage of two SIMs at the same time, but two SIMs can be populated on the application board: connecting the first SIM to the SIM0 interface of the module and connecting the second SIM to the SIM1 interface of the module, as illustrated in Figure 40 top side In this case, the SIM interface and the related external SIM card / chip to be used can be selected by means of the AT+XSIMSWITCH command (see u-blox AT Commands Manual [2]) or by means of uCPU application, performing the SIM switch operation providing a suitable switch to connect only the first or only the second SIM at a time to the SIM0 interface of the module, as illustrated in Figure 40 bottom side In this case, if the SIM hot insertion / removal feature is enabled on the GPIO5 pin by AT commands (see sections 1.8.2 and 1.13, and the u-blox AT Commands Manual [2], +UGPIOC, +UDCONF=50 commands) or by means of uCPU application, than the switch from the first to the second external SIM can be properly done when a Low logic level is present on the GPIO5 pin (“SIM not inserted” = SIM interface not enabled), without the necessity of a module re-boot, so that the SIM interface will be re-enabled by the module to use the second SIM when a high logic level is re-applied on the GPIO5 pin. The application processor will drive the SIM switch using its own GPIO to properly select the SIM that is used by the module. Another GPIO may be used to handle the SIM hot insertion / removal function of TOBY-L4 series modules, which can also be handled by other external circuits or by the cellular module GPIO according to the application requirements. The dual SIM connection circuit illustrated in Figure 40 can be implemented for SIM chips as well. If it is required to switch between more than 2 SIMs, a circuit similar to the one illustrated in Figure 40 bottom side can be implemented, using suitable switches. Follow these guidelines to connect the module to two external UICC / SIM: Connect the contact C1 (VCC) of the first external UICC / SIM to the VSIM pin of the module and the one of the second external UICC / SIM to the VSIM1 pin of the module. Connect the contact C7 (I/O) of the first external UICC / SIM to the SIM_IO pin of the module and the one of the second external UICC / SIM to the SIM1_IO pin of the module. Connect the contact C3 (CLK) of the first external UICC / SIM to the SIM_CLK pin of the module and the one of the second external UICC / SIM to the SIM1_CLK pin of the module. Connect the contact C2 (RST) of the first external UICC / SIM to the SIM_RST pin of the module and the one of the second external UICC / SIM to the SIM1_RST pin of the module. Connect the contact C5 (GND) of each external UICC / SIM to ground. Provide a 100 nF bypass capacitor (e.g. Murata GRM155R71C104K) at the SIM supply (VSIM / VSIM1), close to the related pad of each external UICC / SIM, to prevent digital noise. Provide a bypass capacitor of about 22 pF to 47 pF (e.g. Murata GRM1555C1H470J) on each SIM line, very close to each related pad of each external SIM connector, to prevent RF coupling especially when the RF antenna is placed closer than 10 - 30 cm from the SIM card holders. Provide a very low capacitance (i.e. less than 10 pF) ESD protection (e.g. Tyco Electronics PESD0402-140) on each externally accessible SIM line, close to each pad of each external SIM connector, according to the EMC/ESD requirements of the custom application. Limit the capacitance and series resistance on each SIM signal to match the SIM requirements (20.5 ns is the maximum rise time on the clock line, 1.0 µs is the maximum rise time on the data and reset lines). If a circuit as the one illustrated in Figure 40 bottom side is implemented, use a suitable low on resistance (i.e. few ohms) and low on capacitance (i.e. few pF) 2-throw analog switch (e.g. Fairchild FSA2567) as SIM switch to ensure high-speed data transfer according to SIM requirements.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-83.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 84 of 143 TOBY-L4 seriesC1FIRST SIM CARDVPP (C6)VCC (C1)IO (C7)CLK (C3)RST (C2)GND (C5)C2 C3 C5J1C4 D1 D2 D3 D459VSIM57SIM_IO56SIM_CLK58SIM_RSTSECOND SIM CARDVPP (C6)VCC (C1)IO (C7)CLK (C3)RST (C2)GND (C5)J2C6 C7 C8 C10C9 D5 D6 D7 D8182SIM1_CLK172VSIM1178SIM1_IO177SIM1_RSTTOBY-L4 seriesC1FIRST SIM CARDVPP (C6)VCC (C1)IO (C7)CLK (C3)RST (C2)GND (C5)C2 C3 C5J1C4 D1 D2 D3 D4GNDU159VSIM VSIM 1VSIM2VSIMVCCC114PDT Analog Switch3V857SIM_IO DAT 1DAT2DAT56SIM_CLK CLK 1CLK2CLK58SIM_RST RST 1RST2RSTSELSECOND SIM CARDVPP (C6)VCC (C1)IO (C7)CLK (C3)RST (C2)GND (C5)J2C6 C7 C8 C10C9 D5 D6 D7 D8Application ProcessorGPIOR1 Figure 40: Application circuits for the connection to two removable SIM cards, with SIM detection not implemented Reference Description Part Number – Manufacturer C1 – C4, C6 – C9 33 pF Capacitor Ceramic C0G 0402 5% 25 V GRM1555C1H330JZ01 – Murata C5, C10, C11 100 nF Capacitor Ceramic X7R 0402 10% 16 V GRM155R71C104KA01 – Murata D1 – D8 Very Low Capacitance ESD Protection PESD0402-140 - Tyco Electronics R1 47 k Resistor 0402 5% 0.1 W RC0402JR-0747KL- Yageo Phycomp J1, J2 SIM Card Holder, 6 + 2 p., with card presence switch CCM03-3013LFT R102 - C&K Components U1 4PDT Analog Switch, with Low On-Capacitance and Low On-Resistance FSA2567 - Fairchild Semiconductor Table 31: Example of components for the connection to two removable SIM cards, with SIM detection not implemented](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-84.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 85 of 143 2.5.2 Guidelines for SIM layout design The layout of the SIM card interfaces lines (VSIM, SIM_CLK, SIM_IO, SIM_RST for the SIM0 interface, and VSIM1, SIM1_IO, SIM1_CLK, SIM1_RST for the SIM1 interface) may be critical if the SIM card is placed far away from the TOBY-L4 series modules or in close proximity to the RF antenna: these two cases should be avoided or at least mitigated as described below. In the first case, the long connection can cause the radiation of some harmonics of the digital data frequency as any other digital interface. It is recommended to keep the traces short and avoid coupling with the RF line or sensitive analog inputs. In the second case, the same harmonics can be picked up and create self-interference that can reduce the sensitivity of LTE/3G/2G receiver channels whose carrier frequency is coincidental with the harmonic frequencies. It is strongly recommended to place the RF bypass capacitors suggested in Figure 37 near the SIM connector. In addition, since the SIM card is typically accessed by the end user, it can be subjected to ESD discharges. Add adequate ESD protection as suggested to protect the module SIM pins near the SIM connector. Limit the capacitance and series resistance on each SIM signal to match the SIM specifications. The connections should always be kept as short as possible. Avoid coupling with any sensitive analog circuit, since the SIM signals can cause the radiation of some harmonics of the digital data frequency.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-85.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 86 of 143 2.6 Data communication interfaces 2.6.1 USB interface 2.6.1.1 Guidelines for USB circuit design Different application circuits can be implemented for the USB interface according to specific use-case: USB 2.0 interface, with the module acting as USB device, as illustrated in Figure 41 and Table 32 USB 2.0 interface, with the module acting as USB host, as illustrated in Figure 42 and Table 33 USB 3.0 interface, with the module acting as USB device, as illustrated in Figure 43 and Table 34 USB pull-up or pull-down resistors and external series resistors on the USB_D+ and USB_D– lines as required by the USB 2.0 specification [3] are part of the module USB pins driver and do not need to be externally provided. Series DC decoupling capacitors are internally provided on the USB_SSTX+ and USB_SSTX– lines as required by the USB 3.0 specification [4] and do not need to be externally provided. The USB_SSTX+/USB_SSTX– USB Super-Speed differential transmitter data output lines of the module must be connected to the USB Super-Speed differential receiver data input lines of the external USB 3.0 host. The USB_SSRX+/USB_SSRX– USB Super-Speed differential receiver data input lines of the module must be connected to the USB Super-Speed differential transmitter data output lines of the external USB 3.0 host, with series DC decoupling capacitors being provided on the host side as per the USB 3.0 specification [4]. Routing the USB pins to a connector, they will be externally accessible on the application device. According to the EMC/ESD requirements of the application, an additional ESD protection device with very low capacitance should be provided close to the accessible point on the line connected to this pin. The USB interface pins ESD sensitivity rating is 1 kV (Human Body Model according to JESD22-A114F). A higher protection level could be required if the lines are externally accessible and it can be achieved by mounting a very low capacitance (i.e. less or equal to 1 pF) ESD protection (e.g. Tyco Electronics PESD0402-140 ESD protection device) on the lines connected to these pins, close to the accessible points. The USB pins of the modules can be directly connected to the USB host application processor without additional ESD protections if they are not externally accessible or according to EMC/ESD requirements. D+D–GND28 USB_D+27 USB_D–GNDUSB 2.0 DEVICE CONNECTORVBUSD+D–GNDUSB 2.0 HOST PROCESSORTOBY-L4 series VBUS4VUSB_DETD1 D2 D3 C1 C128 USB_D+27 USB_D–GNDTOBY-L4 series 4VUSB_DET168 USB_ID168 USB_ID170 USB_SSRX+171 USB_SSRX–175 USB_SSTX+176 USB_SSTX–170 USB_SSRX+171 USB_SSRX–175 USB_SSTX+176 USB_SSTX– Figure 41: USB 2.0 interface application circuits, with TOBY-L4 series module acting as a USB device Reference Description Part Number - Manufacturer C1 100 nF Capacitor Ceramic X7R 0402 10% 16 V GRM155R61A104KA01 - Murata D1, D2, D3 Very Low Capacitance ESD Protection PESD0402-140 - Tyco Electronics Table 32: Component for USB 2.0 interface application circuits, with TOBY-L4 series module acting as a USB device](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-86.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 87 of 143 D+D–GND28 USB_D+27 USB_D–GNDUSB 2.0 HOST CONNECTORVBUSD+D–GNDUSB 2.0 DEVICE PROCESSORTOBY-L4 series VBUS4VUSB_DETD1 D2 D3 C2 C228 USB_D+27 USB_D–GNDTOBY-L4 series 4VUSB_DET168 USB_ID168 USB_ID170 USB_SSRX+171 USB_SSRX–175 USB_SSTX+176 USB_SSTX–170 USB_SSRX+171 USB_SSRX–175 USB_SSTX+176 USB_SSTX–BoostINOUTBoostINOUTC15V 5VC1VCC VCCU1 U1 Figure 42: USB 2.0 interface application circuits, with TOBY-L4 series module acting as a USB host Reference Description Part Number - Manufacturer C1, C2 10 µF Capacitor Ceramic X7R 5750 15% 50 V C5750X7R1H106MB - TDK D1, D2, D3 Very Low Capacitance ESD Protection PESD0402-140 - Tyco Electronics U1 DC/DC Boost Regulator Various Manufacturer Table 33: Component for USB 2.0 interface application circuits, with TOBY-L4 series module acting as a USB host D+D–GND28 USB_D+27 USB_D–GNDUSB 3.0 DEVICE CONNECTORVBUSD+D–GNDUSB 2.0 HOST PROCESSORTOBY-L4 series VBUS4VUSB_DETD1 D2 D3 C1 C128 USB_D+27 USB_D–GNDTOBY-L4 series 4VUSB_DET168 USB_ID168 USB_ID170 USB_SSRX+171 USB_SSRX–175 USB_SSTX+176 USB_SSTX–170 USB_SSRX+171 USB_SSRX–175 USB_SSTX+176 USB_SSTX–SSRX+SSRX–SSTX+SSTX–C3SSTX+SSTX–SSRX+SSRX–C2 Figure 43: USB 3.0 interface application circuits, with TOBY-L4 series module acting as a USB device Reference Description Part Number - Manufacturer C1, C2, C3 100 nF Capacitor Ceramic X7R 0402 10% 16 V GRM155R61A104KA01 - Murata D1, D2, D3 Very Low Capacitance ESD Protection PESD0402-140 - Tyco Electronics Table 34: Component for USB 3.0 interface application circuits, with TOBY-L4 series module acting as a USB device USB High-Speed 2.0 host role is not supported by the "50" product versions. USB Super-Speed 3.0 compliant interface will be supported by future firmware versions. If the USB interface pins are not used, they can be left unconnected on the application board, but it is recommended to provide accessible test points directly connected to the VUSB_DET, USB_D+, USB_D– pins, for diagnostic and FW update purposes.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-87.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 88 of 143 2.6.1.2 Guidelines for USB layout design The USB_D+/USB_D–, USB_SSTX+/USB_SSTX– and USB_SSRX+/USB_SSRX– lines require accurate layout design to achieve reliable signaling at the high speed data rates (up to 480 Mbit/s or up to 5 Gbit/s) supported by the USB 2.0 or USB 3.0 interface. The characteristic impedance of the USB_D+/USB_D–, USB_SSTX+/USB_SSTX– and USB_SSRX+/USB_SSRX– lines is specified by the USB 2.0 specification [3] and the USB 3.0 specification [4]. The most important parameter is the differential characteristic impedance applicable for the odd-mode electromagnetic field, which should be as close as possible to 90 differential. Signal integrity may be degraded if the PCB layout is not optimal, especially when the USB signaling lines are very long. Use the following general routing guidelines to minimize signal quality problems: Route USB_D+/USB_D–, USB_SSTX+/USB_SSTX– and USB_SSRX+/USB_SSRX– lines as a differential pair Route USB_D+/USB_D–, USB_SSTX+/USB_SSTX– and USB_SSRX+/USB_SSRX– lines as short as possible Ensure the differential characteristic impedance (Z0) is as close as possible to 90 Ensure the common mode characteristic impedance (ZCM) is as close as possible to 30 Consider design rules for USB_D+/USB_D–, USB_SSTX+/USB_SSTX– and USB_SSRX+/USB_SSRX– similar to RF transmission lines, these being coupled differential micro-strip or buried stripline: avoid any stubs, abrupt change of layout, and route on clear PCB area Figure 44 and Figure 45 provide two examples of coplanar waveguide designs with differential characteristic impedance close to 90 and common mode characteristic impedance close to 30 . The first transmission line can be implemented for a 4-layer PCB stack-up herein illustrated; the second transmission line can be implemented for a 2-layer PCB stack-up herein illustrated. 35 µm35 µm35 µm35 µm270 µm270 µm760 µmL1 CopperL3 CopperL2 CopperL4 CopperFR-4 dielectricFR-4 dielectricFR-4 dielectric350 µm 400 µm400 µm350 µm400 µm Figure 44: Example of USB line design, with Z0 close to 90 and ZCM close to 30 , for the described 4-layer board layup 35 µm35 µm1510 µmL2 CopperL1 CopperFR-4 dielectric740 µm 410 µm410 µm740 µm410 µm Figure 45: Example of USB line design, with Z0 close to 90 and ZCM close to 30 , for the described 2-layer board layup](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-88.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 89 of 143 2.6.2 UART interfaces UART interfaces are not supported by the "50" product version, except for trace logging (diagnostic purposes) and Ring Indicator functionality over the UART0 interface. 2.6.2.1 Guidelines for UART circuit design 4-wire UART If RS-232 compatible signal levels are needed, the Maxim MAX13234E voltage level translator can be used. This chip translates voltage levels from 1.8 V (module side) to the RS-232 standard. If a 1.8 V external Processor / Device is used, the circuit should be implemented as illustrated in Figure 46. TxD1.8V Processor / DeviceRxDRTSCTSGNDTOBY-L4 series TXDxRXDxRTSxCTSxGND0ΩTP0ΩTP Figure 46: 4-wire UART interface application circuit to connect an external 1.8 V processor / device If a 3.0 V external Processor / Device is used, then it is recommended to connect the 1.8 V UART interface of the module by means of appropriate unidirectional voltage translators using the module V_INT output as a 1.8 V supply for the voltage translators on the module side, as illustrated in Figure 47. 5V_INTTxD3V Processor / DeviceRxDRTSCTSGNDTOBY-L4 series TXDxRXDxRTSxCTSxGND1V8B1 A1GNDU1B3A3VCCBVCCAUnidirectionalVoltage TranslatorC1 C23V0DIR3DIR2 OEDIR1VCCB2 A2B4A4DIR4TP0ΩTP0ΩTP Figure 47: 4-wire UART interface application circuit to connect an external 3.0V processor / device Reference Description Part Number - Manufacturer C1, C2 100 nF Capacitor Ceramic X7R 0402 10% 16 V GRM155R61A104KA01 - Murata U1 Unidirectional Voltage Translator SN74AVC4T77416 - Texas Instruments Table 35: Component for 4-wire UART interface application circuit to connect an external 3.0V processor / device Test-Points for diagnostic access are recommended to be provided on the UART0 TXD and RXD lines. They are not required on other UART lines. 16 Voltage translator providing partial power down feature so that the external 3.0 V supply can be ramped up before the V_INT 1.8 V supply](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-89.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 90 of 143 2-wire UART If the functionality of the CTSx and RTSx are not required in the application, or the lines are not available, then: Consider to connect the module RTSx input line to GND or to the CTSx output line of the module, since the module requires RTSx active (low electrical level) if HW flow-control is enabled If RS-232 compatible signal levels are needed, the Maxim MAX13234E voltage level translator can be used. This chip translates voltage levels from 1.8 V (module side) to the RS-232 standard. If a 1.8 V external Processor / Device is used, the circuit that should be implemented as illustrated in Figure 48. TxD1.8V Processor / DeviceRxDGNDTOBY-L4 series TXDxRXDxGND0ΩTP0ΩTP Figure 48: 2-wire UART interface application circuit to connect an external 1.8V processor / device If a 3.0 V external Processor / Device is used, then it is recommended to connect the 1.8 V UART interface of the module by means of appropriate unidirectional voltage translators using the module V_INT output as a 1.8 V supply for the voltage translators on the module side, as illustrated in Figure 49. 5V_INTTxD3V Processor / DeviceRxDGNDTOBY-L4 series TXDxRXDxGND1V8B1 A1GNDU1VCCBVCCAUnidirectionalVoltage TranslatorC1 C23V0DIR1DIR2OEVCCB2 A2TP0ΩTP0ΩTP Figure 49: 2-wire UART interface application circuit to connect an external 3.0 V processor / device Reference Description Part Number - Manufacturer C1, C2 100 nF Capacitor Ceramic X7R 0402 10% 16 V GRM155R61A104KA01 - Murata U1 Unidirectional Voltage Translator SN74AVC2T24517 - Texas Instruments Table 36: Component for 2-wire UART interface application circuit to connect an external 3.0 V processor / device Test-Points for diagnostic access are recommended to be provided on the UART0 TXD and RXD lines for diagnostic purposes. Test-Points are not required on other UART lines. 17 Voltage translator providing partial power down feature so that the external 3.0 V supply can be ramped up before V_INT 1.8 V supply](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-90.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 91 of 143 Ring Indicator If a 1.8 V external Processor / Device is used, the Ring Indicator circuit should be implemented as illustrated in Figure 50. 1.8V Processor / DeviceRIGNDTOBY-L4 series 11 RIGND Figure 50: Ring Indicator application circuit to connect an external 1.8V processor / device If a 3.0 V external Processor / Device is used, then it is recommended to connect the 1.8 V Ring Indicator output of the module by means of appropriate unidirectional voltage translators using the module V_INT output as a 1.8 V supply for the voltage translator on the module side, as illustrated in Figure 51. 5V_INTRI3V Processor / DeviceGNDTOBY-L4 series 11 RIGND1V8B1 A1GNDU1VCCBVCCAUnidirectionalVoltage TranslatorC1 C23V0DIR2OEVCCB2 A2TPDIR1 Figure 51: Ring Indicator application circuit to connect an external 3.0V processor / device Reference Description Part Number - Manufacturer C1, C2 100 nF Capacitor Ceramic X7R 0402 10% 16 V GRM155R61A104KA01 - Murata U1 Unidirectional Voltage Translator SN74AVC2T24518 - Texas Instruments Table 37: Component for the Ring Indicator application circuit to connect an external 3.0V processor / device 18 Voltage translator providing partial power down feature so that the external 3.0 V supply can be ramped up before the V_INT 1.8 V supply](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-91.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 92 of 143 Additional considerations If a 3.0 V external Processor / Device is used, the voltage scaling from any 3.0 V output of the external Processor / Device to the corresponding 1.8 V input of the module can be implemented as an alternative low-cost solution, by means of an appropriate voltage divider. Consider the value of the pull-up integrated at the input of the module for the correct selection of the voltage divider resistance values and mind that any DTE signal connected to the module must be tri-stated or set low when the module is in power-down mode and during the module power-on sequence (at least until the activation of the V_INT supply output of the module), to avoid latch-up of circuits and allow a clean boot of the module (see the remark below). Moreover, the voltage scaling from any 1.8 V output of the cellular module to the corresponding 3.0 V input of the external Processor / Device can be implemented by means of an appropriate low-cost non-inverting buffer with open drain output. The non-inverting buffer should be supplied by the V_INT supply output of the cellular module. Consider the value of the pull-up integrated at each input of the external Processor / Device (if any) and the baud rate required by the application for the appropriate selection of the resistance value for the external pull-up biased by the application processor supply rail. Do not apply voltage to any UART interfaces pin before the switch-on of the UART supply source (V_INT), to avoid latch-up of circuits and allow a clean boot of the module. The ESD sensitivity rating of UART interfaces pins is 1 kV (Human Body Model according to JESD22-A114). A higher protection level could be required if the lines are externally accessible and it can be achieved by mounting an ESD protection (e.g. EPCOS CA05P4S14THSG varistor array) close to the accessible points. If the UART interfaces pins are not used, they can be left unconnected on the application board, but it is recommended to provide accessible test points directly connected to the UART0 TXD and RXD pins for diagnostic purposes. 2.6.2.2 Guidelines for UART layout design The UART serial interface requires the same considerations regarding electro-magnetic interference as any other digital interface. Keep the traces short and avoid coupling with RF line or sensitive analog inputs, since the signals can cause the radiation of some harmonics of the digital data frequency.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-92.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 93 of 143 2.6.3 SPI interfaces SPI interfaces are not supported by the "50" product version. 2.6.3.1 Guidelines for SPI circuit design TOBY-L4 series modules include up to two 1.8 V Serial Peripheral Interfaces to communicate with external SPI slave devices, with the module acting as SPI master, by means of the uCPU API. Figure 52 describes a possible application circuit for the SPI0 interface, where two SPI slave devices are connected to the module using the two SPI0 Chip Select 0 (SPI_CS pin) and SPI0 Chip Select 1 (GPIO4 pin) to select the specific SPI slave device. The external SPI slave device must provide compatible voltage levels (1.80 V typ.), otherwise it is recommended to connect the 1.8 V SPI interface of the module to the external 3.0 V (or similar) SPI device by means of appropriate unidirectional voltage translators (e.g. TI SN74AVC4T774 or SN74AVC2T245, providing partial power down feature so that the digital audio device 3.0 V supply can be also ramped up before V_INT 1.8 V supply), using the module’s V_INT output as a 1.8 V supply for the voltage translators on the module side. TOBY-L4 series(Master, 1.8V)SCLKCSMOSIMISOGNDSPI_SCLKSPI_CSSPI_MOSISPI_MISOSPI Device(Slave, 1.8V)GNDSCLKCSMOSIMISOSPI Device(Slave, 1.8V)GNDGPIO4 Figure 52: SPI interface application circuit for connecting two external SPI slave devices Do not apply voltage to any SPI interface pins before the switch-on of the SPI supply source (V_INT), to avoid latch-up of circuits and allow a clean boot of the module. The ESD sensitivity rating of SPI interfaces pins is 1 kV (Human Body Model according to JESD22-A114). A higher protection level could be required if the lines are externally accessible and it can be achieved by mounting an ESD protection (e.g. EPCOS CA05P4S14THSG varistor array) close to the accessible points. If the SPI interfaces pins are not used, they can be left unconnected on the application board. 2.6.3.2 Guidelines for SPI layout design The SPI serial interface requires the same considerations regarding electro-magnetic interference as any other digital interface. Keep the traces short and avoid coupling with RF line or sensitive analog inputs, since the signals can cause the radiation of some harmonics of the digital data frequency.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-93.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 94 of 143 2.6.4 DDC (I2C) interfaces DDC (I2C) interfaces are not supported by the "50" product version. 2.6.4.1 General guidelines for DDC (I2C) circuit design The DDC I2C-bus pins of the module are open drain outputs conforming to the I2C bus specifications [6]. External pull-up resistors to a suitable 1.8 V supply (e.g. V_INT) are required for operations: for example, 4.7 k resistors can be commonly used. Connect the DDC (I2C) pull-ups to the V_INT 1.8 V supply source, or another 1.8 V supply source enabled after V_INT (e.g., as the GNSS 1.8 V supply present in Figure 54 application circuit), as any external signal connected to the DDC (I2C) interface must not be set high before the switch-on of the V_INT supply of DDC (I2C) pins, to avoid latch-up of circuits and allow a clean boot of the module. The signal shape is defined by the values of the pull-up resistors and the bus capacitance. Long wires on the bus will increase the capacitance. If the bus capacitance is increased, use pull-up resistors with a nominal resistance value lower than 4.7 k, to match the I2C bus specifications [6] regarding the rise and fall times of the signals. Figure 53 and Table 38 describe typical application circuits for connecting TOBY-L4 series modules to 1.8 V I2C devices (see Figure 53 top side) or 3 V I2C devices (see Figure 53 bottom side). 1.8V I2C DeviceSDASCL1V85V_INTR1 R21V8 1V8SDAxSCLxTOBY-L4 seriesR1 R23V0SDAxSCLxR3 R41V8SDA_A SDA_BGNDU1SCL_ASCL_BVCCAVCCBI2C-bus Bidirectional Voltage Translator5V_INTC1 C2SDASCLOEGND GND3V I2C Device TOBY-L4 seriesGND GND Figure 53: Application circuit for connecting TOBY-L4 series modules to 1.8 V or 3 V I2C devices Reference Description Part Number - Manufacturer R1, R2, R3, R4 4.7 k Resistor 0402 5% 0.1 W RC0402JR-074K7L - Yageo Phycomp C1, C2 100 nF Capacitor Ceramic X7R 0402 10% 16 V GRM155R71C104KA01 - Murata U1 I2C-bus Bidirectional Voltage Translator TCA9406DCUR19 - Texas Instruments Table 38: Components for connecting TOBY-L4 series modules to 1.8 V or 3 V I2C devices The ESD sensitivity rating of the DDC (I2C) pins is 1 kV (Human Body Model according to JESD22-A114). A higher protection level could be required if the lines are externally accessible and it can be achieved by mounting an ESD protection (e.g. EPCOS CA05P4S14THSG varistor array) close to the accessible points. If the pins are not used as DDC bus interface, they can be left unconnected. 19 Voltage translator providing partial power down feature so that the external 3 V supply can be also ramped up before V_INT 1.8 V supply](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-94.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 95 of 143 Connection with u-blox 1.8 V GNSS receivers Figure 54 shows an application circuit for connecting the cellular modules to a u-blox 1.8 V GNSS receiver. SDA / SCL pins of the cellular module are directly connected to the relative I2C pins of the u-blox 1.8 V GNSS receiver, with appropriate pull-up resistors connected to the 1.8 V GNSS supply enabled after the V_INT supply of the I2C pins of the cellular module. GPIO2 pin is connected to the shutdown input pin (SHDNn) of the LDO regulators providing the 1.8 V supply rail for the u-blox 1.8 V GNSS receiver implementing the “GNSS enable” function, with an appropriate pull-down resistor mounted on the GPIO2 line to avoid an improper switch-on of the u-blox GNSS receiver. GPIO3 and GPIO4 pins are directly connected respectively to the TXD1 and EXTINT0 pins of the u-blox 1.8 V GNSS receiver providing “GNSS Tx data ready” and “GNSS RTC sharing” functions. R1INOUTGNDGNSS LDORegulatorSHDNnu-blox GNSS1.8 V receiverSDA2SCL2R21V8 1V8VMAIN1V8U122 GPIO2SDASCLC1TxD1 GPIO3555424VCCR3GNSS Tx data readyGNSS supply enabledTOBY-L4 seriesEXTINT0 GPIO425GNSS RTC sharing Figure 54: Application circuit for connecting TOBY-L4 series modules to u-blox 1.8 V GNSS receivers Reference Description Part Number - Manufacturer R1, R2 4.7 k Resistor 0402 5% 0.1 W RC0402JR-074K7L - Yageo Phycomp R3 47 k Resistor 0402 5% 0.1 W RC0402JR-0747KL - Yageo Phycomp U1, C1 Voltage Regulator for GNSS receiver and capacitor See GNSS receiver Hardware Integration Manual Table 39: Components for connecting TOBY-L4 series modules to u-blox 1.8 V GNSS receivers Custom functions over GPIO pins, to improve the integration with u-blox positioning chips and modules, will be supported by future firmware versions.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-95.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 96 of 143 Figure 55 illustrates an alternative application circuit solution in which the cellular module supplies a u-blox 1.8 V GNSS receiver. The V_INT 1.8 V regulated supply output of the cellular module can be used as supply source for a u-blox 1.8 V GNSS receiver (u-blox 6 generation receiver or newer) instead of using an external voltage regulator, as shown in Figure 54. The V_INT supply is able to support the maximum current consumption of these positioning receivers. The internal switching step-down regulator that generates the V_INT supply is set to 1.8 V (typical) when the cellular module is switched on and it is disabled when the module is switched off. The supply of the u-blox 1.8 V GNSS receiver can be switched off using an external p-channel MOS controlled by the GPIO2 pin of the cellular modules by means of a suitable inverting transistor as shown in Figure 55, implementing the “GNSS supply enable” function. If this feature is not required, the V_INT supply output can be directly connected to the u-blox 1.8 V GNSS receiver, so that it will switch on when V_INT output is enabled. According to the V_INT supply output voltage ripple characteristic specified in the TOBY-L4 series Data Sheet [1]: Additional filtering may be needed to properly supply an external LNA, depending on the characteristics of the used LNA, adding a series ferrite bead and a bypass capacitor (e.g. the Murata BLM15HD182SN1 ferrite bead and the Murata GRM1555C1H220J 22 pF capacitor) at the input of the external LNA supply line. u-blox GNSS1.8 V receiverTxD1SDA2SCL2VCC1V8C1R35V_INTR5R4TPT2T1R1 R21V8 1V8GNSS data readyGNSS supply enabled 22 GPIO2SDASCLGPIO3555424TOBY-L4 seriesEXTINT0 GPIO425GNSS RTC sharing Figure 55: Application circuit for connecting TOBY-L4 series modules to u-blox 1.8 V GNSS receivers using V_INT as supply Reference Description Part Number - Manufacturer R1, R2 4.7 k Resistor 0402 5% 0.1 W RC0402JR-074K7L - Yageo Phycomp R3 47 k Resistor 0402 5% 0.1 W RC0402JR-0747KL - Yageo Phycomp R4 10 k Resistor 0402 5% 0.1 W RC0402JR-0710KL - Yageo Phycomp R5 100 k Resistor 0402 5% 0.1 W RC0402JR-07100KL - Yageo Phycomp T1 P-Channel MOSFET Low On-Resistance IRLML6401 - International Rectifier or NTZS3151P - ON Semi T2 NPN BJT Transistor BC847 - Infineon C1 100 nF Capacitor Ceramic X7R 0402 10% 16 V GRM155R71C104KA01 - Murata Table 40: Components for connecting TOBY-L4 series modules to u-blox 1.8 V GNSS receivers using V_INT as supply Custom functions over GPIO pins, to improve the integration with u-blox positioning chips and modules, will be supported by future firmware versions.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-96.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 97 of 143 Connection with u-blox 3.0 V GNSS receivers Figure 56 shows an application circuit for connecting the cellular modules to a u-blox 3.0 V GNSS receiver: As the SDA and SCL pins of the cellular module are not tolerant up to 3.0 V, the connection to the related I2C pins of the u-blox 3.0 V GNSS receiver must be provided using a suitable I2C-bus Bidirectional Voltage Translator with appropriate pull-up resistors (e.g. the TI TCA9406 additionally provides the partial power down feature so that the GNSS 3.0 V supply can be ramped up before the V_INT 1.8 V cellular supply). GPIO2 pin is connected to the shutdown input pin (SHDNn) of the LDO regulators providing the 3.0 V supply rail for the u-blox 3.0 V GNSS receiver implementing the “GNSS enable” function, with an appropriate pull-down resistor mounted on the GPIO2 line to avoid an improper switch-on of the u-blox GNSS receiver. As the GPIO3 and GPIO4 pins of the cellular module are not tolerant up to 3.0 V, the connection to the related pins of the u-blox 3.0 V GNSS receiver must be provided using a suitable Unidirectional General Purpose Voltage Translator (e.g. TI SN74AVC2T245, which additionally provides the partial power down feature so that the 3.0 V GNSS supply can be also ramped up before the V_INT 1.8 V cellular supply). u-blox GNSS 3.0 V receiver24 GPIO31V8B1 A1GNDU3B2A2VCCBVCCAUnidirectionalVoltage TranslatorC4 C53V0TxD1R1INOUTGNSS LDO RegulatorSHDNnR2VMAIN3V0U122 GPIO255 SDA54 SCLR4 R51V8SDA_A SDA_BGNDU2SCL_ASCL_BVCCAVCCBI2C-bus Bidirectional Voltage Translator5V_INTC1C2 C3R3SDA2SCL2VCCDIR1DIR2 OEnOEGNSS data readyGNSS supply enabledGNDTOBY-L4 seriesEXTINT0 GPIO425GNSS RTC sharing Figure 56: Application circuit for connecting TOBY-L4 series modules to u-blox 3.0 V GNSS receivers Reference Description Part Number - Manufacturer R1, R2, R4, R5 4.7 k Resistor 0402 5% 0.1 W RC0402JR-074K7L - Yageo Phycomp R3 47 k Resistor 0402 5% 0.1 W RC0402JR-0747KL - Yageo Phycomp C2, C3, C4, C5 100 nF Capacitor Ceramic X5R 0402 10% 10V GRM155R71C104KA01 - Murata U1, C1 Voltage Regulator for GNSS receiver and capacitor See GNSS receiver Hardware Integration Manual U2 I2C-bus Bidirectional Voltage Translator TCA9406DCUR - Texas Instruments U3 Generic Unidirectional Voltage Translator SN74AVC2T245 - Texas Instruments Table 41: Components for connecting TOBY-L4 series modules to u-blox 3.0 V GNSS receivers Custom functions over GPIO pins, to improve the integration with u-blox positioning chips and modules, will be supported by future firmware versions. 2.6.4.2 Guidelines for DDC (I2C) layout design The DDC (I2C) serial interface requires the same considerations regarding electro-magnetic interference as any other digital interface. Keep the traces short and avoid coupling with RF line or sensitive analog inputs, since the signals can cause the radiation of some harmonics of the digital data frequency.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-97.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 98 of 143 2.6.5 SDIO interface The SDIO interface is not supported by the "50" product version. 2.6.5.1 Guidelines for SDIO circuit design TOBY-L4 series modules include a 4-bit Secure Digital Input Output interface (SDIO_D0, SDIO_D1, SDIO_D2, SDIO_D3, SDIO_CLK, SDIO_CMD), where the module acts as an SDIO host controller designed to communicate with compatible u-blox short range radio communication modules by means of the uCPU API communicate with external SDIO devices by means of the uCPU API Connection with u-blox short range radio communication modules Figure 58 and Table 43 show an application circuit for connecting TOBY-L4 series cellular modules to u-blox EMMY-W161 short range radio communication modules supporting IEEE 802.11a/b/g/n/ac data rates for Wi-Fi: The SDIO pins of the cellular module are connected to the related SDIO pins of the u-blox EMMY-W161 short range radio communication module, with appropriate low value series damping resistors to avoid reflections and other losses in signal integrity, which may create ringing and loss of a square wave shape. The most appropriate value for the series damping resistors on the SDIO lines depends on the specific line lengths and layout implemented. In general, the SDIO series resistors are not strictly required, but it is recommended to slow the SDIO signal, for example with 22 or 33 resistors, and avoid any possible ringing problem without violating the rise / fall time requirements. The V_INT supply output pin of the cellular module is connected to the shutdown input pin (SHDNn) of the two LDO regulators providing the 3.3 V and 1.8 V supply rails for the u-blox EMMY-W161 module, with appropriate pull-down resistors to avoid an improper switch-on of the Wi-Fi module before the switch-on of the V_INT supply source of the cellular module SDIO interface pins. The GPIO1 pin of the cellular module is connected to the active low full power down input pin (PDn) of the u-blox EMMY-W161 module, implementing the Wi-Fi enable function. The WLAN antenna RF input/output (ANT1) of the u-blox EMMY-W161 Wi-Fi module is directly connected to a Wi-Fi antenna considering that the u-blox EMMY-W161 module integrates a 2.4 GHz BAW band pass filter that enables co-existence with LTE RF signals. R2LDO regulatorEMMY-W161Wi-Fi module3V3VCCU1C1R1SD_D019SD_D120SD_D221SD_D322SD_CLK17SD_CMD18OUTINSENSEBYPSHDNnGNDTOBY-L4 series cellular moduleSDIO_D0 66SDIO_D1 68SDIO_D2 63SDIO_D3 67SDIO_CLK 64SDIO_CMD 65V_INT 5C33V325C5LDO regulator 1V8VCCU2C2OUTINSENSEBYPSHDNnGND C4VIO126C6VIO227R3R4R5R6R7ANT1 45ANT2 40Wi-Fi antennaWi-Fi enable PDn28GPIO1 21GNDGND3V3Open Drain Buffer R8 Figure 57: Application circuit for TOBY-L4 cellular module and u-blox EMMY-W161 short range radio communication module](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-98.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 99 of 143 Reference Description Part Number - Manufacturer C1, C2 1 µF Capacitor Ceramic X7R 0603 10% 25 V GRM188R71E105KA12 - Murata C3, C4 10 nF Capacitor Ceramic X7R 0402 10% 16 V GRM155R71C103KA01 - Murata C5, C6 10 µF Capacitor Ceramic X5R 0603 20% 6.3 V GRM188R60J106ME47 - Murata R1 470 k Resistor 0402 5% 0.1 W RK73B1ETTD474J - KOA R2, R3, R4, R5, R6, R7 22 Resistor 0402 5% 0.1 W RK73B1ETTP220J - KOA R8 47 k Resistor 0402 5% 0.1 W RK73B1ETTD473J - KOA R9 47 k Resistor 0402 5% 0.1 W RK73B1ETTD473J - KOA U1 LDO Linear Regulator 3.3 V 0.5 A LT1963CS8-3.3 - Linear Technology U2 LDO Linear Regulator 1.8 V 0.3 A LT1962EMS8-1.8 - Linear Technology Table 42: Components for connecting TOBY-L4 cellular modules and u-blox EMMY-W161 short range communication modules Connection with external SDIO devices Figure 58 and Table 43 show an application circuit example for connecting the SDIO interface of TOBY-L4 series modules to a 1.8 V SDIO device: the SDIO pins of the cellular module are connected to the related SDIO pins of the SDIO device, with appropriate low value series damping resistors to avoid reflections and other losses in signal integrity, which may create ringing and loss of a square wave shape. The most appropriate value for the series damping resistors on the SDIO lines depends on the specific line lengths and layout implemented. In general, the SDIO series resistors are not strictly required, but it is recommended to slow the SDIO signal, for example with 22 or 33 resistors, and avoid any possible ringing problem without violating the rise / fall time requirements. R2SDIO DeviceSD_D0SD_D1SD_D2SD_D3SD_CLKSD_CMDTOBY-L4 series SDIO_D0 66SDIO_D1 68SDIO_D2 63SDIO_D3 67SDIO_CLK 64SDIO_CMD 65R3R4R5R6GNDGNDR1 Figure 58: Application circuit for connecting TOBY-L4 series modules to a 1.8 V SDIO device Reference Description Part Number - Manufacturer R1, R2, R3, R4, R5, R6 22 Resistor 0402 5% 0.1 W RK73B1ETTP220J - KOA Table 43: Components for connecting TOBY-L4 series modules to a 1.8 V SDIO device The ESD sensitivity rating of SDIO interface pins is 1 kV (HMB according to JESD22-A114). A higher protection level could be required if the lines are externally accessible and this can be achieved by mounting a very low capacitance ESD protection (e.g. Tyco Electronics PESD0402-140 ESD) close to the accessible points. If the SDIO interface pins are not used, they can be left unconnected on the application board. 2.6.5.2 Guidelines for SDIO layout design The SDIO serial interface requires the same considerations regarding electro-magnetic interference as any other high speed digital interface. Keep the traces short, avoid stubs and avoid coupling with RF lines / parts or sensitive analog inputs, since the signals can cause the radiation of some harmonics of the digital data frequency. Consider the usage of low value series damping resistors to avoid reflections and other losses in signal integrity, which may create ringing and loss of a square wave shape.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-99.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 100 of 143 2.6.6 RGMII interface The RGMII interface is not supported by the "50" product version. 2.6.6.1 Guidelines for RGMII circuit design TOBY-L4 series modules include an Ethernet Media Access Control (MAC) block supporting up to 1 Gbit/s data rate via a Reduced Gigabit Media-Independent Interface compliant with the RGMII Version 1.3 specification [7] and the RMII Revision 1.2 specification [8]. The module represents an Ethernet MAC controller, which can be connected to a compatible external Ethernet physical transceiver (PHY) chip to provide communication over Ethernet as illustrated in Figure 59. Recommended compatible Ethernet PHY chips are: Marvell 88E1510 Marvell 88E1512 TOBY-L4 seriesEthernet MACRGMIIConnectorEthernet PHYUnshielded Twisted Pair Figure 59: RGMII interface application circuit block diagram The ESD sensitivity rating of RGMII interface pins is 1 kV (HMB according to JESD22-A114). A higher protection level could be required if the lines are externally accessible and it can be achieved by mounting a very low capacitance ESD protection (e.g. Tyco Electronics PESD0402-140 ESD) close to the accessible points. If the RGMII interface pins are not used, they can be left unconnected on the application board. 2.6.6.2 Guidelines for RGMII layout design The RGMII / RMII interface requires the same considerations regarding electro-magnetic interference as any other high speed digital interface. Keep the traces short, avoid stubs and avoid coupling with RF lines / parts or sensitive analog inputs, since the signals can cause the radiation of some harmonics of the digital data frequency. Consider the usage of low value series damping resistors to avoid reflections and other losses in signal integrity, which may create ringing and loss of a square wave shape.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-100.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 101 of 143 2.7 eMMC interface The eMMC interface is not supported by the "50" product version. 2.7.1.1 Guidelines for eMMC circuit design TOBY-L4 series modules include a 4-bit embedded Multi-Media Card interface compliant with JESD84-B451 Embedded Multimedia Card (eMMC) Electrical Standard 4.51 [9], which can be handled by means of the uCPU API. The eMMC interface can be connected to an external eMMC / SD memory as defined by the standard. Pull-up resistors can be added on MMC_D0, MMC_D1, MMC_D2 and MMC_D3 data lines, the MMC_CLK clock line and the MMC_CMD command line, to increase the rise time on the signals so as to compensate for any capacitance on the board, even if not strictly required. The ESD sensitivity rating of eMMC interface pins is 1 kV (HMB according to JESD22-A114). A higher protection level could be required if the lines are externally accessible and it can be achieved by mounting a very low capacitance ESD protection (e.g. Tyco Electronics PESD0402-140 ESD) close to the accessible points. If the eMMC interface pins are not used, they can be left unconnected on the application board. 2.7.1.2 Guidelines for eMMC layout design The eMMC interface requires the same considerations regarding electro-magnetic interference as any other high speed digital interface. Keep the traces short, avoid stubs and avoid coupling with RF lines / parts or sensitive analog inputs, since the signals can cause the radiation of some harmonics of the digital data frequency. Consider the usage of low value series damping resistors to avoid reflections and other losses in signal integrity, which may create ringing and loss of a square wave shape.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-101.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 102 of 143 2.8 Audio interface 2.8.1 Analog audio interface 2.8.1.1 Guidelines for analog audio uplink path circuit design Guidelines for connecting two external microphones Figure 60 and Table 44 show an application circuit connecting the uplink path of the analog audio interface of TOBY-L4 series modules to two electret microphones: One external 2.2 k electret microphone is connected to the MIC1_P / MIC1_N analog audio uplink path One external 2.2 k electret microphone is connected to the MIC2_P / MIC2_N analog audio uplink path The first differential analog audio input (MIC1_P, MIC1_N) and the second differential analog audio input (MIC2_P, MIC2_N) interfaces can be used alternatively, in mutually exclusive way. For example, one can be used for voice call purposes, the other can be used for eCall purposes. As in the example circuit in Figure 60 and Table 44, the following general guidelines are recommended for the design of an analog audio circuit connecting two external electret microphones: Provide a correct supply to the used electret microphones, as for example providing a clean connection from the MIC_BIAS supply output to the microphones. It is suggested to implement a bridge structure: o The microphones, with their nominal intrinsic resistance value, represent one resistor of the bridge. o To achieve good supply noise rejection, the ratio of the two resistances in one leg (e.g. R2 / R3 resistors in Figure 60) should be equal to the ratio of the two resistances in the other leg (e.g. R4 / MIC1), meaning that R2 must be equal to R4 (e.g. 2.2 k) and R3 must be equal to the microphone nominal intrinsic resistance value (e.g. 2.2 k for MIC1). Using the MIC_BIAS supply output of the module, provide a suitable series resistor at the MIC_BIAS supply output and then mount a suitable large bypass capacitor to provide additional supply noise filtering. See the R1 and R5 series resistors (1.5 k) and the C1 and C5 bypass capacitors (10 µF). Do not place a bypass capacitor directly at the MIC_BIAS supply output, since a suitable internal bypass capacitor is already provided to guarantee stable operation of the internal regulator. Connect the reference of the microphone circuit to the MIC_GND pin of the module as a sense line. Provide a suitable series capacitor at both MIC1_P / MIC1_N and MIC2_P / MIC2_N analog uplink inputs for DC blocking (as the C2 / C3 and C7 / C8 100 nF Murata GRM155R71C104K capacitors in Figure 60). This provides a high-pass filter for the microphone DC bias with the correct cut-off frequency according to the value of the resistors of the microphone supply circuit. Then connect the signal lines to the microphone. Provide the correct parts on each line connected to the external microphone as noise and EMI improvements, to minimize RF coupling and TDMA noise, according to the custom application requirements. o Mount an 82 nH series inductor with a Self Resonance Frequency ~1 GHz (e.g. the Murata LQG15HS82NJ02) on each microphone line (L1 / L2 and L3 / L4 inductors in Figure 60). o Mount a 27 pF bypass capacitor (e.g. Murata GRM1555C1H270J) from each microphone line to the solid ground plane (C4 / C5 and C9 / C10 capacitors in Figure 60). Use microphones designed for GSM applications, which typically have internal built-in bypass capacitor(s) with Self-Resonant Frequency in the cellular frequency range(s). Provide additional ESD protection (e.g. Bourns CG0402MLE-18G varistor) if the analog audio lines will be externally accessible on the application device, according to the EMC/ESD requirements of the custom application. Mount the protection close to an accessible point of the line (D1 / D2 and D3 / D4 in Figure 60).](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-102.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 103 of 143 TOBY-L4 seriesMIC1_PR1R2 R4MIC1_NR3C1MIC_BIASC2C3D1L2L1C5C4Microphone Connector MIC1J1D2MIC2_PR6 R8MIC2_NR7C6MIC_GNDC7C8D3L4L3C9C10Microphone Connector MIC2J2D4R5 Figure 60: Application circuit connecting the analog audio interface to two external electret microphones Reference Description Part Number – Manufacturer C1, C6 10 µF Capacitor Ceramic X5R 0603 20% 6.3 V GRM188R60J106ME47 – Murata C2, C3, C7, C8 100 nF Capacitor Ceramic X7R 0402 10% 16 V GRM155R71C104KA88 – Murata C4, C5, C9, C10 27 pF Capacitor Ceramic C0G 0402 5% 25 V GRM1555C1H270JA01 – Murata D1, D2, D3, D4 Low Capacitance ESD Protection CG0402MLE-18G - Bourns J1, J2 Microphone Connector Various Manufacturers L1, L2, L3, L4 82 nH Multilayer inductor 0402 (self resonance frequency ~1 GHz) LQG15HS82NJ02 – Murata MIC1, MIC2 2.2 k Electret Microphone Various Manufacturers R1, R5 1.5 k Resistor 0402 5% 0.1 W RC0402JR-071K5L – Yageo Phycomp R2, R3, R4, R6, R7, R8 2.2 k Resistor 0402 5% 0.1 W RC0402JR-072K2L – Yageo Phycomp Table 44: Example of components for connecting the analog audio interface to two electret microphones](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-103.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 104 of 143 Guidelines for connecting one external microphone Figure 61 and Table 45 show an application circuit connecting the uplink path of the analog audio interface of TOBY-L4 series modules to one electret microphone: One external 2.2 k electret microphone is connected to an analog audio uplink path of the module The same circuit can be implemented for the MIC1_P / MIC1_N and MIC2_P / MIC2_N differential analog audio inputs of the module. As in the example circuit in Figure 61 and Table 45, the following general guidelines are recommended for the design of an analog audio circuit connecting an external electret microphone: Provide a correct supply to the used electret microphone, as for example providing a clean connection from the MIC_BIAS supply output to the microphone. It is suggested to implement a bridge structure: o The electret microphone, with its nominal intrinsic resistance value, represents one resistor of the bridge. o To achieve good supply noise rejection, the ratio of the two resistances in one leg (R2 / R3) should be equal to the ratio of the two resistances in the other leg (R4 / MIC), i.e. R2 must be equal to R4 (e.g. 2.2 k) and R3 must be equal to the microphone nominal intrinsic resistance value (e.g. 2.2 k). Using the MIC_BIAS supply output of the module, provide a suitable series resistor at the MIC_BIAS supply output and then mount a suitable large bypass capacitor to provide additional supply noise filtering. See the R1 series resistor (2.2 k) and the C1 bypass capacitor (10 µF). Do not place a bypass capacitor directly at the MIC_BIAS supply output, since a suitable internal bypass capacitor is already provided to guarantee stable operation of the internal regulator. Connect the reference of the microphone circuit to the MIC_GND pin of the module as a sense line. Provide a suitable series capacitor at both MIC1_P / MIC1_N and/or MIC2_P / MIC2_N analog uplink inputs for DC blocking (as the C2 and C3 Murata GRM155R71C104K 100 nF capacitors in Figure 61). This provides a high-pass filter for the microphone DC bias with the correct cut-off frequency according to the value of the resistors of the microphone supply circuit. Then connect the signal lines to the microphone. Provide the correct parts on each line connected to the external microphone as noise and EMI improvements, to minimize RF coupling and TDMA noise, according to the custom application requirements. o Mount an 82 nH series inductor with a Self Resonance Frequency ~1 GHz (e.g. the Murata LQG15HS82NJ02) on each microphone line (L1 and L2 inductors in Figure 61). o Mount a 27 pF bypass capacitor (e.g. Murata GRM1555C1H270J) from each microphone line to the solid ground plane (C4 and C5 capacitors in Figure 61). Use a microphone designed for GSM applications, which typically has internal built-in bypass capacitor(s) with Self-Resonant Frequency in the cellular frequency range(s). Provide additional ESD protection (e.g. Bourns CG0402MLE-18G varistor) if the analog audio lines will be externally accessible on the application device, according to the EMC/ESD requirements of the custom application. Mount the protection close to an accessible point of the line (D1-D2 in Figure 61).](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-104.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 105 of 143 TOBY-L4 seriesMICx_PR1R2 R4MICx_NR3C1MIC_BIASMIC_GNDC2C3D1L2L1C5C4Microphone Connector MICJ1D2 Figure 61: Application circuit connecting the analog audio interface to one external electret microphone Reference Description Part Number – Manufacturer C1 10 µF Capacitor Ceramic X5R 0603 20% 6.3 V GRM188R60J106ME47 – Murata C2, C3 100 nF Capacitor Ceramic X7R 0402 10% 16 V GRM155R71C104KA88 – Murata C4, C5 27 pF Capacitor Ceramic C0G 0402 5% 25 V GRM1555C1H270JA01 – Murata D1, D2 Low Capacitance ESD Protection CG0402MLE-18G - Bourns J1 Microphone Connector Various Manufacturers L1, L2 82 nH Multilayer inductor 0402 (self resonance frequency ~1 GHz) LQG15HS82NJ02 – Murata MIC 2.2 k Electret Microphone Various Manufacturers R1, R2, R3, R4 2.2 k Resistor 0402 5% 0.1 W RC0402JR-072K2L – Yageo Phycomp Table 45: Example of components for connecting the analog audio interface to one external electret microphone](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-105.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 106 of 143 Guidelines for connecting one external analog audio device output Figure 62 and Table 46 describe application circuits connecting the uplink path of the analog audio interface of TOBY-L4 series modules to analog audio output of generic external analog audio devices: One differential analog audio output is connected to an analog audio uplink path of the module One single-ended analog audio output is connected to an analog audio uplink path of the module The same circuits can be implemented for the MIC1_P / MIC1_N and MIC2_P / MIC2_N differential analog audio inputs of the module. Guidelines for the connection to a differential analog audio output: The MIC1_P / MIC1_N and/or MIC2_P / MIC2_N balanced input of the module must be connected to the differential output of the external audio device by means of series capacitors for DC blocking (e.g. 10 µF) to decouple the bias present at the module input, as illustrated in the Figure 62 left side. Guidelines for the connection to a single-ended analog audio output: A suitable single-ended to differential circuit must be inserted from the single-ended output of the external audio device to the MIC1_P / MIC1_N and/or MIC2_P / MIC2_N balanced input of the module, as illustrated in the Figure 62 right side: 10 µF series capacitors are provided to decouple the bias present at the module input, and a voltage divider is provided to adapt the signal level from the external device to the module. Additional guidelines for any connection: Audio devices with differential analog I/O are preferable, as they are more immune to external disturbances. The DC-block series capacitor acts as a high-pass filter for audio signals, with a cut-off frequency depending on both the values of the capacitor and on the input impedance of the device. For example: for differential input impedance of 600 , the two 10 µF capacitors will set the -3 dB cut-off frequency to 53 Hz, while for a single-ended connection to a 600 external device, the cut-off frequency with just the single 10 µF capacitor will be 103 Hz. In both cases, the high-pass filter has a low enough cut-off for the correct frequency response. Use a suitable power-on sequence to avoid audio bump due to charging of the capacitor: the final audio stage should be always enabled as the last one. The signal levels can be adapted by setting the internal gains, but additional circuitry must be inserted if the audio device output level is too high for MIC1_P / MIC1_N and/or MIC2_P / MIC2_N, as the voltage dividers present in the circuits illustrated in Figure 62 right side to properly adapt the signal level. TOBY-L4 seriesGNDMICx_PAnalog OUT (-)Analog OUT (+)Audio DeviceGNDMICx_NC1C2TOBY-L4 seriesGNDMICx_PAudio DeviceGNDMICx_NAnalog OUTR2R1C3C4 Figure 62: Application circuits to connect the module to audio devices with suitable differential or single-ended output Reference Description Part Number – Manufacturer C1, C2, C3, C4 10 µF Capacitor X5R 0603 5% 6.3 V GRM188R60J106M – Murata R1 0 Resistor 0402 5% 0.1 W RC0402JR-070RL – Yageo Phycomp R2 Not populated Table 46: Example of components for connecting audio devices with suitable analog differential or single-ended output](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-106.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 107 of 143 2.8.1.2 Guidelines for analog audio downlink path circuit design Guidelines for connecting an external low-power receiver / speaker Figure 63 and Table 47 show an application circuit connecting the downlink path of the analog audio interface of TOBY-L4 series modules to a low-power receiver / speaker: A 16 receiver / speaker is connected to the analog audio downlink path of the module As in the example circuit in Figure 63 and Table 47, the following general guidelines are recommended for the design of an analog audio circuit connecting a low-power receiver / speaker: Connect the SPK_P and SPK_N analog downlink outputs directly to the receiver / speaker (which resistance rating must be greater than 14 ). Provide suitable parts on each line connected to the receiver / speaker as noise and EMI improvements, to minimize RF coupling, according to EMC requirements of the custom application. o Mount a 27 pF bypass capacitor (e.g. Murata GRM1555C1H270J) from each speaker line to the solid ground plane (C1 and C2 capacitors in Figure 63). Provide additional ESD protection (e.g. Bourns CG0402MLE-18G varistor) if the analog audio lines will be externally accessible on the application device, according to the EMC/ESD requirements of the custom application. Mount the protection close to an accessible point of the line (D1 and D2 in Figure 63). TOBY-L4 seriesSPK_PSPK_ND1C1 C2SPKSpeaker ConnectorJ1D2 Figure 63: Application circuit connecting the analog audio interface to a low-power speaker Reference Description Part Number – Manufacturer C1, C2 27 pF Capacitor Ceramic C0G 0402 5% 25 V GRM1555C1H270JA01 – Murata D1, D2, Low Capacitance ESD Protection CG0402MLE-18G - Bourns J1 Speaker Connector Various Manufacturers SPK 16 Speaker Various Manufacturers Table 47: Example of components for connecting the analog audio interface to a low-power speaker](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-107.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 108 of 143 Guidelines for connecting an external high-power loudspeaker Figure 64 and Table 48 show an application circuit connecting the downlink path of the analog audio interface of TOBY-L4 series modules to a high-power loudspeaker: An external 8 or 4 loudspeaker is connected to the analog audio downlink path of the module through an external audio amplifier, which must be provided on the application board to amplify the low power audio signal provided by the downlink path of the module. As in the example circuit in Figure 64 and Table 48, the following general guidelines are recommended for the design of an analog audio circuit connecting a high-power loudspeaker: Provide a DC blocking series capacitor at both SPK_P and SPK_N analog downlink outputs (C1 and C2 Murata GRM155R71C473K 47 nF capacitors in Figure 64). Then connect the lines to the differential input of a suitable external audio amplifier, the differential output of which must be connected to the 8 or 4 loudspeaker. (See the Analog Devices SSM2305CPZ filter-less mono 2.8 W class-D Audio Amplifier in the circuit illustrated in Figure 64.) Provide suitable parts on each line connected to the external loudspeaker as noise and EMI improvements, to minimize RF coupling, according to the EMC requirements of the custom application. o Mount a 27 pF bypass capacitor (e.g. Murata GRM1555C1H270J) from each loudspeaker line to the solid ground plane (C3 and C4 capacitors in Figure 64). Provide additional ESD protection (e.g. Bourns CG0402MLE-18G varistor) if the analog audio lines will be externally accessible on the application device, according to the EMC/ESD requirements of the custom application. The protection should be mounted close to an accessible point of the line (D1 and D2 parts in the circuit illustrated in Figure 64). TOBY-L4 seriesSPK_PSPK_NC3 C4LSPKLoud-Speaker ConnectorJ1OUT+IN+GNDU1OUT-IN-C1C2R1R2VDDC6C5Audio AmplifierVCCD1 D2 Figure 64: Application circuit connecting the analog audio interface to a high-power loudspeaker Reference Description Part Number – Manufacturer C1, C2 47 nF Capacitor Ceramic X7R 0402 10% 16V GRM155R71C473KA01 – Murata C3, C4 27 pF Capacitor Ceramic C0G 0402 5% 25 V GRM1555C1H270JA01 – Murata C5 10 µF Capacitor Ceramic X5R 0603 20% 6.3 V GRM188R60J106ME47 – Murata C6 100 nF Capacitor Ceramic X7R 0402 10% 16 V GRM155R71C104KA88 – Murata D1, D2 Low Capacitance ESD Protection CG0402MLE-18G - Bourns J1 Speaker Connector Various Manufacturers LSPK 8 Loud-Speaker Various Manufacturers MIC 2.2 k Electret Microphone Various Manufacturers R1, R2 0 Resistor 0402 5% 0.1 W RC0402JR-070RL – Yageo Phycomp U1 Filter-less Mono 2.8 W Class-D Audio Amplifier SSM2305CPZ – Analog Devices Table 48: Example of components for connecting the analog audio interface to a high-power loudspeaker](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-108.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 109 of 143 Guidelines for connecting one external analog audio device input Figure 65 and Table 49 describe application circuits connecting the downlink path of the analog audio interface of TOBY-L4 series modules to analog audio input of generic external analog audio devices: One differential analog audio input is connected to an analog audio downlink path of the module One single-ended analog audio input is connected to an analog audio downlink path of the module Guidelines for the connection to a differential analog audio input: The SPK_P / SPK_N balanced output of the module must be connected to the differential input of the external audio device by means of series capacitors for DC blocking (e.g. 10 µF) to decouple the bias present at the module output, as illustrated in the left side of Figure 65. Guidelines for the connection to a single-ended analog audio input: A suitable differential to single-ended circuit must be inserted from the SPK_P / SPK_N balanced output of the module to the single-ended input of the external audio device, as illustrated in the Figure 65 right side: 10 µF series capacitors are provided to decouple the bias present at the module output, and a voltage divider is provided to properly adapt the signal level from module output to external audio device input. Additional guidelines for any connection: Audio devices with differential analog I/O are preferable, as they are more immune to external disturbances. The DC-block series capacitor acts as a high-pass filter for audio signals, with a cut-off frequency depending on both the values of capacitor and on the input impedance of the device. For example: for differential input impedance of 600 , the two 10 µF capacitors will set the -3 dB cut-off frequency to 53 Hz, while for single-ended connection to a 600 external device, the cut-off frequency with just the single 10 µF capacitor will be 103 Hz. In both cases. the high-pass filter has a low enough cut-off for the correct frequency response. Use a suitable power-on sequence to avoid audio bump due to charging of the capacitor: the final audio stage should be always enabled as the last one. The signal levels can be adapted by setting the internal gains, but additional circuitry must be inserted if SPK_P / SPK_N output level of the module is too high for the audio device input, as the voltage dividers present in the circuits illustrated in Figure 65 right side to properly adapt the signal level. TOBY-L4 seriesC1C2SPK_NSPK_PGNDAnalog IN (-)Analog IN (+)Audio DeviceGNDTOBY-L4 seriesSPK_NSPK_PGNDAnalog INAudio DeviceGNDC3C4 R2R1 Figure 65: Application circuits to connect the module to audio devices with suitable differential or single-ended input Reference Description Part Number – Manufacturer C1, C2, C3, C4 10 µF Capacitor X5R 0603 5% 6.3 V GRM188R60J106M – Murata R1 0 Ω Resistor 0402 5% 0.1 W RC0402JR-070RL – Yageo Phycomp R2 Not populated Table 49: Example of components for connecting audio devices with suitable analog differential or single-ended input](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-109.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 110 of 143 2.8.1.3 Guidelines for analog audio layout design Accurate design of the analog audio circuit is very important to obtain clear and high quality audio. The GSM signal burst has a repetition rate of 217 Hz that lies in the audible range. A careful layout is required to reduce the risk of noise from audio lines due to both VCC burst noise coupling and RF detection. General guidelines for the uplink path (microphone), which is commonly the most sensitive, are the following: Avoid coupling of any noisy signal to microphone lines: it is strongly recommended to route microphone lines away from the module VCC supply line, any switching regulator line, RF antenna lines, digital lines and any other possible noise source. Avoid coupling between the microphone and speaker / receiver lines. Optimize the mechanical design of the application device, the position, orientation and mechanical fixing (for example, using rubber gaskets) of microphone and speaker parts in order to avoid echo interference between the uplink path and downlink path. Keep ground separation from microphone lines to other noisy signals. Use an intermediate ground layer or vias wall for coplanar signals. For an external audio device providing differential microphone input, route the microphone signal lines as a differential pair embedded in ground to reduce differential noise pick-up. The balanced configuration will help reject the common mode noise. Cross other signals lines on adjacent layers with 90° crossing. Place bypass capacitor for RF very close to the active microphone. The preferred microphone should be designed for GSM applications which typically have an internal built-in bypass capacitor for RF very close to active device. If the integrated FET detects the RF burst, the resulting DC level will be in the pass-band of the audio circuitry and cannot be filtered by any other device. General guidelines for the downlink path (speaker / receiver) are the following: The physical width of the audio output lines on the application board must be wide enough to minimize series resistance since the lines are connected to low impedance speaker transducers. Avoid coupling of any noisy signal to speaker lines: it is recommended to route speaker lines away from the module VCC supply line, any switching regulator line, RF antenna lines, digital lines and any other possible noise source. Avoid coupling between speaker / receiver and microphone lines. Optimize the mechanical design of the application device, the position, orientation and mechanical fixing (for example, using rubber gaskets) of speaker and microphone parts in order to avoid echo interference between the downlink path and uplink path. For external audio device providing differential speaker / receiver output, route the speaker signal lines as a differential pair embedded in ground up to reduce differential noise pick-up. The balanced configuration will help reject the common mode noise. Cross other signals lines on adjacent layers with 90° crossing. Place the RF bypass capacitor close to the speaker. The ESD sensitivity rating of analog audio interface pins is 1 kV (HBM, according to JESD22-A114). A higher protection level could be required if the lines are externally accessible and it can be achieved by mounting a general purpose ESD protection (e.g. EPCOS CA05P4S14THSG varistor array) close to the accessible points. If the analog audio pins functionality is not used, they can be left unconnected on the application board.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-110.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 111 of 143 2.8.2 Digital audio interface The second digital audio interface (I2S1) will be supported by future firmware versions. 2.8.2.1 Guidelines for digital audio circuit design The I2S digital audio interfaces can be connected to an external digital audio device for voice applications. Any external digital audio device compliant with the configuration of the digital audio interface of the TOBY-L4 series cellular module can be used, given that the external digital audio device must provide: The opposite role: slave or master role, as TOBY-L4 series modules may act as master or slave The same mode and frame format: PCM / short synch mode or Normal I2S / long synch mode with o data in 2’s complement notation, linear o MSB transmitted first o data word length = 16-bit (16 clock cycles) o frame length = synch signal period: 17-bit or 18-bit in PCM / short alignment mode (16 + 1 or 16 + 2 clock cycles, with the Word Alignment / Synchronization signal set high for 1 clock cycle or 2 clock cycles) 32-bit in Normal I2S mode / long alignment mode (16 x 2 clock cycles) The same sample rate, i.e. synch signal frequency, <I2S_sample_rate> parameter: o 8 kHz, 11.025 kHz, 12 kHz, 16 kHz, 22.05 kHz, 24 kHz, 32 kHz, 44.1 kHz, 48 kHz, 96 kHz, 192 kHz The same serial clock frequency: o 17 x <I2S_sample_rate> or 18 x <I2S_sample_rate> in PCM / short alignment mode, or o 16 x 2 x <I2S_sample_rate> in Normal I2S mode / long alignment mode Compatible voltage levels (1.80 V typ.), otherwise it is recommended to connect the 1.8 V digital audio interface of the module to the external 3.0 V (or similar) digital audio device by means of appropriate unidirectional voltage translators (e.g. TI SN74AVC4T774 or SN74AVC2T245, providing a partial power down feature so that the digital audio device 3.0 V supply can be also ramped up before V_INT 1.8 V supply), using the module V_INT output as 1.8 V supply for the voltage translators on the module side. An appropriate specific application circuit must be implemented and configured according to the particular external digital audio device or audio codec used and according to the application requirements. Examples of manufacturers offering compatible audio codec parts are the following: Maxim Integrated (as the MAX9860, MAX9867, MAX9880A audio codecs) Texas Instruments / National Semiconductor Cirrus Logic / Wolfson Microelectronics Nuvoton Technology Asahi Kasei Microdevices Realtek Semiconductor Figure 66 and Table 50 describe application circuits for the digital audio interfaces, considering these scenarios: 1.8 V digital audio device with slave role connected to a digital audio interface of the module set as master 1.8 V digital audio device with master role connected to a digital audio interface of the module set as slave 3.0 V digital audio device with slave role connected to a digital audio interface of the module set as master 3.0 V digital audio device with master role connected to a digital audio interface of the module set as slave The same circuits can be implemented for both the I2S0 and the I2S1 digital audio interfaces of the module.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-111.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 112 of 143 TOBY-L4 series(Master, 1.8V)BCLKLRCLKSDINSDOUTGNDV_INTI2Sx_CLKI2Sx_WAI2Sx_TXDI2Sx_RXDAudio Device(Slave, 1.8V)GNDTOBY-L4 series(Slave, 1.8V)BCLKLRCLKSDINSDOUTGNDV_INTI2Sx_CLKI2Sx_WAI2Sx_TXDI2Sx_RXDAudio Device(Master, 1.8V)GNDVDD1V8VDD1V81V8B1 A1GNDU1B3 A3VCCB VCCAUnidirectionalVoltage TranslatorC2C13V0DIR2DIR3OEDIR1B2 A2B4 A4DIR4TOBY-L4 series(Master, 1.8V)BCLKLRCLKSDINSDOUTGNDV_INTI2Sx_CLKI2Sx_WAI2Sx_TXDI2Sx_RXDAudio Device(Slave, 3.0V)GNDVDDTOBY-L4 series(Slave, 1.8V)BCLKLRCLKSDINSDOUTGNDV_INTI2Sx_CLKI2Sx_WAI2Sx_TXDI2Sx_RXDAudio Device(Master, 3.0V)GNDVDD1V8B1 A1GNDU2B3 A3VCCB VCCAUnidirectionalVoltage TranslatorC4C33V0DIR2DIR4OEDIR3B2 A2B4 A4DIR1 Figure 66: I2S interface application circuit with an external audio codec to provide voice capability Reference Description Part Number – Manufacturer C1, C2, C3, C4 100 nF Capacitor Ceramic X5R 0402 10% 10V GRM155R71C104KA01 – Murata U1, U2 Unidirectional Voltage Translator SN74AVC4T77420 - Texas Instruments Table 50: Example of components for an audio voice codec application circuit Do not apply voltage to any I2S pin before the switch-on of the I2S supply source (V_INT), to avoid latch-up of circuits and allow a clean boot of the module. The ESD sensitivity rating of the I2S interface pins is 1 kV (Human Body Model according to JESD22-A114). A higher protection level could be required if the lines are externally accessible and it can be achieved by mounting a general purpose ESD protection (e.g. EPCOS CA05P4S14THSG varistor array) close to the accessible points. If the I2S digital audio pins are not used, they can be left unconnected on the application board. 2.8.2.2 Guidelines for digital audio layout design I2S interface and clock output lines require the same considerations regarding electromagnetic interference as any other high speed digital interface. Keep the traces short and avoid coupling with RF lines / parts or sensitive analog inputs, since the signals can cause the radiation of some harmonics of the digital data frequency. 20 Voltage translator providing partial power down feature so that the external 3 V supply can be also ramped up before V_INT 1.8 V supply](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-112.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 113 of 143 2.9 ADC interfaces The ADC pins are not supported by the "50" product version. 2.9.1.1 Guidelines for ADC circuit design TOBY-L4 series modules include Analog to Digital Converter inputs (ADC1, ADC2), which can be handled by means of the dedicated uCPU API. The ADC pins can be connected to external circuits for general purpose voltage measurements. The voltage value at the ADC input must be within the range reported in the TOBY-L4 series Data Sheet [1]. If an external voltage divider is implemented to increase the measurement voltage range, check the input resistance of the ADC inputs reported in the TOBY-L4 series Data Sheet [1]: if the Thévenin's equivalent of the external circuit has a significant value as compared to the input resistance of the ADC inputs, this should be taken into account and corrected to properly associate the ADC response to the voltage source value, implementing an appropriate ADC calibration procedure. The ESD sensitivity rating of ADC interface pins is 1 kV (Human Body Model according to JESD22-A114). A higher protection level could be required if the lines are externally accessible and it can be achieved by mounting an ESD protection (e.g. EPCOS CA05P4S14THSG varistor array) close to the accessible points. If the ADC pins are not used, they can be left unconnected on the application board. 2.9.1.2 Guidelines for ADC layout design The Analog to Digital Converters (ADC1, ADC2) are high impedance analog inputs. The conversion accuracy will be degraded if noise is injected. Low-pass filter may be used to improve noise rejection; typically L-C tuned for RF rejection gives better results.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-113.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 114 of 143 2.10 General Purpose Input/Output 2.10.1.1 Guidelines for GPIO circuit design A typical usage of TOBY-L4 series modules’ GPIOs can be the following: Wi-Fi enable function provided by GPIO1 (see Figure 58 in section 2.6.5)21 GNSS supply enable function provided by GPIO2 (see Figure 54, Figure 56 in section 2.6.4)21 GNSS Tx data ready function provided by GPIO3 (see Figure 54, Figure 56 in section 2.6.4)21 GNSS RTC sharing function provided by GPIO4 (see Figure 54, Figure 56 in section 2.6.4)21 SIM card detection provided by the GPIO5 (see Figure 39 / Table 30 in section 2.5) Other configurations of the TOBY-L4 series modules’ GPIOs are possible, as illustrated in section 1.13. Use transistors with at least an integrated resistor in the base pin or otherwise put a 10 k resistor on the board in series with the GPIO of TOBY-L4 series modules. Do not apply voltage to any GPIO of the module before the switch-on of the GPIOs supply (V_INT), to avoid latch-up of circuits and allow a clean module boot. If the external signals connected to the module cannot be tri-stated or set low, insert a multi-channel digital switch (e.g. TI SN74CB3Q16244, TS5A3159, TS5A63157) between the two-circuit connections and set to high impedance before V_INT switch-on. The ESD sensitivity rating of the GPIO pins is 1 kV (Human Body Model according to JESD22-A114). A higher protection level could be required if the lines are externally accessible and it can be achieved by mounting an ESD protection (e.g. EPCOS CA05P4S14THSG varistor array) close to the accessible points. If the GPIO pins are not used, they can be left unconnected on the application board. 2.10.1.2 Guidelines for general purpose input/output layout design The general purpose inputs / outputs pins are generally not critical for layout. 21 Not supported by "50" product version](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-114.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 115 of 143 2.11 Reserved pins (RSVD) TOBY-L4 series modules have pins reserved for future use, marked as RSVD. All the RSVD pins are to be left unconnected on the application board except the following RSVD pins as illustrated in Figure 67: the RSVD pin number 6 that must be externally connected to ground TOBY-L4 seriesRSVD6RSVD Figure 67: Application circuit for the reserved pins (RSVD) 2.12 Module placement An optimized placement allows a minimum RF line’s length and a closer path from the DC source for VCC. Make sure that the module, analog parts and RF circuits are clearly separated from any possible source of radiated energy. In particular, digital circuits can radiate digital frequency harmonics, which can produce electromagnetic interference that affects the module, analog parts and RF circuits’ performance. Implement suitable countermeasures to avoid any possible electromagnetic compatibility issues. Make sure that the module, RF and analog parts / circuits, and high speed digital circuits are clearly separated from any sensitive part / circuit which may be affected by electromagnetic interference, or employ countermeasures to avoid any possible electromagnetic compatibility issue. Provide enough clearance between the module and any external part. The heat dissipation during continuous transmission at maximum power can significantly raise the temperature of the application base-board below the TOBY-L4 series modules: avoid placing temperature sensitive devices close to the module.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-115.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 116 of 143 2.13 Module footprint and paste mask Figure 68 and Table 51 describe the suggested footprint (i.e. copper mask) and the paste mask (i.e. stencil) layout for TOBY-L4 series modules, to be implemented on the application PCB. The proposed land pattern layout (i.e. the footprint, the application board top-layer copper mask) reflects the modules’ pads layout, with the pads on the application board designed as the LGA pads of the module. IADFKM1M1M2P2BG1 HJL NM1M1M3II OJJ JEP3FP1 HOM1HG2G2G1HJIHOO0.801.501.450.600.100.17CopperPaste1.101.101.001.000.050.05PasteCopper1.101.100.900.900.100.10 PasteCopper0.801.501.380.600.100.06PasteCopper Figure 68: Suggested footprint and stencil design for TOBY-L4 series modules, to be implemented on application PCB (top view) Parameter Value Parameter Value Parameter Value Parameter Value A 35.6 mm G1 1.10 mm K 3.15 mm N 2.10 mm B 24.8 mm G2 2.00 mm L 7.15 mm O 1.10 mm D 2.40 mm H 0.80 mm M1 1.80 mm P1 1.10 mm E 2.25 mm I 1.50 mm M2 3.40 mm P2 1.25 mm F 1.45 mm J 0.30 mm M3 2.25 mm P3 2.85 mm Table 51: Suggested footprint design dimensions for TOBY-L4 series modules, to be implemented on application PCB The Non Solder Mask Defined (NSMD) pad type is recommended over the Solder Mask Defined (SMD) pad type, implementing the solder mask opening 50 µm larger per side than the corresponding copper pad. The suggested paste mask (i.e. stencil) layout to mount TOBY-L4 series modules on the application PCB is also illustrated in Figure 68. Different stencil apertures layout for any specific pad is recommended: Green marked pads: Paste layout enlarged on the lateral side and reduced on other sides (see Figure 68) Light-Green marked pads: Paste layout reduced circumferentially to Copper layout (see Figure 68) Blue marked pads: Paste layout reduced circumferentially 0.05 mm to Copper layout (see Figure 68) Light-Blue marked pads: Paste layout reduced circumferentially 0.1 mm to Copper layout (see Figure 68) The recommended solder paste thickness is 150 µm, according to application production process requirements. These are recommendations only and not specifications. The exact mask geometries, distances and stencil thicknesses must be adapted to the specific production processes (e.g. soldering) of the customer.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-116.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 117 of 143 2.14 Thermal guidelines Modules’ temperature range and thermal parameters are specified in the TOBY-L4 series Data Sheet [1]. The most critical condition concerning module thermal performance is the uplink transmission at maximum power (data upload in connected mode), because when the baseband processor runs at full speed, radio circuits are all active and the RF power amplifier is driven to higher output RF power. This scenario is not often encountered in real networks (for example, see the Terminal Tx Power distribution for WCDMA, taken from operation on a live network, described in the GSMA TS.09 Battery Life Measurement and Current Consumption Technique [10]); however the application should be correctly designed to cope with it. During transmission at maximum RF power, the TOBY-L4 series modules generate thermal power that may exceed 4 W in the worst case condition: this is an indicative value since the exact generated power strictly depends on operating conditions such as the actual antenna return loss, the number of allocated TX resource blocks, the transmitting frequency band, etc. The generated thermal power must be adequately dissipated through the thermal and mechanical design of the application. The spreading of the actual Module-to-Ambient thermal resistance (Rth,M-A) depends on the module operating condition. The overall temperature distribution is influenced by the configuration of the active components during the specific mode of operation and their different thermal resistance toward the case interface. The actual Module-to-Ambient thermal resistance value and the relative increase of module temperature will differ according to the specific mechanical deployments of the module, e.g. application PCB with different dimensions and characteristics, mechanical shells enclosure, or forced air flow. The increase of the thermal dissipation, i.e. the reduction of the actual Module-to-Ambient thermal resistance, will decrease the temperature of the modules’ internal circuitry for a given operating ambient temperature. This improves the device long-term reliability in particular for applications operating at high ambient temperature. Recommended hardware techniques to be used to improve heat dissipation in the application: Connect each GND pin with solid ground layer of the application board and connect each ground area of the multilayer application board with a complete thermal via stacked down to the main ground layer. Provide a ground plane as wide as possible on the application board. Optimize antenna return loss, to optimize overall electrical performance of the module including a decrease of module thermal power. Optimize the thermal design of any high-power components included in the application, such as linear regulators and amplifiers, to optimize overall temperature distribution in the application device. Select the material, the thickness and the surface of the box (i.e. the mechanical enclosure) of the application device that integrates the module so that it provides good thermal dissipation. Further hardware techniques that may be considered to improve the heat dissipation in the application: Provide a heat sink component on the backside of the application board, below the cellular module, as a large part of the heat is transported through the GND pads of the TOBY-L4 series LGA modules and dissipated over the backside of the application board. Force ventilation air-flow within the mechanical enclosure. Beside the reduction of the Module-to-Ambient thermal resistance implemented with the correct application hardware design, the increase of module temperature can be moderated by suitable application software implementation: Enable power saving configuration by means of the AT+UPSV command or the uCPU API. Enable module connected mode for a given time period and then disable it for a time period long enough to properly mitigate temperature increase.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-117.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 118 of 143 2.15 Design-in checklist This section provides a design-in checklist. 2.15.1 Schematic checklist The following are the most important points for a simple schematic check: DC supply must provide a nominal voltage at the VCC pin within the operating range limits. DC supply must be capable of supporting both the highest peak and the highest averaged current consumption values in connected mode, as specified in the TOBY-L4 series Data Sheet [1]. VCC voltage supply should be clean, with very low ripple/noise: provide the suggested bypass capacitors, in particular if the application device integrates an internal antenna. Do not apply loads which might exceed the limit for the maximum available current from V_INT supply. Check that the voltage level of any connected pin does not exceed the relative operating range. Provide accessible test points directly connected to the following pins of the TOBY-L4 series modules: V_INT, PWR_ON and RESET_N for diagnostic purposes. Capacitance and series resistance must be limited on each SIM signal to match the SIM specifications. Insert the suggested pF capacitors on each SIM signal and low capacitance ESD protections if accessible. Check UART signals direction, as the modules’ signal names follow the ITU-T V.24 Recommendation [5]. Provide accessible test points directly connected to all the UART pins of the TOBY-L4 series modules (TXD, RXD) for diagnostic purposes. Provide accessible test points directly connected to all the UART3 pins of the TOBY-L4 series modules (TXD3, RXD3) for Linux console access. Capacitance and series resistance must be limited on each high speed line of the USB interface. Provide accessible test points directly connected to the USB 2.0 interface pins of the TOBY-L4 series modules (VUSB_DET, USB_D+ and USB_D–) for diagnostic and FW update purposes. Consider providing appropriate low value series damping resistors on SDIO lines to avoid reflections. Add a suitable pull-up resistor (e.g. 4.7 k) to V_INT or another suitable 1.8 V supply on each DDC (I2C) interface line, if the interface is used. Check the digital audio interface specifications to connect a suitable external audio device. Capacitance and series resistance must be limited on master clock output line and each I2S interface line Consider passive filtering parts on each used analog audio line. Use transistors with at least an integrated resistor in the base pin or otherwise put a 10 k resistor on the board in series to the GPIO when those are used to drive LEDs. Provide suitable precautions for EMC / ESD immunity as required on the application board. Do not apply voltage to any generic digital interface pin of TOBY-L4 series modules before the switch-on of the generic digital interface supply source (V_INT). All unused pins can be left unconnected except the RSVD pin number 6 of TOBY-L4 series modules, which must be connected to GND.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-118.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Design-in Page 119 of 143 2.15.2 Layout checklist The following are the most important points for a simple layout check: Check 50 nominal characteristic impedance of the RF transmission line connected to the ANT1 and the ANT2 ports (antenna RF interfaces). Ensure no coupling occurs between the RF interface and noisy or sensitive signals (primarily analog audio input/output signals, SIM signals, high-speed digital lines such as the USB, SDIO, RGMII, eMMC, SPI and other data lines). Optimize placement for minimum length of the RF line. Check the footprint and paste mask designed for TOBY-L4 series modules as illustrated in section 2.13. VCC line should be as wide and as short as possible. Route VCC supply line away from RF lines / parts and other sensitive analog lines / parts. The VCC bypass capacitors in the picoFarad range should be placed as close as possible to the VCC pins, in particular if the application device integrates an internal antenna. Ensure an optimal grounding connecting each GND pin with the application board solid ground layer. Use as many vias as possible to connect the ground planes on a multilayer application board, providing a dense line of vias at the edges of each ground area, in particular along the RF and high speed lines. Keep routing short and minimize parasitic capacitance on the SIM lines to preserve signal integrity. USB 2.0 and USB 3.0 data line traces must meet characteristic impedance requirements as per USB 2.0 specification [3] and USB 3.0 specification [4], and should not be routed close to any RF line / part. Keep the SDIO traces short, avoid stubs, avoid coupling with any RF line / part and consider low value series damping resistors to avoid reflections and other losses in signal integrity. Ensure appropriate RF precautions for the Wi-Fi and Cellular technologies coexistence . Ensure appropriate RF precautions for the GNSS and Cellular technologies coexistence. Route analog audio signals away from noisy sources (primarily RF interface, VCC, switching supplies). The audio outputs lines on the application board must be wide enough to minimize series resistance. 2.15.3 Antenna checklist Antenna termination should provide a 50 characteristic impedance with VSWR at least less than 3:1 (recommended 2:1) on operating bands in the deployment geographical area. Follow the recommendations of the antenna producer for correct antenna installation and deployment (PCB layout and matching circuitry). Ensure compliance with any regulatory agency RF radiation requirement. Ensure high and similar efficiency for both the primary (ANT1) and the secondary (ANT2) antennas. Ensure high isolation between the primary (ANT1) and the secondary (ANT2) antennas. Ensure a low Envelope Correlation Coefficient between the primary (ANT1) and the secondary (ANT2) antennas: the 3D antenna radiation patterns should have radiation lobes in different directions. Ensure high isolation between the cellular antennas and any other antenna or transmitter.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-119.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Handling and soldering Page 120 of 143 3 Handling and soldering No natural rubbers, no hygroscopic materials or materials containing asbestos are employed. 3.1 Packaging, shipping, storage and moisture preconditioning For information about the TOBY-L4 series reels / tapes, Moisture Sensitivity levels (MSD), shipment and storage information, as well as drying for preconditioning, see the TOBY-L4 series Data Sheet [1] and the u-blox Package Information Guide [16]. 3.2 Handling The TOBY-L4 series modules are Electro-Static Discharge (ESD) sensitive devices. Ensure ESD precautions are implemented during handling of the module. Electrostatic discharge (ESD) is the sudden and momentary electric current that flows between two objects at different electrical potentials caused by direct contact or induced by an electrostatic field. The term is usually used in the electronics and other industries to describe momentary unwanted currents that may cause damage to electronic equipment. The ESD sensitivity for each pin of TOBY-L4 series modules (as Human Body Model according to JESD22-A114F) is specified in the TOBY-L4 series Data Sheet [1]. ESD prevention is based on establishing an Electrostatic Protective Area (EPA). The EPA can be a small working station or a large manufacturing area. The main principle of an EPA is that there are no highly charging materials near ESD sensitive electronics, all conductive materials are grounded, workers are grounded, and charge build-up on ESD sensitive electronics is prevented. International standards are used to define typical EPA and can be obtained for example from International Electrotechnical Commission (IEC) or American National Standards Institute (ANSI). In addition to standard ESD safety practices, the following measures should be taken into account whenever handling the TOBY-L4 series modules: Unless there is a galvanic coupling between the local GND (i.e. the work table) and the PCB GND, then the first point of contact when handling the PCB must always be between the local GND and PCB GND. Before mounting an antenna patch, connect the ground of the device. When handling the module, do not come into contact with any charged capacitors and be careful when contacting materials that can develop charges (e.g. patch antenna, coax cable, soldering iron,…). To prevent electrostatic discharge through the RF pin, do not touch any exposed antenna area. If there is any risk that such an exposed antenna area is touched in a non-ESD protected work area, implement suitable ESD protection measures in the design. When soldering the module and patch antennas to the RF pin, make sure to use an ESD safe soldering iron.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-120.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Handling and soldering Page 121 of 143 3.3 Soldering 3.3.1 Soldering paste "No Clean" soldering paste is strongly recommended for TOBY-L4 series modules, as it does not require cleaning after the soldering process has taken place. The paste listed in the example below meets these criteria. Soldering Paste: OM338 SAC405 / Nr.143714 (Cookson Electronics) Alloy specification: 95.5% Sn / 3.9% Ag / 0.6% Cu (95.5% Tin / 3.9% Silver / 0.6% Copper) 95.5% Sn / 4.0% Ag / 0.5% Cu (95.5% Tin / 4.0% Silver / 0.5% Copper) Melting Temperature: +217 °C Stencil Thickness: 150 µm for base boards The final choice of the soldering paste depends on the approved manufacturing procedures. The paste-mask geometry for applying soldering paste should meet the recommendations in section 2.13. The quality of the solder joints on the connectors (“half vias”) should meet the appropriate IPC specification. 3.3.2 Reflow soldering A convection type-soldering oven is strongly recommended for TOBY-L4 series modules over the infrared type radiation oven. Convection heated ovens allow precise control of the temperature and all parts will be heated up evenly, regardless of material properties, thickness of components and surface color. Refer to the ”IPC-7530 Guidelines for temperature profiling for mass soldering (reflow and wave) processes” guide, published in 2001. Reflow profiles are to be selected according to the following recommendations. Failure to observe these recommendations can result in severe damage to the device! Preheat phase Initial heating of component leads and balls. Residual humidity will be dried out. Note that this preheat phase will not replace prior baking procedures. Temperature rise rate: max 3 °C/s If the temperature rise is too rapid in the preheat phase, it may cause excessive slumping. Time: 60 – 120 s If the preheat is insufficient, rather large solder balls tend to be generated. Conversely, if performed excessively, fine balls and large balls will be generated in clusters. End Temperature: 150 °C - 200 °C If the temperature is too low, non-melting tends to be caused in areas containing large heat capacity. Heating/ reflow phase The temperature rises above the liquidus temperature of +217 °C. Avoid a sudden rise in temperature as the slump of the paste could become worse. Limit time above +217 °C liquidus temperature: 40 - 60 s Peak reflow temperature: +245 °C Cooling phase A controlled cooling avoids negative metallurgical effects (solder becomes more brittle) of the solder and possible mechanical tensions in the products. Controlled cooling helps to achieve bright solder fillets with a good shape and low contact angle. Temperature fall rate: max 4 °C/s](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-121.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Handling and soldering Page 122 of 143 To avoid falling off, modules should be placed on the topside of the motherboard during soldering. The soldering temperature profile chosen at the factory depends on additional external factors, such as the choice of soldering paste, size, thickness and properties of the base board, etc. Exceeding the maximum soldering temperature and the maximum liquidus time limit in the recommended soldering profile may permanently damage the module. Preheat Heating Cooling[°C] Peak Temp. 245°C [°C]250 250Liquidus Temperature217 217200 20040 - 60 sEnd Temp.max 4°C/s150 - 200°C150 150max 3°C/s60 - 120 s100 Typical Leadfree 100Soldering Profile50 50Elapsed time [s] Figure 69: Recommended soldering profile The modules must not be soldered with a damp heat process. 3.3.3 Optical inspection After soldering the TOBY-L4 series modules, inspect the modules optically to verify that the module is properly aligned and centered. 3.3.4 Cleaning Cleaning the modules is not recommended. Residues underneath the modules cannot be easily removed with a washing process. Cleaning with water will lead to capillary effects where water is absorbed in the gap between the baseboard and the module. The combination of residues of soldering flux and encapsulated water leads to short circuits or resistor-like interconnections between neighboring pads. Water will also damage the sticker and the ink-jet printed text. Cleaning with alcohol or other organic solvents can result in soldering flux residues flooding into the two housings, areas that are not accessible for post-wash inspections. The solvent will also damage the sticker and the ink-jet printed text. Ultrasonic cleaning will permanently damage the module, in particular the quartz oscillators. For best results, use a "no clean" soldering paste and eliminate the cleaning step after the soldering.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-122.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Handling and soldering Page 123 of 143 3.3.5 Repeated reflow soldering Only a single reflow soldering process is encouraged for boards with a module populated on it. 3.3.6 Wave soldering Boards with combined through-hole technology (THT) components and surface-mount technology (SMT) devices require wave soldering to solder the THT components. TOBY-L4 series LGA modules must not be soldered with a wave soldering process. 3.3.7 Hand soldering Hand soldering is not recommended. 3.3.8 Rework Rework is not recommended. Never attempt a rework on the module itself, e.g. replacing individual components. Such actions immediately terminate the warranty. 3.3.9 Conformal coating Certain applications employ a conformal coating of the PCB using HumiSeal® or other related coating products. These materials affect the HF properties of the cellular modules and it is important to prevent them from flowing into the module. The RF shields do not provide 100% protection for the module from coating liquids with low viscosity, and therefore care is required in applying the coating. Conformal coating of the module will void the warranty. 3.3.10 Casting If casting is required, use viscose or another type of silicon pottant. The OEM is strongly advised to qualify such processes in combination with the cellular modules before implementing this in production. Casting will void the warranty. 3.3.11 Grounding metal covers Attempts to improve grounding by soldering ground cables, wick or other forms of metal strips directly onto the EMI covers is done at the customer's own risk. The numerous ground pins should be sufficient to provide optimum immunity to interferences and noise. u-blox gives no warranty for damages to the cellular modules caused by soldering metal cables or any other forms of metal strips directly onto the EMI covers. 3.3.12 Use of ultrasonic processes The cellular modules contain components which are sensitive to ultrasonic waves. Use of any ultrasonic processes (cleaning, welding etc.) may cause damage to the module. u-blox gives no warranty against damages to the cellular modules caused by any ultrasonic processes.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-123.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Approvals Page 124 of 143 4 Approvals For the complete list and specific details regarding the certification schemes approvals, see the TOBY-L4 series Data Sheet [1], or contact the u-blox office or sales representative nearest you. 4.1 Product certification approval overview Product certification approval is the process of certifying that a product has passed all tests and criteria required by specifications, typically called “certification schemes” that can be divided into three distinct categories: Regulatory certification o Country specific approval required by local government in most regions and countries, such as: CE (Conformité Européenne) marking for the European Union FCC (Federal Communications Commission) approval for the United States Industry certification o Telecom industry specific approval verifying the interoperability between devices and networks: GCF (Global Certification Forum), a partnership between mainly European device manufacturers and network operators to ensure and verify global interoperability between devices and networks PTCRB (PCS Type Certification Review Board), created by United States network operators to ensure and verify interoperability between devices and North America networks Operator certification o Operator specific approval required by some mobile network operator, such as: AT&T network operator in the United States Even using a module already approved under all major certification schemes, the application device integrating the module must be approved under all the certification schemes required by the specific application device to be deployed into the market. The required certification scheme approvals and relative testing specifications differ depending on the country or the region where the device integrating the module is intended to be deployed, on the relative vertical market of the device, on type, features and functionalities of the whole application device, and on the network operators where the device is intended to operate. Check the appropriate applicability of the TOBY-L4 series module’s approvals while starting the certification process of the device integrating the module: the re-use of the u-blox cellular module’s approval can significantly reduce the cost and time-to-market of the application device certification. The certification of the application device that integrates a TOBY-L4 series module and the compliance of the application device with all the applicable certification schemes, directives and standards are the sole responsibility of the application device manufacturer. TOBY-L4 series modules are certified according to all the supported capabilities, functions and options stated in the Protocol Implementation Conformance Statement document (PICS) of the module. The PICS, according to the 3GPP TS 51.010-2 [11], 3GPP TS 34.121-2 [12], 3GPP TS 36.521-2 [14] and 3GPP TS 36.523-2 [15] documents, is a statement of the implemented and supported capabilities, functions and options of a device. The PICS document of the application device integrating TOBY-L4 series modules must be updated from the module PICS statement if any feature stated as supported by the module in its PICS document is not implemented or disabled in the application device.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-124.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Approvals Page 125 of 143 4.2 US Federal Communications Commission notice United States Federal Communications Commission (FCC) IDs: u-blox TOBY-L4006 cellular modules: XPY1EHQ37NN 4.2.1 Safety warnings review the structure Equipment for building-in. The requirements for fire enclosure must be evaluated in the end product The clearance and creepage current distances required by the end product must be withheld when the module is installed The cooling of the end product shall not negatively be influenced by the installation of the module Excessive sound pressure from earphones and headphones can cause hearing loss No natural rubbers, no hygroscopic materials nor materials containing asbestos are employed 4.2.2 Declaration of conformity This device complies with Part 15 of the FCC rules. Operation is subject to the following two conditions: this device may not cause harmful interference this device must accept any interference received, including interference that may cause undesired operation Radiofrequency radiation exposure Information: this equipment complies with FCC radiation exposure limits prescribed for an uncontrolled environment for fixed and mobile use conditions. This equipment should be installed and operated with a minimum distance of 20 cm between the radiator and the body of the user or nearby persons. This transmitter must not be co-located or operating in conjunction with any other antenna or transmitter except in accordance with FCC procedures and as authorized in the module certification filing. The gain of the system antenna(s) used for the TOBY-L4006 modules (i.e. the combined transmission line, connector, cable losses and radiating element gain) must not exceed the value specified in the FCC Grant for mobile and fixed or mobile operating configurations: o 10.2 dBi in the 700 MHz band, i.e. LTE FDD-12 band o 10.2 dBi in the 750 MHz band, i.e. LTE FDD-13 band o 4.0 dBi in the 850 MHz band, i.e. GSM 850, UMTS FDD-5 or LTE FDD-5 band o 5.5 dBi in the 1700 MHz band, i.e. UMTS FDD-4 or LTE FDD-4 band o 2.7 dBi in the 1900 MHz band, i.e. GSM 1900, UMTS FDD-2 or LTE FDD-2 band](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-125.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Approvals Page 126 of 143 4.2.3 Modifications The FCC requires the user to be notified that any changes or modifications made to this device that are not expressly approved by u-blox could void the user's authority to operate the equipment. Manufacturers of mobile or fixed devices incorporating the TOBY-L4006 modules are authorized to use the FCC Grants of the TOBY-L4006 modules for their own final products according to the conditions referenced in the certificates. The FCC Label shall in the above case be visible from the outside, or the host device shall bear a second label stating: "Contains FCC ID: XPY1EHQ37NN" resp. IMPORTANT: Manufacturers of portable applications incorporating the TOBY-L4006 modules are required to have their final product certified and apply for their own FCC Grant related to the specific portable device. This is mandatory to meet the SAR requirements for portable devices. Changes or modifications not expressly approved by the party responsible for compliance could void the user's authority to operate the equipment. Additional Note: as per 47CFR15.105 this equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This equipment generates, uses and can radiate radio frequency energy and, if not installed and used in accordance with the instructions, may cause harmful interference to radio communications. However, there is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one or more of the following measures: o Reorient or relocate the receiving antenna o Increase the separation between the equipment and receiver o Connect the equipment into an outlet on a circuit different from that to which the receiver is connected o Consultant the dealer or an experienced radio/TV technician for help](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-126.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Approvals Page 127 of 143 4.3 Innovation, Science and Economic Development Canada notice ISED Canada (formerly known as IC - Industry Canada) Certification Numbers: u-blox TOBY-L4006 cellular modules: 8595A-1EHQ37NN 4.3.1 Declaration of Conformity This device complies with the ISED Canada licence-exempt RSS standard(s). Operation is subject to the following two conditions: this device may not cause harmful interference this device must accept any interference received, including interference that may cause undesired operation Radiofrequency radiation exposure Information: this equipment complies with radiation exposure limits prescribed for an uncontrolled environment for fixed and mobile use conditions. This equipment should be installed and operated with a minimum distance of 20 cm between the radiator and the body of the user or nearby persons. This transmitter must not be co-located or operating in conjunction with any other antenna or transmitter except as authorized in the certification of the product. The gain of the system antenna(s) used for the TOBY-L4006 modules (i.e. the combined transmission line, connector, cable losses and radiating element gain) must not exceed not exceed the value specified in the ISED Canada Certificate Grant for mobile and fixed or mobile operating configurations: o 7.1 dBi in the 700 MHz band, i.e. LTE FDD-12 band o 7.0 dBi in the 750 MHz band, i.e. LTE FDD-13 band o 0.7 dBi in the 850 MHz band, i.e. GSM 850, UMTS FDD-5 or LTE FDD-5 band o 5.5 dBi in the 1700 MHz band, i.e. UMTS FDD-4 or LTE FDD-4 band o 2.7 dBi in the 1900 MHz band, i.e. GSM 1900, UMTS FDD-2 or LTE FDD-2 band](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-127.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Approvals Page 128 of 143 4.3.2 Modifications The ISED Canada requires the user to be notified that any changes or modifications made to this device that are not expressly approved by u-blox could void the user's authority to operate the equipment. Manufacturers of mobile or fixed devices incorporating the TOBY-L4006 modules are authorized to use the ISED Canada Certificates of the TOBY-L4006 modules for their own final products according to the conditions referenced in the certificates. The ISED Canada Label shall in the above case be visible from the outside, or the host device shall bear a second label stating: "Contains IC: 8595A-1EHQ37NN" resp. Innovation, Science and Economic Development Canada (ISED) Notices This Class B digital apparatus complies with Canadian CAN ICES-3(B) / NMB-3(B) and RSS-210. Operation is subject to the following two conditions: o this device may not cause interference o this device must accept any interference, including interference that may cause undesired operation of the device Radio Frequency (RF) Exposure Information The radiated output power of the u-blox Cellular Module is below the Innovation, Science and Economic Development Canada (ISED) radio frequency exposure limits. The u-blox Cellular Module should be used in such a manner such that the potential for human contact during normal operation is minimized. This device has been evaluated and shown compliant with the ISED RF Exposure limits under mobile exposure conditions (antennas are greater than 20 cm from a person's body). This device has been certified for use in Canada. Status of the listing in the Innovation, Science and Economic Development’s REL (Radio Equipment List) can be found at the following web address: http://www.ic.gc.ca/app/sitt/reltel/srch/nwRdSrch.do?lang=eng Additional Canadian information on RF exposure also can be found at the following web address: http://www.ic.gc.ca/eic/site/smt-gst.nsf/eng/sf08792.html IMPORTANT: Manufacturers of portable applications incorporating the TOBY-L4006 modules are required to have their final product certified and apply for their own Innovation, Science and Economic Development Canada Certificate related to the specific portable device. This is mandatory to meet the SAR requirements for portable devices. Changes or modifications not expressly approved by the party responsible for compliance could void the user's authority to operate the equipment.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-128.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Approvals Page 129 of 143 Avis d'Innovation, Sciences et Développement économique Canada (ISDE) Cet appareil numérique de classe B est conforme aux normes canadiennes CAN ICES-3(B) / NMB-3(B) et CNR-210. Son fonctionnement est soumis aux deux conditions suivantes : o cet appareil ne doit pas causer d'interférence o cet appareil doit accepter toute interférence, notamment les interférences qui peuvent affecter son fonctionnement Informations concernant l'exposition aux fréquences radio (RF) La puissance de sortie émise par l’appareil de sans fil u-blox Cellular Module est inférieure à la limite d'exposition aux fréquences radio d'Innovation, Sciences et Développement économique Canada (ISDE). Utilisez l’appareil de sans fil u-blox Cellular Module de façon à minimiser les contacts humains lors du fonctionnement normal. Ce périphérique a été évalué et démontré conforme aux limites d'exposition aux fréquences radio (RF) d'IC lorsqu'il est installé dans des produits hôtes particuliers qui fonctionnent dans des conditions d'exposition à des appareils mobiles (les antennes se situent à plus de 20 centimètres du corps d'une personne). Ce périphérique est homologué pour l'utilisation au Canada. Pour consulter l'entrée correspondant à l’appareil dans la liste d'équipement radio (REL - Radio Equipment List) d'Industrie Canada rendez-vous sur: http://www.ic.gc.ca/app/sitt/reltel/srch/nwRdSrch.do?lang=fra Pour des informations supplémentaires concernant l'exposition aux RF au Canada rendez-vous sur: http://www.ic.gc.ca/eic/site/smt-gst.nsf/fra/sf08792.html IMPORTANT: les fabricants d'applications portables contenant les modules TOBY-L4006 doivent faire certifier leur produit final et déposer directement leur candidature pour une certification FCC ainsi que pour un certificat ISDE Canada délivré par l'organisme chargé de ce type d'appareil portable. Ceci est obligatoire afin d'être en accord avec les exigences SAR pour les appareils portables. Tout changement ou modification non expressément approuvé par la partie responsable de la certification peut annuler le droit d'utiliser l'équipement.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-129.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Approvals Page 130 of 143 4.4 European Conformance CE mark TOBY-L4906 modules have been evaluated against the essential requirements of the Radio Equipment Directive 2014/53/EU. In order to satisfy the essential requirements of the 2014/53/EU RED, the modules are compliant with the following standards: Radio Spectrum Efficiency (Article 3.2): o EN 301 511 o EN 301 908-1 o EN 301 908-2 o EN 301 908-13 Electromagnetic Compatibility (Article 3.1b): o EN 301 489-1 o EN 301 489-52 Health and Safety (Article 3.1a) o EN 60950-1 o IEC 62368-1 and EN 62368-1 Radiofrequency radiation exposure information: this equipment complies with radiation exposure limits prescribed for an uncontrolled environment for fixed and mobile use conditions. This equipment should be installed and operated with a minimum distance of 20 cm between the radiator and the body of the user or nearby persons. This transmitter must not be co-located or operating in conjunction with any other antenna or transmitter except as authorized in the certification of the product. The gain of the system antenna(s) used for the TOBY-L4906 modules (i.e. the combined transmission line, connector, cable losses and radiating element gain) must not exceed the following values for mobile and fixed or mobile operating configurations: o 2.9 dBi in the 900 MHz band, i.e. GSM 900 or UMTS FDD-8 band o 8.8 dBi in the 1800 MHz band, i.e. GSM 1800 or LTE FDD-3 band o 12.7 dBi in the 1900 MHz band, i.e. LTE TDD-39 band o 12.3 dBi in the 2100 MHz band, i.e. UMTS FDD-1 or LTE FDD-1 band o 13.0 dBi in the 2300 MHz band, i.e. LTE TDD-40 band o 13.0 dBi in the 2500 MHz band, i.e. LTE TDD-41 band The conformity assessment procedure for the modules, referred to in Article 17 and detailed in Annex II of Directive 2014/53/EU, has been followed. Thus, the following marking is included in the product:](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-130.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Approvals Page 131 of 143 4.5 Chinese CCC and SRRC certifications TOBY-L4906 modules have the CCC (China Compulsory Certification) and the SRRC (State Radio Regulation of China) grants.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-131.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Product testing Page 132 of 143 5 Product testing 5.1 u-blox in-series production test u-blox focuses on high quality for its products. All units produced are fully tested automatically in the production line. Stringent quality control process has been implemented in the production line. The defective units are analyzed in detail to improve production quality. This is achieved with automatic test equipment (ATE) in the production line, which logs all production and measurement data. A detailed test report for each unit can be generated from the system. Figure 70 illustrates the typical automatic test equipment (ATE) in a production line. The following typical tests are among the production tests: Digital self-test (firmware download, Flash firmware verification, IMEI programming) Measurement of voltages and currents Adjustment of ADC measurement interfaces Functional tests (serial interface communication, SIM card communication) Digital tests (GPIOs and other interfaces) Measurement and calibration of RF characteristics in all supported bands (such as receiver S/N verification, frequency tuning of the reference clock, calibration of transmitter and receiver power levels, etc.) Verification of RF characteristics after calibration (i.e. modulation accuracy, power levels, spectrum, etc. are checked to ensure they are all within tolerances when calibration parameters are applied) Figure 70: Automatic test equipment for module tests](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-132.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Product testing Page 133 of 143 5.2 Test parameters for OEM manufacturers Because of the testing performed by u-blox (with 100% coverage), an OEM manufacturer does not need to repeat firmware tests or measurements of the module RF performance or tests over analog and digital interfaces in their production test. However, an OEM manufacturer should focus on: Module assembly on the device; it should be verified that: o Soldering and handling processes did not damage the module components o All module pins are well soldered on the device board o There are no short circuits between pins Component assembly on the device; it should be verified that: o Communications with the external host controller can be established o The interfaces between the module and external devices are working o Overall RF performance test of the device including the antenna Dedicated tests can be implemented to check the device. For example, the measurement of module current consumption when set in a specified status can detect a short circuit if compared with a “Golden Device” result. In addition, module AT commands can be used to perform functional tests on digital interfaces (communication with host controller, check SIM interface, GPIOs, etc.), on audio interfaces (audio loop for test purposes can be enabled as described in the u-blox AT Commands Manual [2]), and to perform RF performance tests (see the following section 5.2.2 for details). 5.2.1 “Go/No go” tests for integrated devices A “Go/No go” test is typically performed to compare the signal quality with a “Golden Device” in a location with excellent network coverage and known signal quality. This test should be performed after data connection has been established. AT+CSQ is the typical AT command used to check signal quality in term of RSSI. See the u-blox AT Commands Manual [2] for details of the AT command. These kinds of test may be useful as a “go/no go” test but not for RF performance measurements. This test is suitable to check the functionality of communication with the host controller or SIM card as well as the power supply. It is also a means to verify if the components are well soldered at the antenna interface. 5.2.2 RF functional tests The overall RF functional test of the OEM device integrating the cellular module, including the antenna(s), can be performed in the OEM production line with basic instruments such as a spectrum analyzer (or an RF power meter) and a signal generator with the assistance of the AT+UTEST command over the AT command user interface. The AT+UTEST command provides a simple interface to set the module to Rx or Tx test modes ignoring the LTE/3G/2G signaling protocol. The command can set the module into: transmitting mode in a specified channel and power level in all supported modulation schemes and bands receiving mode in a specified channel to returns the measured power level in all supported bands See the u-blox AT Commands Manual [2] for the AT+UTEST command syntax description.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-133.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Product testing Page 134 of 143 This feature allows the measurement of the transmitter and receiver power levels to check component assembly related to the module antenna interface and to check other device interfaces on which RF performance depends. To avoid module damage during the transmitter test, a suitable antenna according to module specifications or a 50 termination must be connected to the ANT1 port. To avoid module damage during receiver, test the maximum power level received at the ANT1 and ANT2 ports which must meet the module specifications. The AT+UTEST command sets the module to emit RF power ignoring LTE/3G/2G signaling protocol. This emission can generate interference that can be prohibited by law in some countries. The use of this feature is intended for testing purposes in controlled environments by qualified users and must not be used during normal module operation. Follow the instructions suggested in the u-blox documentation. u-blox assumes no responsibilities for the inappropriate use of this feature. Figure 71 illustrates a typical test setup for such an RF functional test. Application BoardTOBY-L4 seriesANT1Application ProcessorAT commandsCellular antennaSpectrumAnalyzerorPowerMeterINWideband antennaTXApplication BoardTOBY-L4 seriesANT1Application ProcessorAT commandsCellular antennasSignalGeneratorOUTWideband antennaRXANT2 Figure 71: Setup with spectrum analyzer or power meter and signal generator for radiated measurements](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-134.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Appendix Page 135 of 143 Appendix A Migration between TOBY-L2 and TOBY-L4 A.1 Overview TOBY-L2 and TOBY-L4 series cellular modules have the same TOBY form factor (35.6 x 24.8 mm LGA), with a different number of pins: as illustrated in Figure 72, TOBY-L2 modules have 152 pins, while TOBY-L4 modules have the same 152 pins of TOBY-L2 modules plus 96 additional pins, reaching a total number of 248 pins. Figure 72 shows that all the functions provided by the 152 pins of TOBY-L2 modules are also available on the same pins of TOBY-L4 modules, which provide additional functions (RGMII and UART3 interfaces) on RSVD pins of TOBY-L2 modules, intended to be left unconnected on a board designed for TOBY-L2 modules. This means that TOBY-L2 and TOBY-L4 series modules can be alternatively mounted on a single application board using exactly the same copper mask, solder mask and paste mask: TOBY-L4 series modules can be mounted on any design appropriately implemented for TOBY-L2 modules, given that any additional interface provided by TOBY-L4 modules will result not connected. SDIO_CMDSDIO_D0GNDVCCVCCGNDANT_DETSDASIM_IOSIM_RSTGPIO5GPIO6SDIO_D2SDIO_CLKRSVDRSVDI2S_WAI2S_CLKI2S_RXDSDIO_D1VCCGNDSCLSIM_CLKVSIMHOST_SELECT1RSVDI2S_TXDSDIO_D3V_INTVUSB_DETGNDRSVDGPIO1RSVDRSVDTXDRSVDUSB_D-HOST_SELECT0GPIO3RESET_NV_BCKPGPIO2PWR_ONRXDUSB_D+GPIO4GNDRSVDGNDGNDRSVDGNDGNDGNDGNDGNDGNDGNDGNDGNDRSVDANT2ANT1GNDRSVDGNDGNDRSVDGNDRSVDRSVDRSVDRSVDRSVDRSVDRSVDRSVDRSVDRSVDRSVDRIDSRRSVDCTSDTRDCDRSVDRSVDRTSRSVD11107542121191816151312292726242386322201714282596566697172747555575860616364474950525368707354565962485167909192 78 77 7693 10079808385868889 828487 81323130 44 45 46145 15243423937363433 403835 41999897969594106105104103102101108107124123130129128127126125136135134133132131138137144143142141140139151150149148147146114113112111110109120119118117116115122121TOBY-L2Pin 93-152: GNDSDIO_CMDSDIO_D0GNDVCCVCCGNDANT_DETSDASIM_IOSIM_RSTGPIO5GPIO6SDIO_D2SDIO_CLKRSVDRSVDI2S_WAI2S_CLKI2S_RXDSDIO_D1VCCGNDSCLSIM_CLKVSIMHOST_SELECT1RSVDI2S_TXDSDIO_D3V_INTVUSB_DETGNDRSVDGPIO1RXD3TXD3TXDETH_TX_CLKUSB_D-HOST_SELECT0GPIO3RESET_NV_BCKPGPIO2PWR_ONRXDUSB_D+GPIO4GNDRSVDGNDGNDRSVDGNDGNDGNDGNDGNDGNDGNDGNDGNDRSVDANT2ANT1GNDRSVDGNDGNDRSVDGNDETH_RX_CLKETH_RX_CTLETH_RXD1ETH_TXD0ETH_TXD1ETH_TXD3ETH_TX_CTLETH_RXD2ETH_RXD0ETH_TXD2ETH_RXD3RIDSRRSVDCTSDTRDCDRSVDRSVDRTSRSVD11RI10DSR7RSVD5V_INT4VUSB_D ET2GND1RSVD21GPIO119RSVD18RSVD16TXD15CTS13DTR12DCD29ETH_ TX_CLK27USB_D –26HOST_ SELECT024GPIO323RESET_N8RSVD6RSVD3V_BCKP22GPIO220PWR_ON17RXD14RTS28USB_D +25GPIO49RSVD65SDIO_C MD66SDIO_D 069GND71VCC72VCC74GND75ANT_D ET55SDA57SIM_IO58SIM_R ST60GPIO561GPIO663SDIO_D 264SDIO_C LK47RSVD49RSVD50I2S_WA52I2S_CL K53I2S_RXD68SDIO_D 170VCC73GND54SCL56SIM_C LK59VSIM62HOST_ SELECT148RSVD51I2S_TXD67SDIO_D 390GND91RSVD92GND78GND 77RSVD76GND93GND100GND79GND80GND83GND85GND86GND88GND89GND82GND84RSVD87ANT281ANT132GND31RSVD30GND44GND45RSVD 46GND145GND152GND43ETH_RX_CL K42ETH_RX_CTL39ETH_RXD137ETH_TXD036ETH_TXD134ETH_TXD333ETH_TX_CTL40ETH_RXD238ETH_RXD035ETH_TXD241ETH_RXD399GND98GND97GND96GND95GND94GND106GND105GND104GND103GND102GND101GND108GND107GND124GND123GND130GND129GND128GND127GND126GND125GND136GND135GND134GND133GND132GND131GND138GND137GND144GND143GND142GND141GND140GND139GND151GND150GND149GND148GND147GND146GND114GND113GND112GND111GND110GND109GND120GND119GND118GND117GND116GND115GND122GND121GNDTOBY-L4155RSVD153RSVD157RSVD156RSVD154RSVD158RSVD195CTS1193RTS1197RSVD196RSVD194RSVD198RSVD207I2S1_RXD206I2S1_TXD203SCL1201RSVD200RSVD217MMC_D2215MMC_CMD214MMC_D0212MMC_D1211MMC_ RST_N209GND208I2S1_CL K222ETH_ MDIO220ETH_ INTR219GND204SDA1202RSVD199RSVD218MMC_CD_N216MMC_CLK213MMC_D3210V_MMC221V_ETH205I2S1_WA223ETH_ MDC240ADC1241GND244RSVD246RSVD247GPIO8230MIC_GND232GND233MIC2_ N235GND236MIC1_ N238GND239ADC2225RSVD227SPK_P228SPK_N243RSVD245RSVD248GPIO7229GND231MIC_ BIAS234MIC2_ P237MIC1_ P226GND242RSVD224RSVD162RXD2161TXD2160RXD1159TXD1168USB_I D163RSVD167RSVD166RSVD165RSVD164RSVD172VSIM1171USB_SSR X–170USB_SSR X+169SPI_MISO182SIM1_C LK181RSVD180RSVD179SPI_SCL K178SIM1_IO173SPI_CS177SIM1_R ST176USB_SSTX–175USB_SSTX+174SPI_MOSI188RSVD183RSVD187RSVD186RSVD185RSVD184RSVD192RSVD191RSVD190RSVD189RSVDPin 93-152: GND Figure 72: TOBY-L2 and TOBY-L4 series modules pad layout and pin assignment TOBY modules are also form-factor compatible with the u-blox LISA, SARA and LARA cellular module families: although TOBY modules, LISA modules (33.2 x 22.4 mm, 76-pin LCC), SARA modules (26.0 x 16.0 mm, 96-pin LGA) and LARA modules (26.0 x 24.0 mm, 100-pin LGA) each have different form factors, the footprints for the TOBY, LISA, SARA and LARA modules have been developed to ensure layout compatibility. With the u-blox “nested design” solution, any TOBY, LISA, SARA or LARA module can be alternatively mounted on the same space of a single “nested” application board as described in the Nested Design Application Note [19].](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-135.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Appendix Page 136 of 143 Figure 73 summarizes the LTE, 3G and 2G operating frequency bands of TOBY-L2 and TOBY-L4 series modules. TOBY-L200704 960800 850 900 9507507001717 55VVIIIVIIIV850900850900II IIIIIV IV1710 21701700 1750 1800 1850 1900 1950 2000 2050 2100 21502500 26902500 2550 2600 2650 27004 42 2 7 72200 2250 2300 2400 24502350TOBY-L201704800 850 900 9507507008941717 551313VV II II17101700 1750 1800 1850 1900 1950 2000 2050 2100 215021554 42 22500 2550 2600 2650 27002200 2250 2300 2400 2450235018001900 19001800TOBY-L210800 850 900 950791750V96070020 205588VVIIIVIIIV850900850900II IIII1700 1750 1800 1850 1900 1950 2000 2050 2100 21501710 21702500 2550 2600 2650 27002500 26903 3 11 7 72200 2250 2300 2400 2450235018001900 19001800TOBY-L280TOBY-L4206TOBY-L4906TOBY-L4006TOBY-L4106800 850 900 95070375070096028285588800 850 900 9507037509607001919VVIIIVIIIV800 850 900 950750960700850900850900900900880699 894800 850 900 950750700800 850 900 95075096070070355131312 1229VVVIIIVIII85085090090020 20 8828285588VVIIIVIIIV850900850900VIIIVIII3 3 11 7 7IIII II3 3 7 7II113 3 11 7 7II18001900 190018002170 2500 26901700 1750 1800 1850 1900 1950 2000 2050 2100 21501710 2170 2500 26902500 2550 2600 2650 27002200 2250 2300 2400 245023501700 1750 1800 1850 1900 1950 2000 2050 2100 215017102500 2550 2600 2650 27002200 2250 2300 2400 245023501700 1750 1800 1850 1900 1950 2000 2050 2100 21501710 217018001900 190018001800 18002500 2550 2600 2650 270026552200 2250 2300 2400 2450235023004039 411710 21551700 1750 1800 1850 1900 1950 2000 2050 2100 215026902500 2550 2600 2650 27002200 2250 2300 2400 245023501700 1750 1800 1850 1900 1950 2000 2050 2100 21501710 21702500 2550 2600 2650 27002500 26902200 2250 2300 2400 245023507 74 42 2II IIIV IV1900 19001800 18003825003 3 11IITOBY-L220800 850 900 950824750960700 1700 1750 1800 1850 1900 1950 2000 2050 2100 21501710 21702500 2550 2600 2650 27002200 2250 2300 2400 2450235019195588VIIIVIII II3 3 11XIXXIX= W-CDMA bands = GSM bands= LTE FDD bandsLEGENDA= LTE TDD bands Figure 73: Summary of TOBY-L2 and TOBY-L4 series modules LTE, 3G and 2G operating frequency bands](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-136.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Appendix Page 137 of 143 A.2 Pin-out comparison between TOBY-L2 and TOBY-L4 TOBY-L2 TOBY-L4 Pin No Pin Name Description Pin Name Description Remarks for migration 1 RSVD Reserved RSVD Reserved 2 GND Ground GND Ground 3 V_BCKP RTC Back-up Supply V_BCKP RTC Back-up Supply 4 VUSB_DET Not supported VUSB_DET VBUS USB supply (5 V) detection 5 V must be applied at VUSB_DET of TOBY-L4 to enable USB device. The pin must be left unconnected on TOBY-L2, as it is not supported. 5 V_INT 1.8 V Interfaces Supply Output V_INT 1.8 V Interfaces Supply Output 6 RSVD Reserved This pin must be connected to GND RSVD Reserved This pin must be connected to GND 7-9 RSVD Reserved RSVD Reserved 10 DSR UART DSR Output22 / GPIO23 DSR GPIO24 / EINT24 11 RI UART RI Output22 / GPIO23 RI UART0 RI Output / GPIO / EINT24 12 DCD UART DCD Output22 / GPIO23 DCD GPIO24 / EINT24 13 DTR UART DTR Input22 / GPIO23 DTR GPIO24 / EINT24 14 RTS UART RTS Input22 RTS UART0 RTS Input24 15 CTS UART CTS Output22 CTS UART0 CTS Output24 16 TXD UART Data Input22 TXD UART0 Data Input24 17 RXD UART Data Output22 RXD UART0 Data Output24 18 RSVD Reserved TXD3 UART3 Data Input24 RSVD UART3 19 RSVD Reserved RXD3 UART3 Data Output24 RSVD UART3 20 PWR_ON Power-on Input Internal 50k pull-up to VCC Switch-on, Switch-off PWR_ON Power-on Input Internal 35k pull-up to 1.3 V Switch-on, Switch-off Internal pull-up slightly different No functional difference 21 GPIO1 GPIO23 GPIO1 GPIO 22 GPIO2 GPIO23 GPIO2 GPIO 23 RESET_N Reset signal Input Internal 50k pull-up to VCC Reset, Switch-on, Switch-off RESET_N Reset signal Input Internal 100k pull-up to V_INT Reset Internal pull-up slightly different. Function slightly different. 24 GPIO3 GPIO23 GPIO3 GPIO 25 GPIO4 GPIO23 GPIO4 GPIO 26 HOST_SELECT0 Not supported HOST_SELECT0 GPIO24 / EINT24 Not supported GPIO / EINT 27 USB_D- USB Data I/O (D-) USB_D- USB Data I/O (D-) 28 USB_D+ USB Data I/O (D+) USB_D+ USB Data I/O (D+) 29 RSVD Reserved ETH_TX_CLK Ethernet Transmission Clock24 RSVD RGMII 30 GND Ground GND Ground 31 RSVD Reserved RSVD Reserved 32 GND Ground GND Ground 33 RSVD Reserved ETH_TX_CTL Ethernet Transmit Control24 RSVD RGMII 34 RSVD Reserved ETH_TXD3 Ethernet Transmit Data [3]24 RSVD RGMII 35 RSVD Reserved ETH_TXD2 Ethernet Transmit Data [2]24 RSVD RGMII 36 RSVD Reserved ETH_TXD1 Ethernet Transmit Data [1]24 RSVD RGMII 37 RSVD Reserved ETH_TXD0 Ethernet Transmit Data [0]24 RSVD RGMII 38 RSVD Reserved ETH_RXD0 Ethernet Receive Data [0]24 RSVD RGMII 39 RSVD Reserved ETH_RXD1 Ethernet Receive Data [1]24 RSVD RGMII 40 RSVD Reserved ETH_RXD2 Ethernet Receive Data [2]24 RSVD RGMII 41 RSVD Reserved ETH_RXD3 Ethernet Receive Data [3]24 RSVD RGMII 42 RSVD Reserved ETH_RX_CTL Ethernet Receive Control24 RSVD RGMII 43 RSVD Reserved ETH_RX_CLK Ethernet Receive Clock24 RSVD RGMII 44 GND Ground GND Ground 45 RSVD Reserved RSVD Reserved 46 GND Ground GND Ground 22 Not supported by "00" product versions 23 Not supported by "00", "01", "60" product versions 24 Not supported by "50" product versions](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-137.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Appendix Page 138 of 143 TOBY-L2 TOBY-L4 Pin No Pin Name Description Pin Name Description Remarks for migration 47-49 RSVD Reserved RSVD Reserved 50 I2S_WA I2S Word Alignment22 / GPIO23 I2S_WA I2S Word Alignment I2S / GPIO I2S 51 I2S_TXD I2S Data Output22 / GPIO23 I2S_TXD I2S Data Output I2S / GPIO I2S 52 I2S_CLK I2S Clock22 / GPIO23 I2S_CLK I2S Clock I2S / GPIO I2S 53 I2S_RXD I2S Data Input22 / GPIO23 I2S_RXD I2S Data Input I2S / GPIO I2S 54 SCL I2C Clock Output25 SCL I2C Clock Output26 55 SDA I2C Data I/O25 SDA I2C Data I/O26 56 SIM_CLK SIM Clock Output SIM_CLK SIM Clock Output 57 SIM_IO SIM Data I/O SIM_IO SIM Data I/O 58 SIM_RST SIM Reset Output SIM_RST SIM Reset Output 59 VSIM SIM Supply Output VSIM SIM Supply Output 60 GPIO5 GPIO25 GPIO5 GPIO 61 GPIO6 GPIO25 GPIO6 GPIO 62 HOST_SELECT1 Not supported HOST_SELECT1 GPIO26 / EINT26 Not supported GPIO / EINT 63 SDIO_D2 SDIO serial data [2]25 SDIO_D2 SDIO serial data [2]26 64 SDIO_CLK SDIO serial clock25 SDIO_CLK SDIO serial clock26 65 SDIO_CMD SDIO command25 SDIO_CMD SDIO command26 66 SDIO_D0 SDIO serial data [0]25 SDIO_D0 SDIO serial data [0]26 67 SDIO_D3 SDIO serial data [3]25 SDIO_D3 SDIO serial data [3]26 68 SDIO_D1 SDIO serial data [1]25 SDIO_D1 SDIO serial data [1]26 69 GND Ground GND Ground 70-72 VCC Module Supply Input 3.40 V – 4.35 V normal range 3.20 V – 4.35 V extended range VCC Module Supply Input 3.40 V – 4.40 V normal range 3.00 V – 4.50 V extended range Larger operating ranges on TOBY-L4 73-74 GND Ground GND Ground 75 ANT_DET Antenna Detection Input25 ANT_DET Antenna Detection Input 76 GND Ground GND Ground 77 RSVD Reserved RSVD Reserved 78-80 GND Ground GND Ground 81 ANT1 RF Antenna Input/Output Up to six LTE bands Up to five 3G bands Up to four 2G bands ANT1 RF Antenna Input/Output Up to seven LTE bands Up to three 3G bands Up to four 2G bands No RF functional difference Different operating bands (Figure 73) 82-83 GND Ground GND Ground 84 RSVD Reserved RSVD Reserved 85-86 GND Ground GND Ground 87 ANT2 RF Antenna Input ANT2 RF Antenna Input No RF functional difference Different operating bands (Figure 73) 88-90 GND Ground GND Ground 91 RSVD Reserved RSVD Reserved 92-152 GND Ground GND Ground 152-248 Pins not available Additional functions Not available Additional functions Table 52: TOBY-L2 and TOBY-L4 series modules pin assignment with remarks for migration For further details regarding the characteristics, capabilities, usage or settings applicable for each interface of the cellular modules, see the TOBY-L4 series Data Sheet [1], the TOBY-L2 series Data Sheet [17], the TOBY-L2 / MPCI-L2 series System Integration Manual [18], and the u-blox AT Commands Manual [2]. 25 Not supported by "00", "01", "60" product versions 26 Not supported by "50" product versions](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-138.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Appendix Page 139 of 143 B Glossary 3GPP 3rd Generation Partnership Project 8-PSK 8 Phase-Shift Keying modulation 16QAM 16-state Quadrature Amplitude Modulation 64QAM 64-state Quadrature Amplitude Modulation ACM Abstract Control Model ADC Analog to Digital Converter AP Application Processor API Application Program Interface ASIC Application-Specific Integrated Circuit AT AT Command Interpreter Software Subsystem, or attention BAW Bulk Acoustic Wave CA Carrier Aggregation CSFB Circuit Switched Fall-Back DC Direct Current DCE Data Communication Equipment DDC Display Data Channel interface DL Down-Link (Reception) DRX Discontinuous Reception DSP Digital Signal Processing DTE Data Terminal Equipment EDGE Enhanced Data rates for GSM Evolution EMC Electro-Magnetic Compatibility EMI Electro-Magnetic Interference eMMC Embedded Multi-Media Card ESD Electro-Static Discharge ESR Equivalent Series Resistance E-UTRA Evolved Universal Terrestrial Radio Access FDD Frequency Division Duplex FEM Front End Module FOAT Firmware Over AT commands FOTA Firmware Over The Air FTP File Transfer Protocol FW Firmware GMSK Gaussian Minimum-Shift Keying modulation GND Ground GNSS Global Navigation Satellite System GPIO General Purpose Input Output GPRS General Packet Radio Service GPS Global Positioning System HBM Human Body Model HSDPA High Speed Downlink Packet Access HSUPA High Speed Uplink Packet Access HTTP HyperText Transfer Protocol HW Hardware I/Q In phase and Quadrature I2C Inter-Integrated Circuit interface I2S Inter IC Sound interface LDO Low-Dropout](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-139.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Appendix Page 140 of 143 LGA Land Grid Array LNA Low Noise Amplifier LPDDR Low Power Double Data Rate synchronous dynamic RAM memory LTE Long Term Evolution M2M Machine-to-Machine MIMO Multi-Input Multi-Output N/A Not Applicable N.A. Not Available OEM Original Equipment Manufacturer device: an application device integrating a u-blox cellular module OTA Over The Air PA Power Amplifier PCM Pulse Code Modulation PCN Product Change Notification / Information Note / Sample Delivery Note PCS Personal Communications Service PFM Pulse Frequency Modulation PMU Power Management Unit PWM Pulse Width Modulation QPSK Quadrature Phase Shift Keying RF Radio Frequency RGMII Reduced Gigabit Media Independent Interface RMII Reduced Media Independent Interface RSE Radiated Spurious Emission RTC Real Time Clock SAW Surface Acoustic Wave SDIO Secure Digital Input Output SDN / PCN / IN Sample Delivery Note / Product Change Notification / Information Note SIM Subscriber Identification Module SMS Short Message Service SPI Serial Peripheral Interface SRF Self Resonant Frequency SSL Secure Socket Layer TBD To Be Defined TCP Transmission Control Protocol TDD Time Division Duplex TDMA Time Division Multiple Access TIS Total Isotropic Sensitivity TP Test-Point TRP Total Radiated Power UART Universal Asynchronous Receiver-Transmitter uCPU u-blox universal Central Processing Unit UICC Universal Integrated Circuit Card UL Up-Link (Transmission) UMTS Universal Mobile Telecommunications System USB Universal Serial Bus VoLTE Voice over LTE VSWR Voltage Standing Wave Ratio W-CDMA Wideband Code Division Multiple Access Wi-Fi Wireless Local Area Network (IEEE 802.11 short range radio technology) WLAN Wireless Local Area Network (IEEE 802.11 short range radio technology) WWAN Wireless Wide Area Network (GSM / UMTS / LTE cellular radio technology)](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-140.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Related documents Page 141 of 143 Related documents [1] u-blox TOBY-L4 series Data Sheet, Docu No UBX-16009856 [2] u-blox AT Commands Manual, Docu No UBX-13002752 [3] Universal Serial Bus Rev. 2.0 specification, http://www.usb.org/developers/docs/usb20_docs/ [4] Universal Serial Bus Rev. 3.0 specification, http://www.usb.org/developers/docs/documents_archive/ [5] ITU-T Recommendation V.24 - 02-2000 - List of definitions for interchange circuits between Data Terminal Equipment (DTE) and Data Circuit-terminating Equipment (DCE), http://www.itu.int/rec/T-REC-V.24-200002-I/en [6] I2C-bus specification and user manual - Rev. 5 - 9 October 2012 - NXP Semiconductors, http://www.nxp.com/documents/user_manual/UM10204.pdf [7] Reduced Gigabit Media-Independent Interface (RGMII) Version 1.3, www.hp.com/rnd/pdfs/RGMIIv1_3.pdf [8] Reduced Media-Independent Interface (RMII) Specification, Rev. 1.2 [9] JESD84-B451 - Embedded Multimedia Card (eMMC), Electrical Standard 4.51 [10] GSM Association TS.09 - Battery Life Measurement and Current Consumption Technique https://www.gsma.com/newsroom/wp-content/uploads//TS.09_v10.0.pdf [11] 3GPP TS 51.010-2 - Technical Specification Group GSM/EDGE Radio Access Network; Mobile Station (MS) conformance specification; Part 2: Protocol Implementation Conformance Statement (PICS) [12] 3GPP TS 34.121-2 - Technical Specification Group Radio Access Network; User Equipment (UE) conformance specification; Radio transmission and reception (FDD); Part 2: Implementation Conformance Statement (ICS) [13] 3GPP TS 36.521-1 - Evolved Universal Terrestrial Radio Access; User Equipment conformance specification; Radio transmission and reception; Part 1: Conformance Testing [14] 3GPP TS 36.521-2 - Evolved Universal Terrestrial Radio Access (E-UTRA); User Equipment conformance specification; Radio transmission and reception; Part 2: Implementation Conformance Statement (ICS) [15] 3GPP TS 36.523-2 - Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Packet Core (EPC); User Equipment conformance specification; Part 2: Implementation Conformance Statement (ICS) [16] u-blox Package Information Guide, Docu No UBX-14001652 [17] u-blox TOBY-L2 series Data Sheet, Docu No UBX-13004573 [18] u-blox TOBY-L2 / MPCI-L2 series System Integration Manual, Docu No UBX- 13004618 [19] u-blox Nested Design Application Note, Docu No UBX-16007243 Some of the above documents can be downloaded from the u-blox web-site (http://www.u-blox.com/).](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-141.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Revision history Page 142 of 143 Revision history Revision Date Name Status / Comments R01 03-Mar-2017 sses Initial release R02 02-Aug-2017 sses Added document applicability to "50" product versions. Updated FW features supported by "00" product versions. Updated 3G maximum data rate. Clarified Rx diversity support. Updated Power-on and Power-off sections. Updated USB, UART, I2C, GPIOs supported functions / features. Updated support of SIM interfaces and digital audio interfaces. Corrected some typo in migration between TOBY-L2 and TOBY-L4. Minor other corrections. R03 03-Jan-2018 sses Added USB capabilities. Added data rate supported by UART, SPI and I2C interfaces. Added SDIO capabilities and application circuit. Updated recommended Ethernet PHY chips. Added analog audio use-cases and digital audio interfaces capabilities. Added GPIOs capabilities. Clarified application circuits with SIM interfaces. Minor other corrections. R04 08-Feb-2018 sses Updated TOBY-4006-50A / TOBY-4106-50A product status. Added FCC, ISED, CE, CCC and SRRC sections including related approvals info. Updated minimum limit for VCC normal operating range.](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-142.png)
![TOBY-L4 series - System Integration Manual UBX-16024839 - R04 Contact Page 143 of 143 Contact For complete contact information visit us at http://www.u-blox.com/ u-blox Offices North, Central and South America u-blox America, Inc. Phone: +1 703 483 3180 E-mail: info_us@u-blox.com Regional Office West Coast: Phone: +1 408 573 3640 E-mail: info_us@u-blox.com Technical Support: Phone: +1 703 483 3185 E-mail: support_us@u-blox.com Headquarters Europe, Middle East, Africa u-blox AG Phone: +41 44 722 74 44 E-mail: info@u-blox.com Support: support@u-blox.com Asia, Australia, Pacific u-blox Singapore Pte. Ltd. Phone: +65 6734 3811 E-mail: info_ap@u-blox.com Support: support_ap@u-blox.com Regional Office Australia: Phone: +61 2 8448 2016 E-mail: info_anz@u-blox.com Support: support_ap@u-blox.com Regional Office China (Beijing): Phone: +86 10 68 133 545 E-mail: info_cn@u-blox.com Support: support_cn@u-blox.com Regional Office China (Chongqing): Phone: +86 23 6815 1588 E-mail: info_cn@u-blox.com Support: support_cn@u-blox.com Regional Office China (Shanghai): Phone: +86 21 6090 4832 E-mail: info_cn@u-blox.com Support: support_cn@u-blox.com Regional Office China (Shenzhen): Phone: +86 755 8627 1083 E-mail: info_cn@u-blox.com Support: support_cn@u-blox.com Regional Office India: Phone: +91 80 4050 9200 E-mail: info_in@u-blox.com Support: support_in@u-blox.com Regional Office Japan (Osaka): Phone: +81 6 6941 3660 E-mail: info_jp@u-blox.com Support: support_jp@u-blox.com Regional Office Japan (Tokyo): Phone: +81 3 5775 3850 E-mail: info_jp@u-blox.com Support: support_jp@u-blox.com Regional Office Korea: Phone: +82 2 542 0861 E-mail: info_kr@u-blox.com Support: support_kr@u-blox.com Regional Office Taiwan: Phone: +886 2 2657 1090 E-mail: info_tw@u-blox.com Support: support_tw@u-blox.com](https://usermanual.wiki/u-blox/1EHQ37NN.TempConfidential-TOBY-L4-SysIntegrManual-UBX-16024839/User-Guide-3759877-Page-143.png)