u blox TOBYL200 GSM/UMTS/LTE Data Module User Manual TOBY L2 series

u-blox AG GSM/UMTS/LTE Data Module TOBY L2 series

System Integration Manual

TOBY-L2 and MPCI-L2 series

LTE/DC-HSPA+/EGPRS modules

System Integration Manual

Abstract

This document describes the features and the system integration of

TOBY-L2 and MPCI-L2 series multi-mode cellular modules.

These modules are a complete and cost efficient LTE/3G/2G solution

offering up to 150 Mb/s download and 50 Mb/s upload data rates,

covering up to six LTE bands, up to five WCDMA/DC-HSPA+ bands

and four GSM/EGPRS bands in the compact TOBY LGA form factor of

TOBY-L2 modules or in the industry standard PCI Express Mini Card

form factor of MPCI-L2 modules.

TOBY-L2 series

www.u-blox.com

UBX-13004618 - R04

MPCI-L2 series

TOBY-L2 and MPCI-L2 series - System Integration Manual

UBX-13004618 - R04

Page 2 of 141

Document Information

Title

TOBY-L2 and MPCI-L2 series

Subtitle

LTE/DC-HSPA+/EGPRS modules

Document type

System Integration Manual

Document number

UBX-13004618

Revision and date

R04

30-Sep-2014

Document status

Advance Information

Document status explanation

Objective Specification

Document contains target values. Revised and supplementary data will be published later.

Advance Information

Document contains data based on early testing. Revised and supplementary data will be published later.

Early Production Information

Document contains data from product verification. Revised and supplementary data may be published later.

Production Information

Document contains the final product specification.

This document applies to the following products:

Name

Type number

Firmware version

PCN / IN

TOBY-L200

TOBY-L200-00S-00

09.40

UBX-14040967

TOBY-L210

TOBY-L210-00S-00

09.40

UBX-14040967

MPCI-L200

MPCI-L200-00S-00

09.34

UBX-14040967

MPCI-L210

MPCI-L210-00S-00

09.34

UBX-14040967

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.

u-blox® is a registered trademark of u-blox Holding AG in the EU and other countries. PCI, PCI Express, PCIe, and PCI-SIG are trademarks or

registered trademarks of PCI-SIG. Microsoft and Windows are either registered trademarks or trademarks of Microsoft Corporation in the

United States and/or other countries. ARM® is a registered trademark of ARM Limited in the EU and other countries. All other registered

trademarks or trademarks mentioned in this document are property of their respective owners.

TOBY-L2 and MPCI-L2 series - System Integration Manual

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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-L2 and MPCI-L2 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-L200) and firmware version

 Module configuration

 Clear description of your question or the problem

 A short description of the application

 Your complete contact details

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Contents

Preface ................................................................................................................................ 3

Contents .............................................................................................................................. 4

1 System description ....................................................................................................... 8

1.1 Overview .............................................................................................................................................. 8

1.2 Architecture ........................................................................................................................................ 10

1.2.1 Internal blocks ............................................................................................................................. 11

1.3 Pin-out ............................................................................................................................................... 12

1.3.1 TOBY-L2 series pin assignment .................................................................................................... 12

1.3.2 MPCI-L2 series pin assignment .................................................................................................... 16

1.4 Operating modes ................................................................................................................................ 18

1.5 Supply interfaces ................................................................................................................................ 20

1.5.1 Module supply input (VCC or 3.3Vaux) ....................................................................................... 20

1.5.2 RTC supply input/output (V_BCKP) .............................................................................................. 27

1.5.3 Generic digital interfaces supply output (V_INT) ........................................................................... 28

1.6 System function interfaces .................................................................................................................. 29

1.6.1 Module power-on ....................................................................................................................... 29

1.6.2 Module power-off ....................................................................................................................... 31

1.6.3 Module reset ............................................................................................................................... 33

1.6.4 Module configuration selection by host processor ....................................................................... 33

1.7 Antenna interface ............................................................................................................................... 34

1.7.1 Antenna RF interfaces (ANT1 / ANT2) .......................................................................................... 34

1.7.2 Antenna detection interface (ANT_DET) ...................................................................................... 37

1.8 SIM interface ...................................................................................................................................... 37

1.8.1 SIM interface ............................................................................................................................... 37

1.8.2 SIM detection interface ............................................................................................................... 37

1.9 Data communication interfaces .......................................................................................................... 38

1.9.1 Universal Serial Bus (USB) ............................................................................................................ 38

1.9.2 Asynchronous serial interface (UART)........................................................................................... 42

1.9.3 DDC (I2C) interface ...................................................................................................................... 44

1.9.4 Secure Digital Input Output interface (SDIO) ................................................................................ 45

1.10 Audio .............................................................................................................................................. 45

1.10.1 Digital audio over I2S interface ..................................................................................................... 45

1.11 General Purpose Input/Output ........................................................................................................ 46

1.12 Mini PCIe specific signals (W_DISABLE#, LED_WWAN#) .................................................................. 47

1.13 Reserved pins (RSVD) ...................................................................................................................... 47

1.14 Not connected pins (NC) ................................................................................................................. 47

1.15 System features............................................................................................................................... 48

1.15.1 Network indication ...................................................................................................................... 48

1.15.2 Antenna supervisor ..................................................................................................................... 48

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1.15.3 Jamming detection ...................................................................................................................... 48

1.15.4 IP modes of operation ................................................................................................................. 49

1.15.5 Dual stack IPv4/IPv6 ..................................................................................................................... 49

1.15.6 TCP/IP and UDP/IP ....................................................................................................................... 49

1.15.7 FTP and FTPS ............................................................................................................................... 49

1.15.8 HTTP and HTTPS .......................................................................................................................... 50

1.15.9 SSL .............................................................................................................................................. 50

1.15.10 AssistNow clients and GNSS integration ................................................................................... 50

1.15.11 Hybrid positioning and CellLocate® .......................................................................................... 50

1.15.12 Firmware update Over AT (FOAT)............................................................................................. 53

1.15.13 Firmware update Over The Air (FOTA) ...................................................................................... 53

1.15.14 In-band Modem (eCall / ERA-GLONASS) .................................................................................. 54

1.15.15 SIM Access Profile (SAP) ........................................................................................................... 54

1.15.16 Smart temperature management ............................................................................................. 56

1.15.17 Power saving ........................................................................................................................... 58

2 Design-in ..................................................................................................................... 59

2.1 Overview ............................................................................................................................................ 59

2.2 Supply interfaces ................................................................................................................................ 60

2.2.1 Module supply (VCC or 3.3Vaux)................................................................................................. 60

2.2.2 RTC supply output (V_BCKP) ....................................................................................................... 72

2.2.3 Generic digital interfaces supply output (V_INT) ........................................................................... 74

2.3 System functions interfaces ................................................................................................................ 75

2.3.1 Module power-on (PWR_ON) ...................................................................................................... 75

2.3.2 Module reset (RESET_N or PERST#) .............................................................................................. 76

2.3.3 Module configuration selection by host processor ....................................................................... 77

2.4 Antenna interface ............................................................................................................................... 78

2.4.1 Antenna RF interfaces (ANT1 / ANT2) .......................................................................................... 78

2.4.2 Antenna detection interface (ANT_DET) ...................................................................................... 86

2.5 SIM interface ...................................................................................................................................... 88

2.5.1 Guidelines for SIM circuit design.................................................................................................. 88

2.5.2 Guidelines for SIM layout design ................................................................................................. 94

2.6 Data communication interfaces .......................................................................................................... 95

2.6.1 Universal Serial Bus (USB) ............................................................................................................ 95

2.6.2 Asynchronous serial interface (UART)........................................................................................... 97

2.6.3 DDC (I2C) interface .................................................................................................................... 101

2.6.4 Secure Digital Input Output interface (SDIO) .............................................................................. 105

2.7 Audio interface ................................................................................................................................. 106

2.7.1 Digital audio interface ............................................................................................................... 106

2.8 General Purpose Input/Output .......................................................................................................... 108

2.9 Mini PCIe specific signals (W_DISABLE#, LED_WWAN#) .................................................................... 109

2.10 Reserved pins (RSVD) .................................................................................................................... 110

2.11 Module placement ........................................................................................................................ 111

2.12 TOBY-L2 series module footprint and paste mask ......................................................................... 112

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2.13 MPCI-L2 series module installation ................................................................................................ 113

2.14 Thermal guidelines ........................................................................................................................ 115

2.15 ESD guidelines .............................................................................................................................. 116

2.15.1 ESD immunity test overview ...................................................................................................... 116

2.15.2 ESD immunity test of TOBY-L2 and MPCI-L2 series reference designs ........................................ 117

2.15.3 ESD application circuits .............................................................................................................. 117

2.16 Schematic for TOBY-L2 and MPCI-L2 series module integration .................................................... 118

2.17 Design-in checklist ........................................................................................................................ 120

2.17.1 Schematic checklist ................................................................................................................... 120

2.17.2 Layout checklist ......................................................................................................................... 121

2.17.3 Antenna checklist ...................................................................................................................... 121

3 Handling and soldering ........................................................................................... 122

3.1 Packaging, shipping, storage and moisture preconditioning ............................................................. 122

3.2 Handling ........................................................................................................................................... 122

3.3 Soldering .......................................................................................................................................... 123

3.3.1 Soldering paste.......................................................................................................................... 123

3.3.2 Reflow soldering ....................................................................................................................... 123

3.3.3 Optical inspection ...................................................................................................................... 124

3.3.4 Cleaning .................................................................................................................................... 124

3.3.5 Repeated reflow soldering ......................................................................................................... 125

3.3.6 Wave soldering.......................................................................................................................... 125

3.3.7 Hand soldering .......................................................................................................................... 125

3.3.8 Rework ...................................................................................................................................... 125

3.3.9 Conformal coating .................................................................................................................... 125

3.3.10 Casting ...................................................................................................................................... 125

3.3.11 Grounding metal covers ............................................................................................................ 125

3.3.12 Use of ultrasonic processes ........................................................................................................ 125

4 Approvals .................................................................................................................. 126

4.1 Product certification approval overview ............................................................................................. 126

4.2 Federal Communications Commission and Industry Canada notice ................................................... 127

4.2.1 Safety warnings review the structure ......................................................................................... 127

4.2.2 Declaration of Conformity – United States only ......................................................................... 127

4.2.3 Modifications ............................................................................................................................ 127

4.3 R&TTED and European Conformance CE mark ................................................................................. 129

5 Product testing ......................................................................................................... 130

5.1 u-blox in-series production test ......................................................................................................... 130

5.2 Test parameters for OEM manufacturer ............................................................................................ 131

5.2.1 “Go/No go” tests for integrated devices .................................................................................... 131

5.2.2 RF functional tests ..................................................................................................................... 131

Appendix ........................................................................................................................ 133

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A Glossary .................................................................................................................... 133

B Migration between TOBY-L1 and TOBY-L2 ............................................................ 135

B.1 Overview .......................................................................................................................................... 135

B.2 Pin-out comparison between TOBY-L1 and TOBY-L2 ........................................................................ 136

B.3 Schematic for TOBY-L1 and TOBY-L2 integration .............................................................................. 138

Related documents......................................................................................................... 139

Revision history .............................................................................................................. 140

Contact ............................................................................................................................ 141

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1 System description

1.1 Overview

TOBY-L2 and MPCI-L2 series comprises LTE/3G/2G multi-mode modules supporting up to six LTE bands, up to

five UMTS/DC-HSPA+ bands and four GSM/(E)GPRS bands for voice and/or data transmission as following:

 TOBY-L200 and MPCI-L200 are designed primarily for operation in America

 TOBY-L210 and MPCI-L210 are designed primarily for operation in Europe, Asia and other countries

TOBY-L2 and MPCI-L2 series are designed in two different form-factors suitable for applications as following:

 TOBY-L2 modules are designed in the small TOBY 152-pin Land Grid Array form-factor (35.6 x 24.8 mm),

easy to integrate in compact designs and form-factor compatible with the u-blox cellular module families:

this allows customers to take the maximum advantage of their hardware and software investments, and

provides very short time-to-market.

 MPCI-L2 modules are designed in the industry standard PCI Express Full-Mini Card form-factor (51 x 30 mm)

easy to integrate into industrial and consumer applications and also ideal for manufacturing of small series.

With LTE Category 4 data rates at up to 150 Mb/s (down-link) and 50 Mb/s (up-link), the modules are ideal for

applications requiring the highest data-rates and high-speed internet access. TOBY-L2 and MPCI-L2 series

modules are the perfect choice for consumer fixed-wireless terminals, mobile routers and gateways, and

applications requiring video streaming. They are also optimally suited for industrial (M2M) applications, such as

remote access to video cameras, digital signage, telehealth, and security and surveillance systems.

Table 1 summarizes the TOBY-L2 and MPCI-L2 series main features and interfaces.

Module

LTE

UMTS

GSM

Positioning

Interfaces

Audio

Features

LTE category

Bands

HSDPA category

HSUPA category

Bands

GPRS/EDGE multi-slot class

Bands

GNSS receiver

GNSS Via Modem

Assist Now Software

CellLocate®

UART

USB 2.0

SDIO

DCC (I2C)

GPIOs

MIMO 2x2 / Rx Diversity

Analog audio

Digital Audio

Network indication

Antenna supervisor

Jamming detection

Embedded TCP/UDP stack

Embedded HTTP,FTP,SSL

FOTA

eCall / ERA GLONASS

Dual stack IPv4/IPv6

TOBY-L200

2,4,5,

7,17

850/900/AWS

1900/2100

Quad

•

TOBY-L210

1,3,5,

7,8,20

850/900

1900/2100

Quad

•

MPCI-L200

2,4,5,

7,17

850/900/AWS

1900/2100

Quad

•

MPCI-L210

1,3,5,

7,8,20

850/900

1900/2100

Quad

•

F = will be supported in future product version “01”

Table 1: TOBY-L2 and MPCI-L2 series main features summary

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Table 2 reports a summary of LTE, 3G and 2G cellular radio access technologies characteristics and features of

the TOBY-L2 and MPCI-L2 series modules.

4G LTE

3G UMTS/HSDPA/HSUPA

2G GSM/GPRS/EDGE

3GPP Release 9

Long Term Evolution (LTE)

Evolved Uni.Terrestrial Radio Access (E-UTRA)

Frequency Division Duplex (FDD)

DL Multi-Input Multi-Output (MIMO) 2 x 2

3GPP Release 8

Dual-Cell HS Packet Access (DC-HSPA+)

UMTS Terrestrial Radio Access (UTRA)

Frequency Division Duplex (FDD)

DL Rx diversity

3GPP Release 8

Enhanced Data rate GSM Evolution (EDGE)

GSM EGPRS Radio Access (GERA)

Time Division Multiple Access (TDMA)

DL Advanced Rx Performance (DARP) Phase 1

Band support:

 TOBY-L200 / MPCI-L200:

 Band 17 (700 MHz)

 Band 5 (850 MHz)

 Band 4 (1700 MHz)

 Band 2 (1900 MHz)

 Band 7 (2600 MHz)

 TOBY-L210 / MPCI-L210:

 Band 20 (800 MHz)

 Band 5 (850 MHz)

 Band 8 (900 MHz)

 Band 3 (1800 MHz)

 Band 1 (2100 MHz)

 Band 7 (2600 MHz)

Band support:

 TOBY-L200 / MPCI-L200:

 Band 5 (850 MHz)

 Band 8 (900 MHz)

 Band 4 (AWS, 1700 MHz)

 Band 2 (1900 MHz)

 Band 1 (2100 MHz)

 TOBY-L210 / MPCI-L210:

 Band 5 (850 MHz)

 Band 8 (900 MHz)

 Band 2 (1900 MHz)

 Band 1 (2100 MHz)

Band support

 TOBY-L200 / MPCI-L200:

 GSM 850 MHz

 E-GSM 900 MHz

 DCS 1800 MHz

 PCS 1900 MHz

 TOBY-L210 / MPCI-L210:

 GSM 850 MHz

 E-GSM 900 MHz

 DCS 1800 MHz

 PCS 1900 MHz

LTE Power Class

 Power Class 3 (23 dBm)

for LTE mode

WCDMA/HSDPA/HSUPA Power Class

 Power Class 3 (24 dBm)

for UMTS/HSDPA/HSUPA mode

GSM/GPRS Power Class

 Power Class 4 (33 dBm)

for GSM/E-GSM bands

 Power Class 1 (30 dBm)

for DCS/PCS bands

EDGE Power Class

 Power Class E2 (27 dBm)

for GSM/E-GSM bands

 Power Class E2 (26 dBm)

for DCS/PCS bands

Data rate

 LTE category 4:

up to 150 Mb/s DL, 50 Mb/s UL

Data rate

 TOBY-L200 / MPCI-L200:

 HSDPA cat.14, up to 21 Mb/s DL1

 HSUPA cat.6, up to 5.6 Mb/s UL

 TOBY-L210 / MPCI-L210:

 HSDPA cat.24, up to 42 Mb/s DL

 HSUPA cat.6, up to 5.6 Mb/s UL

Data rate2

 GPRS multi-slot class 123, CS1-CS4,

up to 85.6 kb/s DL/UL

 EDGE multi-slot class 123, MCS1-MCS9

up to 236.8 kb/s DL/UL

Table 2: TOBY-L2 and MPCI-L2 series LTE, 3G and 2G characteristics summary

HSDPA category 24 capable

GPRS/EDGE multi-slot class determines the number of timeslots available for upload and download and thus the speed at which data can

be transmitted and received, with higher classes typically allowing faster data transfer rates.

GPRS/EDGE multi-slot class 12 implies a maximum of 4 slots in DL (reception) and 4 slots in UL (transmission) with 5 slots in total.

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1.2 Architecture

Figure 1 summarizes the internal architecture of TOBY-L2 series modules.

Cellular

Base-band

Processor

Memory

Power Management Unit

26 MHz

32.768 kHz

ANT1

Transceiver

ANT2

V_INT (I/O)

V_BCKP (RTC)

VCC (Supply)

SIM

USB

GPIO

Power On

External Reset

PAs

LNAs Filters

Filters

Duplexer

Filters

PAs

LNAs Filters

Filters

Duplexer

Filters

LNAs FiltersFilters

Switch

DDC(I2C)

SDIO

UART

Digital audio (I2S)

ANT_DET

Host Select

Figure 1: TOBY-L2 series block diagram

As described in the Figure 2, each MPCI-L2 series module integrates one TOBY-L2 series module:

 The MPCI-L200 integrates a TOBY-L200 module

 The MPCI-L210 integrates a TOBY-L210 module

The TOBY-L2 module represents the core of the device, providing the related LTE/3G/2G modem and processing

functionalities. Additional signal conditioning circuitry is implemented for PCI Express Mini Card compliance, and

two UF.L connectors are available for easy antenna integration.

ANT1

SIM

USB

W_DISABLE#

TOBY-L2

series

Signal

Conditioning

ANT2

PERST#

LED_WWAN#

U.FL

3.3Vaux (Supply)

Boost

Converter

VCC

Figure 2: MPCI-L2 series block diagram

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1.2.1 Internal blocks

As described in Figure 2, each MPCI-L2 series module integrates one TOBY-L2 series module, which consists of

the following internal sections: RF, baseband and power management.

RF section

The RF section is composed of RF transceiver, PAs, LNAs, crystal oscillator, filters, duplexers and RF switches.

Tx signal is pre-amplified by 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 LTE Down-Link MIMO 2 x 2 and 3G Receiver Diversity radio

technologies supported by the modules as LTE category 4 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/Q signals for Tx, down-conversion and

demodulation of the dual RF signals for Rx. The RF transceiver contains:

Automatically gain controlled direct conversion Zero-IF receiver,

Highly linear RF demodulator / modulator capable GMSK, 8-PSK, QPSK, 16-QAM, 64-QAM,

Fractional-N Sigma-Delta RF synthesizer,

VCO.

 Power Amplifiers (PA) amplify the Tx signal modulated by the RF transceiver

 RF switches connect primary (ANT1) and secondary (ANT2) antenna ports to the suitable Tx / Rx path

 Low Noise Amplifiers (LNA) enhance the received sensitivity

 SAW duplexers separate the Tx and Rx signal paths and provide RF filtering

 SAW band pass filters enhance the rejection of out-of-band signals

 26 MHz crystal oscillator generates the clock reference in active-mode or connected-mode.

Baseband and power management section

The Baseband and Power Management section is composed of the following main elements:

 A mixed signal ASIC, which integrates

Microprocessor for control functions

DSP core for LTE/3G/2G Layer 1 and digital processing of Rx and Tx signal paths

Memory interface controller

Dedicated peripheral blocks for control of the USB, SIM and GPIO digital interfaces

Analog front end interfaces to RF transceiver ASIC

 Memory system, which includes NAND flash and LPDDR

 Voltage regulators to derive all the subsystem supply voltages from the module supply input VCC

 Voltage sources for external use: V_BCKP and V_INT (not available on MPCI-L2 series modules)

 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

enable power saving configuration using the AT+UPSV command.

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1.3 Pin-out

1.3.1 TOBY-L2 series pin assignment

Table 3 lists the pin-out of the TOBY-L2 series modules, with pins grouped by function.

Function

Pin Name

Pin No

I/O

Description

Remarks

Power

VCC

70,71,72

Module supply input

VCC pins are internally connected each other.

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 and

requirements for the VCC module supply.

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

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

I/O

RTC supply

input/output

V_BCKP = 3.0 V (typical) generated by internal regulator

when valid VCC supply is present.

See section 1.5.2 for functional description.

See section 2.2.2 for external circuit design-in.

V_INT

Generic digital

interfaces supply

output

V_INT = 1.8 V (typical) generated by internal regulator

when the module is switched on.

See section 1.5.3 for functional description.

See section 2.2.3 for external circuit design-in.

System

PWR_ON

Power-on input

Internal active pull-up to the VCC enabled.

See section 1.6.1 for functional description.

See section 2.3.1 for external circuit design-in.

RESET_N

External reset input

Internal active pull-up to the VCC enabled.

See section 1.6.3 for functional description.

See section 2.3.2 for external circuit design-in.

HOST_SELECT0

Selection of module

configuration by the

host processor

Note: Not supported by TOBY-L2x0-00S product version

See section 1.6.4 for functional description.

See section 2.3.3 for external circuit design-in.

HOST_SELECT1

Selection of module

configuration by the

host processor

Note: Not supported by TOBY-L2x0-00S product version

See section 1.6.4 for functional description.

See section 2.3.3 for external circuit design-in.

Antennas

ANT1

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 for functional description / requirements.

See section 2.4 for external circuit design-in.

ANT2

Secondary antenna

Rx only for MIMO 2x2 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 for functional description / requirements

See section 2.4 for external circuit design-in.

ANT_DET

Antenna detection

Note: antenna detection not supported by TOBY-L2x0-00S.

See section 1.7.2 for functional description.

See section 2.4.2 for external circuit design-in.

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Function

Pin Name

Pin No

I/O

Description

Remarks

SIM

VSIM

SIM supply output

VSIM = 1.8 V / 3 V automatically generated according to

the connected SIM type.

See section 1.8 for functional description.

See section 2.5 for external circuit design-in.

SIM_IO

I/O

SIM 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

SIM clock

3.25 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

SIM 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

USB detect input

Input for VBUS (5 V typical) USB supply sense.

See section 1.9.1 for functional description.

See section 2.6.1 for external circuit design-in.

USB_D-

I/O

USB Data Line D-

USB interface for AT commands, data communication,

FOAT, FW update by u-blox EasyFlash tool and diagnostic.

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 [4] are part of the

USB pad driver and need not be provided externally.

See section 1.9.1 for functional description.

See section 2.6.1 for external circuit design-in.

USB_D+

I/O

USB Data Line D+

USB interface for AT commands, data communication,

FOAT, FW update by u-blox EasyFlash tool and diagnostic.

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 [4] are part of the

USB pad driver and need not be provided externally.

See section 1.9.1 for functional description.

See section 2.6.1 for external circuit design-in.

UART

RXD

UART data output

Note: UART not supported by TOBY-L2x0-00S.

1.8 V output, Circuit 104 (RXD) in ITU-T V.24,

for AT command, data communication, FOAT.

Add Test-Point and series 0  to access for diagnostic.

See section 1.9.2 for functional description.

See section 2.6.2 for external circuit design-in.

TXD

UART data input

Note: UART not supported by TOBY-L2x0-00S.

1.8 V input, Circuit 103 (TXD) in ITU-T V.24,

for AT command, data communication, FOAT.

Add Test-Point and series 0  to access for diagnostic.

See section 1.9.2 for functional description.

See section 2.6.2 for external circuit design-in.

CTS

UART clear to send

output

Note: UART not supported by TOBY-L2x0-00S.

1.8 V output, Circuit 106 (CTS) in ITU-T V.24.

Add Test-Point and series 0  to access for diagnostic.

See section 1.9.2 for functional description.

See section 2.6.2 for external circuit design-in.

RTS

UART ready to send

input

Note: UART not supported by TOBY-L2x0-00S.

1.8 V input, Circuit 105 (RTS) in ITU-T V.24.

Add Test-Point and series 0  to access for diagnostic.

See section 1.9.2 for functional description.

See section 2.6.2 for external circuit design-in.

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Function

Pin Name

Pin No

I/O

Description

Remarks

DSR

O /

I/O

UART data set ready

output / GPIO

Note: UART / GPIO not supported by TOBY-L2x0-00S.

1.8 V, Circuit 107 in ITU-T V.24, configurable as GPIO.

Add Test-Point and series 0  to access for diagnostic.

See section 1.9.2 and 1.11 for functional description.

See section 2.6.2 and 2.8 for external circuit design-in.

O /

I/O

UART ring indicator

output / GPIO

Note: UART / GPIO not supported by TOBY-L2x0-00S.

1.8 V, Circuit 125 in ITU-T V.24, configurable as GPIO.

Add Test-Point and series 0  to access for diagnostic.

See section 1.9.2 and 1.11 for functional description.

See section 2.6.2 and 2.8 for external circuit design-in.

DTR

I /

I/O

UART data terminal

ready input / GPIO

Note: UART / GPIO not supported by TOBY-L2x0-00S.

1.8 V, Circuit 108/2 in ITU-T V.24, configurable as GPIO.

Add Test-Point and series 0  to access for diagnostic.

See section 1.9.2 and 1.11 for functional description.

See section 2.6.2 and 2.8 for external circuit design-in.

DCD

O /

I/O

UART data carrier

detect output / GPIO

Note: UART / GPIO not supported by TOBY-L2x0-00S.

1.8 V, Circuit 109 in ITU-T V.24, configurable as GPIO.

Add Test-Point and series 0  to access for diagnostic.

See section 1.9.2 and 1.11 for functional description.

See section 2.6.2 and 2.8 for external circuit design-in.

DDC

SCL

I2C bus clock line

Note: I2C not supported by TOBY-L2x0-00S.

1.8 V open drain, for communication with u-blox GNSS

receivers and other I2C-slave devices as an audio codec.

External pull-up required.

See section 1.9.3 for functional description.

See section 2.6.3 for external circuit design-in.

SDA

I/O

I2C bus data line

Note: I2C not supported by TOBY-L2x0-00S.

1.8 V open drain, for communication with u-blox GNSS

receivers and other I2C-slave devices as an audio codec.

External pull-up required.

See section 1.9.3 for functional description.

See section 2.6.3 for external circuit design-in.

SDIO

SDIO_D0

I/O

SDIO serial data [0]

Note: SDIO not supported by TOBY-L2x0-00S.

SDIO interface for communication with external Wi-Fi chip

See section 1.9.4 for functional description.

See section 2.6.4 for external circuit design-in.

SDIO_D1

I/O

SDIO serial data [1]

Note: Not supported by TOBY-L2x0-00S.

SDIO interface for communication with external Wi-Fi chip

See section 1.9.4 for functional description.

See section 2.6.4 for external circuit design-in.

SDIO_D2

I/O

SDIO serial data [2]

Note: SDIO not supported by TOBY-L2x0-00S.

SDIO interface for communication with external Wi-Fi chip

See section 1.9.4 for functional description.

See section 2.6.4 for external circuit design-in.

SDIO_D3

I/O

SDIO serial data [3]

Note: SDIO not supported by TOBY-L2x0-00S.

SDIO interface for communication with external Wi-Fi chip

See section 1.9.4 for functional description.

See section 2.6.4 for external circuit design-in.

SDIO_CLK

SDIO serial clock

Note: SDIO not supported by TOBY-L2x0-00S.

SDIO interface for communication with external Wi-Fi chip

See section 1.9.4 for functional description.

See section 2.6.4 for external circuit design-in.

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Function

Pin Name

Pin No

I/O

Description

Remarks

SDIO_CMD

I/O

SDIO command

Note: SDIO not supported by TOBY-L2x0-00S.

SDIO interface for communication with external Wi-Fi chip

See section 1.9.4 for functional description.

See section 2.6.4 for external circuit design-in.

Audio

I2S_TXD

O /

I/O

I2S transmit data /

GPIO

Note: I2S and GPIO not supported by TOBY-L2x0-00S.

I2S transmit data output, alternatively configurable as GPIO.

See sections 1.10 and 1.11 for functional description.

See sections 2.7 and 2.8 for external circuit design-in.

I2S_RXD

I /

I/O

I2S receive data /

GPIO

Note: I2S and GPIO not supported by TOBY-L2x0-00S.

I2S receive data input, alternatively configurable as GPIO.

See sections 1.10 and 1.11 for functional description.

See sections 2.7 and 2.8 for external circuit design-in.

I2S_CLK

I/O /

I/O

I2S clock /

GPIO

Note: I2S and GPIO not supported by TOBY-L2x0-00S.

I2S serial clock, alternatively configurable as GPIO.

See sections 1.10 and 1.11 for functional description.

See sections 2.7 and 2.8 for external circuit design-in.

I2S_WA

I/O /

I/O

I2S word alignment /

GPIO

Note: I2S and GPIO not supported by TOBY-L2x0-00S.

I2S word alignment, alternatively configurable as GPIO.

Note: I2S not supported by TOBY-L2x0-00S.

See sections 1.10 and 1.11 for functional description.

See sections 2.7 and 2.8 for external circuit design-in.

GPIO

GPIO1

I/O

GPIO

Note: GPIO not supported by TOBY-L2x0-00S except for

Wireless Network status indication configured on GPIO1.

1.8 V GPIO with alternatively configurable functions

See section 1.11 for functional description.

See section 2.8 for external circuit design-in.

GPIO2

I/O

GPIO

Note: GPIO not supported by TOBY-L2x0-00S.

1.8 V GPIO with alternatively configurable functions

See section 1.11 for functional description.

See section 2.8 for external circuit design-in.

GPIO3

I/O

GPIO

Note: GPIO not supported by TOBY-L2x0-00S.

1.8 V GPIO with alternatively configurable functions

See section 1.11 for functional description.

See section 2.8 for external circuit design-in.

GPIO4

I/O

GPIO

Note: GPIO not supported by TOBY-L2x0-00S.

1.8 V GPIO with alternatively configurable functions

See section 1.11 for functional description.

See section 2.8 for external circuit design-in.

GPIO5

I/O

GPIO

Note: GPIO not supported by TOBY-L2x0-00S.

1.8 V GPIO with alternatively configurable functions

See section 1.11 for functional description.

See section 2.8 for external circuit design-in.

GPIO6

I/O

GPIO

Note: GPIO not supported by TOBY-L2x0-00S.

1.8 V GPIO

See section 1.11 for functional description.

See section 2.8 for external circuit design-in.

Reserved

RSVD

N/A

Reserved pin

This pin must be connected to ground.

See section 2.10

RSVD

1, 7-9, 18,

19, 29, 31,

33-43, 45,

47-49, 77,

84, 91

N/A

Reserved pin

Leave unconnected.

See section 2.10

Table 3: TOBY-L2 series module pin definition, grouped by function

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1.3.2 MPCI-L2 series pin assignment

Table 4 lists the pin-out of the MPCI-L2 series modules, with pins grouped by function.

Function

Pin Name

Pin No

I/O

Description

Remarks

Power

3.3Vaux

2, 24, 39,

41, 52

Module supply input

3.3Vaux pins are internally connected each other.

3.3Vaux 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 and

requirements for the 3.3Vaux module supply.

See section 2.2.1 for external circuit design-in.

GND

4, 9, 15, 18,

21, 26, 27,

29, 34, 35,

37, 40, 43, 50

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.

Auxiliary

Signals

PERST#

External reset input

Internal 45 k pull-up to 3.3 V supply.

See section 1.6.3 for functional description.

See section 2.3.2 for external circuit design-in.

Antennas

ANT1

U.FL

I/O

Primary antenna

Main Tx / Rx antenna interface.

50  nominal characteristic impedance.

Antenna circuit affects the RF performance and

compliance of the device integrating the module with

applicable required certification schemes.

See section 1.7 for functional description / requirements.

See section 2.4 for external circuit design-in.

ANT2

U.FL

Secondary antenna

Rx only for MIMO 2x2 and Rx diversity.

50  nominal characteristic impedance.

Antenna circuit affects the RF performance and

compliance of the device integrating the module with

applicable required certification schemes.

See section 1.7 for functional description / requirements

See section 2.4 for external circuit design-in.

SIM

UIM_PWR

SIM supply output

UIM_PWR = 1.8 V / 3 V automatically generated

according to the connected SIM type.

See section 1.8 for functional description.

See section 2.5 for external circuit design-in.

UIM_DATA

I/O

SIM data

Data input/output for 1.8 V / 3 V SIM

Internal 4.7 k pull-up to UIM_PWR.

See section 1.8 for functional description.

See section 2.5 for external circuit design-in.

UIM_CLK

SIM clock

3.25 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.

UIM_RESET

SIM 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.

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Function

Pin Name

Pin No

I/O

Description

Remarks

USB

USB_D-

I/O

USB Data Line D-

USB interface for AT commands, data communication,

FOAT, FW update by u-blox EasyFlash tool and diagnostic.

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 [4] are part of the

USB pad driver and need not be provided externally.

See section 1.9.1 for functional description.

See section 2.6.1 for external circuit design-in.

USB_D+

I/O

USB Data Line D+

USB interface for AT commands, data communication,

FOAT, FW update by u-blox EasyFlash tool and diagnostic.

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 [4] are part of the

USB pad driver and need not be provided externally.

See section 1.9.1 for functional description.

See section 2.6.1 for external circuit design-in.

Specific

Signals

LED_WWAN#

LED indicator output

Open drain active low output.

See section 1.12 for functional description.

See section 2.9 for external circuit design-in.

W_DISABLE#

Wireless radio

disable input

Internal 22 k pull-up to 3.3Vaux.

See section 1.12 for functional description.

See section 2.9 for external circuit design-in.

Not

Connected

1, 3, 5-7, 11,

13, 16, 17, 19,

23, 25, 28,

30-33, 44-46,

47-49, 51

N/A

Not connected

Internally not connected.

See section 1.14 for the description.

Table 4: MPCI-L2 series module pin definition, grouped by function

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1.4 Operating modes

TOBY-L2 and MPCI-L2 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 or 3.3Vaux supply not present or below operating range: module is switched off.

Power-Off Mode

VCC or 3.3Vaux 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-L2 and MPCI-L2 series modules operating modes definition

Operating Mode

Description

Transition between operating modes

Not-Powered Mode

Module is switched off.

Application interfaces are not accessible.

When VCC or 3.3Vaux supply is removed, the modules

enter not-powered mode.

When in not-powered mode, TOBY-L2 modules cannot be

switched on by PWR_ON, RESET_N or RTC alarm and

enter active-mode after applying VCC supply (see 1.6.1).

When in not-powered mode, MPCI-L2 modules cannot be

switched on by RTC alarm and enter active-mode after

applying 3.3Vaux supply (see 1.6.1).

Power-Off Mode

Module is switched off: normal shutdown by an

appropriate power-off event (see 1.6.2).

Application interfaces are not accessible.

MPCI-L2 modules do not support Power-Off Mode

but halt mode (see 1.6.2 and u-blox AT Commands

Manual [3], AT+CFUN=127 command).

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, TOBY-L2 modules can be

switched on by PWR_ON, RESET_N or an RTC alarm.

When in power-off mode, TOBY-L2 modules enter the

not-powered mode after removing VCC supply.

Idle-Mode

Module is switched on with application interfaces

disabled or suspended: the module is temporarily not

ready to communicate with an external device by

means of the application interfaces as configured to

reduce the current consumption.

The module enters the low power idle-mode

whenever possible if power saving is enabled by

AT+UPSV (see u-blox AT Commands Manual [3])

reducing current consumption (see 1.5.1.5).

Power saving configuration is not enabled by default:

it can be enabled by the AT+UPSV command (see

the u-blox AT Commands Manual [3]).

The modules automatically switch from active-mode to low

power idle-mode whenever possible if power saving is

enabled (see sections 1.5.1.5, 1.9.1.4, 1.9.2.4 and u-blox

AT Commands Manual [3], AT+UPSV).

The modules wake up from idle-mode to active-mode in

the following events:

 Automatic periodic monitoring of the paging channel

for the paging block reception according to network

conditions (see 1.5.1.5)

 The connected USB host forces a remote wakeup of

the module as USB device (see 1.9.1.4)

 A preset RTC alarm occurs (see u-blox AT Commands

Manual [3], AT+CALA)

Active-Mode

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 (see 1.9.1.4,

1.9.2.4 and u-blox AT Commands Manual [3]).

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, 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 connection is initiated or when RF

Tx/Rx is required due to a connection previously initiated,

the module switches from active to connected-mode.

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Operating Mode

Description

Transition between operating modes

Connected-Mode

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 (see sections 1.9.1.4, 1.9.2.4

and u-blox AT Commands Manual [3]).

When a data connection is initiated, the module enters

connected-mode from idle-mode.

If power saving configuration is enabled by the AT+UPSV

command, the module automatically switches from

connected to active and then idle-mode whenever possible

and the module wakes up from idle to active and then

connected mode if RF Transmission/Reception is necessary.

When a data connection is terminated, the module returns

to the active-mode.

Table 6: TOBY-L2 and MPCI-L2 series modules operating modes description

Figure 3 describes the transition between the different operating modes.

TOBY-L2 Switch ON:

•Apply VCC

MPCI-L2 Switch ON:

•Apply 3.3Vaux

If power saving is enabled

and there is no activity for

a defined time interval

Any wake up event described

in the module operating

modes summary table above

Incoming/outgoing call or

other dedicated device

network communication

No RF Tx/Rx in progress,

Call terminated,

Communication dropped

TOBY-L2x0

Switch ON:

•PWR_ON

•RESET_N

•RTC alarm

Not

powered

Power off

ActiveConnected Idle

TOBY-L2x0

Switch OFF:

•AT+CPWROFF

•RESET_N

MPCI-L2:

•Remove 3.3Vaux

TOBY-L2:

•Remove VCC

Figure 3: TOBY-L2 and MPCI-L2 series modules operating modes transition

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1.5 Supply interfaces

1.5.1 Module supply input (VCC or 3.3Vaux)

TOBY-L2 modules are supplied via the three VCC pins, and MPCI-L2 modules are supplied via the five 3.3Vaux

pins. All supply voltages used inside the modules are generated from the VCC or the 3.3Vaux supply input by

integrated voltage regulators, including the V_BCKP RTC supply, the V_INT generic digital interface supply, and

the VSIM or UIM_PWR SIM interface supply.

The current drawn by the TOBY-L2 and MPCI-L2 series modules through the VCC or 3.3Vaux pins can vary by

several orders of magnitude depending on radio access technology, operation mode and state. It is important

that the supply source is able to support both the high peak of current consumption during 2G transmission at

maximum RF power level (as described in the section 1.5.1.2) and the high average current consumption during

3G and LTE transmission at maximum RF power level (as described in the sections 1.5.1.3 and 1.5.1.4).

1.5.1.1 VCC or 3.3Vaux supply requirements

Table 7 summarizes the requirements for the VCC or 3.3Vaux modules supply. See section 2.2.1 for suggestions

to properly design a VCC or 3.3Vaux supply circuit compliant with the requirements listed in Table 7.

The supply circuit affects the RF compliance of the device integrating TOBY-L2 and MPCI-L2

series modules with applicable required certification schemes as well as antenna circuit design.

Compliance is guaranteed if the requirements summarized in the Table 7 are fulfilled.

Item

Requirement

Remark

VCC or 3.3Vaux

nominal voltage

Within VCC or 3.3Vaux normal operating range:

See “Supply/Power pins” section in the TOBY-L2 Data

Sheet [1] or in the MPCI-L2 Data Sheet [2].

The modules cannot be switched on if the supply voltage

is below the normal operating range minimum limit.

VCC or 3.3Vaux

voltage during

normal operation

Within VCC or 3.3Vaux extended operating range:

See “Supply/Power pins” section in the TOBY-L2 Data

Sheet [1] or in the MPCI-L2 Data Sheet [2].

The modules may switch off if the supply voltage drops

below the extended operating range minimum limit.

VCC or 3.3Vaux

average current

Support with adequate margin the highest averaged

current consumption value in connected-mode

conditions specified for VCC in TOBY-L2 Data Sheet [1]

or specified for 3.3Vaux in MPCI-L2 Data Sheet [2].

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 current

consumption profiles in 2G, 3G and LTE connected-mode.

VCC or 3.3Vaux

peak current

Support with margin the highest peak current

consumption value in 2G connected-mode conditions

specified for VCC in TOBY-L2 Data Sheet [1] or

specified for 3.3Vaux in MPCI-L2 Data Sheet [2].

The specified maximum peak of current consumption

occurs during GSM single transmit slot in 850/900 MHz

connected-mode, in case of mismatched antenna.

Section 1.5.1.2 describes 2G Tx peak/pulse current.

VCC or 3.3Vaux

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 applicable certification schemes.

Figure 5 describes supply voltage drop during 2G Tx slots.

VCC or 3.3Vaux

voltage ripple during

RF transmission

Noise in the supply has to 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 or 3.3Vaux

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 applicable certification schemes.

Figure 5 describes supply voltage under/over-shoot

Table 7: Summary of VCC or 3.3Vaux modules supply requirements

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1.5.1.2 VCC or 3.3Vaux current consumption in 2G connected-mode

When a GSM call is established, the VCC or 3.3Vaux 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 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

high peak (see the “Current consumption” section in the TOBY-L2 Data Sheet [1] or the MPCI-L2 Data Sheet [2])

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 quite less high than the one in the low bands, due to 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]

slot

unused

slot

unused

slot

unused

slot

unused

slot

MON

slot

unused

slot

unused

slot

unused

slot

unused

slot

unused

slot

MON

slot

unused

slot

GSM frame

4.615 ms

(1 frame = 8 slots)

Current [A]

200 mA

60-120 mA

1900 mA

Peak current depends

on TX power and

actual antenna load

GSM frame

4.615 ms

(1 frame = 8 slots)

60-120 mA

10-40 mA

0.0

1.5

1.0

0.5

2.0

2.5

Figure 4: VCC or 3.3Vaux current consumption profile versus time during a 2G single-slot call (1 TX slot, 1 RX slot)

Figure 5 illustrates VCC or 3.3Vaux voltage profile versus time during a 2G single-slot call, according to the

relative VCC or 3.3Vaux current consumption profile described in Figure 4.

Time [ms]

undershoot

overshoot

ripple

drop

Voltage [mV]

3.8 V

(typ)

slot

unused

slot

unused

slot

unused

slot

unused

slot

MON

slot

unused

slot

unused

slot

unused

slot

unused

slot

unused

slot

MON

slot

unused

slot

GSM frame

4.615 ms

(1 frame = 8 slots)

GSM frame

4.615 ms

(1 frame = 8 slots)

Figure 5: VCC or 3.3Vaux voltage profile versus time during a 2G single-slot call (1 TX slot, 1 RX slot)

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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 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 in case of 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.

Time [ms]

slot

unused

slot

MON

slot

unused

slot

unused

slot

MON

slot

unused

slot

GSM frame

4.615 ms

(1 frame = 8 slots)

Current [A]

200mA

60-130mA

Peak current depends

on TX power and

actual antenna load

GSM frame

4.615 ms

(1 frame = 8 slots)

1600 mA

0.0

1.5

1.0

0.5

2.0

2.5

Figure 6: VCC or 3.3Vaux current consumption profile during a 2G GPRS/EDGE multi-slot connection (4 TX slots, 1 RX slot)

In case of 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.

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1.5.1.3 VCC or 3.3Vaux 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 again on output RF power, which is always regulated by network commands.

These power control commands are logically divided into a slot of 666 µs, thus 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 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 high (see the

“Current consumption” section in TOBY-L2 Data Sheet [1] or in MPCI-L2 Data Sheet [2]). Even at lowest output

RF power (approximately 0.01 µW or -50 dBm), the current is still not so low due to module baseband

processing and transceiver activity.

Figure 7 shows an example of current consumption profile of the module in 3G WCDMA/DC-HSPA+ continuous

transmission mode.

Time

[ms]

3G frame

10 ms

(1 frame = 15 slots)

Current [mA]

Current consumption value

depends on TX power and

actual antenna load

170 mA

1 slot

666 µs

850 mA

300

200

100

500

400

600

700

800

Figure 7: VCC or 3.3Vaux current consumption profile versus time during a 3G connection (TX and RX continuously enabled)

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1.5.1.4 VCC or 3.3Vaux current consumption in LTE connected-mode

During a LTE connection, the module can transmit and receive continuously due to LTE radio access technology.

The current consumption is strictly dependent on the transmitted RF output power, which is always regulated by

network commands. 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.

Figure 8 shows an example of the module current consumption profile versus time in LTE connected-mode.

Detailed current consumption values can be found in TOBY-L2 Data Sheet [1] and in MPCI-L2 Data Sheet [2].

Time

[ms]

Current [mA]

Current consumption value

depends on TX power and

actual antenna load

1 Slot

1 Resource Block

(0.5 ms) 1 LTE Radio Frame

(10 ms)

300

200

100

500

400

600

700

800

Figure 8: VCC or 3.3Vaux current consumption profile versus time during LTE connection (TX and RX continuously enabled)

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1.5.1.5 VCC or 3.3Vaux current consumption in cyclic idle/active mode (power saving enabled)

The power saving configuration is by default disabled, but it can be enabled using the AT+UPSV command (see

the u-blox AT Commands Manual [3]). 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 to 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 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 broadcast channel sent to all users on the same serving cell.

In case of 2G radio access technology, the paging period can vary from 470.76 ms (DRX = 2, length of 2 x 51 2G

frames = 2 x 51 x 4.615 ms) up to 2118.42 ms (DRX = 9, length of 9 x 51 2G frames = 9 x 51 x 4.615 ms).

In case of 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).

In case of LTE radio access technology, the paging period can vary from 320 ms (DRX = 5, 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 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. Detailed current consumption

values can be found in TOBY-L2 Data Sheet [1] and in MPCI-L2 Data Sheet [2].

~50 ms

IDLE MODE ACTIVE MODE IDLE MODE

Active Mode

Enabled

Idle Mode

Enabled

2G case: 0.44-2.09 s

3G case: 0.61-5.09 s

LTE case: 0.27-2.51 s

IDLE MODE

~50 ms

ACTIVE MODE

Time [s]

Current [mA]

Time [ms]

Current [mA]

Enabled

100

Figure 9: VCC or 3.3Vaux current consumption profile with power saving enabled and module registered with the network:

the module is in idle-mode and periodically wakes up to active-mode to monitor the paging channel for paging block reception

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1.5.1.6 VCC or 3.3Vaux 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 u-blox AT Commands Manual [3] for detail usage).

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 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.

ACTIVE MODE

2G case: 0.44-2.09 s

3G case: 0.61-5.09 s

LTE case: 0.32-2.56 s

Paging period

Time [s]

Current [mA]

Time [ms]

Current [mA]

Enabled

100

Figure 10: VCC or 3.3Vaux 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

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1.5.2 RTC supply input/output (V_BCKP)

The RTC supply V_BCKP pin is not available on MPCI-L2 series modules.

The V_BCKP pin of TOBY-L2 series modules connects the supply for the Real Time Clock (RTC). A linear LDO

regulator integrated in the Power Management Unit internally generates this supply, as shown in Figure 11, with

low current capability (see the TOBY-L2 series Data Sheet [1]). The output of this regulator is always enabled

when the main module voltage supply applied to the VCC pins is within the valid operating range.

Baseband

Processor

VCC

V_BCKP

Linear

LDO

Power

Management

TOBY-L2 series

32 kHz

RTC

Figure 11: TOBY-L2 series RTC supply (V_BCKP) simplified block diagram

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 available the programmable alarm functions.

The RTC functions are available also in power-down mode when the V_BCKP voltage is within its valid range

(specified in the “Input characteristics of Supply/Power pins” table in TOBY-L2 series Data Sheet [1]). The RTC

can be supplied from an external back-up battery through the V_BCKP, when the main module voltage supply is

not applied to the VCC pins. 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 very low current consumption, but is highly temperature dependent. For example, V_BCKP current

consumption at the maximum operating temperature can be higher than the typical value at 25 °C specified in

the “Input characteristics of Supply/Power pins” table in the TOBY-L2 series Data Sheet [1].

If V_BCKP is left unconnected and the module main supply is not applied to the VCC pins, the RTC is supplied

from the bypass capacitor mounted inside the module. However, this capacitor is not able to provide a long

buffering time: within few milliseconds the voltage on V_BCKP will go below the valid range (1.4 V min). This

has no impact on cellular connectivity, as all the module functionalities do not rely on date and time setting.

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1.5.3 Generic digital interfaces supply output (V_INT)

The generic digital interfaces supply V_INT pin is not available on MPCI-L2 series modules.

The V_INT output pin of the TOBY-L2 series modules is connected to an internal 1.8 V supply with current

capability specified in the TOBY-L2 series Data Sheet [1]. 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 TOBY-L2 module, as described in Figure 12. The output of this regulator is enabled when

the module is switched on and it is disabled when the module is switched off.

Baseband

Processor

VCC

V_INT

Switching

Step-Down

Power

Management

TOBY-L2 series

Digital I/O

Figure 12: TOBY-L2 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. The V_INT output voltage ripple is specified in the TOBY-L2 series Data Sheet [1].

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1.6 System function interfaces

1.6.1 Module power-on

The PWR_ON input pin is not available on MPCI-L2 series modules.

When the TOBY-L2 and MPCI-L2 series modules are in the not-powered mode (switched off, i.e. the VCC or

3.3Vaux module supply is not applied), they can be switched on as following:

 Rising edge on the VCC or 3.3Vaux supply input to a valid voltage for module supply, so that the module

switches on applying a proper VCC or 3.3Vaux supply within the normal operating range.

 Alternately, the RESET_N or PERST# pin can be held to the low level during the VCC or 3.3Vaux rising

edge, so that the module switches on releasing the RESET_N or PERST# pin when the VCC or 3.3Vaux

module supply voltage stabilizes at its proper nominal value within the normal operating range.

The status of the PWR_ON input pin of TOBY-L2 modules while applying the VCC module supply is not relevant:

during this phase the PWR_ON pin can be set high or low by the external circuit.

When the TOBY-L2 modules are in the power-off mode (i.e. switched off with valid VCC module supply applied),

they can be switched on as following:

 Low level on the PWR_ON pin, which is normally set high by an internal pull-up, for a valid time period.

 Low level on the RESET_N pin, which is normally set high by an internal pull-up, for a valid time period.

 RTC alarm, i.e. pre-programmed alarm by AT+CALA command (see u-blox AT Commands Manual [3]).

As described in Figure 13, the TOBY-L2 series PWR_ON input is equipped with an internal active pull-up resistor

to the VCC module supply: the PWR_ON input voltage thresholds are different from the other generic digital

interfaces. Detailed electrical characteristics are described in TOBY-L2 series Data Sheet [1].

Baseband

Processor

PWR_ON

TOBY-L2 series

VCC

Power-on

Power

Management

Power-on

50k

Figure 13: TOBY-L2 series PWR_ON input description

For more pin information and electrical characteristics, see the TOBY-L2 Data Sheet [1] and MPCI-L2 Data

Sheet [2].

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Figure 14 shows the module power-on sequence from the not-powered mode, describing the following phases:

 The external supply is applied to the VCC or 3.3Vaux module supply inputs, representing the start-up event.

 The PWR_ON and the RESET_N or PERST# pins suddenly rise to high logic level due to internal pull-ups.

 The V_BCKP RTC supply output is suddenly enabled by the module as VCC reaches a valid voltage value.

 All the generic digital pins of the module are tri-stated until the switch-on of their supply source (V_INT).

 The internal reset signal is held low: the baseband core and all the digital pins are held in the reset state.

The reset state of all the digital pins is reported in the pin description table of TOBY-L2 Series Data Sheet [1].

 When the internal reset signal is released, any digital pin is set in a proper sequence from the reset state to

the default operational configured state. The duration of this pins’ configuration phase differs within 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.

VCC or 3.3Vaux

V_BCKP

PWR_ON

RESET_N or PERST#

V_INT

Internal Reset

System State

BB Pads State

Internal Reset → Operational Operational

Tristate / Floating

Internal Reset

OFF

0 ms

~10 ms

~20 s

Start of interface

configuration

Module interfaces

are configured

Start-up

event

~5 ms

Figure 14: TOBY-L2 and MPCI-L2 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-L2 module power-on sequence.

 The USB interface to sense the start of the MPCI-L2 module power-on sequence: the module, as USB

device, informs the host of the attach event via a reply on its status change pipe for proper bus

enumeration process according to Universal Serial Bus Revision 2.0 specification [6].

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 TOBY-L2 module.

Before the TOBY-L2 and MPCI-L2 series module is fully ready to operate, the host application processor

should not send any AT command over the AT communication interfaces (USB, UART) of the module.

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1.6.2 Module power-off

TOBY-L2 series can be properly switched off by:

 AT+CPWROFF command (see u-blox AT Commands Manual [3]). The current parameter settings are saved in

the module’s non-volatile memory and a proper network detach is performed.

The MPCI-L2 series modules do not switch off by the AT+CPWROFF command as the TOBY-L2 modules,

but the AT+CPWROFF command causes a reset (reboot) of the module due to the MPCI-L2 module’s

internal configuration: the command stores the actual parameter settings in the non-volatile memory of

MPCI-L2 modules and performs a network detach, with a subsequent reset (reboot) of the module.

An abrupt under-voltage shutdown occurs on TOBY-L2 and MPCI-L2 series modules when the VCC or 3.3Vaux

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 the proper network detach.

It is highly recommended to avoid an abrupt removal of the VCC supply during TOBY-L2 modules normal

operations: the power off procedure must be started by the AT+CPWROFF command, waiting the

command response for a proper time period (see u-blox AT Commands Manual [3]), and then a proper

VCC supply has to 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.

It is highly recommended to avoid an abrupt removal of the 3.3Vaux supply during MPCI-L2 modules

normal operations: the power off procedure must be started by setting the MPCI-L2 module in the halt

mode by the AT+CFUN=127 command (which stores the actual parameter settings in the non-volatile

memory of the module and performs a network detach), waiting the command response for a proper

time period (see the u-blox AT Commands Manual [3]), and then the 3.3Vaux supply can be removed.

An abrupt hardware shutdown occurs on TOBY-L2 series modules when a low level is applied on the RESET_N

pin for a specific time period. In this case, the current parameter settings are not saved in the module’s

non-volatile memory and a proper network detach is not performed.

It is highly recommended to avoid an abrupt hardware shutdown of the module by forcing a low level on

the RESET_N input pin during module normal operation: the RESET_N line should be set low only if reset

or shutdown via AT commands fails or if the module does not reply to a specific AT command after a time

period longer than the one defined in the u-blox AT Commands Manual [3].

An over-temperature or an under-temperature shutdown occurs on TOBY-L2 and MPCI-L2 series modules when

the temperature measured within the cellular module reaches the dangerous area, if the optional Smart

Temperature Supervisor feature is enabled and configured by the dedicated AT command. For more details see

u-blox AT Commands Manual [3], +USTS AT command.

The Smart Temperature Supervisor feature is not supported by the TOBY-L2x0-00S and MPCI-L2x0-00S

product versions.

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Figure 15 describes the TOBY-L2 power-off sequence by means of AT+CPWROFF with the following phases:

 When the +CPWROFF AT command is sent, the module starts the switch-off routine.

 The module replies OK on the AT interface: the switch-off routine is in progress.

 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), except the RTC supply (V_BCKP).

 Then, the module remains in power-off mode as long as a switch on event does not occur (e.g. applying a

proper low level to the PWR_ON input, or applying a proper low level to the RESET_N input), and enters

not-powered mode if the supply is removed from the VCC pins.

VCC

V_BCKP

PWR_ON

RESET_N

V_INT

Internal Reset

System State

BB Pads State Operational

OFF

Tristate / Floating

Operational → Tristate

AT+CPWROFF

sent to the module

0 s

~2.5 s

~5 s

replied by the module

VCC

can be removed

Figure 15: TOBY-L2 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.

Figure 16 describes the MPCI-L2 power-off procedure with the following phases:

 When the AT+CFUN=127 command is issued, the module starts the halt mode setting routine.

 The module replies OK on the AT interface: after this, the module is set in the halt mode.

 Then, the module remains in the Halt mode and enters not-powered mode if the supply is removed from the

3.3Vaux pins.

3.3Vaux

PERST#

Internal Reset

System State

BB Pads State

OFF

Tristate / Floating

Operational

AT+CFUN=127

sent to the module

0 s

~2.5 s

~5 s

replied by the module

3.3Vaux

can be removed

Figure 16: MPCI-L2 series power-off procedure description

The duration of each phase in the TOBY-L2 and MPCI-L2 series modules’ switch-off routines can largely

vary depending on the application / network settings and the concurrent module activities.

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1.6.3 Module reset

TOBY-L2 and MPCI-L2 series modules can be properly reset (rebooted) by:

 AT+CFUN command (see u-blox AT Commands Manual [3]).

MPCI-L2 series modules can be additionally properly reset (rebooted) by:

 AT+CPWROFF command (see u-blox AT Commands Manual [3]): the behavior differs than TOBY-L2 series, as

MPCI-L2 modules will reboot rather than remain switched off due to modules’ internal configuration.

In the cases listed above an “internal” or “software” reset of the module is executed: the current parameter

settings are saved in the module’s non-volatile memory and a proper network detach is performed.

An abrupt hardware reset occurs on TOBY-L2 and MPCI-L2 series modules when a low level is applied on the

RESET_N or PERST# input pin for a specific time period. In this case, the current parameter settings are not

saved in the module’s non-volatile memory and a proper 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 or PERST# input during modules normal operation: the RESET_N or PERST# line should be set

low only if reset or shutdown via AT commands fails or 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 [3].

As described in Figure 17, the RESET_N and PERST# input pins are equipped with an internal pull-up to the

VCC supply in the TOBY-L2 series and to the 3.3 V in the MPCI-L2 series.

Baseband

Processor

RESET_N

TOBY-L2 series

VCC

Reset

Power

Management

Reset

50k

Baseband

Processor

PERST#

MPCI-L2 series

Reset

Power

Management

Reset

45k

3.3 V

Figure 17: TOBY-L2 and MPCI-L2 series RESET_N and PERST# input equivalent circuit description

For more electrical characteristics details see TOBY-L2 Data Sheet [1] and MPCI-L2 Data Sheet [2].

1.6.4 Module configuration selection by host processor

The HOST_SELECT0 and HOST_SELECT1 pins are not available on MPCI-L2 series modules.

The functionality of the HOST_SELECT0 and HOST_SELECT1 pins is not supported by TOBY-L2x0-00S.

TOBY-L2 series modules include two input pins (HOST_SELECT0 and HOST_SELECT1) for the selection of the

module configuration by the host application processor.

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1.7 Antenna interface

1.7.1 Antenna RF interfaces (ANT1 / ANT2)

TOBY-L2 and MPCI-L2 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 of TOBY-L2 series modules has a nominal characteristic impedance of 50  and must be

connected to the primary Tx / Rx antenna through a 50  transmission line to allow proper RF transmission

and reception.

The ANT1 Hirose U.FL-R-SMT coaxial connector receptacle of MPCI-L2 series modules has a nominal

characteristic impedance of 50  and must be connected to the primary Tx / Rx antenna through a mated RF

plug with a 50  coaxial cable assembly to allow proper RF transmission and reception.

 The ANT2 represents the secondary RF input for the reception of the LTE RF signals for the Down-Link

MIMO 2 x 2 radio technology supported by TOBY-L2 and MPCI-L2 series modules as required feature for LTE

category 4 UEs, and for the reception of the 3G RF signals for the Down-Link Rx diversity radio technology

supported by TOBY-L2 and MPCI-L2 series modules as additional feature for 3G DC-HSDPA category 24 UEs.

The ANT2 pin of TOBY-L2 series modules has a nominal characteristic impedance of 50  and must be

connected to the secondary Rx antenna through a 50  transmission line to allow proper RF reception.

The ANT2 Hirose U.FL-R-SMT coaxial connector receptacle of MPCI-L2 series modules has a nominal

characteristic impedance of 50  and must be connected to the secondary Rx antenna through a mated RF

plug with a 50  coaxial cable assembly to allow proper RF reception.

The Multiple Input Multiple Output (MIMO) radio technology is an essential component of LTE radio systems

based on the use of multiple antennas at both the transmitter and receiver sides to improve communication

performance and achieve highest possible bit rate. A MIMO m x n system consists of m transmit and n receive

antennas, where the data to be transmitted is divided into m independent data streams. Note that the terms

Input and Output refer to the radio channel carrying the signal, not to the devices having antennas, so that in

the Down-Link MIMO 2 x 2 system supported by TOBY-L2 and MPCI-L2 series modules:

 The LTE data stream is divided into 2 independent streams by the Tx-antennas of the base station

 The cellular modules, at the receiver side, receives both LTE data streams by 2 Rx-antennas (ANT1 / ANT2)

Base Station

Tx-1

Antenna

Tx-2

Antenna

TOBY-L2 series

MPCI-L2 series

ANT1

Rx-1

Antenna

ANT2

Rx-2

Antenna

Data Stream 1

Data Stream 2

Figure 18: Description of the LTE Down-Link MIMO 2 x 2 radio technology supported by TOBY-L2 and MPCI-L2 series modules

TOBY-L2 and MPCI-L2 series modules support the LTE MIMO 2 x 2 radio technology in the Down-Link path only

(from the base station to the module): the ANT1 port is the only one RF interface that is used by the module to

transmit the RF signal in the Up-Link path (from the module to the base station).

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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 to properly design antennas circuits compliant with these requirements.

The antenna circuits affect the RF compliance of the device integrating TOBY-L2 and MPCI-L2

series modules with 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-L2 series Data Sheet [1] and the

MPCI-L2 series Data Sheet [2]

The required frequency range of the antenna connected

to 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

primary 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.

For additional info see the section 4.2.2.

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

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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-L2 series Data Sheet [1] and the

MPCI-L2 series Data Sheet [2]

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

secondary 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 of 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 primary and secondary antenna needs

to be enough low to comply with 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

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1.7.2 Antenna detection interface (ANT_DET)

Antenna detection interface (ANT_DET) is not available on MPCI-L2 series modules.

Antenna detection interface (ANT_DET) is not supported by the TOBY-L2x0-00S product version.

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 antenna detection is forced by the +UANTR AT command. See the u-blox AT

Commands Manual [3] for more details on this feature.

The ANT_DET pin generates a DC current (for detailed characteristics see the TOBY-L2 series Data Sheet [1]) 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 antenna detection circuit on application board and diagnostic circuit on antenna assembly

design-in guidelines.

1.8 SIM interface

1.8.1 SIM interface

TOBY-L2 and MPCI-L2 series modules provide high-speed SIM/ME interface including automatic detection and

configuration of the voltage required by the connected SIM card or chip.

Both 1.8 V and 3 V SIM types are supported. Activation and deactivation with automatic voltage switch from

1.8 V to 3 V are implemented, according to ISO-IEC 7816-3 specifications. The VSIM or UIM_PWR supply

output provides internal short circuit protection to limit start-up current and protect the SIM to short circuits.

The SIM driver supports the PPS (Protocol and Parameter Selection) procedure for baud-rate selection, according

to the values determined by the SIM card or chip.

1.8.2 SIM detection interface

SIM detection interface (GPIO5) is not available on MPCI-L2 series modules.

SIM detection interface (GPIO5) is not supported by the TOBY-L2x0-00S product version.

The GPIO5 pin is by default configured to detect the SIM card mechanical / physical presence. The pin is

configured as input with an internal active pull-down enabled, and it can sense SIM card presence only if

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 (for more details see the u-blox AT Commands Manual [3]).

The optional function “SIM card hot insertion/removal” can be additionally enabled on the GPIO5 pin by specific

AT command (see the u-blox AT Commands Manual [3]).

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1.9 Data communication interfaces

TOBY-L2 and MPCI-L2 series modules provide the following serial communication interface:

 USB interface: High-Speed USB 2.0 compliant interface available for the communication with an external

host application processor, for AT commands, data communication, FW upgrade by means of the FOAT

feature, FW upgrade by means of the u-blox EasyFlash tool and for diagnostic purpose (see section 1.9.1 for

functional description)

TOBY-L2 series modules additionally provide the following serial communication interfaces:

 UART interface: asynchronous serial interface available for the communication with an external host

application processor, for AT commands, data communication, FW upgrade by means of the FOAT feature

(see section 1.9.2 for functional description)

 DDC interface: I2C bus compatible interface available for the communication with u-blox GNSS positioning

chips/modules and with external I2C devices as an audio codec (see section 1.9.3 for functional description)

 SDIO interface: Secure Digital Input Output interface available for the communication with an external Wi-Fi

chip or module (see section 1.9.4 for functional description)

1.9.1 Universal Serial Bus (USB)

1.9.1.1 USB features

TOBY-L2 and MPCI-L2 series modules include a High-Speed USB 2.0 compliant interface with maximum data

rate of 480 Mb/s, representing the main interface for transferring high speed data with a host application

processor: the USB interface is available for AT commands, data communication, FW upgrade by means of the

FOAT feature, FW upgrade by means of the u-blox EasyFlash tool and for diagnostic purpose.The module itself

acts as a USB device and can be connected to a USB host such as a Personal Computer or an embedded

application microprocessor equipped with compatible drivers.

The USB_D+ / USB_D- lines carry the USB serial bus data and signaling, providing all the functionalities for the

bus attachment, configuration, enumeration, suspension or remote wakeup according to the Universal Serial Bus

Revision 2.0 specification [6]

The additional VUSB_DET input pin is available on TOBY-L2 series modules as optional feature to sense the USB

VBUS supply (5.0 V typical) from the host, providing the complete bus detach functionality for further reduction

of the module current consumption in particular during low-power idle mode with power saving enabled:

TOBY-L2 series modules disable the USB interface when a low logic level is sensed after a high-to-low logic level

transition on the VUSB_DET input pin, reducing the current consumption.

The VUSB_DET pin is not available on MPCI-L2 series modules.

The USB interface is controlled and operated with:

 AT commands according to 3GPP TS 27.007 [8], 3GPP TS 27.005 [9], 3GPP TS 27.010 [10]

 u-blox AT commands

For the complete list of supported AT commands and their syntax see u-blox AT Commands Manual [3].

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TOBY-L2 and MPCI-L2 modules provide by default the following USB profile with the listed set of USB functions:

 1 RNDIS for Ethernet-over-USB connection

 1 CDC-ACM for AT commands and data communication

The USB profile of TOBY-L2 and MPCI-L2 modules 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 [6].

The VID and PID of the default USB profile configuration with the set of functions described above (1 RNDIS for

Ethernet-over-USB and 1 CDC-ACM for AT commands and data) are the following:

 VID = 0x1546

 PID = 0x1146

Figure 19 summarizes the USB end-points available with the default USB profile configuration.

Default profile configuration

Interface 0 Wireless Controller –Remote NDIS

Interface 1 Communication Data

EndPoint Transfer: Interrupt

EndPoint Transfer: Bulk

Interface 2 Communication Control –AT commands

EndPoint Transfer: Interrupt

Interface 3 Communication Data

EndPoint Transfer: Bulk

Function RNDIS

Function CDC Serial

Figure 19: TOBY-L2 and MPCI-L2 series USB End-Points summary for the default USB profile configuration

The USB of the modules can be configured by the AT+UUSBCONF command (for more details see the u-blox AT

Commands Manual [3]) to select different sets of USB functions available in mutually exclusive way, selecting the

active USB profile consisting of a specific set of functions with various capabilities and purposes, such as:

 CDC-ACM for AT commands and data

 CDC-ACM for GNSS tunneling

 CDC-ACM for SIM Access Profile (SAP)

 CDC-ACM for diagnostic

 RNDIS for Ethernet-over-USB

 CDC-ECM for Ethernet-over-USB

 CDC-NCM for Ethernet-over-USB

 MBIM for Ethernet-over-USB

CDC-ACM for GNSS tunneling, CDC-ACM for SIM Access Profile (SAP), and CDC-NCM and MBIM

functions are not supported by the TOBY-L2x0-00S and MPCI-L2x0-00S product versions.

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For example, the default USB profile configuration which provides 2 functions (1 RNDIS for Ethernet-over-USB

and 1 CDC-ACM for AT commands and data) can be changed by means of the AT+UUSBCONF command

switching to a USB profile configuration which provides the following 6 functions:

 3 CDC-ACM for AT commands and data

 1 CDC-ACM for GNSS tunneling

 1 CDC-ACM for SIM Access Profile (SAP)

 1 CDC-ACM for diagnostic

As each USB profile of TOBY-L2 and MPCI-L2 modules identifies itself by its specific VID and PID combination

included in the USB device descriptor according to the USB 2.0 specifications [6], the VID and PID combination

changes as following by switching the active USB profile configuration to the set of 6 functions described above:

 VID = 0x1546

 PID = 0x1141

Alternatively, as another example, the USB profile configuration can be changed by means of the

AT+UUSBCONF command switching to a USB profile configuration which provides the following 4 functions:

 1 CDC-ECM for Ethernet-over-USB

 3 CDC-ACM for AT commands and data

In case of this USB profile with the set of 4 functions described above, the VID and PID are the following:

 VID = 0x1546

 PID = 0x1143

The switch of the active USB profile selected by the AT+UUSBCONF command is not performed immediately.

The settings are saved in the non-volatile memory of the module at the power off, and the new configuration is

effective at the subsequent reboot of the module.

If the USB is connected to the 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,

VID and PID are the following:

 VID = 0x1546

 PID = 0x1140

This VID and PID combination identifies a USB profile where no USB function described above is available: 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 (roughly 20 s, depending on the host / device enumeration timings), the VID and PID

are updated to the ones related to the USB profile selected by the AT+UUSBCONF command.

For more details regarding the TOBY-L2 and MPCI-L2 series modules USB configurations and capabilities,

see the u-blox AT Commands Manual [3], +UUSBCONF AT command.

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1.9.1.2 USB in Windows

The USB drivers (INF files) are provided for Windows systems and should be installed properly by following the

step-by-step instruction in EVK-L20 / EVK-L21 User Guide [4].

USB drivers are available for the following operating system platforms:

 Windows Vista

 Windows 7

 Windows 8

 Windows 8.1

 Windows Embedded Compact 7

The module firmware can be upgraded over the USB interface by means of the FOAT feature, or using the u-blox

EasyFlash tool (for more details see Firmware Update Application Note [4]).

1.9.1.3 USB in Linux/Android

It is not required to install a specific driver for each Linux-based or Android-based operating system (OS) to use

the module USB interface, which is compatible with standard Linux/Android USB kernel drivers.

The full capability and configuration of the module USB interface can be reported by running ‘lsusb –v’ or an

equivalent command available in the host operating system when the module is connected.

1.9.1.4 USB and power saving

If power saving is enabled by the AT+UPSV command, the modules automatically enter the USB suspended state

when the device has observed no bus traffic for a specific time period according to the USB 2.0 specification [6].

In suspended state, the module maintains any USB internal status as device. In addition, the module enters the

suspended state when the hub port it is attached to is disabled. This is referred to as USB selective suspend.

The module exits suspend mode when there is bus activity. If the USB is connected and not suspended, the

module is forced to stay in active-mode, therefore the AT+UPSV settings are overruled but they have effect on

the power saving configuration of the other interfaces.

The modules are capable of USB remote wake-up signaling: i.e. it may request the host to exit suspend mode or

selective suspend by using electrical signaling to indicate remote wake-up. This notifies the host that it should

resume from its suspended mode, if necessary, and service the external event. Remote wake-up is accomplished

using electrical signaling described in the USB 2.0 specifications [6].

For the module current consumption description with power saving enabled and USB suspended, or with power

saving disabled and USB not suspended, see the sections 1.5.1.5, 1.5.1.6 and the TOBY-L2 Data Sheet [1] or the

MPCI-L2 Data Sheet [2].

The additional VUSB_DET input pin available on TOBY-L2 series modules provides the complete bus detach

functionality: the modules disable the USB interface when a low logic level is sensed after a high-to-low logic

level transition on the VUSB_DET input pin. This allows a further reduction of the module current consumption,

in particular as compared to the USB suspended status during low-power idle mode with power saving enabled.

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1.9.2 Asynchronous serial interface (UART)

The UART interface is not available on MPCI-L2 series modules.

The UART interface is not supported by the TOBY-L2x0-00S product version.

1.9.2.1 UART features

The UART interface is a 9-wire 1.8 V unbalanced asynchronous serial interface (UART) that can be connected to

an application host processor for AT commands and data communication.

The module firmware can be upgraded over the UART interface by means of the Firmware upgrade over AT

(FOAT) feature only: for more details see section 1.15 and Firmware update application note [4].

UART interface provides RS-232 functionality conforming to the ITU-T V.24 Recommendation (more details

available in ITU Recommendation [7]), with CMOS compatible signal levels: 0 V for low data bit or ON state, and

1.8 V for high data bit or OFF state. For detailed electrical characteristics see TOBY-L2 Data Sheet [1].

TOBY-L2 modules are designed to operate as LTE/3G/2G cellular modems, i.e. the data circuit-terminating

equipment (DCE) is according to the ITU-T V.24 Recommendation [7]. A customer application processor

connected to the module through the UART interface represents the data terminal equipment (DTE).

The signal names of the UART interface of the TOBY-L2 series modules conform to the ITU-T V.24

Recommendation [7]: e.g. TXD line represents the data transmitted by the DTE (application processor data

output) and received by the DCE (module data input).

The UART interface is controlled and operated with:

 AT commands according to 3GPP TS 27.007 [8], 3GPP TS 27.005 [9], 3GPP TS 27.010 [10]

 u-blox AT commands

For the complete list of supported AT commands and their syntax see u-blox AT Commands Manual [3].

1.9.2.2 UART interface configuration

The UART interface of TOBY-L2 series modules is configured as described in Table 11 (for information about

further settings, see the u-blox AT Commands Manual [3]).

Interface

AT Settings

Comments

UART interface

AT interface: enabled

AT command interface is enabled by default on the UART physical interface

MUX protocol: disabled

Multiplexing mode is disabled by default and it can be enabled by AT+CMUX command.

For more details, see the Mux Implementation Application Note [11].

The following virtual channels are defined:

 Channel 0: Control channel

 Channel 1 – 5: AT commands / data connection

 Channel 6: GNSS tunneling

 Channel 7: SIM Access Profile

Table 11: Default UART interface configuration

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1.9.2.3 UART signals behavior

At the module switch-on, before the UART interface initialization (as described in the power-on sequence

reported in Figure 14), each pin is first tri-stated and then is set to its relative internal reset state. At the end of

the boot sequence, the UART interface is initialized, the module is by default in active-mode, and the UART

interface is enabled.

1.9.2.4 UART and power-saving

The power saving configuration is controlled by the AT+UPSV command (for the complete description, see the

u-blox AT Commands Manual [3]). When power saving is enabled, the module automatically enters low power

idle-mode whenever possible, and otherwise the active-mode is maintained by the module (see section 1.4 for

definition and description of module operating modes referred to in this section).

The AT+UPSV command configures both the module power saving and also the UART behavior in relation to the

power saving. The conditions for the module entering low power idle-mode also depend on the UART power

saving configuration, as the module does not enter the low power idle-mode according to any required activity

related to the network (within or outside an active call) or any other required concurrent activity related to the

functions and interfaces of the module, including the UART interface.

1.9.2.5 UART multiplexer protocol

TOBY-L2 series modules have a software layer with multiplexer functionality as per 3GPP TS 27.010 Multiplexer

Protocol [10], available on the UART physical link.

This is a data link protocol (layer 2 of OSI model) which uses HDLC-like framing and operates between the

module (DCE) and the application processor (DTE) and allows a number of simultaneous sessions over the used

physical link (the UART interface): the user can concurrently use AT command interface on one MUX channel

and data communication on another multiplexer channel.

The following virtual channels are defined:

 Channel 0: control channel

 Channel 1 – 5: AT commands / data connection

 Channel 6: GNSS tunneling

 Channel 7: SIM Access Profile

For more details, see Mux implementation Application Note [11].

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1.9.3 DDC (I2C) interface

The I2C bus compatible Display Data Channel interface is not available on the MPCI-L2 series modules, as

AssistNow embedded GNSS positioning aiding, CellLocate® positioning through cellular information and

custom functions over GPIOs for the integration with u-blox positioning chips / modules.

The I2C bus compatible Display Data Channel interface is not supported by the TOBY-L2x0-00S product

version, as AssistNow embedded GNSS positioning aiding, CellLocate® positioning through cellular

information and custom functions over GPIOs for the integration with u-blox positioning chips / modules.

The SDA and SCL pins of TOBY-L2 series modules represent an I2C bus compatible Display Data Channel (DDC)

interface for the communication with u-blox GNSS receivers and with other external I2C devices as audio codecs:

an I2C master can communicate with more I2C slaves in accordance to the I2C bus specifications [12].

The DDC (I2C) interface is the only one interface dedicated for communication between u-blox cellular module

and u-blox positioning receivers. The AT commands interface is not available on the DDC (I2C) interface.

The DDC (I2C) interface pads of the module, serial data (SDA) and serial clock (SCL), are open drain output and

external pull up resistors must be used conforming to the I2C bus specifications [12].

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 GNSS receiver (details in GNSS Implementation Application Note [13]).

Combining a u-blox cellular module with a u-blox GNSS receiver allows designers to full access the GNSS receiver

directly via the cellular module: it relays control messages to the GNSS receiver via a dedicated DDC (I2C)

interface. A 2nd interface connected to the GNSS receiver is not necessary: AT commands via the AT interfaces of

the cellular module (UART, USB) allows a full control of the GNSS receiver from any host processor.

u-blox cellular modules feature embedded GNSS aiding that is a set of specific features developed by u-blox to

enhance GNSS performance, decreasing Time To First Fix (TTFF), thus allowing to calculate the position in a

shorter time with higher accuracy.

Additional custom functions over GPIO pins are designed to improve the integration with u-blox GNSS receivers:

 GNSS receiver power-on/off: “GNSS supply enable” function over the GPIO2 pin improves the positioning

receiver power consumption. When the GNSS functionality is not required, the positioning receiver can be

completely switched off by the cellular module controlled by the application processor over AT commands

 The wake up from idle-mode when the GNSS receiver is ready to send data: “GNSS data ready” function

over the GPIO3 pin improves the cellular module power consumption. When power saving is enabled in the

cellular module by the AT+UPSV command and the GNSS receiver does not send data by the DDC (I2C)

interface, the module automatically enters idle-mode whenever possible. With the “GNSS data ready”

function the GNSS receiver can indicate to the cellular module that it is ready to send data: the positioning

receiver can wake up the cellular module to avoid data loss even if power saving is enabled.

 The RTC synchronization signal to the GNSS receiver: “GNSS RTC sharing” function over the GPIO4 pin

improves GNSS receiver performance, decreasing the Time To First Fix (TTFF), and thus allowing to calculate

the position in a shorter time with higher accuracy. When GNSS local aiding is enabled, the cellular module

automatically uploads data such as position, time, ephemeris, almanac, health and ionospheric parameter

from the positioning receiver into its local memory, and restores this to the GNSS receiver at the next power

up of the positioning receiver

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1.9.4 Secure Digital Input Output interface (SDIO)

Secure Digital Input Output interface is not available on MPCI-L2 series modules.

Secure Digital Input Output interface is not supported by the TOBY-L2x0-00S product version.

TOBY-L2 series modules include a 4-bit Secure Digital Input Output interface (SDIO_D0, SDIO_D1, SDIO_D2,

SDIO_D3, SDIO_CLK, SDIO_CMD) designed to communicate with an external Wi-Fi chip.

1.10 Audio

1.10.1 Digital audio over I2S interface

Digital audio over I2S interface is not available on MPCI-L2 series modules.

Digital audio over I2S interface is not supported by the TOBY-L2x0-00S product version.

TOBY-L2 series modules include a 4-wire I2S digital audio interface (I2S_TXD, I2S_RXD, I2S_CLK, I2S_WA) that

can be configured by AT command to transfer digital audio data with an external device as an audio codec (for

more details see u-blox AT Commands Manual [3]).

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1.11 General Purpose Input/Output

General Purpose Input / Output pins are not supported by the TOBY-L2x0-00S product version except for

the Wireless Wide Area Network status indication configured on the GPIO1 pin.

General Purpose Input / Output pins are not available on MPCI-L2 series modules.

TOBY-L2 series modules include 14 pins (GPIO1-GPIO6, I2S_TXD, I2S_RXD, I2S_CLK, I2S_WA, DTR, DSR,

DCD, RI) that can be configured as General Purpose Input/Output or to provide custom functions via u-blox AT

commands (see the u-blox AT Commands Manual [3]), as summarized in Table 12.

Function

Description

Default GPIO

Configurable GPIOs

Network status

indication

Network status: registered home network, registered

roaming, data transmission, no service

GPIO1

GNSS supply enable

Enable/disable the supply of u-blox GNSS receiver

connected to cellular module

GPIO2

GNSS data ready

Sense when u-blox GNSS receiver connected to the module

is ready for sending data by the DDC (I2C)

GPIO3

GNSS RTC sharing

Real Time Clock synchronization signal to u-blox GNSS

receiver connected to cellular module

GPIO4

SIM card detection

SIM card physical presence detection

GPIO5

SIM card hot

insertion/removal

SIM card hot insertion/removal

GPIO5

I2S digital audio interface

I2S_RXD, I2S_TXD,

I2S_CLK, I2S_WA

I2S_RXD, I2S_TXD,

I2S_CLK, I2S_WA

26 MHz clock output

26 MHz clock output for an external audio codec or an

external Wi-Fi chip/module

GPIO6

Wi-Fi enable

Enable/disable the supply of the external Wi-Fi chip or

module connected to the cellular module

GPIO1, GPIO4, DSR

Wi-Fi data ready

Sense when the external Wi-Fi chip/module connected to

the cellular module is ready for sending data by the SDIO,

waking up the cellular module from low power idle mode

GPIO3, DTR

Wi-Fi reset

Reset the external Wi-Fi chip or module connected to the

cellular module

GPIO3, DCD

Wi-Fi power saving

Enable/disable the low power mode of the external Wi-Fi

chip/module connected to the cellular module

GPIO2, RI

32 kHz clock output

32 kHz clock output for an external Wi-Fi chip or module

GPIO4

Antenna tuning

4-bit tunable antenna control signals mapping the actual

operating RF band over a 4-pin interface provided for the

implementation of external antenna tuning solutions

I2S_RXD, I2S_TXD,

I2S_CLK, I2S_WA

DSR, DTR, DCD, RI

DSR

UART data set ready output

DSR

DTR

UART data terminal ready input

DTR

DCD

UART data carrier detect output

DCD

UART ring indicator output

General purpose input

Input to sense high or low digital level

All

General purpose output

Output to set the high or the low digital level

All

Pin disabled

Tri-state with an internal active pull-down enabled

All

Table 12: TOBY-L2 series GPIO custom functions configuration

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1.12 Mini PCIe specific signals (W_DISABLE#, LED_WWAN#)

Mini PCI Express specific signals (W_DISABLE#, LED_WWAN#) are not available on TOBY-L2 series.

MPCI-L2 series modules include the W_DISABLE# active-low input signal to disable the radio operations as

specified by the PCI Express Mini Card Electromechanical Specification [14].

As described in Figure 20, the W_DISABLE# input is equipped with an internal pull-up to the 3.3Vaux supply.

The W_DISABLE# input detailed electrical characteristics are described in the MPCI-L2 series Data Sheet [2].

Baseband

Processor

W_DISABLE#

MPCI-L2 series

3.3Vaux

W_DISABLE#

22k

Figure 20: MPCI-L2 series modules W_DISABLE# input circuit description

MPCI-L2 series modules include the LED_WWAN# active-low open drain output to provide the Wireless Wide

Area Network status indication as specified by the PCI Express Mini Card Electromechanical Specification [14].

For more electrical characteristics details see the MPCI-L2 Data Sheet [2].

1.13 Reserved pins (RSVD)

Pins reserved for future use, marked as RSVD, are not available on MPCI-L2 series.

TOBY-L2 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.

1.14 Not connected pins (NC)

Pins internally not connected, marked as NC, are not available on TOBY-L2 series.

MPCI-L2 series modules have pins internally not connected, marked as NC: they can be left unconnected or they

can be connected on the application board according to any application requirement, given that none function is

provided by the modules over these pins.

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1.15 System features

1.15.1 Network indication

Network status indication over GPIO1 is not available on MPCI-L2 series modules which include the

LED_WWAN# active-low open drain output to provide the Wireless Wide Area Network status indication

as specified by the PCI Express Mini Card Electromechanical Specification [14].

General Purpose Input / Output pins are not supported by the TOBY-L2x0-00S product version except for

the Wireless Wide Area Network status indication configured on the GPIO1 pin.

The GPIO1 can be configured by the AT+UGPIOC command to indicate network status as described below:

 No service (no network coverage or not registered)

 Registered 2G / 3G / LTE home network

 Registered 2G / 3G / LTE visitor network (roaming)

 Call enabled (RF data transmission / reception)

For the detailed description of the network status indication configuration, see u-blox AT Commands Manual [3],

GPIO commands.

1.15.2 Antenna supervisor

Antenna supervisor (i.e. antenna detection) is not available on MPCI-L2 series.

Antenna supervisor (i.e. antenna detection) is not supported by the TOBY-L2x0-00S product version.

The antenna detection function provided by the ANT_DET pin is based on an ADC measurement as optional

feature that can be implemented if the application requires it. The antenna supervisor is forced by the +UANTR

AT command (see the u-blox AT Commands Manual [3] for more details).

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 1.7.2 for detailed antenna detection interface functional description and see section 2.4.2 for

detection circuit on application board and diagnostic circuit on antenna assembly design-in guidelines.

1.15.3 Jamming detection

Congestion detection (i.e. jamming detection) is not supported by TOBY-L2x0-00S and MPCI-L2x0-00S.

In real network situations modules can experience various kind of out-of-coverage conditions: limited service

conditions when roaming to networks not supporting the specific SIM, limited service in cells which are not

suitable or barred due to operators’ choices, no cell condition when moving to poorly served or highly interfered

areas. In the latter case, interference can be artificially injected in the environment by a noise generator covering

a given spectrum, thus obscuring the operator’s carriers entitled to give access to the LTE/3G/2G service.

The congestion (i.e. jamming) detection feature can be enabled and configured by the +UCD AT command: the

feature consists of detecting an anomalous source of interference and signaling the start and stop of such

conditions to the host application processor with an unsolicited indication, which can react appropriately by e.g.

switching off the radio transceiver of the module (i.e. configuring the module in “airplane mode” by means of

the +CFUN AT command) in order to reduce power consumption and monitoring the environment at constant

periods (for more details see the u-blox AT Commands Manual [3]).

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1.15.4 IP modes of operation

IP modes of operation refer to the TOBY-L2 and MPCI-L2 series modules configuration related to the network IP

termination and network interfaces settings in general. IP modes of operation are the following:

 Bridge mode: In bridge mode the module acts as a cellular modem dongle connected to the host over

serial interface (USB). The IP termination of the network is placed on the host IP stack. The module is

configured as a bridge which means the network IP address is assigned to the host (host IP termination).

 Router mode: In router mode the module acts as a cellular modem router which means the IP termination

of the network is placed on the internal IP stack of the module (on-target IP termination). In particular, in

this configuration the application processor belongs to a private network and is not aware of the mobile

connectivity setup of the module.

For more details about IP modes of operation see the u-blox AT Commands Manual [3].

1.15.5 Dual stack IPv4/IPv6

TOBY-L2 and MPCI-L2 series support both Internet Protocol version 4 and Internet Protocol version 6 in parallel.

For more details about dual stack IPv4/IPv6 see the u-blox AT Commands Manual [3].

1.15.6 TCP/IP and UDP/IP

Embedded TCP/IP and UDP/IP stack as well as Direct Link mode are not supported by the TOBY-L2x0-00S

and MPCI-L2x0-00S product versions.

TOBY-L2 and MPCI-L2 series modules provide embedded TCP/IP and UDP/IP protocol stack: a PDP context can be

configured, established and handled via the data connection management packet switched data commands.

TOBY-L2 and MPCI-L2 series modules provide Direct Link mode to establish a transparent end-to-end

communication with an already connected TCP or UDP socket via serial interfaces (USB, UART). In Direct Link

mode, data sent to the serial interface from an external application processor is forwarded to the network and

vice-versa.

For more details about embedded TCP/IP and UDP/IP functionalities see the u-blox AT Commands Manual [3].

1.15.7 FTP and FTPS

Embedded FTP and FTPS services as well as Direct Link mode are not supported by the TOBY-L2x0-00S

and MPCI-L2x0-00S product versions.

TOBY-L2 and MPCI-L2 series provide embedded File Transfer Protocol (FTP) and Secure File Transfer Protocol

(FTPS, i.e. FTP with SSL encryption) services. Files are read and stored in the local file system of the module.

FTP files can also be transferred using FTP Direct Link:

 FTP download: data coming from the FTP server is forwarded to the host processor via USB / UART serial

interfaces (for FTP without Direct Link mode the data is always stored in the module’s Flash File System)

 FTP upload: data coming from the host processor via USB / UART serial interface is forwarded to the FTP

server (for FTP without Direct Link mode the data is read from the module’s Flash File System)

When Direct Link is used for a FTP file transfer, only the file content pass through USB / UART serial interface,

whereas all the FTP commands handling is managed internally by the FTP application.

For more details about embedded FTP and FTPS functionalities see u-blox AT Commands Manual [3].

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1.15.8 HTTP and HTTPS

Embedded HTTP and HTTPS services are not supported by TOBY-L2x0-00S and MPCI-L2x0-00S.

TOBY-L2 and MPCI-L2 series modules provide the embedded Hyper-Text Transfer Protocol (HTTP) and the Secure

Hyper-Text Transfer Protocol (HTTPS, i.e. HTTP with TLS / SSL encryption) services via AT commands for sending

requests to a remote HTTP server, receiving the server response and transparently storing it in the module’s Flash

File System (FFS).

For more details about embedded HTTP and HTTPS functionalities see the u-blox AT Commands Manual [3].

1.15.9 SSL

Embedded Transport Layer Security (TLS) / Secure Sockets Layer (SSL) protocols are not supported by the

TOBY-L2x0-00S and MPCI-L2x0-00S product versions.

TOBY-L2 and MPCI-L2 series modules provide the Transport Layer Security (TLS) / Secure Sockets Layer (SSL)

encryption protocols to enable security over the FTP and HTTP protocols via AT commands.

For more details about embedded TLS / SSL functionalities see the u-blox AT Commands Manual [3].

1.15.10 AssistNow clients and GNSS integration

AssistNow clients and u-blox GNSS receiver integration are not available on MPCI-L2 series.

AssistNow clients and u-blox GNSS receiver integration are not supported by TOBY-L2x0-00S.

For customers using u-blox GNSS receivers, TOBY-L2 series cellular modules feature embedded AssistNow clients.

AssistNow A-GPS provides better GNSS performance and faster Time-To-First-Fix. The clients can be enabled and

disabled with an AT command (see the u-blox AT Commands Manual [3]).

TOBY-L2 series cellular modules act as a stand-alone AssistNow client, making AssistNow available with no

additional requirements for resources or software integration on an external host micro controller. Full access to

u-blox GNSS receivers is available via the TOBY-L2 series cellular module, through the DDC (I2C) interface, while

the available GPIOs can handle the positioning chipset / module power-on/off. This means that cellular module

and GNSS receiver can be controlled through a single serial port from any host processor.

1.15.11 Hybrid positioning and CellLocate®

Hybrid positioning and CellLocate® are not available on MPCI-L2 series.

Hybrid positioning and CellLocate® are not supported by the TOBY-L2x0-00S product version.

Although GNSS is a widespread technology, its reliance on the visibility of extremely weak GNSS satellite signals

means that positioning is not always possible. Especially difficult environments for GNSS are indoors, in enclosed

or underground parking garages, as well as in urban canyons where GNSS signals are blocked or jammed by

multipath interference. The situation can be improved by augmenting GNSS receiver data with cellular network

information to provide positioning information even when GNSS reception is degraded or absent. This additional

information can benefit numerous applications.

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Positioning through cellular information: CellLocate®

u-blox CellLocate® enables the estimation of device position based on the parameters of the mobile network cells

visible to the specific device. To estimate its position the u-blox cellular module sends the CellLocate® server the

parameters of network cells visible to it using a UDP connection. In return the server provides the estimated

position based on the CellLocate® database. The u-blox cellular module can either send the parameters of the

visible home network cells only (normal scan) or the parameters of all surrounding cells of all mobile operators

(deep scan).

The CellLocate® database is compiled from the position of devices which observed, in the past, a specific cell or

set of cells (historical observations) as follows:

1. Several devices reported their position to the CellLocate® server when observing a specific cell (the As in the

picture represent the position of the devices which observed the same cell A)

2. CellLocate® server defines the area of Cell A visibility

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3. If a new device reports the observation of Cell A CellLocate® is able to provide the estimated position from

the area of visibility

4. The visibility of multiple cells provides increased accuracy based on the intersection of areas of visibility.

CellLocate® is implemented using a set of two AT commands that allow configuration of the CellLocate® service

(AT+ULOCCELL) and requesting position according to the user configuration (AT+ULOC). The answer is provided

in the form of an unsolicited AT command including latitude, longitude and estimated accuracy.

The accuracy of the position estimated by CellLocate® depends on the availability of historical observations

in the specific area.

Hybrid positioning

With u-blox Hybrid positioning technology, u-blox cellular devices can be triggered to provide their current

position using either a u-blox GNSS receiver or the position estimated from CellLocate®. The choice depends on

which positioning method provides the best and fastest solution according to the user configuration, exploiting

the benefit of having multiple and complementary positioning methods.

Hybrid positioning is implemented through a set of three AT commands that allow configuration of the GNSS

receiver (AT+ULOCGNSS), configuration of the CellLocate® service (AT+ULOCCELL), and requesting the position

according to the user configuration (AT+ULOC). The answer is provided in the form of an unsolicited AT

command including latitude, longitude and estimated accuracy (if the position has been estimated by

CellLocate®), and additional parameters if the position has been computed by the GNSS receiver.

The configuration of mobile network cells does not remain static (e.g. new cells are continuously added or

existing cells are reconfigured by the network operators). For this reason, when a Hybrid positioning method has

been triggered and the GNSS receiver calculates the position, a database self-learning mechanism has been

implemented so that these positions are sent to the server to update the database and maintain its accuracy.

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The use of hybrid positioning requires a connection via the DDC (I2C) bus between the TOBY-L2 series cellular

module and the u-blox GNSS receiver (see sections 1.9.3 and 2.6.3).

See GNSS Implementation Application Note [13] for the complete description of the feature.

u-blox is extremely mindful of user privacy. When a position is sent to the CellLocate® server u-blox is

unable to track the SIM used or the specific device.

1.15.12 Firmware update Over AT (FOAT)

This feature allows upgrading the module firmware over USB / UART serial interfaces, using AT commands.

 The +UFWUPD AT command triggers a reboot followed by the upgrade procedure at specified a baud rate

 A special boot loader on the module performs firmware installation, security verifications and module reboot

 Firmware authenticity verification is performed via a security signature during the download. The firmware is

then installed, overwriting the current version. In case of power loss during this phase, the boot loader

detects a fault at the next wake-up, and restarts the firmware download. After completing the upgrade, the

module is reset again and wakes-up in normal boot

For more details about Firmware update Over AT procedure see the Firmware Update Application Note [4] and

the u-blox AT Commands Manual [3], +UFWUPD AT command.

1.15.13 Firmware update Over The Air (FOTA)

Firmware update Over The Air (FOTA) is not supported by TOBY-L2x0-00S and MPCI-L2x0-00S.

This feature allows upgrading the module firmware over the LTE/3G/2G air interface. The main idea with

updating Firmware over the air is to reduce the amount of data required for transmission to the module. This is

achieved by downloading only a “delta file” instead of the full firmware. The delta contains only the differences

between the two firmware versions (old and new), and is compressed.

For more details about Firmware update Over The Air procedure see the Firmware Update Application Note [4]

and the u-blox AT Commands Manual [3], +UFOTA AT command.

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1.15.14 In-band Modem (eCall / ERA-GLONASS)

In-band modem for eCall / ERA-GLONASS emergency applications is not supported by TOBY-L2x0-00S

and MPCI-L2 series.

In-band Modem solution for eCall and ERA-GLONASS emergency call applications over cellular networks is

implemented according to 3GPP TS 26.267 [15], BS EN 16062:2011 [16] and ETSI TS 122 101 [17] specifications.

eCall (European) and ERA-GLONASS (Russian) are initiatives to combine mobile communications and satellite

positioning to provide rapid assistance to motorists in the event of a collision, implementing automated

emergency response system based the first on GPS the latter on GLONASS positioning system.

When activated, the in-vehicle systems (IVS) automatically initiate an emergency call carrying both voice and data

(including location data) directly to the nearest Public Safety Answering Point (PSAP) to determine whether

rescue services should be dispatched to the known position.

Figure 21: eCall and ERA-GLONASS automated emergency response systems diagram flow

For more details regarding the In-band Modem solution for the European eCall and the Russian ERA-GLONASS

emergency call applications, see the u-blox eCall / ERA-GLONASS Application Note [18].

1.15.15 SIM Access Profile (SAP)

SIM Access Profile (SAP) is not supported by TOBY-L2x0-00S and MPCI-L2 series.

SIM access profile (SAP) feature allows accessing and using a remote SIM card / chipping instead of the local SIM

directly connected to the module SIM interface.

A dedicated SAP channel over USB and a dedicated multiplexed SAP channel over UART are implemented for

communication with the remote SIM card/chip.

Communication between TOBY-L2 series module and the remote SIM is conformed to client-server paradigm:

The module is the SAP client establishing a connection and performing data exchange to a SAP server directly

connected to the remote SIM that is used by the module for LTE/3G/2G network-related operations. The SAP

communication protocol is based on the SIM Access Profile Interoperability Specification [19].

A typical application using the SAP feature is the scenario where a device such as an embedded car-phone with

an integrated TOBY-L2 series module uses a remote SIM included in an external user device (e.g. a simple SIM

card reader or a portable phone), which is brought into the car. The car-phone accesses the LTE/3G/2G network

using the remote SIM in the external device.

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TOBY-L2 series modules, acting as an SAP client, can be connected to an SAP server by a completely wired

connection, as shown in Figure 22.

Device including TOBY-L2

LTE/3G/2G

Interface

Local SIM

(optional)

TOBY-L2

SAP Client

Application

Processor

Device including SIM

SAP

Serial Interface

Remote SIM

Mobile

Equipment

SAP Server

SAP

Serial Interface

(SAP channel over

USB or UART)

Figure 22: Remote SIM access via completely wired connection

As stated in the SIM Access Profile Interoperability Specification [19], the SAP client can be connected to the SAP

server by means of a Bluetooth wireless link, using additional Bluetooth transceivers. In this case, the application

processor wired to TOBY-L2 series module establishes and controls the Bluetooth connection using the SAP

profile, and routes data received over a serial interface channel to data transferred over a Bluetooth interface

and vice versa, as shown in Figure 23.

Device including TOBY-L2

SAP

Serial Interface

(SAP channel over

USB or UART)

LTE/3G/2G

Interface

Local SIM

(optional)

TOBY-L2

SAP Client

Application

Processor

SAP

Bluetooth

Interface

Bluetooth

Transceiver

Device including SIM

Remote SIM

Mobile

Equipment

SAP Server

Bluetooth

Transceiver

Figure 23: Remote SIM access via Bluetooth and wired connection

The application processor can start an SAP connection negotiation between TOBY-L2 series module SAP client

and an SAP server using custom AT command (for more details see u-blox AT Commands Manual [3]).

While the connection with the SAP server is not fully established, the TOBY-L2 series module continues to

operate with the attached (local) SIM, if present. Once the connection is established and negotiated, the module

performs a detach operation from the local SIM followed by an attach operation to the remote one. Then the

remotely attached SIM is used for any LTE/3G/2G network operation.

URC indications are provided to inform the user about the state of both the local and remote SIM. The insertion

and the removal of the local SIM card are notified if a proper card presence detection circuit using the GPIO5 of

TOBY-L2 series modules is implemented as shown in section 2.5, and if the related “SIM card detection” and

“SIM hot insertion/removal” functions described in section 1.8.2 are enabled by AT commands (for more details

see u-blox AT Commands Manual [3]).

Upon SAP deactivation, the TOBY-L2 series modules perform a detach operation from the remote SIM followed

by an attach operation to the local one, if present.

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1.15.16 Smart temperature management

Smart temperature management is not supported by TOBY-L2x0-00S and MPCI-L2x0-00S.

Cellular modules – independent of the specific model – always have a well defined operating temperature range.

This range should be respected to guarantee full device functionality and long life span.

Nevertheless there are environmental conditions that can affect operating temperature, e.g. if the device is

located near a heating/cooling source, if there is/isn’t air circulating, etc.

The module itself can also influence the environmental conditions; such as when it is transmitting at full power.

In this case its temperature increases very quickly and can raise the temperature nearby.

The best solution is always to properly design the system where the module is integrated. Nevertheless an extra

check/security mechanism embedded into the module is a good solution to prevent operation of the device

outside of the specified range.

Smart Temperature Supervisor (STS)

The Smart Temperature Supervisor is activated and configured by a dedicated AT+USTS command. See the

u-blox AT Commands Manual [3] for more details.

The cellular module measures the internal temperature (Ti) and its value is compared with predefined thresholds

to identify the actual working temperature range.

Temperature measurement is done inside the cellular module: the measured value could be different from

the environmental temperature (Ta).

Warning

area

t-1 t+1 t+2

t-2

Valid temperature range

Safe

area

Dangerous

area

Dangerous

area

Warning

area

Figure 24: Temperature range and limits

The entire temperature range is divided into sub-regions by limits (see Figure 24) named t-2, t-1, t+1 and t+2.

 Within the first limit, (t-1 < Ti < t+1), the cellular module is in the normal working range, the Safe Area

 In the Warning Area, (t-2 < Ti < t.1) or (t+1 < Ti < t+2), the cellular module is still inside the valid temperature

range, but the measured temperature approaches the limit (upper or lower). The module sends a warning to

the user (through the active AT communication interface), which can take, if possible, the necessary actions

to return to a safer temperature range or simply ignore the indication. The module is still in a valid and good

working condition

 Outside the valid temperature range, (Ti < t-2) or (Ti > t+2), the device is working outside the specified range

and represents a dangerous working condition. This condition is indicated and the device shuts down to

avoid damage

For security reasons the shutdown is suspended in case an emergency call in progress. In this case the

device will switch off at call termination.

The user can decide at anytime to enable/disable the Smart Temperature Supervisor feature. If the feature

is disabled there is no embedded protection against disallowed temperature conditions.

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Figure 25 shows the flow diagram implemented for the Smart Temperature Supervisor.

IF STS

enabled

Read

temperature

(t-1<Ti<t+1)

(t-2<Ti<t+2)

Send

notification

(warning)

Send

notification

(dangerous)

Wait emergency

call termination

emerg.

call in

progress

Shut the device

down

Yes

Send

shutdown

notification

Feature enabled

(full logic or

indication only)

Full Logic

Enabled

Feature disabled:

no action

Temperature is

within normal

operating range

Yes

Tempetature

is within

warning area

Tempetature is

outside valid

temperature range

Featuere enabled

in full logic mode

Feature enabled in

indication only mode:

no further actions

Send

notification

(safe)

Previously

outside of

Safe Area

Tempetature

is back to

safe area

further

actions

Yes

Figure 25: Smart Temperature Supervisor (STS) flow diagram

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Threshold Definitions

When the application of cellular module operates at extreme temperatures with Smart Temperature Supervisor

enabled, the user should note that outside the valid temperature range the device will automatically shut down

as described above.

The input for the algorithm is always the temperature measured within the cellular module (Ti, internal). This

value can be higher than the working ambient temperature (Ta, ambient), as (for example) during transmission

at maximum power a significant fraction of DC input power is dissipated as heat This behavior is partially

compensated by the definition of the upper shutdown threshold (t+2) that is slightly higher than the declared

environmental temperature limit.

The sensor measures board temperature inside the shields, which can differ from ambient temperature.

1.15.17 Power saving

The power saving configuration is by default disabled, but it can be enabled using the AT+UPSV command (for

the complete description of the AT+UPSV command, see the u-blox AT Commands Manual [3]).

When power saving is enabled, the module automatically enters the low power idle-mode whenever possible,

reducing current consumption (see section 1.5.1.5, TOBY-L2 Data Sheet [1] and MPCI-L2 Data Sheet [2]).

During the low power idle-mode, the module is not ready to communicate with an external device, as it is

configured to reduce power consumption. The module wakes up from low power idle-mode to active-mode in

the following events:

 Automatic periodic monitoring of the paging channel for the reception of the paging block sent by the base

station according to network conditions (see section 1.5.1.5)

 The connected USB host forces a remote wakeup of the module as USB device (see section 1.9.1.4)

 A preset RTC alarm occurs (see u-blox AT Commands Manual [3], AT+CALA)

For the definition and the description of TOBY-L2 and MPCI-L2 series modules operating modes, including the

events forcing transitions between the different operating modes, see the section 1.4.

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2 Design-in

2.1 Overview

For an optimal integration of TOBY-L2 and MPCI-L2 series modules in the final application board follow the

design guidelines stated in this section.

Every application circuit must be properly designed to guarantee the correct functionality of the relative

interface, however a number of points require high attention during the design of the application device.

The following list provides a rank of importance in the application design, starting from the highest relevance:

1. Module antenna connection: ANT1, ANT2 and ANT_DET.

Antenna circuit directly affects the RF compliance of the device integrating a TOBY-L2 and MPCI-L2 series

module with applicable certification schemes. Very carefully follow the suggestions provided in the relative

section 2.4 for schematic and layout design.

2. Module supply: VCC or 3.3Vaux and GND pins.

The supply circuit affects the RF compliance of the device integrating a TOBY-L2 and MPCI-L2 series module

with applicable required certification schemes as well as antenna circuit design. Very carefully follow the

suggestions provided in the relative section 2.2.1 for schematic and layout design.

3. USB interface: USB_D+, USB_D- pins.

Accurate design is required to guarantee USB 2.0 high-speed interface functionality. Carefully follow the

suggestions provided in the relative section 2.6.1 for schematic and layout design.

4. SIM interface: VSIM, SIM_CLK, SIM_IO, SIM_RST or UIM_PWR, UIM_DATA, UIM_CLK, UIM_RESET pins.

Accurate design is required to guarantee SIM card functionality reducing the risk of RF coupling. Carefully

follow the suggestions provided in the relative section 2.5 for schematic and layout design.

5. SDIO interface: SDIO_D0, SDIO_D1, SDIO_D2, SDIO_D3, SDIO_CLK, SDIO_CMD pins.

Accurate design is required to guarantee SDIO interface functionality. Carefully follow the suggestions

provided in the relative section 2.6.4 for schematic and layout design.

6. System functions: RESET_N or PERST#, PWR_ON pins.

Accurate design is required to guarantee that the voltage level is well defined during operation. Carefully

follow the suggestions provided in the relative section 2.3 for schematic and layout design.

7. Other supplies: V_BCKP RTC supply and V_INT generic digital interfaces supply.

Accurate design is required to guarantee proper functionality. Follow the suggestions provided in the

corresponding sections 2.2.2 and 2.2.3 for schematic and layout design.

8. Other digital interfaces: UART, I2C, I2S, Host Select, GPIOs, Mini PCIe specific signals and Reserved pins.

Accurate design is required to guarantee proper functionality. Follow the suggestions provided in sections

2.6.2, 2.6.3, 2.7.1, 2.3.3, 2.8, 2.9 and 2.10 for schematic and layout design.

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2.2 Supply interfaces

2.2.1 Module supply (VCC or 3.3Vaux)

2.2.1.1 General guidelines for VCC or 3.3Vaux supply circuit selection and design

VCC or 3.3Vaux pins are internally connected. Application design shall connect all the available pads to the

external supply to minimize 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-L2 and MPCI-L2 series modules must be sourced through the VCC or the 3.3Vaux pins with a proper DC

power supply that should meet the following prerequisites to comply with the modules’ VCC or 3.3Vaux

requirements summarized in Table 7.

The proper DC power supply can be selected according to the application requirements (see Figure 26) 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, for TOBY-L2 series only

 Primary (disposable) battery, for TOBY-L2 series only

Main Supply

Available?

Battery

Li-Ion 3.7 V

Linear LDO

Regulator

Main Supply

Voltage > 5V?

Switching Step-Down

Regulator

No, portable device

No, less than 5 V

Yes, greater than 5 V

Yes, always available

Figure 26: 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-L2 and MPCI-L2 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 2.2.1.2, 2.2.1.6, 2.2.1.9, 2.2.1.10 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 2.2.1.3, 2.2.1.6, 2.2.1.9, 2.2.1.10 for specific design-in.

If TOBY-L2 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 2.2.1.4,

2.2.1.6, 2.2.1.9, 2.2.1.10 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 has to be designed to prevent over-voltage on VCC

pins of the module, and it should be selected according to the application requirements: a DC/DC switching

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charger is the typical choice when the charging source has an high nominal voltage (e.g. ~12 V), whereas a

linear charger is the 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 in the application as possible supply source, then a proper charger / regulator with

integrated power path management function can be selected to supply the module while simultaneously and

independently charging the battery. See 2.2.1.7, 2.2.1.8 and 2.2.1.6, 2.2.1.9, 2.2.1.10 for specific design-in.

The use of a primary (not rechargeable) battery is in general uncommon, but appropriate parts can be selected

given that the most cells available are seldom capable of delivering the maximum current specified in TOBY-L2

series Data Sheet [1] during connected-mode. Carefully evaluate the usage of super-capacitors as supply source

since aging and temperature conditions significantly affect the actual capacitor characteristics. See 2.2.1.5 and

2.2.1.6, 2.2.1.9, 2.2.1.10 for specific design-in.

Rechargeable 3-cell Li-Ion or Li-Pol and Ni-MH chemistry batteries reach a maximum voltage that is above the

maximum rating for the 3.3Vaux supply of MPCI-L2 modules, and should therefore be avoided. The use of

rechargeable, not-rechargeable battery or super-capacitors is very uncommon for Mini PCI Express applications,

so that these supply sources types are not considered for MPCI-L2 modules.

The usage of more than one DC supply at the same time should be carefully evaluated: depending on the supply

source characteristics, different DC supply systems can result as mutually exclusive.

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 or 3.3Vaux supply circuit design using a switching regulator

The use of a switching regulator is suggested when the difference from the available supply rail to the VCC or

the 3.3Vaux 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 or the typical 3.3 V value of the 3.3Vaux supply.

The characteristics of the switching regulator connected to VCC or 3.3Vaux pins should meet the following

prerequisites to comply with the module VCC or 3.3Vaux 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 or 3.3Vaux pins within the specified operating range and must be capable of delivering to

VCC or 3.3Vaux pins the maximum peak / pulse current consumption during Tx burst at maximum Tx

power specified in the TOBY-L2 series Data Sheet [1] or in the MPCI-L2 series Data Sheet [2].

 Low output ripple: the switching regulator together with its output circuit must be capable of providing a

clean (low noise) VCC or 3.3Vaux 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 carefully evaluated since this can produce noise in the VCC or 3.3Vaux 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 or 3.3Vaux 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 the noise on the VCC or 3.3Vaux 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.

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Figure 27 and Table 13 show an example of a high reliability power supply circuit, where the module VCC or

3.3Vaux 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.

12V

C2C1

VIN

RUN

SYNC

BOOST

GND

C7 C8

D1 R4

TOBY-L2 series

71 VCC

72 VCC

70 VCC

GND

12V

C2C1

VIN

RUN

SYNC

BOOST

GND

C7 C8

D1 R6

MPCI-L2 series

24 3.3Vaux

39 3.3Vaux

23.3Vaux

GND

41 3.3Vaux

52 3.3Vaux

Figure 27: Example of high reliability VCC and 3.3Vaux supply application circuit using a step-down regulator

Reference

Description

Part Number - Manufacturer

10 µF Capacitor Ceramic X7R 5750 15% 50 V

C5750X7R1H106MB - TDK

10 nF Capacitor Ceramic X7R 0402 10% 16 V

GRM155R71C103KA01 - Murata

680 pF Capacitor Ceramic X7R 0402 10% 16 V

GRM155R71H681KA01 - Murata

22 pF Capacitor Ceramic C0G 0402 5% 25 V

GRM1555C1H220JZ01 - Murata

10 nF Capacitor Ceramic X7R 0402 10% 16 V

GRM155R71C103KA01 - Murata

470 nF Capacitor Ceramic X7R 0603 10% 25 V

GRM188R71E474KA12 - Murata

22 µF Capacitor Ceramic X5R 1210 10% 25 V

GRM32ER61E226KE15 - Murata

330 µF Capacitor Tantalum D_SIZE 6.3 V 45 m

T520D337M006ATE045 - KEMET

Schottky Diode 40 V 3 A

MBRA340T3G - ON Semiconductor

10 µH Inductor 744066100 30% 3.6 A

744066100 - Wurth Electronics

470 k Resistor 0402 5% 0.1 W

2322-705-87474-L - Yageo

15 k Resistor 0402 5% 0.1 W

2322-705-87153-L - Yageo

22 k Resistor 0402 5% 0.1 W

2322-705-87223-L - Yageo

390 k Resistor 0402 1% 0.063 W

RC0402FR-07390KL - Yageo

100 k Resistor 0402 5% 0.1 W

2322-705-70104-L - Yageo

330 k Resistor 0402 1% 0.063 W

RC0402FR-07330KL - Yageo

Step-Down Regulator MSOP10 3.5 A 2.4 MHz

LT3972IMSE#PBF - Linear Technology

Table 13: Components for high reliability VCC and 3.3Vaux supply application circuit using a step-down regulator

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Figure 28 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-L2 series

12V

C6C1

VCC

INH

FSW

SYNC

OUT

GND

D1 R1

GND

COMP

71 VCC

72 VCC

70 VCC

12V

C6C1

VCC

INH

FSW

SYNC

OUT

GND

D1 R6

GND

COMP

MPCI-L2 series

24 3.3Vaux

39 3.3Vaux

23.3Vaux

41 3.3Vaux

52 3.3Vaux

Figure 28: Example of low cost VCC and 3.3Vaux supply application circuit using step-down regulator

Reference

Description

Part Number - Manufacturer

22 µF Capacitor Ceramic X5R 1210 10% 25 V

GRM32ER61E226KE15 – Murata

100 µF Capacitor Tantalum B_SIZE 20% 6.3V 15m

T520B107M006ATE015 – Kemet

5.6 nF Capacitor Ceramic X7R 0402 10% 50 V

GRM155R71H562KA88 – Murata

6.8 nF Capacitor Ceramic X7R 0402 10% 50 V

GRM155R71H682KA88 – Murata

56 pF Capacitor Ceramic C0G 0402 5% 50 V

GRM1555C1H560JA01 – Murata

220 nF Capacitor Ceramic X7R 0603 10% 25 V

GRM188R71E224KA88 – Murata

Schottky Diode 25V 2 A

STPS2L25 – STMicroelectronics

5.2 µH Inductor 30% 5.28A 22 m

MSS1038-522NL – Coilcraft

4.7 k Resistor 0402 1% 0.063 W

RC0402FR-074K7L – Yageo

910  Resistor 0402 1% 0.063 W

RC0402FR-07910RL – Yageo

82  Resistor 0402 5% 0.063 W

RC0402JR-0782RL – Yageo

8.2 k Resistor 0402 5% 0.063 W

RC0402JR-078K2L – Yageo

39 k Resistor 0402 5% 0.063 W

RC0402JR-0739KL – Yageo

1.5 k Resistor 0402 1% 0.063 W

RC0402FR-071K5L – Yageo

330  Resistor 0402 1% 0.063 W

RC0402FR-07330RL – Yageo

Step-Down Regulator 8-VFQFPN 3 A 1 MHz

L5987TR – ST Microelectronics

Table 14: Components for low cost VCC and 3.3Vaux supply application circuit using a step-down regulator

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2.2.1.3 Guidelines for VCC or 3.3Vaux 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 and the VCC or the

3.3Vaux value is low. The linear regulators provide high efficiency when transforming a 5 VDC supply to a

voltage value within the module VCC or 3.3Vaux normal operating range.

The characteristics of the Low Drop-Out (LDO) linear regulator connected to VCC or 3.3Vaux pins should meet

the following prerequisites to comply with the module VCC or 3.3Vaux 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 or 3.3Vaux pins within the specified operating range and must be capable of delivering to

VCC or 3.3Vaux pins the maximum peak / pulse current consumption during Tx burst at maximum Tx

power specified in TOBY-L2 series Data Sheet [1] or in MPCI-L2 series Data Sheet [2].

 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 max input

voltage to the minimum output voltage to evaluate the power dissipation of the regulator).

Figure 29 and the components listed in Table 15 show an example of a power supply circuit, where the VCC or

3.3Vaux module supply is provided by an LDO linear regulator capable of delivering the required current, with

proper 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 or 3.3Vaux normal operating range (e.g. ~4.1 V for the VCC and ~3.44 V

for the 3.3Vaux as in the circuits described in Figure 29 and Table 15). This reduces the power on the linear

regulator and improves the thermal design of the circuit.

C1 R1

IN OUT

ADJ

GND

C2R2

SHDN

TOBY-L2 series

71 VCC

72 VCC

70 VCC

GND

C1 R1

IN OUT

ADJ

GND

C2R4

SHDN

MPCI-L2 series

GND

24 3.3Vaux

39 3.3Vaux

23.3Vaux

41 3.3Vaux

52 3.3Vaux

Figure 29: Suggested schematic design for the VCC and 3.3Vaux 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

330 µF Capacitor Tantalum D_SIZE 6.3 V 45 m

T520D337M006ATE045 - KEMET

47 k Resistor 0402 5% 0.1 W

RC0402JR-0747KL - Yageo Phycomp

9.1 k Resistor 0402 5% 0.1 W

RC0402JR-079K1L - Yageo Phycomp

3.9 k Resistor 0402 5% 0.1 W

RC0402JR-073K9L - Yageo Phycomp

3.3 k Resistor 0402 5% 0.1 W

RC0402JR-073K3L - Yageo Phycomp

1.8 k Resistor 0402 5% 0.1 W

RC0402JR-071K8L - Yageo Phycomp

LDO Linear Regulator ADJ 3.0 A

LT1764AEQ#PBF - Linear Technology

Table 15: Suggested components for VCC and 3.3Vaux supply application circuit using an LDO linear regulator

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Figure 30 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 proper power handling capability. The regulator described 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 VCC normal operating range (e.g. ~4.1 V as in the circuit described in Figure 30

and Table 16). This reduces the power on the linear regulator and improves the whole thermal design of the

supply circuit.

IN OUT

ADJ

GND

C2R1

TOBY-L2 series

71 VCC

72 VCC

70 VCC

GND

IN OUT

ADJ

GND

C2R3

MPCI-L2 series

GND

24 3.3Vaux

39 3.3Vaux

23.3Vaux

41 3.3Vaux

52 3.3Vaux

Figure 30: Suggested schematic design for the VCC and 3.3Vaux 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

330 µF Capacitor Tantalum D_SIZE 6.3 V 45 m

T520D337M006ATE045 - KEMET

27 k Resistor 0402 5% 0.1 W

RC0402JR-0727KL - Yageo Phycomp

4.7 k Resistor 0402 5% 0.1 W

RC0402JR-074K7L - Yageo Phycomp

12 k Resistor 0402 5% 0.1 W

RC0402JR-0712KL - Yageo Phycomp

2.7 k Resistor 0402 5% 0.1 W

RC0402JR-072K7L - Yageo Phycomp

LDO Linear Regulator ADJ 3.0 A

LP38501ATJ-ADJ/NOPB - Texas Instrument

Table 16: Suggested components for VCC voltage supply application circuit using an LDO linear regulator

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 VCC requirements 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 current

consumption during Tx burst at maximum Tx power specified in TOBY-L2 series Data Sheet [1] and must be

capable of extensively delivering a DC current as the maximum average current consumption specified in

TOBY-L2 series Data Sheet [1]. The maximum discharge current is not always reported in battery data sheets,

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.

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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 VCC pins should meet the following

prerequisites to comply with the module VCC requirements 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 maximum Tx power specified in TOBY-L2 series Data Sheet [1] and must be

capable of extensively delivering a DC current as the maximum average current consumption specified in

TOBY-L2 series Data Sheet [1]. The maximum discharge current is not always reported in battery data sheets,

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 summarized in Table 7 during transmit bursts.

2.2.1.6 Additional guidelines for VCC or 3.3Vaux 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 / 3.3Vaux 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 VCC supply and five pins to 3.3Vaux supply. Several pins are designated for GND

connection. Even if all the VCC / 3.3Vaux pins and all the GND pins are internally connected within the module,

it is recommended to properly connect all of them to supply the module to minimize series resistance losses.

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 or 3.3Vaux supply can rise up as specified in TOBY-L2 series Data

Sheet [1] or in MPCI-L2 series Data Sheet [2]), 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 / 3.3Vaux pins:

 68 pF capacitor with Self-Resonant Frequency in the 800/900 MHz range (e.g. Murata GRM1555C1H680J)

to filter EMI in the RF low frequencies bands

 15 pF capacitor with Self-Resonant Frequency in 1800/1900 MHz range (e.g. Murata GRM1555C1E150J)

to filter EMI in the RF high frequencies bands

 8.2 pF capacitor with Self-Resonant Frequency in 2500/2600 MHz range (e.g. Murata GRM1555C1H8R2D)

to filter EMI in the RF very high frequencies band

 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 properly placed on the VCC / 3.3Vaux line for additional noise filtering if

required by the specific application according to the whole application board design.

The necessity of each part depends on the specific design, but it is recommended to provide all the bypass

capacitors described in Figure 31 / Table 17 if the application device integrates an internal antenna.

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GND

C3 C4

TOBY-L2 series

VCC

C1 C5 C6

3V8

GND

C3 C4

MPCI-L2 series

C1 C5 C6

3V3

3.3Vaux

Figure 31: Suggested schematic for the VCC / 3.3Vaux bypass capacitors to reduce ripple / noise on supply voltage profile

Reference

Description

Part Number - Manufacturer

68 pF Capacitor Ceramic C0G 0402 5% 50 V

GRM1555C1H680JA01 - Murata

15 pF Capacitor Ceramic C0G 0402 5% 50 V

GRM1555C1H150JA01 - Murata

8.2 pF Capacitor Ceramic C0G 0402 5% 50 V

GRM1555C1H8R2DZ01 - Murata

10 nF Capacitor Ceramic X7R 0402 10% 16 V

GRM155R71C103KA01 - Murata

100 nF Capacitor Ceramic X7R 0402 10% 16 V

GRM155R71C104KA01 - Murata

330 µF Capacitor Tantalum D_SIZE 6.3 V 45 m

T520D337M006ATE045 - KEMET

Table 17: Suggested components to reduce ripple / noise on VCC / 3.3Vaux

ESD sensitivity rating of the VCC / 3.3Vaux supply pins is 1 kV (HBM according to JESD22-A114). Higher

protection level can be required if the line is externally accessible on the application board, e.g. if

accessible battery connector is directly connected to the supply pins. Higher protection level can be

achieved by mounting an ESD protection (e.g. EPCOS CA05P4S14THSG varistor) close to accessible point.

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2.2.1.7 Guidelines for external battery charging circuit

TOBY-L2 modules do not have an on-board charging circuit. Figure 32 provides an example of a battery charger

design, 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 proper pulse and DC

discharge current capabilities and proper DC series resistance, is directly connected to the VCC supply input of

TOBY-L2 module. Battery charging is completely managed by the STMicroelectronics L6924U Battery Charger IC

that, from a USB power source (5.0 V typ.), charges as a linear charger the battery, 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.

Alternatively the L6924U, providing input voltage range up to 12 V, can charge from an AC wall adapter. When

a current-limited adapter is used, it can operate in quasi-pulse mode, reducing power dissipation.

C5 C8C7C6 C9

GND

TOBY-L2 series

71 VCC

72 VCC

70 VCC

USB

Supply

C3 R4

IUSB

IAC

IEND

TPRG

VIN

VINSNS

MODE

ISEL

C2C1

5V0

GND

VOUT

VOSNS

VREF

Li-Ion/Li-Pol

Battery Pack

Li-Ion/Li-Polymer

Battery Charger IC

C10

Figure 32: Li-Ion (or Li-Polymer) battery charging application circuit

Reference

Description

Part Number - Manufacturer

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

1 nF Capacitor Ceramic X7R 0402 10% 50 V

GRM155R71H102KA01 - Murata

330 µF Capacitor Tantalum D_SIZE 6.3 V 45 m

T520D337M006ATE045 - KEMET

100 nF Capacitor Ceramic X7R 0402 10% 16 V

GRM155R61A104KA01 - Murata

68 pF Capacitor Ceramic C0G 0402 5% 50 V

GRM1555C1H680JA01 - Murata

15 pF Capacitor Ceramic C0G 0402 5% 50 V

GRM1555C1H150JA01 - Murata

C10

8.2 pF Capacitor Ceramic C0G 0402 5% 50 V

GRM1555C1H8R2DZ01 - Murata

Low Capacitance ESD Protection

USB0002RP or USB0002DP - AVX

R1, R2

24 k Resistor 0402 5% 0.1 W

RC0402JR-0724KL - Yageo Phycomp

3.3 k Resistor 0402 5% 0.1 W

RC0402JR-073K3L - Yageo Phycomp

1.0 k Resistor 0402 5% 0.1 W

RC0402JR-071K0L - Yageo Phycomp

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

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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 33 reports a simplified block diagram circuit showing the working principle of a charger / regulator with

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 currents.

A power management IC should meet the following prerequisites to comply with the module VCC requirements

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

GND

Power path management IC

VoutVin

Li-Ion/Li-Pol

Battery Pack

GND

System

12 V

Primary

Source

Charge

controller

DC/DC converter

and battery FET

control logic

Vbat

Figure 33: Charger / regulator with integrated power path management circuit block diagram

Figure 34 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

proper pulse and DC discharge current capabilities and proper DC series resistance according to the rechargeable

battery recommendations 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 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 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.

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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 the 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 as the charging current, the charging timings, the input current limit, the input voltage limit,

the system output voltage can be easily set according to the specific application requirements, as the actual

electrical characteristics of the battery and the external supply / charging source: proper resistors or capacitors

have to be accordingly connected to the related pins of the IC.

C10 C13

GND

C12C11 C14

TOBY-L2 series

71 VCC

72 VCC

70 VCC

Primary

Source

ILIM

ISET

TMR

AGND

VIN

C2C1

12V

NTC

PGND

SYS

BAT

Li-Ion/Li-Pol

Battery Pack

Li-Ion/Li-Polymer Battery

Charger / Regulator with

Power Path Managment

VCC

C3 C6

BST

VLIM

C7 C8 C9

C15

Figure 34: Li-Ion (or Li-Polymer) battery charging and power path management application circuit

Reference

Description

Part Number - Manufacturer

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

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

C9, C15

8.2 pF Capacitor Ceramic C0G 0402 5% 50 V

GRM1555C1H8R2DZ01 - 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

1.0 k Resistor 0402 5% 0.1 W

RC0402JR-071K0L - Yageo Phycomp

22 k Resistor 0402 5% 1/16 W

RC0402JR-0722KL - Yageo Phycomp

1.2 µH Inductor 6 A 21 m 20%

7447745012 - Wurth

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 Li-Ion (or Li-Polymer) battery charging and power path management application circuit

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2.2.1.9 Guidelines for VCC or 3.3Vaux supply layout design

Good connection of the module VCC or 3.3Vaux pins with DC supply source is required for correct RF

performance. Guidelines are summarized in the following list:

 All the available VCC / 3.3Vaux pins must be connected to the DC source

 VCC / 3.3Vaux 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 / 3.3Vaux 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 / 3.3Vaux track and other signal routing

 Coupling between VCC / 3.3Vaux 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 / 3.3Vaux pins. If the main DC source is a switching DC-DC converter, place the

large capacitor close to the DC-DC output and minimize VCC / 3.3Vaux track length. Otherwise consider

using separate capacitors for DC-DC converter and module tank capacitor

 The bypass capacitors in the pF range described in Figure 31 and Table 17 should be placed as close as

possible to the VCC / 3.3Vaux pins. This is highly recommended if the application device integrates an

internal antenna

 Since VCC / 3.3Vaux input provide the supply to RF Power Amplifiers, voltage ripple at high frequency may

result in unwanted spurious modulation of 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-L2 and MPCI-L2 series modules in the worst case

 If VCC / 3.3Vaux is protected by 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)

2.2.1.10 Guidelines for grounding layout design

Good connection of the module GND pins with 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 application board solid GND layer. It is strongly recommended that each GND

pad surrounding VCC pins have one or more dedicated via down to the application board solid ground layer

 The VCC supply current flows back to main DC source through GND as ground current: provide adequate

return path with suitable uninterrupted ground plane to main DC source

 It is recommended to implement one layer of the application board as 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 complete via stack down to the

main ground layer of the board

 If the whole application device is composed by more than one PCB, then it is required to provide a good and

solid ground connection between the GND areas of all the different PCBs

 Good grounding of GND pads also ensures thermal heat sink. This is critical during connection, when the

real network commands the module to transmit at maximum power: proper grounding helps prevent

module overheating.

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2.2.2 RTC supply output (V_BCKP)

The RTC supply V_BCKP pin is not available on MPCI-L2 series modules.

2.2.2.1 Guidelines for V_BCKP circuit design

TOBY-L2 series modules provide the V_BCKP RTC supply input/output, which can be mainly used to:

 Provide RTC back-up when VCC supply is removed

If RTC timing is required to run for a time interval of T [s] when VCC supply is removed, place a capacitor with a

nominal capacitance of C [µF] at the V_BCKP pin. Choose the capacitor using the following formula:

C [µF] = (Current_Consumption [µA] x T [s]) / Voltage_Drop [V]

= 1.25 x T [s]

For example, a 100 µF capacitor can be placed at V_BCKP to provide RTC backup holding the V_BCKP voltage

within its valid range for around 80 s at 25 °C, after the VCC supply is removed. If a longer buffering time is

required, a 70 mF super-capacitor can be placed at V_BCKP, with a 4.7 k series resistor to hold the V_BCKP

voltage within its valid range for approximately 15 hours at 25 °C, after the VCC supply is removed. The purpose

of the series resistor is to limit the capacitor charging current due to the large capacitor specifications, and also

to let a fast rise time of the voltage value at the V_BCKP pin after VCC supply has been provided. These

capacitors allow the time reference to run during battery disconnection.

TOBY-L2 series

(a)

3V_BCKP

TOBY-L2 series

(superCap)

(b)

3V_BCKP

TOBY-L2 series

(c)

3V_BCKP

Figure 35: Real time clock supply (V_BCKP) application circuits: (a) using a 100 µF capacitor to let the RTC run for ~80 s after VCC

removal; (b) using a 70 mF capacitor to let RTC run for ~15 hours after VCC removal; (c) using a non-rechargeable battery

Reference

Description

Part Number - Manufacturer

100 µF Tantalum Capacitor

GRM43SR60J107M - Murata

4.7 kΩ Resistor 0402 5% 0.1 W

RC0402JR-074K7L - Yageo Phycomp

70 mF Capacitor

XH414H-IV01E - Seiko Instruments

Table 20: Example of components for V_BCKP buffering

If very long buffering time is required to allow the RTC time reference to run during a disconnection of the VCC

supply, then an external battery can be connected to V_BCKP pin. The battery should be able to provide a

proper nominal voltage and must never exceed the maximum operating voltage for V_BCKP (specified in the

Input characteristics of Supply/Power pins table in TOBY-L2 series Data Sheet [1]). The connection of the battery

to V_BCKP should be done with a suitable series resistor for a rechargeable battery, or with an appropriate

series diode for a non-rechargeable battery. The purpose of the series resistor is to limit the battery charging

current due to the battery specifications, and also to allow a fast rise time of the voltage value at the V_BCKP

pin after the VCC supply has been provided. The purpose of the series diode is to avoid a current flow from the

module V_BCKP pin to the non-rechargeable battery.

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If the RTC timing is not required when the VCC supply is removed, it is not needed to connect the

V_BCKP pin to an external capacitor or battery. In this case the date and time are not updated when VCC

is disconnected. If VCC is always supplied, then the internal regulator is supplied from the main supply

and there is no need for an external component on V_BCKP.

Combining a cellular module with a u-blox GNSS positioning receiver, the positioning receiver VCC supply is

controlled by the cellular module by means of the “GNSS supply enable” function provided by the GPIO2 of the

cellular module. In this case the V_BCKP supply output of the cellular module can be connected to the V_BCKP

backup supply input pin of the GNSS receiver to provide the supply for the positioning real time clock and

backup RAM when the VCC supply of the cellular module is within its operating range and the VCC supply of

the GNSS receiver is disabled. This enables the u-blox GNSS receiver to recover from a power breakdown with

either a hot start or a warm start (depending on the duration of the positioning VCC outage) and to maintain

the configuration settings saved in the backup RAM. See section 2.6.3 for more details regarding the application

circuit with a u-blox GNSS receiver.

V_BCKP supply output pin provides internal short circuit protection to limit 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 maximum available current from V_BCKP supply (see

TOBY-L2 series Data Sheet [1]) as this can cause malfunctions in internal circuitry.

ESD sensitivity rating of the V_BCKP supply pin is 1 kV (Human Body Model according to JESD22-A114).

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.

2.2.2.2 Guidelines for V_BCKP layout design

V_BCKP supply requires careful layout: avoid injecting noise on this voltage domain as it may affect the stability

of the internal circuitry.

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2.2.3 Generic digital interfaces supply output (V_INT)

The generic digital interfaces supply V_INT pin is not available on MPCI-L2 series modules.

2.2.3.1 Guidelines for V_INT circuit design

TOBY-L2 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 2.6.2)

 Pull-up DDC (I2C) interface signals (see section 2.6.3 for more details)

 Supply a 1.8 V u-blox 6 or subsequent u-blox GNSS receiver generation (see section 2.6.3 for more details)

V_INT supply output pin provides internal short circuit protection to limit 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 maximum available current from V_INT supply (see

the TOBY-L2 series Data Sheet [1]) as this can cause malfunctions in internal circuitry.

Since the V_INT supply is generated by an internal switching step-down regulator, the V_INT voltage

ripple can range as specified in the TOBY-L2 series Data Sheet [1]: 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.

ESD sensitivity rating of the V_INT supply pin is 1 kV (Human Body Model according to JESD22-A114).

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 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.

2.2.3.2 Guidelines for V_INT layout design

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.

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2.3 System functions interfaces

2.3.1 Module power-on (PWR_ON)

The PWR_ON input pin is not available on MPCI-L2 series modules.

2.3.1.1 Guidelines for PWR_ON circuit design

TOBY-L2 series PWR_ON input is equipped with an internal active pull-up resistor to the VCC module supply as

described in Figure 36: 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 described in Figure 36 and Table 21.

ESD sensitivity rating of the PWR_ON pin is 1 kV (Human Body Model according to JESD22-A114). 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 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

PWR_ON input is equipped with an internal active pull-up resistor to the VCC supply, as described in Figure 36.

A compatible push-pull output of an application processor can also be used. In any case, take care to set the

proper level in all the possible scenarios to avoid an inappropriate module switch-on.

TOBY-L2 series

50 k

VCC

20 PWR_ON

Power-on

push button

ESD

Open

Drain

Output

Application

Processor

TOBY-L2 series

50 k

VCC

20 PWR_ON

TP TP

Figure 36: 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 21: 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.

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-L2 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.

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2.3.2 Module reset (RESET_N or PERST#)

2.3.2.1 Guidelines for RESET_N and PERST# circuit design

The TOBY-L2 series RESET_N is equipped with an internal pull-up to the VCC supply and the MPCI-L2 series

PERST# is equipped with an internal pull-up to the 3.3 V rail, as described in Figure 37. An external pull-up

resistor is not required and should not be provided.

If connecting the RESET_N or PERST# 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 device

(e.g. the EPCOS CA05P4S14THSG varistor) should be provided close to accessible point on the line connected to

this pin, as described in Figure 37 and Table 22.

ESD sensitivity rating of the RESET_N and PERST# pins is 1 kV (HBM according to JESD22-A114). 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 or PERST# pin, and it can be achieved by

mounting an ESD protection (e.g. EPCOS CA05P4S14THSG varistor) close to accessible point.

An open drain output is suitable to drive the RESET_N and PERST# inputs from an application processor as they

are equipped with an internal pull-up to VCC supply and to the 3.3 V rail respectively, as described in Figure 37.

A compatible push-pull output of an application processor can also be used. In any case, take care to set the

proper level in all the possible scenarios to avoid an inappropriate module reset, switch-on or switch-off.

TOBY-L2 series

VCC

23 RESET_N

Power-on

push button

ESD

Open

Drain

Output

Application

Processor

TOBY-L2 series

VCC

23 RESET_N

TP TP

50 k50 k

MPCI-L2 series

22 PERST#

Power-on

push button

ESD

Open

Drain

Output

Application

Processor

MPCI-L2 series

22 PERST#

45 k45 k

3V3 3V3

Figure 37: RESET_N and PERST# 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 22: Example of ESD protection component for the RESET_N and PERST# 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 providing direct access on the

application board by means of an accessible test point directly connected to the RESET_N pin.

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2.3.2.2 Guidelines for RESET_N and PERST# layout design

The RESET_N and PERST# circuits require 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 RESET_N and PERST# pins as short

as possible.

2.3.3 Module configuration selection by host processor

The HOST_SELECT0 and HOST_SELECT1 pins are not available on MPCI-L2 series modules.

2.3.3.1 Guidelines for HOST_SELECTx circuit design

The functionality of the HOST_SELECT0 and HOST_SELECT1 pins is not supported by the

TOBY-L2x0-00S product version: the two input pins should be not driven by the host application

processor.

TOBY-L2 series modules include two input pins (HOST_SELECT0 and HOST_SELECT1) for the selection of the

module configuration by the host application processor.

Guidelines for HOST_SELECT0 and HOST_SELECT1 pins circuit design will be described in detail in a

successive release of the document.

Do not apply voltage to 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 proper boot of the module. If the external signals

connected to the cellular module cannot be tri-stated or set low, insert a multi channel digital switch (e.g.

TI SN74CB3Q16244, TS5A3159, or TS5A63157) between the two-circuit connections and set to high

impedance before V_INT switch-on.

ESD sensitivity rating of the HOST_SELECT0 and HOST_SELECT1 pins is 1 kV (HBM as per JESD22-A114).

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 accessible points

If the HOST_SELECT0 and HOST_SELECT1 pins are not used, they can be left unconnected on the

application board.

2.3.3.2 Guidelines for HOST_SELECTx layout design

The input pins for the selection of the module configuration by the host application processor (HOST_SELECT0

and HOST_SELECT1) are generally not critical for layout.

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2.4 Antenna interface

TOBY-L2 and MPCI-L2 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 LTE MIMO 2 x 2 or 3G 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 proper transmission / reception of RF signals.

Two antennas (one connected to ANT1 pin and one connected to ANT2 pin) must be used to support the

Down-Link MIMO 2 x 2 radio technology. This is a required feature for LTE category 4 User Equipments

(up to 150 Mb/s Down-Link data rate) according to 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

perspective 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-L2 and MPCI-L2 series modules

with all the applicable required certification schemes depends on antennas 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 physical restriction to the design of the PCB where the

TOBY-L2 and MPCI-L2 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 proper 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 physical restriction to the design of the PCB:

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 has to 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 has to be as high as possible and

the correlation between the 3D radiation patterns of the two antennas has to 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 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

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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 of cases, selecting external or internal antennas, these recommendations should be observed:

 Select antennas providing optimal return loss (or V.S.W.R.) figure over all the operating frequencies.

 Select antennas providing optimal efficiency figure 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 figure (i.e. combined antenna directivity and efficiency figure) so

that the electromagnetic field radiation intensity do not exceed the regulatory limits specified in some

countries (e.g. by FCC in the United States, as reported in the section 4.2.2).

 Select antennas capable to provide 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 TOBY-L2 series ANT1 / ANT2 pins RF connection design

Proper transition between ANT1 / ANT2 pads and the application board PCB must be provided, implementing

the following design-in guidelines for the layout of the application PCB 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 adjacent pads metal definition and up to 400 µm on the area

below the module, to reduce parasitic capacitance to ground, as described in the left picture in Figure 38

 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 described in the right picture in Figure 38

Min.

250 µm

Min. 400 µm GND

ANT1

GND clearance

on very close buried layer

below ANT1 pad

GND clearance

on top layer

around ANT1 pad

Min.

250 µm

Min. 400 µm

GND

ANT2

GND clearance

on very close buried layer

below ANT2 pad

GND clearance

on top layer

around ANT2 pad

Figure 38: GND keep-out area on top layer around ANT1 / ANT2 pads and on very close buried layer below ANT1 / ANT2 pads

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Guidelines for MPCI-L2 series ANT1 / ANT2 receptacles RF connection design

The Hirose U.FL-R-SMT RF receptacles implemented on the MPCI-L2 series modules for ANT1 / ANT2 ports

require a suitable mated RF plug from the same connector series. Due to its wide usage in the industry, several

manufacturers offer compatible equivalents.

Table 23 lists some RF connector plugs that fit MPCI-L2 series modules RF connector receptacles, based on the

declaration of the respective manufacturers. Only the Hirose has been qualified for the MPCI-L2 series modules;

contact other producers to verify compatibility.

Manufacturer

Series

Remarks

Hirose

U.FL® Ultra Small Surface Mount Coaxial Connector

Recommended

I-PEX

MHF® Micro Coaxial Connector

Tyco

UMCC® Ultra-Miniature Coax Connector

Amphenol RF

AMC® Amphenol Micro Coaxial

Lighthorse Technologies, Inc

IPX ultra micro-miniature RF connector

Table 23: MPCI-L2 series U.FL compatible plug connector

Typically the RF plug is available as a cable assembly: several kinds are available and the user should select the

cable assembly best suited to the application. The key characteristics are:

 RF plug type: select U.FL or equivalent

 Nominal impedance: 50 

 Cable thickness: typically from 0.8 mm to 1.37 mm. Select thicker cables to minimize insertion loss

 Cable length: standard length is typically 100 mm or 200 mm, custom lengths may be available on request.

Select shorter cables to minimize insertion loss

 RF connector on the other side of the cable: for example another U.FL (for board-to-board connection) or

SMA (for panel mounting)

For applications requiring an internal integrated SMT antenna, it is suggested to use a U-FL-to-U.FL cable to

provide RF path from the MPCI-L2 series module to PCB strip line or micro strip connected to antenna pads as

shown in Figure 39. Take care that the PCB-to-RF-cable transition, strip line and antenna pads must be designed

so that the characteristic impedance is as close as possible to 50 : see the following subsections for specific

guidelines regarding RF transmission line design and RF termination design.

If an external antenna is required, consider that the connector is typically rated for a limited number of insertion

cycles. In addition, the RF coaxial cable may be relatively fragile compared to other types of cables. To increase

application ruggedness, connect U.FL to a more robust connector (e.g. SMA or MMCX) fixed on panel or on

flange as shown in Figure 39.

MPCI-L2 series

Baseboard

Stripline/Microstrip Internal

Antenna

Baseboard

Application

Chassis Connector to

External Antenna

MPCI-L2 series

Latch for

Mini PCIe

Latch for Mini PCIe

Figure 39: Example of RF connections, U.FL-to-U.FL cable for internal antenna and U.FL-to-SMA for external antenna

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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 board.

Figure 40 and Figure 41 provide two examples of proper 50  coplanar waveguide designs. The first example of

RF transmission line can be implemented in case of 4-layer PCB stack-up herein described, and the second

example of RF transmission line can be implemented in case of 2-layer PCB stack-up herein described.

35 µm

270 µm

760 µm

L1 Copper

L3 Copper

L2 Copper

L4 Copper

FR-4 dielectric

380 µm 500 µm500 µm

Figure 40: Example of 50  coplanar waveguide transmission line design for the described 4-layer board layup

35 µm

1510 µm

L2 Copper

L1 Copper

FR-4 dielectric

1200 µm 400 µm400 µm

Figure 41: Example of 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 example of Figure 40 and Figure 41)

 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 40, 1510 µm in Figure 41)

 the dielectric constant of the dielectric material (e.g. dielectric constant of the FR-4 dielectric material in

Figure 40 and Figure 41)

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 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 40, 400 µm in Figure 41)

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 lines 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 component present

on the RF transmission lines, if 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 transmission lines, as described in Figure 42,

 Ensure solid metal connection of the adjacent metal layer on the PCB stack-up to main ground layer,

providing enough vias on the adjacent metal layer, as described in Figure 42,

 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 transmission lines or crossing the transmission lines on buried metal layer,

 Do not route microstrip lines below discrete component or other mechanics placed on top layer

An example of proper RF circuit design is reported in Figure 42. In this case, the ANT1 and ANT2 pins are

directly connected to SMA connectors by means of proper 50  transmission lines, designed with proper layout.

SMA Connector

Primary Antenna

SMA Connector

Secondary Antenna

TOBY-L2 series

Figure 42: Suggested circuit and layout for antenna RF circuits on application board

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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 perfect 50  load on all the supported frequency bands. Therefore, to

reduce as much as possible performance degradation due to antennas mismatch, RF terminations must provide

optimal return loss (or V.S.W.R.) figure 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 proper 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 annular pads of the four GND posts, as shown in Figure 42

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, to remove stray capacitance and thus

keep the RF line 50 , e.g. the active pad of UFL connectors needs to have a GND keep-out (i.e. clearance, a

void area) at least on 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 V.S.W.R.).

 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

wavelength of the minimum frequency that has to be radiated. As 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 closed metal case.

 Do not place the antennas in close vicinity to 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/3G antennas providing low Envelope Correlation Coefficient (ECC) between primary

(ANT1) and secondary (ANT2) antenna: the antenna 3D radiation patterns should have lobes in different

directions. The ECC between primary and secondary antenna needs to be enough low to comply with the

radiated performance requirements specified by related certification schemes, as indicated in Table 10.

 Place the two LTE/3G antennas providing enough high isolation (see Table 10) between primary (ANT1) and

secondary (ANT2) antenna. 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), antenna 3D radiation patterns (uncorrelated patterns improve isolation).

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Examples of antennas

Table 24 lists some examples of possible internal on-board surface-mount antennas.

Manufacturer

Part Number

Product Name

Description

Taoglas

PCS.06.A

Havok

GSM / WCDMA / LTE SMD Antenna

698..960 MHz, 1710..2170 MHz, 2500..2690 MHz

42.0 x 10.0 x 3.0 mm

700..960 MHz, 1710..2170 MHz

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

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

FXUB63.07.0150C

GSM / WCDMA / LTE PCB Antenna with cable and U.FL

698..960 MHz, 1575.42 MHz, 1710..2170 MHz, 2400..2690 MHz

96.0 x 21.0 mm

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,

2400..2700 MHz, 3400..3600 MHz, 4800..6000 MHz

120.2 x 50.4 mm

Taoglas

FXUB70.A.07.C.001

GSM / WCDMA / LTE PCB MIMO Antenna with cables and U.FL

698..960 MHz, 1575.42 MHz, 1710..2170 MHz, 2400..2690 MHz

182.2 x 21.2 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

EAD

FSQS35241-UF-10

SQ7

GSM / WCDMA / LTE PCB Antenna with cable and U.FL

690..960 MHz, 1710..2170 MHz, 2500..2700 MHz

110.0 x 21.0 mm

Table 25: Examples of internal antennas with cable and connector

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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..2170 MHz, 2490..2690 MHz

105 x 30 x 7.7 mm

Taoglas

TG.30.8112

GSM / WCDMA / LTE swivel dipole Antenna with SMA(M)

698..960 MHz, 1575.42 MHz, 1710..2170 MHz, 2400..2700 MHz

148.6 x 49 x 10 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.

CMS69273

GSM / WCDMA / LTE ceiling-mount Antenna with cable and N-type(F)

698..960 MHz, 1575.42 MHz, 1710..2700 MHz

86 x Ø 199 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

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2.4.2 Antenna detection interface (ANT_DET)

Antenna detection interface (ANT_DET) is not available on MPCI-L2 series modules.

Antenna detection interface (ANT_DET) is not supported by the TOBY-L2x0-00S product version.

2.4.2.1 Guidelines for ANT_DET circuit design

Figure 43 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 Board

Antenna Cable

TOBY-L2 series

ANT1

ANT_DET R1

C1 D1

C2 J1

Z0= 50 ohm Z0= 50 ohm Z0= 50 ohm

Primary Antenna Assembly

Radiating

Element

Diagnostic

Circuit

Antenna Cable

ANT2

C3 J2

Z0= 50 ohm Z0= 50 ohm Z0= 50 ohm

Secondary Antenna Assembly

Radiating

Element

Diagnostic

Circuit

Figure 43: Suggested schematic for antenna detection circuit on application board and diagnostic circuit on antennas assembly

Reference

Description

Part Number - Manufacturer

27 pF Capacitor Ceramic C0G 0402 5% 50 V

GRM1555C1H270J - Murata

C2, C3

33 pF Capacitor Ceramic C0G 0402 5% 50 V

GRM1555C1H330J - Murata

Very Low Capacitance ESD Protection

PESD0402-140 - Tyco Electronics

L1, L2

68 nH Multilayer Inductor 0402 (SRF ~1 GHz)

LQG15HS68NJ02 - Murata

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 antenna detection circuit on application board and diagnostic circuit on antennas assembly

The antenna detection circuit and diagnostic circuit suggested in Figure 43 and Table 27 are explained here:

 When antenna detection is forced by AT+UANTR command, ANT_DET generates a DC current measuring

the resistance (R2 // R3) from 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 43) 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

nominal characteristics impedance as close as possible to 50 .

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The DC impedance at 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 43, 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 antenna path with similar characteristics (respectively: removal of

linear antenna or RF cable shorted to GND for PIFA antenna).

Furthermore, any other DC signal injected to the RF connection from ANT connector to 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 load resistor.

For example:

Consider an antenna with 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 u-blox AT Commands Manual [3]) means that that the antenna is not connected or

the RF cable is broken.

 Reported values below the measurement range minimum limit (1 k) highlights a short to GND at antenna

or along the RF cable.

 Measurement inside the valid measurement range and outside the expected range may indicate an improper

connection, damaged antenna or wrong value of antenna load resistor for diagnostic.

 Reported value could differ from the real resistance value of the diagnostic resistor mounted inside the

antenna assembly due to antenna cable length, antenna cable capacity and the used measurement method.

If the primary / secondary antenna detection function is not required by the customer application, the

ANT_DET pin can be left not connected and the ANT1 / ANT2 pins can be directly connected to the

related antenna connector by means of a 50  transmission line as described in Figure 42.

2.4.2.1 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 described in

Figure 43 and Table 27, is explained here:

 The ANT1 / ANT2 pins have to 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) has to be placed in series to the 50  RF line.

 The ANT_DET pin has to be connected to the 50  transmission line by means of a sense line.

 Choke inductors in series at the ANT_DET pin (L1, L2) have to 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 have to be placed as ESD protection.

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2.5 SIM interface

SIM detection interface (GPIO5) is not available on MPCI-L2 series modules.

SIM detection interface (GPIO5) is not supported by the TOBY-L2x0-00S product version: the pin should

not be driven by any external device.

2.5.1 Guidelines for SIM circuit design

Guidelines for SIM cards, SIM connectors and SIM chips selection

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 contacts mapping is defined by ISO/IEC 7816 and ETSI TS 102 221 as follows:

 Contact C1 = VCC (Supply)  It must be connected to VSIM or UIM_PWR

 Contact C2 = RST (Reset)  It must be connected to SIM_RST or UIM_RESET

 Contact C3 = CLK (Clock)  It must be connected to SIM_CLK or UIM_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 must be connected to VSIM or UIM_PWR

 Contact C7 = I/O (Data input/output)  It must be connected to SIM_IO or UIM_DATA

 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 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 (not available on MPCI-L2 series) is required by the

custom application, otherwise a connector without 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 or UIM_PWR

 Case Pin 7 = UICC Contact C2 = RST (Reset)  It must be connected to SIM_RST or UIM_RESET

 Case Pin 6 = UICC Contact C3 = CLK (Clock)  It must be connected to SIM_CLK or UIM_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 must be connected to VSIM or UIM_PWR

 Case Pin 3 = UICC Contact C7 = I/O (Data I/O)  It must be connected to SIM_IO or UIM_DATA

 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.

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Guidelines for single SIM card connection without detection

A removable SIM card placed in a SIM card holder must be connected to the SIM card interface of TOBY-L2 and

MPCI-L2 series modules as described in Figure 44, 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 contacts C1 (VCC) and C6 (VPP) to the VSIM / UIM_PWR pin of the module.

 Connect the UICC / SIM contact C7 (I/O) to the SIM_IO / UIM_DATA pin of the module.

 Connect the UICC / SIM contact C3 (CLK) to the SIM_CLK / UIM_CLK pin of the module.

 Connect the UICC / SIM contact C2 (RST) to the SIM_RST / UIM_RESET 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 in case 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. ESD sensitivity rating of the

SIM interface pins is 1 kV (HBM). So that, according to EMC/ESD requirements of the custom application,

higher protection level can be required if the lines are externally accessible on the application device.

 Limit capacitance and series resistance on each SIM signal to match the SIM requirements (27.7 ns is the

maximum allowed rise time on clock line, 1.0 µs is the maximum allowed rise time on data and reset lines).

TOBY-L2 series

VSIM

SIM_IO

SIM_CLK

SIM_RST

SIM CARD

HOLDER

SIM Card

Bottom View

(contacts side)

VPP (C6)

VCC (C1)

IO (C7)

CLK (C3)

RST (C2)

GND (C5)

C2 C3 C5

C4 D1 D2 D3 D4

MPCI-L2 series

UIM_PWR

UIM_DATA

UIM_CLK

UIM_RESET

SIM CARD

HOLDER

SIM Card

Bottom View

(contacts side)

VPP (C6)

VCC (C1)

IO (C7)

CLK (C3)

RST (C2)

GND (C5)

C2 C3 C5

C4 D1 D2 D3 D4

Figure 44: 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

100 nF Capacitor Ceramic X7R 0402 10% 16 V

GRM155R71C104KA01 - Murata

D1, D2, D3, D4

Very Low Capacitance ESD Protection

PESD0402-140 - Tyco Electronics

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

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Guidelines for single SIM chip connection

A solderable SIM chip (M2M UICC Form Factor) must be connected the SIM card interface of TOBY-L2 and

MPCI-L2 series modules as described in Figure 45.

Follow these guidelines to connect the module to a solderable SIM chip without SIM presence detection:

 Connect the UICC / SIM contacts C1 (VCC) and C6 (VPP) to the VSIM / UIM_PWR pin of the module.

 Connect the UICC / SIM contact C7 (I/O) to the SIM_IO / UIM_DATA pin of the module.

 Connect the UICC / SIM contact C3 (CLK) to the SIM_CLK / UIM_CLK pin of the module.

 Connect the UICC / SIM contact C2 (RST) to the SIM_RST / UIM_RESET 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 in case the RF antenna is placed closer than 10 - 30 cm from the SIM lines.

 Limit capacitance and series resistance on each SIM signal to match the SIM requirements (27.7 ns is the

maximum allowed rise time on clock line, 1.0 µs is the maximum allowed rise time on data and reset lines).

TOBY-L2 series

VSIM

SIM_IO

SIM_CLK

SIM_RST

SIM CHIP

SIM Chip

Bottom View

(contacts side)

VPP (C6)

VCC (C1)

IO (C7)

CLK (C3)

RST (C2)

GND (C5)

C2 C3 C5

C1 C5

C2 C6

C3 C7

C4 C8

MPCI-L2 series

UIM_PWR

UIM_DATA

UIM_CLK

UIM_RESET

SIM CHIP

SIM Chip

Bottom View

(contacts side)

VPP (C6)

VCC (C1)

IO (C7)

CLK (C3)

RST (C2)

GND (C5)

C2 C3 C5

C1 C5

C2 C6

C3 C7

C4 C8

Figure 45: 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

100 nF Capacitor Ceramic X7R 0402 10% 16 V

GRM155R71C104KA01 - Murata

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

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Guidelines for single SIM card connection with detection

A removable SIM card placed in a SIM card holder must be connected to the SIM card interface of TOBY-L2

modules as described in Figure 46, where the optional SIM card detection feature is implemented.

Follow these guidelines to connect the module to a SIM connector implementing SIM presence detection:

 Connect the UICC / SIM contacts C1 (VCC) and C6 (VPP) 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 mechanical switch integrated in the SIM connector (e.g. the SW2 pin as described in

Figure 46) to the GPIO5 input pin of the module.

 Connect the other pin of the mechanical switch integrated in the SIM connector (e.g. the SW1 pin as

described in Figure 46) 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 46.

 Provide a weak (e.g. 470 k) pull-down resistor at the SIM detection line, as the R2 resistor in Figure 46

 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 in case 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,

higher protection level can be required if the lines are externally accessible on the application device.

 Limit capacitance and series resistance on each SIM signal to match the SIM requirements (27.7 ns is the

maximum allowed rise time on clock line, 1.0 µs is the maximum allowed rise time on data and reset lines).

TOBY-L2 series

V_INT

GPIO5

SIM CARD

HOLDER

SIM Card

Bottom View

(contacts side)

VPP (C6)

VCC (C1)

IO (C7)

CLK (C3)

RST (C2)

GND (C5)

C2 C3 C5

SW1

SW2

D1 D2 D3 D4 D5 D6

VSIM

SIM_IO

SIM_CLK

SIM_RST

Figure 46: 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

100 nF Capacitor Ceramic X7R 0402 10% 16 V

GRM155R71C104KA01 - Murata

D1, … , D6

Very Low Capacitance ESD Protection

PESD0402-140 - Tyco Electronics

1 k Resistor 0402 5% 0.1 W

RC0402JR-071KL - Yageo Phycomp

470 k Resistor 0402 5% 0.1 W

RC0402JR-07470KL- Yageo Phycomp

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

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Guidelines for dual SIM card / chip connection

Two SIM card / chip can be connected to the SIM interface of TOBY-L2 and MPCI-L2 series modules as described

in the application circuits of Figure 47.

TOBY-L2 and MPCI-L2 series modules do not support the usage of two SIM at the same time, but two SIM can

be populated on the application board, providing a proper switch to connect only the first or only the second

SIM at a time to the SIM interface of the modules, as described in Figure 47.

TOBY-L2x0-00S and MPCI-L2 modules do not support SIM hot insertion / removal: the physical connection

between the external SIM and the module has to be provided before the module boot and then held for normal

operation. Switching from one SIM to another can only be properly done within one of these two time periods:

 after module switch-off by the AT+CPWROFF and before module switch-on by PWR_ON

 after network deregistration by AT+COPS=2 and before module reset by AT+CFUN=16

TOBY-L2 modules (except TOBY-L2x0-00S) support SIM hot insertion / removal on the GPIO5 pin: if the feature

is enabled using the specific AT commands (see sections 1.8.2 and 1.11, and u-blox AT Commands Manual [3],

+UGPIOC, +UDCONF commands), the switch from first SIM to the second 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.

In the application circuit example represented in Figure 47, 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-L2 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 described in Figure 47 can be implemented for SIM chips as well, providing

proper connection between SIM switch and SIM chip as described in Figure 45.

If it is required to switch between more than 2 SIM, a circuit similar to the one described in Figure 47 can be

implemented: in case of 4 SIM circuit, using proper 4-throw switch instead of the suggested 2-throw switches.

Follow these guidelines to connect the module to two external SIM connectors:

 Use a proper 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.

 Connect the contacts C1 (VCC) and C6 (VPP) of the two UICC / SIM to the VSIM / UIM_PWR pin of the

module by means of a proper 2-throw analog switch (e.g. Fairchild FSA2567).

 Connect the contact C7 (I/O) of the two UICC / SIM to the SIM_IO / UIM_DATA pin of the module by

means of a proper 2-throw analog switch (e.g. Fairchild FSA2567).

 Connect the contact C3 (CLK) of the two UICC / SIM to the SIM_CLK / UIM_CLK pin of the module by

means of a proper 2-throw analog switch (e.g. Fairchild FSA2567).

 Connect the contact C2 (RST) of the two UICC / SIM to the SIM_RST / UIM_RESET pin of the module by

means of a proper 2-throw analog switch (e.g. Fairchild FSA2567).

 Connect the contact C5 (GND) of the two UICC / SIM to ground.

 Provide a 100 nF bypass capacitor (e.g. Murata GRM155R71C104K) at the SIM supply (VSIM / UIM_PWR),

close to the related pad of the two SIM connectors, 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 two SIM connectors, to prevent RF coupling especially in case 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 the two SIM connectors, according to the EMC/ESD

requirements of the custom application.

 Limit capacitance and series resistance on each SIM signal to match the SIM requirements (27.7 ns is the

maximum allowed rise time on clock line, 1.0 µs is the maximum allowed rise time on data and reset lines).

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TOBY-L2 series

FIRST

SIM CARD

VPP (C6)

VCC (C1)

IO (C7)

CLK (C3)

RST (C2)

GND (C5)

C2 C3 C5

C4 D1 D2 D3 D4

GND

VSIM VSIM 1VSIM

2VSIM

VCC

C11

4PDT

Analog

Switch

3V8

SIM_IO DAT 1DAT

2DAT

SIM_CLK CLK 1CLK

2CLK

SIM_RST RST 1RST

2RST

SEL

SECOND

SIM CARD

VPP (C6)

VCC (C1)

IO (C7)

CLK (C3)

RST (C2)

GND (C5)

C6 C7 C8 C10

C9 D5 D6 D7 D8

Application

Processor

GPIO

MPCI-L2 series

FIRST

SIM CARD

VPP (C6)

VCC (C1)

IO (C7)

CLK (C3)

RST (C2)

GND (C5)

C2 C3 C5

C4 D1 D2 D3 D4

GND

UIM_PWR VSIM 1VSIM

2VSIM

VCC

C11

4PDT

Analog

Switch

3V8

UIM_DATA DAT 1DAT

2DAT

UIM_CLK CLK 1CLK

2CLK

UIM_RESET RST 1RST

2RST

SEL

SECOND

SIM CARD

VPP (C6)

VCC (C1)

IO (C7)

CLK (C3)

RST (C2)

GND (C5)

C6 C7 C8 C10

C9 D5 D6 D7 D8

Application

Processor

GPIO

Figure 47: Application circuit 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

47 kΩ 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

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

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2.5.2 Guidelines for SIM layout design

The layout of the SIM card interface lines (VSIM, SIM_CLK, SIM_IO, SIM_RST or UIM_PWR, UIM_DATA,

UIM_CLK, UIM_RESET) may be critical if the SIM card is placed far away from the TOBY-L2 and MPCI-L2 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 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 harmonic frequencies. It is

strongly recommended to place the RF bypass capacitors suggested in Figure 44 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 module SIM pins near the SIM connector.

Limit 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.

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2.6 Data communication interfaces

2.6.1 Universal Serial Bus (USB)

2.6.1.1 Guidelines for USB circuit design

The USB_D+ and USB_D- lines carry the USB serial data and signaling. The lines are used in single ended mode

for full speed signaling handshake, as well as in differential mode for high speed signaling and data transfer.

USB pull-up or pull-down resistors and external series resistors on USB_D+ and USB_D- lines as required by the

USB 2.0 specification [6] are part of the module USB pin driver and do not need to be externally provided.

The additional VUSB_DET input pin can be optionally connected the USB VBUS supply (5.0 V typical) provided

by the host, to allow the complete bus detach functionality for further reduction of the current consumption: the

module disables the USB interface after a high-to-low logic level transition on the VUSB_DET input pin.

Routing the USB pins to a connector, they will be externally accessible on the application device. According to

EMC/ESD requirements of the application, an additional ESD protection device with very low capacitance should

be provided close to accessible point on the line connected to this pin, as described in Figure 48 and Table 32.

The USB interface pins ESD sensitivity rating is 1 kV (Human Body Model according to JESD22-A114F).

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 accessible points.

The USB_D+ and USB_D- 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-

GND

28 USB_D+

27 USB_D-

GND

USB DEVICE

CONNECTOR

VBUS

D+

D-

GND

28 USB_D+

27 USB_D-

GND

USB HOST

PROCESSOR

D+

D-

GND

38 USB_D+

36 USB_D-

GND

USB DEVICE

CONNECTOR

VBUS

TOBY-L2 series TOBY-L2 series

MPCI-L2 series MPCI-L2 series

D+

D-

GND

38 USB_D+

36 USB_D-

GND

USB HOST

PROCESSOR

VBUS 4VUSB_DET

4VUSB_DET

D1 D2 C1

D1 D2

Figure 48: USB Interface application circuits

Reference

Description

Part Number - Manufacturer

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 application circuits

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2.6.1.2 Guidelines for USB layout design

The USB_D+ / USB_D- lines require accurate layout design to achieve reliable signaling at the high speed data

rate (up to 480 Mb/s) supported by the USB serial interface.

The characteristic impedance of the USB_D+ / USB_D- lines is specified by the Universal Serial Bus Revision 2.0

specification [6]. 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 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- lines as a differential pair

 Route USB_D+ / USB_D- 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- similar to RF transmission lines, being them coupled differential

micro-strip or buried stripline: avoid any stubs, abrupt change of layout, and route on clear PCB area

Figure 49 and Figure 50 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 in case of 4-layer PCB stack-up herein described, the second transmission line can be

implemented in case of 2-layer PCB stack-up herein described.

35 µm

270 µm

760 µm

L1 Copper

L3 Copper

L2 Copper

L4 Copper

FR-4 dielectric

350 µm 400 µm400 µm350 µm400 µm

Figure 49: Example of USB line design, with Z0 close to 90  and ZCM close to 30 , for the described 4-layer board layup

35 µm

1510 µm

L2 Copper

L1 Copper

FR-4 dielectric

740 µm 410 µm410 µm740 µm410 µm

Figure 50: Example of USB line design, with Z0 close to 90  and ZCM close to 30 , for the described 2-layer board layup

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2.6.2 Asynchronous serial interface (UART)

The UART interface is not available on MPCI-L2 series modules.

2.6.2.1 Guidelines for UART circuit design

The UART is not supported by TOBY-L2x0-00S: the pins should be not driven by any external device.

Providing the full RS-232 functionality (using the complete V.24 link)

If RS-232 compatible signal levels are needed, two different external voltage translators can be used to provide

full RS-232 (9 lines) functionality: e.g. using the Texas Instruments SN74AVC8T245PW for the translation from

1.8 V to 3.3 V, and the Maxim MAX3237E for the translation from 3.3 V to RS-232 compatible signal level.

If a 1.8 V host processor is used, for complete RS-232 functionality, the complete UART interface of the module

(DCE) must be connected to a 1.8 V application processor (DTE) as described in Figure 51.

TxD

Application Processor

(1.8V DTE)

RxD

RTS

CTS

DTR

DSR

DCD

GND

TOBY-L2 series

(1.8V DCE)

16 TXD

13 DTR

17 RXD

14 RTS

15 CTS

10 DSR

11 RI

12 DCD

GND

0ΩTP

Figure 51: UART interface application circuit with complete V.24 link in DTE/DCE serial communication (1.8V DTE)

If a 3.0 V Application Processor is used, appropriate unidirectional voltage translators must be provided using the

module V_INT output as 1.8 V supply, as described in Figure 52.

5V_INT

TxD

Application Processor

(3.0V DTE)

RxD

RTS

CTS

DTR

DSR

DCD

GND

TOBY-L2 series

(1.8V DCE)

16 TXD

13 DTR

17 RXD

14 RTS

15 CTS

10 DSR

11 RI

12 DCD

GND

1V8

B1 A1

GND

B3A3

VCCBVCCA

Unidirectional

Voltage Translator

C1 C2

3V0

DIR3

DIR2 OE

DIR1

VCC

B2 A2

B4A4

DIR4

1V8

B1 A1

GND

B3A3

VCCBVCCA

Unidirectional

Voltage Translator

C3 C4

3V0

DIR1

DIR3 OE

B2 A2

B4A4

DIR4

DIR2

0ΩTP

Figure 52: UART interface application circuit with complete V.24 link in DTE/DCE serial communication (3.0 V DTE)

Reference

Description

Part Number - Manufacturer

C1, C2, C3, C4

100 nF Capacitor Ceramic X7R 0402 10% 16 V

GRM155R61A104KA01 - Murata

U1, U2

Unidirectional Voltage Translator

SN74AVC4T774 - Texas Instruments

Table 33: Component for UART application circuit with complete V.24 link in DTE/DCE serial communication (3.0 V DTE)

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Providing the TXD, RXD, RTS and CTS lines only (not using the complete V.24 link)

If the functionality of the DSR, DCD, RI and DTR lines is not required in, or the lines are not available:

 Connect the module DTR input line to GND using a 0  series resistor, since the module requires DTR active

 Leave DSR, DCD and RI lines of the module unconnected and floating

If RS-232 compatible signal levels are needed, the Maxim 13234E 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 Application Processor is used, the circuit should be implemented as described in Figure 53.

TxD

Application Processor

(1.8V DTE)

RxD

RTS

CTS

DTR

DSR

DCD

GND

TOBY-L2 series

(1.8V DCE)

16 TXD

13 DTR

17 RXD

14 RTS

15 CTS

10 DSR

11 RI

12 DCD

GND

0ΩTP

Figure 53: UART interface application circuit with partial V.24 link (5-wire) in the DTE/DCE serial communication (1.8V DTE)

If a 3.0 V Application Processor is used, appropriate unidirectional voltage translators must be provided using the

module V_INT output as 1.8 V supply, as described in Figure 54.

5V_INT

TxD

Application Processor

(3.0V DTE)

RxD

RTS

CTS

DTR

DSR

DCD

GND

TOBY-L2 series

(1.8V DCE)

16 TXD

13 DTR

17 RXD

14 RTS

15 CTS

10 DSR

11 RI

12 DCD

GND

1V8

B1 A1

GND

B3A3

VCCBVCCA

Unidirectional

Voltage Translator

C1 C2

3V0

DIR3

DIR2 OE

DIR1

VCC

B2 A2

B4A4

DIR4

0ΩTP

Figure 54: UART interface application circuit with partial V.24 link (5-wire) in DTE/DCE serial communication (3.0 V DTE)

Reference

Description

Part Number - Manufacturer

C1, C2

100 nF Capacitor Ceramic X7R 0402 10% 16 V

GRM155R61A104KA01 - Murata

Unidirectional Voltage Translator

SN74AVC4T774 - Texas Instruments

Table 34: Component for UART application circuit with partial V.24 link (5-wire) in DTE/DCE serial communication (3.0 V DTE)

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Providing the TXD and RXD lines only (not using the complete V24 link)

If the functionality of the CTS, RTS, DSR, DCD, RI and DTR lines is not required in the application, or the lines

are not available, the circuit with a 1.8 V Application Processor should be implemented as described in Figure 55:

 Connect the module RTS input line to GND or to the CTS output line of the module: since the module

requires RTS active (low electrical level) if HW flow-control is enabled (AT&K3, that is the default setting),

the pin can be connected using a 0  series resistor to GND or to the active-module CTS (low electrical level)

when the module is in active-mode, the UART interface is enabled and the HW flow-control is enabled

 Connect the module DTR input line to GND using a 0  series resistor, as the module requires DTR active

 Leave DSR, DCD and RI lines of the module unconnected and floating

TxD

Application Processor

(1.8V DTE)

RxD

RTS

CTS

DTR

DSR

DCD

GND

TOBY-L2 series

(1.8V DCE)

16 TXD

13 DTR

17 RXD

14 RTS

15 CTS

10 DSR

11 RI

12 DCD

GND

0ΩTP

Figure 55: UART interface application circuit with partial V.24 link (3-wire) in the DTE/DCE serial communication (1.8V DTE)

If a 3.0 V Application Processor is used, appropriate unidirectional voltage translators must be provided using the

module V_INT output as 1.8 V supply, as described in Figure 56.

5V_INT

TxD

Application Processor

(3.0V DTE)

RxD

DTR

DSR

DCD

GND

TOBY-L2 series

(1.8V DCE)

16 TXD

13 DTR

17 RXD

10 DSR

11 RI

12 DCD

GND

1V8

B1 A1

GND

VCCBVCCA

Unidirectional

Voltage Translator

C1 C2

3V0

DIR1

DIR2 OE

VCC

B2 A2

RTS

CTS

14 RTS

15 CTS

0ΩTP

Figure 56: UART interface application circuit with partial V.24 link (3-wire) in DTE/DCE serial communication (3.0 V DTE)

Reference

Description

Part Number - Manufacturer

C1, C2

100 nF Capacitor Ceramic X7R 0402 10% 16 V

GRM155R61A104KA01 - Murata

Unidirectional Voltage Translator

SN74AVC2T245 - Texas Instruments

Table 35: Component for UART application circuit with partial V.24 link (3-wire) in DTE/DCE serial communication (3.0 V DTE)

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Additional considerations

Do not apply voltage to any UART interface pin before the switch-on of the UART supply source (V_INT),

to avoid latch-up of circuits and allow a proper boot of the module. If the external signals connected to

the cellular module cannot be tri-stated or set low, insert a multi channel digital switch (e.g. TI

SN74CB3Q16244, TS5A3159, or TS5A63157) between the two-circuit connections and set to high

impedance before V_INT switch-on.

ESD sensitivity rating of UART interface pins is 1 kV (Human Body Model according to JESD22-A114).

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 accessible points.

If the UART interface pins are not used, they can be left unconnected on the application board, but it is

recommended providing accessible test points directly connected to all the UART pins (TXD, RXD, RTS,

CTS, DTR, DSR, DCD, RI) for diagnostic purpose, in particular providing a 0  series jumper on each line

to detach each UART pin of the module from the DTE application processor.

2.6.2.2 Guidelines for UART layout design

The UART serial interface requires the same consideration 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.

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2.6.3 DDC (I2C) interface

The I2C bus compatible Display Data Channel interface is not available on MPCI-L2 series modules.

2.6.3.1 Guidelines for DDC (I2C) circuit design

I2C bus function is not supported by TOBY-L2x0-00S: the pins should be not driven by any external device.

General considerations

The DDC I2C-bus master interface can be used to communicate with u-blox GNSS receivers and other external

I2C-bus slaves as an audio codec. Beside the general considerations reported below, see:

 the following parts of this section for specific guidelines for the connection to u-blox GNSS receivers

 the section 2.7.1 for an application circuit example with an external audio codec I2C-bus slave

To be compliant with the I2C bus specifications, the module bus interface pads are open drain output and pull up

resistors must be mounted externally. Resistor values must conform to I2C bus specifications [12]: for example,

4.7 k resistors can be commonly used. Pull-ups must be connected to a supply voltage of 1.8 V (typical), since

this is the voltage domain of the DDC pins which are not tolerant to higher voltage values (e.g. 3.0 V).

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 57 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 pins, to avoid latch-up of circuits and let a proper 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 nominal resistance

value lower than 4.7 k, to match the I2C bus specifications [12] regarding rise and fall times of the signals.

Capacitance and series resistance must be limited on the bus to match the I2C specifications (1.0 µs is the

maximum allowed rise time on the SCL and SDA lines): route connections as short as possible.

If the pins are not used as DDC bus interface, they can be left unconnected.

ESD sensitivity rating of the DDC (I2C) pins is 1 kV (Human Body Model according to JESD22-A114).

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 accessible points.

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Connection with u-blox 1.8 V GNSS receivers

Figure 57 shows an application circuit for connecting TOBY-L2 cellular modules to a u-blox 1.8 V GNSS receiver.

 SDA / SCL pins of the TOBY-L2 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 TOBY-L2 cellular module.

 GPIO3 and GPIO4 pins are directly connected respectively to the TxD1 and EXTINT0 pins of the u-blox

1.8 V GNSS receiver to provide “GNSS data ready” and “GNSS RTC sharing” functions.

 A pull-down resistor is mounted on GPIO2 line to avoid an improper switch on of the u-blox GNSS receiver.

 The V_BCKP output of the cellular module is connected to the V_BCKP input pin of the GNSS receiver to

provide the supply for the GNSS RTC and backup RAM when the VCC supply of the cellular module is within

its operating range and the VCC supply of the GNSS receiver is disabled. This enables the u-blox GNSS

receiver to recover from a power breakdown with either a hot start or a warm start (depending on the

duration of the GNSS VCC outage) and to maintain the configuration settings saved in the backup RAM.

TOBY-L2 series

(except TOBY-L2x0-00S)

INOUT

GND

GNSS LDO

Regulator

SHDN

u-blox GNSS

1.8 V receiver

SDA2

SCL2

1V8 1V8

VMAIN1V8

22 GPIO2

SDA

SCL

TxD1

EXTINT0

GPIO3

GPIO4

VCC

V_BCKP V_BCKP

GNSS data ready

GNSS RTC sharing

GNSS supply enabled

Figure 57: Application circuit for connecting TOBY-L2 modules to u-blox 1.8 V GNSS receivers

Reference

Description

Part Number - Manufacturer

R1, R2

4.7 kΩ Resistor 0402 5% 0.1 W

RC0402JR-074K7L - Yageo Phycomp

47 kΩ Resistor 0402 5% 0.1 W

RC0402JR-0747KL - Yageo Phycomp

Voltage Regulator for GNSS receiver

See GNSS receiver Hardware Integration Manual

Table 36: Components for connecting TOBY-L2 modules to u-blox 1.8 V GNSS receivers

Figure 58 illustrates an alternative application circuit solution in which the TOBY-L2 supplies a u-blox 1.8 V GNSS

receiver. The V_INT 1.8 V regulated supply output of a TOBY-L2 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 57. 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 TOBY-L2 cellular modules by means of a proper inverting transistor as shown in Figure 58,

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.

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According to the V_INT supply output voltage ripple characteristic specified in the TOBY-L2 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 GNSS

1.8 V receiver

TxD1

EXTINT0

V_BCKP V_BCKP

SDA2

SCL2

VCC

1V8

5V_INT

R1 R2

1V8 1V8

GNSS data ready

GNSS RTC sharing

GNSS supply enabled

TOBY-L2 series

(except TOBY-L2x0-00S)

22 GPIO2

SDA

SCL

GPIO3

GPIO4

Figure 58: Application circuit for connecting TOBY-L2 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

47 k Resistor 0402 5% 0.1 W

RC0402JR-0747KL - Yageo Phycomp

10 k Resistor 0402 5% 0.1 W

RC0402JR-0710KL - Yageo Phycomp

100 k Resistor 0402 5% 0.1 W

RC0402JR-07100KL - Yageo Phycomp

P-Channel MOSFET Low On-Resistance

IRLML6401 - International Rectifier or NTZS3151P - ON Semi

NPN BJT Transistor

BC847 - Infineon

100 nF Capacitor Ceramic X7R 0402 10% 16 V

GRM155R71C104KA01 - Murata

Table 37: Components for connecting TOBY-L2 modules to u-blox 1.8 V GNSS receivers using V_INT as supply

For additional guidelines regarding the design of applications with u-blox 1.8 V GNSS receivers see the GNSS

Implementation Application Note [13] and the Hardware Integration Manual of the u-blox GNSS receivers.

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Connection with u-blox 3.0 V GNSS receivers

Figure 59 shows an application circuit for connecting TOBY-L2 cellular modules to a u-blox 3.0 V GNSS receiver:

 As the SDA and SCL pins of the TOBY-L2 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 proper I2C-bus Bidirectional

Voltage Translator with proper 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).

 As the GPIO3 and GPIO4 pins of the TOBY-L2 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 proper 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).

 A pull-down resistor is mounted on GPIO2 line to avoid an improper switch on of the u-blox GNSS receiver.

 The V_BCKP supply output of the cellular module can be directly connected to the V_BCKP backup supply

input pin of the GNSS receiver as in the application circuit for a u-blox 1.8 V GNSS receiver.

TOBY-L2 series

(except TOBY-L2x0-00S)

u-blox GNSS

3.0 V receiver

24 GPIO3

25 GPIO4

1V8

B1 A1

GND

B2A2

VCCBVCCA

Unidirectional

Voltage Translator

C4 C5

3V0

TxD1

EXTINT0

INOUT

GND

GNSS LDO

Regulator

SHDN

VMAIN3V0

22 GPIO2

55 SDA

54 SCL

R4 R5

1V8

SDA_A SDA_B

GND

SCL_ASCL_B

VCCA

VCCB

I2C-bus Bidirectional

Voltage Translator

2V_INT

C2 C3

SDA2

SCL2

VCC

DIR1

DIR2

3V_BCKPV_BCKP

GNSS data ready

GNSS RTC sharing

GNSS supply enabled

Figure 59: Application circuit for connecting TOBY-L2 modules to u-blox 3.0 V GNSS receivers

Reference

Description

Part Number - Manufacturer

R1, R2, R4, R5

4.7 kΩ Resistor 0402 5% 0.1 W

RC0402JR-074K7L - Yageo Phycomp

47 kΩ 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

related output bypass

See GNSS receiver Hardware Integration Manual

I2C-bus Bidirectional Voltage Translator

TCA9406DCUR - Texas Instruments

Generic Unidirectional Voltage Translator

SN74AVC2T245 - Texas Instruments

Table 38: Components for connecting TOBY-L2 modules to u-blox 3.0 V GNSS receivers

For additional guidelines regarding the design of applications with u-blox 3.0 V GNSS receivers see the GNSS

Implementation Application Note [13] and the Hardware Integration Manual of the u-blox GNSS receivers.

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2.6.3.2 Guidelines for DDC (I2C) layout design

The DDC (I2C) serial interface requires the same consideration 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.

2.6.4 Secure Digital Input Output interface (SDIO)

The SDIO Secure Digital Input Output interface is not available on MPCI-L2 series modules.

2.6.4.1 Guidelines for SDIO circuit design

The functionality of the SDIO_D0, SDIO_D1, SDIO_D2, SDIO_D3, SDIO_CLK, SDIO_CMD pins is not

supported by TOBY-L2x0-00S: the pins should be not driven improperly by any external device.

TOBY-L2 series modules include a 4-bit Secure Digital Input Output interface (SDIO_D0, SDIO_D1, SDIO_D2,

SDIO_D3, SDIO_CLK, SDIO_CMD) available to communicate with an external Wi-Fi chip.

Guidelines for SDIO circuit design will be described in detail in a successive release of the document.

Do not apply voltage to any SDIO interface pin before the switch-on of SDIO interface supply source

(V_INT), to avoid latch-up of circuits and allow a proper boot of the module. If the external signals

connected to the cellular module cannot be tri-stated or set low, insert a multi channel digital switch (e.g.

TI SN74CB3Q16244, TS5A3159, or TS5A63157) between the two-circuit connections and set to high

impedance before V_INT switch-on.

ESD sensitivity rating of SDIO interface pins is 1 kV (Human Body Model according to JESD22-A114).

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

accessible points.

If the SDIO interface pins are not used, they can be left unconnected on the application board.

2.6.4.2 Guidelines for SDIO layout design

The SDIO serial interface requires the same consideration regarding electro-magnetic 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.

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. However, the resistor value should not be so high

that the rise / fall time requirements are violated: for example, 22  or 33  resistor may be sufficient to slow

the signal and remove the ringing problem.

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2.7 Audio interface

2.7.1 Digital audio interface

The I2S interface is not available on MPCI-L2 series modules.

2.7.1.1 Guidelines for digital audio circuit design

The I2S interface is not supported by TOBY-L2x0-00S: the pins should be not driven by any external device.

I2S digital audio interface can be connected to an external digital audio device for voice applications. The external

digital audio device must be properly configured according to the cellular module configuration, with the

opposite role, the same mode, the same sample rate and voltage level.

Any external digital audio device compliant with the configuration of the digital audio interface of the TOBY-L2

cellular module can be used. Examples of compatible audio codec parts, suitable to provide analog audio voice

capability on the application device, are the following:

 Marvell 88PM805

 Maxim MAX9860

 Maxim MAX9867

 Maxim MAX9880A

An appropriate specific application circuit has to be implemented and configured according to the particular

external digital audio device or audio codec used and according to the application requirements.

Figure 60 and Table 39 describe an application circuit for the I2S digital audio interface providing voice capability

using an external audio voice codec. DAC and ADC integrated in the external audio codec respectively converts

an incoming digital data stream to analog audio output through a mono amplifier and converts the microphone

input signal to the digital bit stream over the digital audio interface.

The module’s I2S interface (I2S master) is connected to the related pins of the external audio codec (I2S slave).

The GPIO6 of the TOBY-L2 series module (that provides a suitable digital output clock) is connected to the clock

input of the external audio codec to provide clock reference.

The external audio codec is controlled by the wireless module using the DDC (I2C) interface: this interface can be

concurrently used to communicate with u-blox GNSS receivers and to control an external audio codec.

The V_INT output supplies the external audio codec, defining proper digital interfaces voltage level.

Additional components are provided for EMC and ESD immunity conformity: a 10 nF bypass capacitor and a

series chip ferrite bead noise/EMI suppression filter provided on each microphone line input and speaker line

output of the external codec as described in Figure 60 and Table 39. The necessity of these or other additional

parts for EMC improvement may depend on the specific application board design.

As various external audio codecs other than the one described in Figure 60 / Table 39 can be used to provide

voice capability, the appropriate specific application circuit has to be implemented and configured according to

the particular external digital audio device or audio codec used and according to the application requirements.

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R2R1

BCLK

GND

LRCLK

TOBY-L2 series

(except TOBY-L2x0-00S)

Audio

Codec

SDIN

SDOUT

SDA

SCL

SDA

SCL

GPIO6 MCLK

GND

IRQn

R3 C3C2

V_INT

VDD

1V8

MICBIAS

C4 R4

EMI1

MICLN

MICLP

Microphone

Connector

EMI2

MIC

C12 C11

MICGND

R5 C8 C7

SPK

Speaker

Connector

OUTP

OUTN

C10 C9C14 C13

EMI3

EMI4

I2S_CLK

I2S_WA

I2S_TXD

I2S_RXD

Figure 60: I2S interface application circuit with an external audio codec to provide voice capability

Reference

Description

Part Number – Manufacturer

100 nF Capacitor Ceramic X5R 0402 10% 10V

GRM155R71C104KA01 – Murata

C2, C4, C5, C6

1 µF Capacitor Ceramic X5R 0402 10% 6.3 V

GRM155R60J105KE19 – Murata

10 µF Capacitor Ceramic X5R 0603 20% 6.3 V

GRM188R60J106ME47 – Murata

C7, C8, C9, C10

27 pF Capacitor Ceramic COG 0402 5% 25 V

GRM1555C1H270JZ01 – Murata

C11, C12, C13, C14

10 nF Capacitor Ceramic X5R 0402 10% 50V

GRM155R71C103KA88 – Murata

D1, D2

Low Capacitance ESD Protection

USB0002RP or USB0002DP – AVX

EMI1, EMI2, EMI3,

EMI4

Chip Ferrite Bead Noise/EMI Suppression Filter

1800 Ohm at 100 MHz, 2700 Ohm at 1 GHz

BLM15HD182SN1 – Murata

Microphone Connector

Various manufacturers

Speaker Connector

Various manufacturers

MIC

2.2 k Electret Microphone

Various manufacturers

R1, R2

4.7 kΩ Resistor 0402 5% 0.1 W

RC0402JR-074K7L - Yageo Phycomp

10 kΩ Resistor 0402 5% 0.1 W

RC0402JR-0710KL - Yageo Phycomp

R4, R5

2.2 kΩ Resistor 0402 5% 0.1 W

RC0402JR-072K2L – Yageo Phycomp

SPK

32  Speaker

Various manufacturers

16-Bit Mono Audio Voice Codec

MAX9860ETG+ - Maxim

Table 39: Example of components for audio voice codec application circuit

Do not apply voltage to any I2S pin before the switch-on of I2S supply source (V_INT), to avoid latch-up of

circuits and allow a proper boot of the module. If the external signals connected to the cellular module

cannot be tri-stated or set low, insert a multi channel digital switch (e.g. TI SN74CB3Q16244, TS5A3159,

or TS5A63157) between the two-circuit connections and set to high impedance before V_INT switch-on.

ESD sensitivity rating of I2S interface pins is 1 kV (Human Body Model according to JESD22-A114). 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 accessible points.

If the I2S digital audio pins are not used, they can be left unconnected on the application board.

2.7.1.2 Guidelines for digital audio layout design

I2S interface and clock output lines require the same consideration regarding electro-magnetic 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.

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2.8 General Purpose Input/Output

GPIOs are not supported by the TOBY-L2x0-00S product version except for the Wireless Wide Area

Network status indication configured on the GPIO1 pin: the pins should be not driven by any external

device.

GPIOs are not available on MPCI-L2 series modules.

2.8.1.1 Guidelines for TOBY-L2 series GPIO circuit design

A typical usage of TOBY-L2 modules’ GPIOs can be the following:

 Network indication provided over GPIO1 pin (see Figure 61 / Table 40 below)

 GNSS supply enable provided over GPIO2 (see Figure 57 / Table 36 or Figure 59 / Table 38 in section 2.6.3)

 GNSS data ready provided over GPIO3 (see Figure 57 / Table 36 or Figure 59 / Table 38 in section 2.6.3)

 GNSS RTC sharing provided over GPIO4 (see Figure 57 / Table 36 or Figure 59 / Table 38 in section 2.6.3)

 SIM card detection provided over GPIO5 (see Figure 46 / Table 30 or Figure 47 / Table 31 in section 2.5)

 Clock output provided over GPIO6 (see Figure 60 / Table 39 in section 2.7.1)

TOBY-L2 series

GPIO1

3V8

Network Indicator

DL1

Figure 61: Application circuit for network indication provided over GPIO1

Reference

Description

Part Number - Manufacturer

10 k Resistor 0402 5% 0.1 W

Various manufacturers

47 k Resistor 0402 5% 0.1 W

Various manufacturers

820  Resistor 0402 5% 0.1 W

Various manufacturers

DL1

LED Red SMT 0603

LTST-C190KRKT - Lite-on Technology Corporation

NPN BJT Transistor

BC847 - Infineon

Table 40: Components for network indication application circuit

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 of TOBY-L2 modules.

Do not apply voltage to any GPIO of TOBY-L2 before the switch-on of the GPIOs supply (V_INT), to avoid

latch-up of circuits and allow a proper 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.

ESD sensitivity rating of the GPIO pins is 1 kV (Human Body Model according to JESD22-A114).

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 accessible points.

If the GPIO pins are not used, they can be left unconnected on the application board.

2.8.1.2 Guidelines for general purpose input/output layout design

The general purpose inputs / outputs pins are generally not critical for layout.

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2.9 Mini PCIe specific signals (W_DISABLE#, LED_WWAN#)

Mini PCI Express specific signals (W_DISABLE#, LED_WWAN#) are not available on TOBY-L2 series.

2.9.1.1 Guidelines for W_DISABLE# circuit design

As described in Figure 62, the MPCI-L2 series modules W_DISABLE# wireless disable input is equipped with an

internal pull-up to the 3.3Vaux supply: an external pull-up resistor is not required and should not be provided.

If connecting the W_DISABLE# 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 device should be

provided close to accessible point, as described in Figure 62 and Table 41.

ESD sensitivity rating of the W_DISABLE# pin is 1 kV (HBM according to JESD22-A114). 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 W_DISABLE# pin, and it can be achieved by mounting an ESD

protection (e.g. EPCOS CA05P4S14THSG varistor) close to accessible point.

An open drain output is suitable to drive the W_DISABLE# input from an application processor as it is equipped

with an internal pull-up to the 3.3Vaux supply as described in Figure 62.

A compatible push-pull output of an application processor can also be used. In any case, take care to set the

proper level in all the possible scenarios to avoid an inappropriate disabling of the radio operations.

MPCI-L2 series

3.3Vaux

20 W_DISABLE#

Power-on

push button

ESD

Open

Drain

Output

Application

Processor

MPCI-L2 series

3.3Vaux

20 W_DISABLE#

TP TP

22 k22 k

Figure 62: W_DISABLE# application circuit using a push button and an open drain output of an application processor

Reference

Description

Remarks

ESD

Varistor for ESD protection

CT0402S14AHSG - EPCOS

Table 41: Example of ESD protection component for the W_DISABLE# application circuit

If the W_DISABLE# functionality is not required by the application, the pin can be left unconnected.

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2.9.1.2 Guidelines for LED_WWAN# circuit design

As described in Figure 63 and Table 42, the MPCI-L2 series modules LED_WWAN# active-low open drain output

can be directly connected to a system-mounted LED to provide the Wireless Wide Area Network status indication

as specified by the PCI Express Mini Card Electromechanical Specification [14].

Open

Drain

Output

3V3

LED_WWAN#

MPCI-L2 series

Figure 63: LED_WWAN# application circuit

Reference

Description

Remarks

LED Green SMT 0603

LTST-C190KGKT - Lite-on Technology Corporation

470  Resistor 0402 5% 0.1 W

Various manufacturers

Table 42: Example of components for the LED_WWAN# application circuit

ESD sensitivity rating of the LED_WWAN# pin is 1 kV (Human Body Model according to JESD22-A114).

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) close to accessible point.

If the LED_WWAN# functionality is not required by the application, the pin can be left unconnected.

2.9.1.3 Guidelines for W_DISABLE# and LED_WWAN# layout design

The W_DISABLE# and LED_WWAN# circuits are generally not critical for layout.

2.10 Reserved pins (RSVD)

Pins reserved for future use, marked as RSVD, are not available on MPCI-L2 series.

TOBY-L2 series modules have pins reserved for future use. All the RSVD pins are to be left unconnected on the

application board except the RSVD pin number 6 which must be connected to ground as described in Figure 64.

TOBY-L2 series

RSVD

Figure 64: Application circuit for the reserved pins (RSVD)

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2.11 Module placement

An optimized placement allows a minimum RF line’s length and closer path from DC source for VCC / 3.3Vaux.

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 Electro-

Magnetic Interference that affects the module, analog parts and RF circuits’ performance. Implement proper

countermeasures to avoid any possible Electro-Magnetic Compatibility issue.

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 Electro-Magnetic Interference, or employ

countermeasures to avoid any possible Electro-Magnetic 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-L2 and MPCI-L2 series modules: avoid placing

temperature sensitive devices close to the module.

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2.12 TOBY-L2 series module footprint and paste mask

Figure 65 and Table 43 describe the suggested footprint (i.e. copper mask) layout for TOBY-L2 series modules.

The proposed land pattern layout slightly reflects the modules’ pads layout, with most of the lateral pads

designed wider on the application board (1.8 x 0.8 mm) than on the module (1.5 x 0.8 mm).

G H J1DF2

KM1 M1 M2 P2

M1 M1 M3

Module placement outline

Figure 65: TOBY-L2 series module suggest footprint (application board top view)

Parameter

Value

Parameter

Value

Parameter

Value

35.6 mm

0.80 mm

5.20 mm

24.8 mm

1.50 mm

4.50 mm

2.40 mm

1.80 mm

2.10 mm

2.25 mm

0.30 mm

1.10 mm

1.45 mm

3.15 mm

1.10 mm

1.30 mm

7.15 mm

1.25 mm

1.10 mm

1.80 mm

2.85 mm

Table 43: TOBY-L2 series module suggest footprint dimensions

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 layout for TOBY-L2 series modules slightly reflects the copper mask layout described

in Figure 65 and Table 43, as different stencil apertures layout for any specific pad is recommended:

 Blue marked pads: Paste layout reduced circumferentially about 0.025 mm to Copper layout

 Green marked pads: Paste layout enlarged circumferentially about 0.025 mm to Copper layout

 Purple marked pads: Paste layout one to one to Copper layout

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 etc.) of the customer.

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2.13 MPCI-L2 series module installation

MPCI-L2 series modules are fully compliant with the 52-pin PCI Express Full-Mini Card Type F2 form factor, i.e.,

top-side and bottom-side keep-out areas, 50.95 mm nominal length, 30 mm nominal width, and all the other

dimensions as defined by the PCI Express Mini Card Electromechanical Specification [14], except for the card

thickness (which nominal value is 3.7 mm), as described in Figure 66.

3.7 mm

Side View

Pin 1 Pin 51

ANT1ANT2

Top View

Hole GND HoleGND 30 mm

Pin 52 Pin 2

Bottom View

Hole GND HoleGND

50.95 mm

Figure 66: MPCI-L2 series mechanical description (top, side and bottom views)

MPCI-L2 series modules are fully compliant with the 52-pin PCI Express Full-Mini card edge type system

connector as defined by the PCI Express Mini Card Electromechanical Specification [14]. Table 44 describes some

examples of 52-pin mating system connectors for the MPCI-L2 series PCI Express Full-Mini card modules.

Manufacturer

Part Number

Description

JAE Electronics

MM60 series

52-circuit, 0.8 mm pitch, PCI Express Mini card edge female connector

Molex

67910 series

52-circuit, 0.8 mm pitch, PCI Express Mini card edge female connector

TE Connectivity / AMP

2041119 series

52-circuit, 0.8 mm pitch, PCI Express Mini card edge female connector

FCI

10123824 series

52-circuit, 0.8 mm pitch, PCI Express Mini card edge female connector

Table 44: MPCI-L2 series PCI Express Full-Mini card compatible connector

It is recommended to use the two mounting holes described in Figure 66 to fix (ground) the MPCI-L2

module to the main ground of the application board with suitable screws and fasteners.

Follow the recommendations provided by the connector manufacturer and the guidelines available in the

PCI Express Mini Card Electromechanical Specification [14] for the development of the footprint (i.e. the

copper mask) PCB layout for the mating edge system connector. The exact geometries, distances and

stencil thicknesses should be adapted to the specific production processes (e.g. soldering etc.).

Follow the recommendations provided by the connector manufacturer to properly insert and remove the

MPCI-L2 series modules.

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MPCI-L2 series modules are equipped with two Hirose U.FL-R-SMT RF receptacles for ANT1 / ANT2 ports, which

require a suitable mated RF plug from the same connector series as the examples listed in Table 23.

To mate the connectors, the mating axes of both connectors must be aligned. The "click" will confirm the fully

mated connection. Do not attempt to insert on an extreme angle: insert the RF plug connectors vertically into

the ANT1 / ANT2 RF receptacles of the modules, as described in Figure 67.

Correct Wrong

Figure 67: Precautions during RF connector mating

To unplug the RF cable assembly it is encouraged to use a suitable extraction tool for the RF connector, such as

the Hirose U.FL-LP-N or the Hirose U.FL-LP(V)-N extraction jig, according to the RF cable assembly type used.

Hook the end portion of the extraction jig onto the connector cover and pull off vertically in the direction of the

connector mating axis, as described in Figure 68.

Extraction Jig

RF Cable Assembly

U.FL Receptacle

Figure 68: Precautions during RF connector extraction

Any attempt to unplug the RF connectors by pulling on the cable assembly without using a suitable extraction

tool may result in damage and affect the RF performance.

Do not forcefully twist, deform, or apply any excessive pull force to the RF cables or damage the RF connectors,

otherwise the RF performance may be reduced.

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2.14 Thermal guidelines

Modules’ operating temperature range is specified in TOBY-L2 Data Sheet [1] and MPCI-L2 Data Sheet [2].

The most critical condition concerning module thermal performance is the uplink transmission at maximum

power (data upload in connected-mode), 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; however the application should be correctly designed to cope with it.

During transmission at maximum RF power the TOBY-L2 and MPCI-L2 series modules generate thermal power

that can exceed 3 W: this is an indicative value since the exact generated power strictly depends on operating

condition such as the number of allocated TX resource blocks, 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 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 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 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.

A few hardware techniques may be used to reduce the Module-to-Ambient thermal resistance 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 complete thermal via stacked down to main ground layer.

 Use the two mounting holes described in Figure 66 to fix (ground) the MPCI-L2 modules to the main ground

of the application board with suitable screws and fasteners.

 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.

 Force ventilation air-flow within mechanical enclosure.

 Provide a heat sink component attached to the module top side, with electrically insulated / high thermal

conductivity adhesive, or on the backside of the application board, below the cellular module.

 Follow the thermal guidelines for integrating wireless wide area network mini card add-in cards, such as the

MPCI-L2 series modules, as provided in the PCI Express Mini Card Electromechanical Specification [14]

For example, the Module-to-Ambient thermal resistance (Rth,M-A) is strongly reduced with forced air ventilation

and a heat-sink installed on the back of the application board, decreasing the module temperature variation.

Beside the reduction of the Module-to-Ambient thermal resistance implemented by proper application hardware

design, the increase of module temperature can be moderated by proper application software implementation:

 Enable module connected-mode for a given time period and then disable it for a time period enough long to

properly mitigate temperature increase.

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2.15 ESD guidelines

The sections 2.15.1 and 2.15.2 are related to EMC / ESD immunity. The modules are ESD sensitive devices. The

ESD sensitivity for each pin (as Human Body Model according to JESD22-A114F) is specified in TOBY-L2 series

Data Sheet [1] or MPCI-L2 series Data Sheet [2]. Special precautions are required when handling the pins; for

ESD handling guidelines see section 3.2.

2.15.1 ESD immunity test overview

The immunity of devices integrating TOBY-L2 and MPCI-L2 series modules to Electro-Static Discharge (ESD) is

part of the Electro-Magnetic Compatibility (EMC) conformity which is required for products bearing the CE

marking, compliant with the R&TTE Directive (99/5/EC), the EMC Directive (89/336/EEC) and the Low Voltage

Directive (73/23/EEC) issued by the Commission of the European Community.

Compliance with these directives implies conformity to the following European Norms for device ESD immunity:

ESD testing standard CENELEC EN 61000-4-2 [20] and the radio equipment standards ETSI EN 301 489-1 [21],

ETSI EN 301 489-7 [22], ETSI EN 301 489-24 [23], which requirements are summarized in Table 45.

The ESD immunity test is performed at the enclosure port, defined by ETSI EN 301 489-1 [21] as the physical

boundary through which the electromagnetic field radiates. If the device implements an integral antenna, the

enclosure port is seen as all insulating and conductive surfaces housing the device. If the device implements a

removable antenna, the antenna port can be separated from the enclosure port. The antenna port includes the

antenna element and its interconnecting cable surfaces.

The applicability of ESD immunity test to the whole device depends on the device classification as defined by ETSI

EN 301 489-1 [21]. Applicability of ESD immunity test to the relative device ports or the relative interconnecting

cables to auxiliary equipment, depends on device accessible interfaces and manufacturer requirements, as

defined by ETSI EN 301 489-1 [21].

Contact discharges are performed at conductive surfaces, while air discharges are performed at insulating

surfaces. Indirect contact discharges are performed on the measurement setup horizontal and vertical coupling

planes as defined in CENELEC EN 61000-4-2 [20].

For the definition of integral antenna, removable antenna, antenna port and device classification see ETSI

EN 301 489-1 [21]. For the contact / air discharges definitions see CENELEC EN 61000-4-2 [20].

Application

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