Siemens MD741-1 EGPRS/GSM Router User Manual MC75

Siemens AG EGPRS/GSM Router MC75

Contents

UserMan1 MC75

Hardware Interface Descri
p
tion
MC75
Siemens Cellular Engine
Version: 00.190a
DocID: MC75_V00.190a
s
MC75 Hardware Interface Description
Strictly confidential / Draft s
MC75_V00.190a Page 2 of 91 15.02.2005
Document Name: MC75 Hardware Interface Description
Version: 00.190a
Date: February 15, 2005
DocId: MC75_V00.190a
Status: Strictly confidential / Draft
General note
Product is deemed accepted by Recipient and is provided without interface to Recipient´s products.
The Product constitutes pre-release version and code and may be changed substantially before
commercial release. The Product is provided on an “as is” basis only and may contain deficiencies or
inadequacies. The Product is provided without warranty of any kind, express or implied. To the
maximum extent permitted by applicable law, Siemens further disclaims all warranties, including
without limitation any implied warranties of merchantability, fitness for a particular purpose and
noninfringement of third-party rights. The entire risk arising out of the use or performance of the
Product and documentation remains with Recipient. This Product is not intended for use in life support
appliances, devices or systems where a malfunction of the product can reasonably be expected to
result in personal injury. Applications incorporating the described product must be designed to be in
accordance with the technical specifications provided in these guidelines. Failure to comply with any
of the required procedures can result in malfunctions or serious discrepancies in results. Furthermore,
all safety instructions regarding the use of mobile technical systems, including GSM products, which
also apply to cellular phones must be followed. Siemens AG customers using or selling this product
for use in any applications do so at their own risk and agree to fully indemnify Siemens for any
damages resulting from illegal use or resale. To the maximum extent permitted by applicable law, in
no event shall Siemens or its suppliers be liable for any consequential, incidental, direct, indirect,
punitive or other damages whatsoever (including, without limitation, damages for loss of business
profits, business interruption, loss of business information or data, or other pecuniary loss) arising out
the use of or inability to use the Product, even if Siemens has been advised of the possibility of such
damages. Subject to change without notice at any time.
Copyright
Transmittal, reproduction, dissemination and/or editing of this document as well as utilization of its
contents and communication thereof to others without express authorization are prohibited. Offenders
will be held liable for payment of damages. All rights created by patent grant or registration of a utility
model or design patent are reserved.
Copyright © Siemens AG 2005
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Contents
0 Document History .........................................................................................................6
1 Introduction ...................................................................................................................8
1.1 Related Documents ...............................................................................................8
1.2 Terms and Abbreviations.......................................................................................9
1.3 Type Approval......................................................................................................12
1.4 Safety Precautions...............................................................................................14
2 Product Concept .........................................................................................................16
2.1 Key Features at a Glance ....................................................................................16
2.2 MC75 System Overview ......................................................................................19
2.3 Circuit Concept ....................................................................................................20
3 Application Interface...................................................................................................21
3.1 Power Supply.......................................................................................................22
3.1.1 Minimizing Power Losses ......................................................................22
3.1.2 Measuring the Supply Voltage VBATT+ ....................................................23
3.1.3 Monitoring Power Supply by AT Command ...........................................23
3.2 Power Up / Power Down Scenarios.....................................................................24
3.2.1 Turn on MC75 ........................................................................................24
3.2.1.1 Turn on MC75 Using Ignition Line IGT ..................................................24
3.2.1.2 Turn on MC75 Using the VCHARGE Signal ..........................................26
3.2.1.3 Reset MC75 via AT+CFUN Command ..................................................27
3.2.1.4 Reset MC75 in Case of Emergency via EMERG_RST..........................27
3.2.2 Turn off MC75 ........................................................................................28
3.2.2.1 Turn off MC75 Using AT Command.......................................................28
3.2.2.2 Leakage Current in Power Down Mode .................................................29
3.2.3 Automatic Shutdown ..............................................................................30
3.2.3.1 Temperature Dependent Shutdown.......................................................30
3.2.3.2 Temperature Control during Emergency call .........................................31
3.2.3.3 Undervoltage Shutdown if Battery NTC is Present ................................31
3.2.3.4 Undervoltage Shutdown if no Battery NTC is Present ...........................32
3.2.3.5 Overvoltage Shutdown...........................................................................32
3.3 Automatic EGPRS/GPRS Multislot Class Change ..............................................33
3.4 Charging Control..................................................................................................34
3.4.1 Battery Pack Requirements ...................................................................34
3.4.2 Batteries Recommended for Use with MC75.........................................35
3.4.3 Charger Requirements...........................................................................36
3.4.4 Implemented Charging Technique.........................................................36
3.4.5 Operating Modes during Charging.........................................................37
3.5 RTC Backup ........................................................................................................38
3.6 SIM Interface .......................................................................................................39
3.7 Serial Interface ASC0 ..........................................................................................40
3.8 Serial Interface ASC1 ..........................................................................................42
3.9 USB Interface ......................................................................................................43
3.9.1 Installing the USB Modem Driver...........................................................44
3.10 I2C Interface .........................................................................................................46
3.11 SD Memory Card Interface ..................................................................................47
3.12 Audio Interfaces...................................................................................................49
3.12.1 Speech Processing................................................................................50
3.12.2 Microphone Circuit.................................................................................50
3.12.2.1 Single-ended Microphone Input.............................................................50
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3.12.2.2 Differential Microphone Input.................................................................51
3.12.2.3 Line Input Configuration with OpAmp ....................................................52
3.12.3 Loudspeaker Circuit...............................................................................53
3.12.4 Digital Audio Interface DAI.....................................................................54
3.13 Control Signals ....................................................................................................56
3.13.1 Synchronization Signal ..........................................................................56
3.13.2 Using the SYNC Pin to Control a Status LED........................................57
4 Antenna Interface........................................................................................................58
4.1 Antenna Installation .............................................................................................58
4.2 Antenna Pad ........................................................................................................60
4.2.1 Suitable Cable Types.............................................................................60
4.3 Antenna Connector..............................................................................................61
5 Electrical, Reliability and Radio Characteristics......................................................65
5.1 Absolute Maximum Ratings .................................................................................65
5.2 Operating Temperatures......................................................................................65
5.3 Pin Assignment and Signal Description...............................................................66
5.4 Electrostatic Discharge ........................................................................................72
5.5 Reliability Characteristics.....................................................................................73
6 Mechanics....................................................................................................................74
6.1 Mechanical Dimensions of MC75 ........................................................................74
6.2 Mounting MC75 to the Application Platform ........................................................76
6.3 Board-to-Board Application Connector ................................................................77
7 Sample Application.....................................................................................................80
8 Reference Approval ....................................................................................................82
8.1 Reference Equipment for Type Approval.............................................................82
8.2 Compliance with FCC Rules and Regulations.....................................................83
9 Appendix......................................................................................................................84
9.1 List of Parts and Accessories ..............................................................................84
9.2 Fasteners and Fixings for Electronic Equipment .................................................86
9.2.1 Fasteners from German Supplier ETTINGER GmbH ............................86
9.3 Data Sheets of Recommended Batteries ............................................................89
Tables
Table 1: Temperature dependent behavior ............................................................................ 31
Table 2: Specifications of battery packs suitable for use with MC75 ..................................... 35
Table 3: Comparison Charge-only and Charge mode............................................................ 37
Table 4: AT commands available in Charge-only mode......................................................... 37
Table 5: Signals of the SIM interface (board-to-board connector) ......................................... 39
Table 6: DCE-DTE wiring of ASC0......................................................................................... 41
Table 7: DCE-DTE wiring of ASC1......................................................................................... 42
Table 8: SD card interface......................................................................................................47
Table 9: Overview of USC pin functions................................................................................. 54
Table 10: Return loss in the active band ................................................................................58
Table 11: Product specifications of U.FL-R-SMT connector .................................................. 61
Table 12: Material and finish of U.FL-R-SMT connector and recommended plugs ...............62
Table 13: Ordering information for Hirose U.FL Series .......................................................... 64
Table 14: Absolute maximum ratings ..................................................................................... 65
Table 15: Operating temperatures ......................................................................................... 65
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Table 16: Signal description...................................................................................................67
Table 17: Measured electrostatic values................................................................................72
Table 18: Summary of reliability test conditions ..................................................................... 73
Table 19: Technical specifications of Molex board-to-board connector .................................77
Table 20: List of parts and accessories..................................................................................84
Table 21: Molex sales contacts (subject to change) ..............................................................85
Table 22: Hirose sales contacts (subject to change)..............................................................85
Figures
Figure 1: MC75 system overview ...........................................................................................19
Figure 2: MC75 block diagram ............................................................................................... 20
Figure 3: Power supply limits during transmit burst................................................................ 22
Figure 4: Position of the reference points BATT+ and GND .................................................. 23
Figure 5: Power-on with operating voltage at BATT+ applied before activating IGT.............. 25
Figure 6: Power-on with IGT held low before switching on operating voltage at BATT+ .......26
Figure 7: Signal states during turn-off procedure ...................................................................29
Figure 8: Battery pack circuit diagram....................................................................................35
Figure 9: RTC supply from capacitor...................................................................................... 38
Figure 10: RTC supply from rechargeable battery .................................................................38
Figure 11: RTC supply from non-chargeable battery .............................................................38
Figure 12: Serial interface ASC0............................................................................................ 40
Figure 13: Serial interface ASC1............................................................................................ 42
Figure 14: USB circuit ............................................................................................................43
Figure 15: I2C interface connected to VCC of application ..................................................... 46
Figure 16: I2C interface connected to VEXT line of MC75..................................................... 46
Figure 17: SD card interface (example with power supply from module’s VEXT line) ........... 48
Figure 18: Audio block diagram.............................................................................................. 49
Figure 19: Single ended microphone input............................................................................. 50
Figure 20: Differential microphone input ................................................................................ 51
Figure 21: Line input configuration with OpAmp .................................................................... 52
Figure 22: Differential loudspeaker configuration...................................................................53
Figure 23: Single ended loudspeaker configuration............................................................... 53
Figure 24: PCM interface application ..................................................................................... 54
Figure 25: PCM timing............................................................................................................ 55
Figure 26: SYNC signal during transmit burst ........................................................................ 56
Figure 27: LED Circuit (Example)...........................................................................................57
Figure 28: Never use antenna connector and antenna pad at the same time ....................... 59
Figure 29: Restricted area around antenna pad..................................................................... 59
Figure 30: Mechanical dimensions of U.FL-R-SMT connector...............................................61
Figure 31: U.FL-R-SMT connector with U.FL-LP-040 plug ....................................................62
Figure 32: U.FL-R-SMT connector with U.FL-LP-066 plug ....................................................62
Figure 33: Specifications of U.FL-LP-(V)-040(01) plug .......................................................... 63
Figure 34: Pin assignment (component side of MC75) .......................................................... 66
Figure 35: MC75 – top view ................................................................................................... 74
Figure 36: Dimensions of MC75............................................................................................. 75
Figure 37: Molex board-to-board connector 52991-0808 on MC75 .......................................78
Figure 38: Mating board-to-board connector 53748-0808 on application .............................. 79
Figure 39: MC75 sample application (draft) ........................................................................... 81
Figure 40: Reference equipment for Type Approval ..............................................................82
Figure 41: Lithium Ion battery from VARTA ...........................................................................90
Figure 42: Lithium Polymer battery from VARTA ................................................................... 91
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0 Document History
Preceding document: "MC75 Hardware Interface Description" Version 00.111
New document: "MC75 Hardware Interface Description" Version 00.190a
Chapter What is new
2.3 Updated Figure 2
8.2 Added notes regarding FCC regulations
Preceding document: "MC75 Hardware Interface Description" Version 00.111
New document: "MC75 Hardware Interface Description" Version 00.190
Chapter What is new
3.4.5 Described effect of AT^SMSO during Charge-only mode.
3.12.2 Corrected several parameters in figures.
3.13 More detailed description of AT^SSYNC command.
8.2 Changed antenna gain and FCC identifier.
Preceding document: "MC75 Hardware Interface Description" Version 00.02
New document: "MC75 Hardware Interface Description" Version 00.111
Chapter What is new
3.1.2 / 3.1.3 Added description of how to measure VBATT+.
3.2.3.5 Orderly shutdown in case of overvoltage (description is preliminary)
3.4.1 / 3.4.2
9.3
Updated battery requirements. Added description of VARTA batteries.
Added data sheets of VARTA batteries.
3.9.1 Added info about usbser.sys file.
3.12.2 Added filter in microphone circuit figures.
3.12.3 Added figures “Differential loudspeaker configuration” and “Single ended loudspeaker
configuration”.
3.10 More detailed description of how to connect the I2C interface.
5.1 Updated Table 14: Absolute maximum ratings.
6.1 Updated Figure 36.
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Preceding document: "MC75 Hardware Interface Description" Version 00.02
New document: "MC75 Hardware Interface Description" Version 00.65
Chapter What is new
--- Deleted section about limitations of MC75 Preview Release.
Throughout
manual
Supply voltage range now 3.2V – 4.3V (instead of 3.2V – 4.2V)
2.1 / 5.3 Operating temperature specified.
3.2.2.2 Added section Leakage Current in Power Down Mode.
3.4 Added Lithium Polymer batteries. Updated recommended battery specifications. More
detailed description of trickle charging.
3.6 Use CCGND as separate ground line for the SIM interface.
3.9 Corrected description and figure of USB interface. Described driver installation.
3.12.4 / 5.3 USC4 pin marked as input.
5.3 Added specifications of USB interface.
5.4 Table 17: Added electrostatic values of USB and SD card interfaces.
6.1 Updated Figure 36.
Preceding document: "MC75 Hardware Interface Description" Version 00.02
New document: "MC75 Hardware Interface Description" Version 00.30
Chapter What is new
Completely revised and updated all chapters and technical specifications. Added new chapters and
appendix.
Preceding document: "MC75 Hardware Interface Description" Version 00.01
New document: "MC75 Hardware Interface Description" Version 00.02
Chapter What is new
5 Changed description of VEXT pin.
Changed description of pin 55 and renamed pin from EMERGOFF to EMERG_RST.
3.11 Corrected Figure 17: SD card interface.
7 Changed sample application.
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1 Introduction
This document describes the hardware of the Siemens MC75 module that connects to the
cellular device application and the air interface. It helps you quickly retrieve interface
specifications, electrical and mechanical details and information on the requirements to be
considered for integrating further components.
1.1 Related Documents
[1] MC75 AT Command Set
[2] MC75 Release Notes 00.190
[3] DSB75 Support Box - Evaluation Kit for Siemens Cellular Engines
[4] Application 07: Rechargeable Lithium Batteries in GSM Applications (not yet available)
[5] Multiplexer User's Guide (not yet available)
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1.2 Terms and Abbreviations
Abbreviation Description
ADC Analog-to-Digital Converter
AGC Automatic Gain Control
ANSI American National Standards Institute
ARFCN Absolute Radio Frequency Channel Number
ARP Antenna Reference Point
ASC0 / ASC1 Asynchronous Controller. Abbreviations used for first and second serial interface of
MC75
B Thermistor Constant
B2B Board-to-board connector
BER Bit Error Rate
BTS Base Transceiver Station
CB or CBM Cell Broadcast Message
CE Conformité Européene (European Conformity)
CHAP Challenge Handshake Authentication Protocol
CPU Central Processing Unit
CS Coding Scheme
CSD Circuit Switched Data
CTS Clear to Send
DAC Digital-to-Analog Converter
DAI Digital Audio Interface
dBm0 Digital level, 3.14dBm0 corresponds to full scale, see ITU G.711, A-law
DCE Data Communication Equipment (typically modems, e.g. Siemens GSM engine)
DCS 1800 Digital Cellular System, also referred to as PCN
DRX Discontinuous Reception
DSB Development Support Box
DSP Digital Signal Processor
DSR Data Set Ready
DTE Data Terminal Equipment (typically computer, terminal, printer or, for example, GSM
application)
DTR Data Terminal Ready
DTX Discontinuous Transmission
EDGE Enhanced Data Rates for Global Evolution
EFR Enhanced Full Rate
EGSM Enhanced GSM
EGPRS Enhanced General Packet Radio Service
EMC Electromagnetic Compatibility
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Abbreviation Description
ESD Electrostatic Discharge
ETS European Telecommunication Standard
FCC Federal Communications Commission (U.S.)
FDMA Frequency Division Multiple Access
FR Full Rate
GMSK Gaussian Minimum Shift Keying
GPRS General Packet Radio Service
GSM Global Standard for Mobile Communications
HiZ High Impedance
HR Half Rate
I/O Input/Output
IC Integrated Circuit
IMEI International Mobile Equipment Identity
ISO International Standards Organization
ITU International Telecommunications Union
kbps kbits per second
LED Light Emitting Diode
Li-Ion / Li+ Lithium-Ion
Li battery Rechargeable Lithium Ion or Lithium Polymer battery
Mbps Mbits per second
MMI Man Machine Interface
MO Mobile Originated
MS Mobile Station (GSM engine), also referred to as TE
MSISDN Mobile Station International ISDN number
MT Mobile Terminated
NTC Negative Temperature Coefficient
OEM Original Equipment Manufacturer
PA Power Amplifier
PAP Password Authentication Protocol
PBCCH Packet Switched Broadcast Control Channel
PCB Printed Circuit Board
PCL Power Control Level
PCM Pulse Code Modulation
PCN Personal Communications Network, also referred to as DCS 1800
PCS Personal Communication System, also referred to as GSM 1900
PDU Protocol Data Unit
PLL Phase Locked Loop
PPP Point-to-point protocol
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Abbreviation Description
PSK Phase Shift Keying
PSU Power Supply Unit
R&TTE Radio and Telecommunication Terminal Equipment
RAM Random Access Memory
RF Radio Frequency
RMS Root Mean Square (value)
ROM Read-only Memory
RTC Real Time Clock
RTS Request to Send
Rx Receive Direction
SAR Specific Absorption Rate
SD Secure Digital
SELV Safety Extra Low Voltage
SIM Subscriber Identification Module
SMS Short Message Service
SRAM Static Random Access Memory
TA Terminal adapter (e.g. GSM engine)
TDMA Time Division Multiple Access
TE Terminal Equipment, also referred to as DTE
Tx Transmit Direction
UART Universal asynchronous receiver-transmitter
URC Unsolicited Result Code
USB Universal Serial Bus
USSD Unstructured Supplementary Service Data
VSWR Voltage Standing Wave Ratio
Phonebook abbreviations
FD SIM fixdialing phonebook
LD SIM last dialing phonebook (list of numbers most recently dialed)
MC Mobile Equipment list of unanswered MT calls (missed calls)
ME Mobile Equipment phonebook
ON Own numbers (MSISDNs) stored on SIM or ME
RC Mobile Equipment list of received calls
SM SIM phonebook
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1.3 Type Approval
MC75 is designed to comply with the directives and standards listed below. Please note that
the product is still in a pre-release state and, therefore, type approval and testing procedures
have not yet been completed.
European directives
99/05/EC “Directive of the European Parliament and of the council of 9 March
1999 on radio equipment and telecommunications terminal
equipment and the mutual recognition of their conformity”, in short
referred to as R&TTE Directive 1999/5/EC
89/336/EC Directive on electromagnetic compatibility
73/23/EC Directive on electrical equipment designed for use within certain
voltage limits (Low Voltage Directive)
Standards of North American Type Approval
CFR Title 47 “Code of Federal Regulations, Part 22 and Part 24 (Telecommuni-
cations, PCS)”; US Equipment Authorization FCC
UL 60 950 “Product Safety Certification” (Safety requirements)
NAPRD.03 “Overview of PCS Type certification review board
Mobile Equipment Type Certification and IMEI control”
PCS Type Certification Review board (PTCRB), Version 3.1.0
RSS133 (Issue2) Canadian Standard
Standards of European Type Approval
3GPP TS 51.010-1 “Digital cellular telecommunications system (Phase 2); Mobile
Station (MS) conformance specification”
ETSI EN 301 511 “V7.0.1 (2000-12) Candidate Harmonized European Standard
(Telecommunications series) Global System for Mobile
communications (GSM); Harmonized standard for mobile stations in
the GSM 900 and DCS 1800 bands covering essential requirements
under article 3.2 of the R&TTE directive (1999/5/EC) (GSM 13.11
version 7.0.1 Release 1998)”
GCF-CC “Global Certification Forum - Certification Criteria” V3.16.0
ETSI EN 301 489-1 “V1.2.1 Candidate Harmonized European Standard
(Telecommunications series) Electro Magnetic Compatibility and
Radio spectrum Matters (ERM); Electro Magnetic Compatibility
(EMC) standard for radio equipment and services; Part 1: Common
Technical Requirements”
ETSI EN 301 489-7 “V1.1.1 Candidate Harmonized European Standard
(Telecommunications series) Electro Magnetic Compatibility and
Radio spectrum Matters (ERM); Electro Magnetic Compatibility
(EMC) standard for radio equipment and services; Part 7: Specific
conditions for mobile and portable radio and ancillary equipment of
digital cellular radio telecommunications systems (GSM and DCS)”
EN 60 950 Safety of information technology equipment (2000)
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Requirements of quality
IEC 60068 Environmental testing
DIN EN 60529 IP codes
Compliance with international rules and regulations
Manufacturers of mobile or fixed devices incorporating MC75 modules are advised to have
their completed product tested and approved for compliance with all applicable national and
international regulations. As a quad-band GSM/GPRS engine designed for use on any GSM
network in the world, MC75 is required to pass all approvals relevant to operation on the
European and North American markets. For the North American market this includes the
Rules and Regulations of the Federal Communications Commission (FCC) and PTCRB, for
the European market the R&TTE Directives and GCF Certification Criteria must be fully
satisfied.
The FCC Equipment Authorization granted to the MC75 Siemens reference application is
valid only for the equipment described in Section 8.1.
SAR requirements specific to portable mobiles
Mobile phones, PDAs or other portable transmitters and receivers incorporating a GSM
module must be in accordance with the guidelines for human exposure to radio frequency
energy. This requires the Specific Absorption Rate (SAR) of portable MC75 based
applications to be evaluated and approved for compliance with national and/or international
regulations.
Since the SAR value varies significantly with the individual product design manufacturers are
advised to submit their product for approval if designed for portable use. For European and
US markets the relevant directives are mentioned below. It is the responsibility of the
manufacturer of the final product to verify whether or not further standards, recommendations
or directives are in force outside these areas.
Products intended for sale on US markets
ES 59005/ANSI C95.1 Considerations for evaluation of human exposure to
Electromagnetic Fields (EMFs) from Mobile Telecommunication
Equipment (MTE) in the frequency range 30MHz - 6GHz
Products intended for sale on European markets
EN 50360 Product standard to demonstrate the compliance of mobile phones
with the basic restrictions related to human exposure to
electromagnetic fields (300 MHz - 3 GHz)
Note: Usage of MC75 in a fixed, mobile or portable application is not allowed without a
new FCC certification.
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1.4 Safety Precautions
The following safety precautions must be observed during all phases of the operation, usage,
service or repair of any cellular terminal or mobile incorporating MC75. Manufacturers of the
cellular terminal are advised to convey the following safety information to users and
operating personnel and to incorporate these guidelines into all manuals supplied with the
product. Failure to comply with these precautions violates safety standards of design,
manufacture and intended use of the product. Siemens AG assumes no liability for
customer’s failure to comply with these precautions.
When in a hospital or other health care facility, observe the restrictions on the
use of mobiles. Switch the cellular terminal or mobile off, if instructed to do so
by the guidelines posted in sensitive areas. Medical equipment may be
sensitive to RF energy.
The operation of cardiac pacemakers, other implanted medical equipment
and hearing aids can be affected by interference from cellular terminals or
mobiles placed close to the device. If in doubt about potential danger, contact
the physician or the manufacturer of the device to verify that the equipment is
properly shielded. Pacemaker patients are advised to keep their hand-held
mobile away from the pacemaker, while it is on.
Switch off the cellular terminal or mobile before boarding an aircraft. Make
sure it cannot be switched on inadvertently. The operation of wireless
appliances in an aircraft is forbidden to prevent interference with
communications systems. Failure to observe these instructions may lead to
the suspension or denial of cellular services to the offender, legal action, or
both.
Do not operate the cellular terminal or mobile in the presence of flammable
gases or fumes. Switch off the cellular terminal when you are near petrol
stations, fuel depots, chemical plants or where blasting operations are in
progress. Operation of any electrical equipment in potentially explosive
atmospheres can constitute a safety hazard.
Your cellular terminal or mobile receives and transmits radio frequency
energy while switched on. Remember that interference can occur if it is used
close to TV sets, radios, computers or inadequately shielded equipment.
Follow any special regulations and always switch off the cellular terminal or
mobile wherever forbidden, or when you suspect that it may cause
interference or danger.
Road safety comes first! Do not use a hand-held cellular terminal or mobile
when driving a vehicle, unless it is securely mounted in a holder for
speakerphone operation. Before making a call with a hand-held terminal or
mobile, park the vehicle.
Speakerphones must be installed by qualified personnel. Faulty installation or
operation can constitute a safety hazard.
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SOS
IMPORTANT!
Cellular terminals or mobiles operate using radio signals and cellular
networks. Because of this, connection cannot be guaranteed at all times
under all conditions. Therefore, you should never rely solely upon any
wireless device for essential communications, for example emergency calls.
Remember, in order to make or receive calls, the cellular terminal or mobile
must be switched on and in a service area with adequate cellular signal
strength.
Some networks do not allow for emergency calls if certain network services or
phone features are in use (e.g. lock functions, fixed dialing etc.). You may
need to deactivate those features before you can make an emergency call.
Some networks require that a valid SIM card be properly inserted in the
cellular terminal or mobile.
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2 Product Concept
2.1 Key Features at a Glance
Feature Implementation
General
Frequency bands Quad band: GSM 850/900/1800/1900 MHz
GSM class Small MS
Output power
(according to
Release 99, V5)
Class 4 (+33 dBm ±2 dB) for EGSM850
Class 4 (+33 dBm ±2 dB) for EGSM900
Class 1 (+30 dBm ±2 dB) for GSM1800
Class 1 (+30 dBm ±2 dB) for GSM1900
Class E2 (+27 dBm ± 3 dB) for GSM 850 8-PSK
Class E2 (+27 dBm ± 3 dB) for GSM 900 8-PSK
Class E2 (+26 dBm +3 /-4 dB) for GSM 1800 8-PSK
Class E2 (+26 dBm +3 /-4 dB) for GSM 1900 8-PSK
The values stated above are maximum limits. According to
Release 99, Version 5, the maximum output power in a multislot
configuration may be lower. The nominal reduction of maximum
output power varies with the number of uplink timeslots used and
amounts to 3.0 dB for 2 Tx, 4.8 dB for 3 Tx and 6.0 dB for 4 Tx.
Power supply 3.2V to 4.3V
Power consumption Sleep mode: max. TBD
Power down mode: typically 50µA
Operating temperature -30°C to +65°C ambient temperature
Auto switch-off at +90°C board temperature (preliminary)
Physical Dimensions: 33.9mm x 44.6mm x max. 3.5mm
Weight: approx. 10g
GSM / GPRS/ EGPRS features
Data transfer GPRS
• Multislot Class 12
• Full PBCCH support
• Mobile Station Class B
• Coding Scheme 1 – 4
EGPRS
• Multislot Class 10
• Mobile Station Class B
• Modulation and Coding Scheme MCS 1 – 9
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Feature Implementation
CSD
• V.110, RLP, non-transparent
• 2.4, 4.8, 9.6, 14.4 kbps
• USSD
PPP-stack for GPRS data transfer
SMS • Point-to-point MT and MO
• Cell broadcast
• Text and PDU mode
• Storage: SIM card plus 25 SMS locations in mobile equipment
• Transmission of SMS alternatively over CSD or GPRS.
Preferred mode can be user defined.
Fax Group 3; Class 1
Audio Speech codecs:
• Half rate HR (ETS 06.20)
• Full rate FR (ETS 06.10)
• Enhanced full rate EFR (ETS 06.50/06.60/06.80)
• Adaptive Multi Rate AMR
Speakerphone operation
Echo cancellation, noise suppression
DTMF
7 ringing tones
Software
AT commands AT-Hayes GSM 07.05 and 07.07, Siemens
AT commands for RIL compatibility (NDIS/RIL)
MicrosoftTM compatibility RIL / NDIS for Pocket PC and Smartphone
SIM Application Toolkit SAT Release 99
TCP/IP stack Access by AT commands
IP adresses IP version 6
Firmware update Download over serial interface ASC0
Download over SIM interface
Download over USB
Interfaces
2 serial interfaces
ASC0
• 8-wire modem interface with status and control lines,
unbalanced, asynchronous
• 1.2 kbps to 460 kbps
• Autobauding TBD
• Supports RTS0/CTS0 hardware handshake and software
XON/XOFF flow control.
• Multiplex ability according to GSM 07.10 Multiplexer Protocol.
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Feature Implementation
ASC1
• 4-wire, unbalanced asynchronous interface
• 1.2 kbps to 460 kbps
• Autobauding TBD
• Supports RTS1/CTS1 hardware handshake and software
XON/XOFF flow control
USB Supports a USB 2.0 Full Speed (12 Mbit/s) slave interface.
I2C I2C bus for transmission rates up to 400 kbps
SD card interface Interface for SD memory card or multimedia card
Audio • 2 analog interfaces
• 1 digital interface (PCM)
SIM interface Supported SIM cards: 3V, 1.8V
Antenna 50 Ohms. External antenna can be connected via antenna
connector or solderable pad.
Module interface 80-pin board-to-board connector
Power on/off, Reset
Power on/off • Switch-on by hardware pin IGT
• Switch-off by AT command (AT^SMSO)
• Automatic switch-off in case of critical temperature and
voltage conditions.
Reset • Orderly shutdown and reset by AT command
• Emergency reset by hardware pin EMERG_RST
Special features
Charging Supports management of rechargeable Lithium Ion and Lithium
Polymer batteries
Real time clock Timer functions via AT commands
Phonebook SIM and phone
Evaluation kit
DSB75 DSB75 Evaluation Board designed to test and type approve
Siemens cellular engines and provide a sample configuration for
application engineering.
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2.2 MC75 System Overview
User Application
MC75
Antenna
Interface
Application Interface
USB SIM Serial 1
(
Modem)
Analog
Audio
Digital
Audio Charge Power
Supply
SD
interface
USB
Host
I2C
Slave
SIM card
Headphones
or Headset
Audio
Codec
UART
SD
memory
card
Serial 2
Charger
Charging
circuit
I
2
C
Figure 1: MC75 system overview
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2.3 Circuit Concept
Figure 2 shows a block diagram of the MC75 module and illustrates the major functional
components:
Baseband Block:
• Digital baseband processor with DSP
• Analog processor with power supply unit (PSU)
• Flash / SRAM (stacked)
• Application interface (board-to-board connector)
RF section:
• RF transceiver
• RF power amplifier
• RF front end
• Antenna connector
Digital Baseband
Processor with DSP
Analog Contro ller
wit h PSU
BATT+
GND
IGT
EM ERG_RS T
ASC(0)
5
SIM Inte rfa ce
CCIN
CCRST
CCIO
CCCLK
CCVCC
D(0:15)
A(0:24)
RD; WR; CS; WAI T
RF Control Bus
Interface
RF - Baseband
NTC
BATT_TEMP
VDDL P
SYN C
RF Part
Trans ceiver
RF Power
Amplifier
SRAM
Flash
6
8
MC75
Application Interface (80 pins)
I / Q
4
Au di o a na log
10
SD Ca rd
USB
3
I2C
2
VEX T
ISENSE
VSE NSE
VC HA RG E
CHARGEGATE
3
RESET
Reset
BATTYPE
TE M P2
REFCHG
ASC(1)
4
26 MHz
Front End
DAI
7
8
PWR_IN D
Measuring
Network
32 .76 8kH z
26 MHz
RTC
Figure 2: MC75 block diagram
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3 Application Interface
MC75 is equipped with an 80-pin board-to-board connector that connects to the external
application. The host interface incorporates several sub-interfaces described in the following
chapters:
• Power supply - see Section 3.1
• Charger interface – Section 3.4
• SIM interface - see Section 3.6
• Serial interface ASC0 - see Section 3.7
• Serial interface ASC1 - see Section 3.8
• Serial interface USB - see Section 3.9.
• Serial interface I²C - see Section 3.10
• SD card interface - see Section 3.11
• Two analog audio interfaces - see Section 3.12
• Digital audio interface (DAI) - see Section 3.12 and 3.12.4
• Status and control lines: IGT, EMERG_RST, PWR_IND, SYNC - see Table 16
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3.1 Power Supply
MC75 needs to be connected to a power supply at the B2B connector (5 pins each BATT+
and GND).
The power supply of MC75 has to be a single voltage source at BATT+. It must be able to
provide the peak current during the uplink transmission.
All the key functions for supplying power to the device are handled by the power
management section of the analog controller. This IC provides the following features:
• Stabilizes the supply voltages for the GSM baseband using low drop linear voltage
regulators.
• Switches the module's power voltages for the power up and down procedures.
• Delivers, across the VEXT pin, a regulated voltage for an external application. This
voltage is not available in Power-down mode.
• SIM switch to provide SIM power supply.
3.1.1 Minimizing Power Losses
When designing the power supply for your application please pay specific attention to power
losses. Ensure that the input voltage VBATT+ never drops below 3.2 V on the MC75 board, not
even in a transmit burst where current consumption can rise to typical peaks of 2A. It should
be noted that MC75 switches off when exceeding these limits. Any voltage drops that may
occur in a transmit burst should not exceed 400mV.
The best approach to reducing voltage drops is to use a board-to-board connection as
recommended, and a low impedance power source. The resistance of the power supply lines
on the host board and of a battery pack should also be considered.
Note: If the application design requires an adapter cable between both board-to-board
connectors, use a flex cable as short as possible in order to minimize power
losses.
Example: If the length of the flex cable reaches the maximum length of 100mm, this
connection may cause, for example, a resistance of 30m in the BATT+ line and
30m in the GND line. As a result, a 2A transmit burst would add up to a total
voltage drop of 120mV. Plus, if a battery pack is involved, further losses may
occur due to the resistance across the battery lines and the internal resistance of
the battery including its protection circuit.
Figure 3: Power supply limits during transmit burst
Transmit
burst 2A
Transmit
burst 2A
Ripple
Drop
min. 3.2V
BATT+
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3.1.2 Measuring the Supply Voltage VBATT+
The reference points for measuring the supply voltage VBATT+ on the module are BATT+ and
GND, both accessible at a capacitor located close to the board-to-board connector of the
module.
Figure 4: Position of the reference points BATT+ and GND
3.1.3 Monitoring Power Supply by AT Command
To monitor the supply voltage you can also use the AT^SBV command which returns the
value related to the reference points BATT+ and GND.
The module continuously measures the voltage at intervals depending on the operating
mode of the RF interface. The duration of measuring ranges from 0.5s in TALK/DATA mode
to 50s when MC75 is in IDLE mode or Limited Service (deregistered). The displayed voltage
(in mV) is averaged over the last measuring period before the AT^SBV command was
executed.
Reference
point
BATT+
Reference
point GND
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3.2 Power Up / Power Down Scenarios
In general, be sure not to turn on MC75 while it is beyond the safety limits of voltage and
temperature stated in Chapter 5. MC75 would immediately switch off after having started and
detected these inappropriate conditions. In extreme cases this can cause permanent
damage to the module.
3.2.1 Turn on MC75
MC75 can be started in a variety of ways as described in the following sections:
• Hardware driven start-up by IGT line: starts normal operating state (see Section 3.2.1.1)
• Software controlled reset by AT+CFUN command: starts normal operating state (see
Section 3.2.1.3)
• Hardware driven start-up by VCHARGE line: starts charging algorithm and charge-only
mode (see Section 3.2.1.2)
• Wake-up from Power-down mode by using RTC interrupt: starts Alarm mode
3.2.1.1 Turn on MC75 Using Ignition Line IGT
When the MC75 module is in Power-down mode, it can be started to normal operation by
driving the IGT (ignition) line to ground. This must be accomplished with an open
drain/collector driver to avoid current flowing into this pin.
The module will start up when both of the following two conditions are met:
• The supply voltage applied at BATT+ must be in the operating range.
• The IGT line needs to be driven low for at least 300ms.
Considering different strategies of host application design the figures below show two
approaches to meet this requirement: The example in Figure 5 assumes that IGT is activated
after BATT+ has already been applied. The example in Figure 6 assumes that IGT is held
low before BATT+ is switched on. In either case, to power on the module, ensure that low
state of IGT takes at least 300ms from the moment the voltage at BATT+ is available.
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If configured to a fix baud rate (AT+IPR0), the module will send the URC “^SYSSTART” to
notify that it is ready to operate. If autobauding is enabled (AT+IPR=0) there will be no
notification.
EMERG_RST
VEXT
TXD0/TXD1/RTS0/RST1/DTR0 (driven by the application)
CTS0/CTS1/DSR0/DCD0
ca. 500 ms
Serial interfaces
ASC0 and ASC1
Undefined Active
PWR_IND
t = 300ms
min
120ms
BATT+
IGT
HiZ
Figure 5: Power-on with operating voltage at BATT+ applied before activating IGT
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EMERG_RST
PWR_IND
t = 300ms
min
120ms
BATT+
IGT
HiZ
VEXT
TXD0/TXD1/RTS0/RST1/DTR0 (driven by the application)
CTS0/CTS1/DSR0/DCD0
ca. 500 ms
Serial interfaces
ASC0 and ASC1
Undefined Active
Figure 6: Power-on with IGT held low before switching on operating voltage at BATT+
3.2.1.2 Turn on MC75 Using the VCHARGE Signal
As detailed in Section 3.4.5, the charging adapter can be connected regardless of the
module’s operating mode.
If the charger is connected to the charger input of the external charging circuit and the
module’s VCHARGE pin while MC75 is off, and the battery voltage is above the undervoltage
lockout threshold, processor controlled fast charging starts (see Section 3.4.4). MC75 enters
a restricted mode, referred to as Charge-only mode where only the charging algorithm will be
launched.
During the Charge-only mode MC75 is neither logged on to the GSM network nor are the
serial interfaces fully accessible. To switch to normal operation and log on to the GSM
network, the IGT line needs to be activated as described in Section 3.2.1.
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3.2.1.3 Reset MC75 via AT+CFUN Command
To reset and restart the MC75 module use the command AT+CFUN. You can enter
AT+CFUN=,1 or AT+CFUN=x,1, where x may be in the range from 0 to 9. See [1] for details.
If configured to a fix baud rate (AT+IPR0), the module will send the URC “^SYSSTART” to
notify that it is ready to operate. If autobauding is enabled (AT+IPR=0) there will be no
notification. To register to the network SIM PIN authentication is necessary after restart.
3.2.1.4 Reset MC75 in Case of Emergency via EMERG_RST
Caution: Use the EMERG_RST pin only when, due to serious problems, the software is not
responding for more than 5 seconds. Pulling the EMERG_RST pin causes the loss of all
information stored in the volatile memory since the processor restarts immediately.
Therefore, this procedure is intended only for use in case of emergency, e.g. if MC75 does
not respond, if reset or shutdown via AT command fails.
The EMERG_RST signal is available on the application interface. To control the
EMERG_RST line it is recommended to use an open drain / collector driver.
To actually reset the MC75 module, the EMERG_RST line must be pulled to ground for
≥10ms. After releasing the line MC75 will start again.
After hardware driven restart, notification via “^SYSSTART” URC is the same as in case of
restart by IGT or AT command. To register to the network SIM PIN authentication is
necessary after restart.
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3.2.2 Turn off MC75
MC75 can be turned off as follows:
• Normal shutdown: Software controlled by AT^SMSO command
• Automatic shutdown: Takes effect if board or battery temperature is out of range or if
undervoltage or overvoltage conditions occur.
3.2.2.1 Turn off MC75 Using AT Command
The best and safest approach to powering down MC75 is to issue the AT^SMSO command.
This procedure lets MC75 log off from the network and allows the software to enter into a
secure state and safe data before disconnecting the power supply. The mode is referred to
as Power-down mode. In this mode, only the RTC stays active.
Before switching off the device sends the following response:
^SMSO: MS OFF
OK
^SHUTDOWN
After sending AT^SMSO do not enter any other AT commands. There are two ways to verify
when the module turns off:
• Wait for the URC “^SHUTDOWN”. It indicates that data have been stored non-volatile
and the module turns off in less than 1 second.
• Also, you can monitor the PWR_IND pin. High state of PWR_IND definitely indicates that
the module is switched off.
Be sure not to disconnect the supply voltage VBATT+ before the URC “^SHUTDOWN” has
been issued and the PWR_IND signal has gone high. Otherwise you run the risk of losing
data. Signal states during turn-off are shown in Figure 7.
While MC75 is in Power-down mode the application interface is switched off and must not be
fed from any other source. Therefore, your application must be designed to avoid any current
flow into any digital pins of the application interface, especially of the serial interfaces. No
special care is required for the USB interface which is protected from reverse current.
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VEXT See note 1
TXD0/TXD1/RTS0/RTS1/DTR0 (driven by the application)
Serial interfaces
ASC0 and ASC1
Undefined
Active
PWR_IND
CTS0/CTS1/DSR0/DTR0
Figure 7: Signal states during turn-off procedure
Note 1: Depending on capacitance load from host application
3.2.2.2 Leakage Current in Power Down Mode
The leakage current in Power Down mode varies depending on the following conditions:
• If the supply voltage at BATT+ was disconnected and then applied again without starting
up the MC75 module, the leakage current ranges between 90µA and 100µA.
• If the MC75 module is started and afterwards powered down with AT^SMSO, then the
leakage current is only 50µA.
Therefore, in order to minimize the leakage current take care to start up the module at least
once before it is powered down.
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3.2.3 Automatic Shutdown
Automatic shutdown takes effect if
• the MC75 board is exceeding the critical limits of overtemperature or undertemperature
• the battery is exceeding the critical limits of overtemperature or undertemperature
• undervoltage or overvoltage is detected
The automatic shutdown procedure is equivalent to the Power-down initiated with the
AT^SMSO command, i.e. MC75 logs off from the network and the software enters a secure
state avoiding loss of data.
Alert messages transmitted before the device switches off are implemented as Unsolicited
Result Codes (URCs). The presentation of these URCs can be enabled or disabled with the
two AT commands AT^SBC and AT^SCTM. The URC presentation mode varies with the
condition, please see Chapters 3.2.3.1 to 3.2.3.4 for details. For further instructions on AT
commands refer to [1].
3.2.3.1 Temperature Dependent Shutdown
The board temperature is constantly monitored by an internal NTC resistor located on the
PCB. The NTC that detects the battery temperature must be part of the battery pack circuit
as described in 3.4.1 The values detected by either NTC resistor are measured directly on
the board or the battery and therefore, are not fully identical with the ambient temperature.
Each time the board or battery temperature goes out of range or back to normal, MC75
instantly displays an alert (if enabled).
• URCs indicating the level "1" or "-1" allow the user to take appropriate precautions, such
as protecting the module from exposure to extreme conditions. The presentation of the
URCs depends on the settings selected with the AT^SCTM write command:
AT^SCTM=1: Presentation of URCs is always enabled.
AT^SCTM=0 (default): Presentation of URCs is enabled for 15 seconds time after
start-up of MC75. After 15 seconds operation, the presentation will be disabled, i.e.
no alert messages can be generated.
• URCs indicating the level "2" or "-2" are instantly followed by an orderly shutdown. The
presentation of these URCs is always enabled, i.e. they will be output even though the
factory setting AT^SCTM=0 was never changed.
The maximum temperature ratings are stated in Table 15. Refer to Table 1 for the associated
URCs. All statements are based on test conditions according to IEC 60068-2-2 (still air).
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Table 1: Temperature dependent behavior
Sending temperature alert (15 s after MC75 start-up, otherwise only if URC presentation enabled)
^SCTM_A: 1 Caution: Tamb of battery close to overtemperature limit.
^SCTM_B: 1 Caution: Tamb of board close to overtemperature limit.
^SCTM_A: -1 Caution: Tamb of battery close to undertemperature limit.
^SCTM_B: -1 Caution: Tamb of board close to undertemperature limit.
^SCTM_A: 0 Battery back to uncritical temperature range.
^SCTM_B: 0 Board back to uncritical temperature range.
Automatic shutdown (URC appears no matter whether or not presentation was enabled)
^SCTM_A: 2 Alert: Tamb of battery equal or beyond overtemperature limit. MC75 switches
off.
^SCTM_B: 2 Alert: Tamb of board equal or beyond overtemperature limit. MC75 switches off.
^SCTM_A: -2 Alert: Tamb of battery equal or below undertemperature limit. MC75 switches off.
^SCTM_B: -2 Alert: Tamb of board equal or below undertemperature limit. MC75 switches off.
3.2.3.2 Temperature Control during Emergency call
If the temperature limit is exceeded while an emergency call is in progress the engine
continues to measure the temperature, but deactivates the shutdown functionality. If the
temperature is still out of range when the call ends, the module switches off immediately
(without another alert message).
3.2.3.3 Undervoltage Shutdown if Battery NTC is Present
In applications where the module’s charging technique is used and an NTC is connected to
the BATT_TEMP terminal, the software constantly monitors the applied voltage. If the
measured battery voltage is no more sufficient to set up a call the following URC will be
presented:
^SBC: Undervoltage.
The message will be reported, for example, when you attempt to make a call while the
voltage is close to the critical limit and further power loss is caused during the transmit burst.
To remind you that the battery needs to be charged soon, the URC appears several times
before the module switches off.
To enable or disable the URC use the AT^SBC command. The URC will be enabled when
you enter the write command and specify the current consumption of your host application.
Step by step instructions are provided in [1].
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3.2.3.4 Undervoltage Shutdown if no Battery NTC is Present
The undervoltage protection is also effective in applications, where no NTC connects to the
BATT_TEMP terminal. Thus, you can take advantage of this feature even though the
application handles the charging process or MC75 is fed by a fixed supply voltage. All you
need to do is executing the write command AT^SBC=<current> which automatically enables
the presentation of URCs. You do not need to specify <current>.
Whenever the supply voltage falls below the specified value (see table TBD.) the URC
^SBC: Undervoltage
appears several times before the module switches off.
3.2.3.5 Overvoltage Shutdown
In the event of the voltage rising above the maximum voltage (see Table TBD) the module
sends a URC and then performs an orderly shutdown. Further details: TBD
Keep in mind that several MC75 components are directly linked to BATT+ and, therefore, the
supply voltage remains applied at major parts of MC75, even if the module is switched off.
Especially the power amplifier is very sensitive to high voltage and might even be destroyed.
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3.3 Automatic EGPRS/GPRS Multislot Class Change
Temperature control is also effective for operation in EGPRS Multislot Class 10 and GPRS
Multislot Class 12. If the board temperature increases to the limit specified for restricted
operation1) while data are transmitted over EGPRS or GPRS, the module automatically
reverts
• from EGPRS Multislot Class 10 (2 Tx slots) to EGPRS Multislot Class 8 (1Tx),
• from GPRS Multislot Class 12 (4 Tx slots) to GPRS Multislot Class 8 (1Tx),
• from GPRS Multislot Class 10 (2 Tx slots) to GPRS Multislot Class 8 (1Tx)
This reduces the power consumption and, consequently, causes the board’s temperature to
decrease. Once the temperature drops to a value of 5 degrees below the limit of restricted
operation, MC75 returns to the higher Multislot Class. If the temperature stays at the critical
level or even continues to rise, MC75 will not switch back to the higher class.
After a transition from EGPRS Multislot Class 10 to EGPRS Multislot Class 8 a possible
switchback to EGPRS Multislot Class 10 is blocked for one minute. The same applies when
a transition occurs from GPRS Multislot Class 12 or 10 to GPRS Multislot Class 8.
Please note that there is not one single cause of switching over to a lower Multislot Class.
Rather it is the result of an interaction of several factors, such as the board temperature that
depends largely on the ambient temperature, the operating mode and the transmit power.
Furthermore, take into account that there is a delay until the network proceeds to a lower or,
accordingly, higher Multislot Class. The delay time is network dependent. In extreme cases,
if it takes too much time for the network and the temperature cannot drop due to this delay,
the module may even switch off as described in Section 3.2.3.1.
1) See Table 15 for temperature limits known as restricted operation.
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3.4 Charging Control
MC75 integrates a charging management for rechargeable Lithium Ion and Lithium Polymer
batteries. You can skip this chapter if charging is not your concern, or if you are not using the
implemented charging algorithm.
MC75 has no on-board charging circuit. To benefit from the implemented charging
management you are required to install a charging circuit within your application according to
the Figure 39.
The following sections contain an overview of charging and battery specifications. Please
refer to [4] for greater detail, especially regarding requirements for batteries and chargers,
appropriate charging circuits, recommended batteries and an analysis of operational issues
typical of battery powered GSM/GPRS applications.
3.4.1 Battery Pack Requirements
The charging algorithm has been optimized for rechargeable Lithium batteries that meet the
characteristics listed below and in Table 2. It is recommended that the battery pack you want
to integrate into your MC75 application is compliant with these specifications. This ensures
reliable operation, proper charging and, particularly, allows you to monitor the battery
capacity using the AT^SBC command (see [1] for details). Failure to comply with these
specifications might cause AT^SBC to deliver incorrect battery capacity values.
• Li-Ion or Lithium Polymer battery pack specified for a maximum charging voltage of 4.2 V
and a recommended capacity of 1000 to 1200 mAh.
• Since charging and discharging largely depend on the battery temperature, the battery
pack should include an NTC resistor. If the NTC is not inside the battery it must be in
thermal contact with the battery. The NTC resistor must be connected between
BATT_TEMP and GND.
The B value of the NTC should be in the range: 10 kΩ +5% @ 25°C, B25/85 = 3423K to B
=3435K ± 3% (alternatively acceptable: 10 kΩ +2% @ 25°C, B25/50 = 3370K +3%). Please
note that the NTC is indispensable for proper charging, i.e. the charging process will not
start if no NTC is present.
• Ensure that the pack incorporates a protection circuit capable of detecting overvoltage
(protection against overcharging), undervoltage (protection against deep discharging)
and overcurrent. Due to the discharge current profile typical of GSM applications, the
circuit must be insensitive to pulsed current.
• On the MC75 module, a built-in measuring circuit constantly monitors the supply voltage.
In the event of undervoltage, it causes MC75 to power down. Undervoltage thresholds
are specific to the battery pack and must be evaluated for the intended model. When you
evaluate undervoltage thresholds, consider both the current consumption of MC75 and of
the application circuit.
• The internal resistance of the battery and the protection should be as low as possible. It
is recommended not to exceed 150m, even in extreme conditions at low temperature.
The battery cell must be insensitive to rupture, fire and gassing under extreme conditions
of temperature and charging (voltage, current).
• The battery pack must be protected from reverse pole connection. For example, the
casing should be designed to prevent the user from mounting the battery in reverse
orientation.
• It is recommended that the battery pack be approved to satisfy the requirements of CE
conformity.
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Figure 8 shows the circuit diagram of a typical
battery pack design that includes the protection
elements described above.
Figure 8: Battery pack circuit diagram
Table 2: Specifications of battery packs suitable for use with MC75
Battery type Rechargeable Lithium Ion or Lithium Polymer battery
Nominal voltage 3.6V / 3.7V
Capacity Recommended: 1000mAh to 1200mAh
Minimum: 500mAh
NTC 10k ± 5% @ 25°C
B value range: B (25/85)=3423K to B =3435K ± 3%
Overcharge detection voltage 4.325 ± 0.025V
Overdischarge detection voltage 2.5 ± 0.05V
Overcurrent detection 3 ± 0.5A
Overcurrent detection delay time 4ms
Short detection delay time 50µs
Internal resistance <130m
Note: A maximum internal resistance of 150m should not
be exceeded even after 500 cycles and under extreme
conditions.
3.4.2 Batteries Recommended for Use with MC75
When you choose a battery for your MC75 application you can take advantage of one of the
following two batteries offered by VARTA Microbattery GmbH. Both batteries meet all
requirements listed above. They have been thoroughly tested by Siemens and proved to be
equally suited for MC75.
• LIP 633450A1B PCM.STB, type Lithium Ion
This battery is listed in the standard product range of VARTA. Incorporated in a shrink
sleeve, the battery is CE approved. Therefore it has been chosen for integration into the
reference setup submitted for Type Approval of Siemens GSM modules.
• LPP 503759CA PCM.NTC.LT50, type Lithium Polymer
This battery has been especially designed by VARTA for use with Siemens GSM
modules. It has the same properties as the above Li-Ion battery, except that it is type
Polymer, is smaller, comes without casing and is not CE approved.
Specifications, construction drawings and sales contacts for both VARTA batteries can be
found in Section 9.3.
to BATT_TEMP to GND
NTC
Polyfuse
ϑ
Protection Circuit
+-
Battery cell
to BATT+
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3.4.3 Charger Requirements
For using the implemented charging algorithm and the reference charging circuit
recommended in [4] and in Figure 39, the charger has to meet the following requirements:
Output voltage: 5.2Volts ±0.2V (stabilized voltage)
Output current: 500mA
Chargers with a higher output current are acceptable, but please
consider that only 500mA will be applied when a 0.3 Ohms shunt
resistor is connected between VSENSE and ISENSE. See [4] for
further details.
3.4.4 Implemented Charging Technique
If the external charging circuit of your application and the charger meet the requirements
listed above, charging is enabled in various stages depending on the battery condition:
Trickle charging:
• Trickle charge current flows over the VCHARGE line.
• Trickle charging is done when a charger is present (connected to VCHARGE) and the
battery is deeply discharged or has undervoltage. If deeply discharged (Deep Discharge
Lockout at VBATT+= 0…2.5V) the battery is charged with 5mA, in case of undervoltage
(Undervoltage Lockout at VBATT+= 2.5…3.2V) it is charged with 25mA
Software controlled charging:
• Controlled over the CHARGEGATE.
• Temperature conditions: 0°C to 45°C
• Software controlled charging is done when the charger is present (connected to
VCHARGE) and the battery voltage is at least above the undervoltage threshold.
Software controlled charging passes the following stages:
- Power ramp: Depending on the discharge level of the battery (i.e. the measured battery
voltage VBATT+) the software adjusts the maximum charge current for charging the
battery. The duration of power ramp charging is very short (less than 30 seconds).
- Fast charging: Battery is charged with constant current (approx. 500mA) until the
battery voltage reaches 4.2V (approx. 70% of the battery capacity).
- Top-up charging: The battery is charged with constant voltage of 4.2V at stepwise
reducing charge current until full battery capacity is reached.
• The duration of software controlled charging depends on the battery capacity and the
level of discharge.
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3.4.5 Operating Modes during Charging
Of course, the battery can be charged regardless of the engine's operating mode. When the
GSM module is in Normal mode (SLEEP, IDLE, TALK, GPRS IDLE or GPRS DATA mode), it
remains operational while charging is in progress (provided that sufficient voltage is applied).
The charging process during the Normal mode is referred to as Charge mode.
If the charger is connected to the charger input of the external charging circuit and the
module’s VCHARGE pin while MC75 is in Power-down mode, MC75 goes into Charge-only
mode.
Table 3: Comparison Charge-only and Charge mode
How to activate mode
Description of mode
Charge mode
Connect charger to charger input of host
application charging circuit and module’s
VCHARGE pin while MC75 is
• operating, e.g. in IDLE or TALK mode
• in SLEEP mode
• Battery can be charged while GSM module
remains operational and registered to the
GSM network.
• In IDLE and TALK mode, the serial interfaces
are accessible. All AT commands can be
used to full extent.
NOTE: If the module operates at maximum
power level (PCL5) and GPRS Class 12 at the
same time current consumption is higher than the
current supplied by the charger.
Charge-only mode
Connect charger to charger input of host
application charging circuit and module’s
VCHARGE pin while MC75 is
• in Power-down mode
• in Normal mode: Connect charger to
the VCHARGE pin, then enter
AT^SMSO.
NOTE: While trickle charging is in
progress, be sure that the host
application is switched off. If the
application is fed from the trickle charge
current the module might be prevented
from proceeding to software controlled
charging since the current would not be
sufficient.
• Battery can be charged while GSM engine is
deregistered from GSM network.
• Charging runs smoothly due to constant
current consumption.
• The AT interface is accessible and allows to
use the commands listed below.
Table 4: AT commands available in Charge-only mode
AT command Use
AT+CALA Set alarm time
AT+CCLK Set date and time of RTC
AT^SBC Query status of charger connection. Enable / disable “^SBC” URCs.
AT^SCTM Query temperature range, enable/disable URCs to report critical temperature
ranges
AT^SMSO AT^SMSO shuts down the module, but if the charger remains connected the
module will automatically restart into Charge-only mode.
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3.5 RTC Backup
The internal Real Time Clock of MC75 is supplied from a separate voltage regulator in the
analog controller which is also active when MC75 is in POWER DOWN status. An alarm
function is provided that allows to wake up MC75 without logging on to the GSM network.
In addition, you can use the VDDLP pin on the board-to-board connector to backup the RTC
from an external capacitor or a battery (rechargeable or non-chargeable). The capacitor is
charged by the BATT+ line of MC75. If the voltage supply at BATT+ is disconnected the RTC
can be powered by the capacitor. The size of the capacitor determines the duration of
buffering when no voltage is applied to MC75, i.e. the larger the capacitor the longer MC75
will save the date and time.
A serial 1k resistor placed on the board next to VDDLP limits the charge current of an
empty capacitor or battery.
The following figures show various sample configurations. Please refer to Table 16 for the
parameters required.
Baseband
processor
RTC
PSU
+
BATT+
1k
B2B
VDDLP
Figure 9: RTC supply from capacitor
RTC
+
BATT+
1k
B2B
VDDLP
Baseband
processor PSU
Figure 10: RTC supply from rechargeable battery
RTC
+
+
BATT+
1k
VDDLP
B2B
Baseband
processor PSU
Figure 11: RTC supply from non-chargeable battery
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3.6 SIM Interface
The baseband processor has an integrated SIM interface compatible with the ISO 7816 IC
Card standard. This is wired to the host interface (board-to-board connector) in order to be
connected to an external SIM card holder. Six pins on the board-to-board connector are
reserved for the SIM interface.
The SIM interface supports 3V and 1.8V SIM cards. Please refer to Table 16 for electrical
specifications of the SIM interface lines depending on whether a 3V or 1.8V SIM card is
used.
The CCIN pin serves to detect whether a tray (with SIM card) is present in the card holder.
Using the CCIN pin is mandatory for compliance with the GSM 11.11 recommendation if the
mechanical design of the host application allows the user to remove the SIM card during
operation. To take advantage of this feature, an appropriate SIM card detect switch is
required on the card holder. For example, this is true for the model supplied by Molex, which
has been tested to operate with MC75 and is part of the Siemens reference equipment
submitted for type approval. See Chapter 8 for Molex ordering numbers.
Table 5: Signals of the SIM interface (board-to-board connector)
Signal Description
CCGND Separate ground connection for SIM card to improve EMC.
Be sure to use this ground line for the SIM interface rather than any other ground pin or
plane on the module. A design example for grounding the SIM interface is shown in
Figure 39.
CCCLK Chipcard clock, various clock rates can be set in the baseband processor.
CCVCC SIM supply voltage.
CCIO Serial data line, input and output.
CCRST Chipcard reset, provided by baseband processor.
CCIN Input on the baseband processor for detecting a SIM card tray in the holder. If the SIM is
removed during operation the SIM interface is shut down immediately to prevent
destruction of the SIM.
The CCIN pin is mandatory for applications that allow the user to remove the SIM card
during operation.
The CCIN pin is solely intended for use with a SIM card. It must not be used for any other
purposes. Failure to comply with this requirement may invalidate the type approval of
MC75.
The total cable length between the board-to-board connector pins on MC75 and the pins of
the external SIM card holder must not exceed 100 mm in order to meet the specifications of
3GPP TS 51.010-1 and to satisfy the requirements of EMC compliance.
To avoid possible cross-talk from the CCCLK signal to the CCIO signal be careful that both
lines are not placed closely next to each other. A useful approach is using the CCGND line to
shield the CCIO line from the CCCLK line.
Note: No guarantee can be given, nor any liability accepted, if loss of data is encountered
after removing the SIM card during operation.
Also, no guarantee can be given for properly initializing any SIM card that the user
inserts after having removed a SIM card during operation. In this case, the application
must restart MC75.
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3.7 Serial Interface ASC0
MC75 offers an 8-wire unbalanced, asynchronous modem interface ASC0 conforming to
ITU-T V.24 protocol DCE signalling. The electrical characteristics do not comply with ITU-T
V.28. The significant levels are 0V (for low data bit or active state) and 2.9V (for high data bit
or inactive state). For electrical characteristics please refer to Table 16.
MC75 is designed for use as a DCE. Based on the conventions for DCE-DTE connections it
communicates with the customer application (DTE) using the following signals:
• Port TXD @ application sends data to the module’s TXD0 signal line
• Port RXD @ application receives data from the module’s RXD0 signal line
GSM module (DCE) Application (DTE)
TXD
RXD
RTS
CTS
RING
DCD
DSR
DTR
TXD0
RXD0
RTS0
CTS0
RING0
DCD0
DSR0
DTR0
Figure 12: Serial interface ASC0
Features
• Includes the data lines TXD0 and RXD0, the status lines RTS0 and CTS0 and, in
addition, the modem control lines DTR0, DSR0, DCD0 and RING0.
• ASC0 is primarily designed for controlling voice calls, transferring CSD, fax and GPRS
data and for controlling the GSM engine with AT commands.
• Full Multiplex capability allows the interface to be partitioned into three virtual channels,
yet with CSD and fax services only available on the first logical channel. Please note that
when the ASC0 interface runs in Multiplex mode, ASC1 cannot be used. For more details
on Multiplex mode see [5].
• The DTR0 signal will only be polled once per second from the internal firmware of MC75.
• The RING0 signal serves to indicate incoming calls and other types of URCs (Unsolicited
Result Code). It can also be used to send pulses to the host application, for example to
wake up the application from power saving state. See [1] for details on how to configure
the RING0 line by AT^SCFG.
• By default, configured for 8 data bits, no parity and 1 stop bit. The setting can be
changed using the AT command AT+ICF and, if required, AT^STPB. For details see [1].
• ASC0 can be operated at bit rates from 300bps to 460800 bps.
• Autobauding supports the following bit rates: TBD.
• Autobauding is not compatible with multiplex mode.
• Supports RTS0/CTS0 hardware flow control and XON/XOFF software flow control.
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Table 6: DCE-DTE wiring of ASC0
DCE DTE V.24
circuit Pin function Signal direction Pin function Signal direction
103 TXD0 Input TXD Output
104 RXD0 Output RXD Input
105 RTS0 Input RTS Output
106 CTS0 Output CTS Input
108/2 DTR0 Input DTR Output
107 DSR0 Output DSR Input
109 DCD0 Output DCD Input
125 RING0 Output /RING Input
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3.8 Serial Interface ASC1
MC75 offers a 4-wire unbalanced, asynchronous modem interface ASC1 conforming to ITU-
T V.24 protocol DCE signalling. The electrical characteristics do not comply with ITU-T V.28.
The significant levels are 0V (for low data bit or active state) and 2.9V (for high data bit or
inactive state). For electrical characteristics please refer to Table 16.
MC75 is designed for use as a DCE. Based on the conventions for DCE-DTE connections it
communicates with the customer application (DTE) using the following signals:
• Port TXD @ application sends data to module’s TXD1 signal line
• Port RXD @ application receives data from the module’s RXD1 signal line
GSM module (DCE) Application (DTE)
TXD
RXD
RTS
CTS
TXD1
RXD1
RTS1
CTS1
Figure 13: Serial interface ASC1
Features
• Includes only the data lines TXD1 and RXD1 plus RTS1 and CTS1 for hardware
handshake.
• On ASC1 no RING line is available. The indication of URCs on the second interface
depends on the settings made with the AT^SCFG command. For details refer to [1].
• Configured for 8 data bits, no parity and 1 or 2 stop bits.
• ASC1 can be operated at bit rates from 300bps to 460800 bps.
• Autobauding TBD.
• Supports RTS1/CTS1 hardware flow control and XON/XOFF software flow control.
Table 7: DCE-DTE wiring of ASC1
DCE DTE V.24
circuit Pin function Signal direction Pin function Signal direction
103 TXD1 Input TXD Output
104 RXD1 Output RXD Input
105 RTS1 Input RTS Output
106 CTS1 Output CTS Input
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3.9 USB Interface
MC75 supports a USB 2.0 Full Speed (12 Mbit/s) device interface. It is primarily intended for
use as command and data interface and for downloading firmware.
The USB I/O-pins are capable of driving the signal at min 3.0V. They are 5V I/O compliant.
To properly connect the module’s USB interface to the host a USB 2.0 compatible connector
is required. Furthermore, the USB modem driver delivered with MC75 must be installed as
described below.
The USB host is responsible for supplying, across the VUSB_IN line, power to the module’s
USB interface, but not to other MC75 interfaces. This is because MC75 is designed as a self-
powered device compliant with the “Universal Serial Bus Specification Revision 2.0”1.
MCU
USB
Transceiver
lin.
Regulator
PSU
Baseband controller
GSM module
Host
22Ohms
22Ohms
1.5kOhms
USB_DP
USB_DN
VUSB_IN
5V3V
D+
D-
VBUS
GND
80 pole board-to-board connector
Figure 14: USB circuit
1 The specification is ready for download on http://www.usb.org/developers/docs/
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3.9.1 Installing the USB Modem Driver
This section assumes you are familiar with installing and configuring a modem under
Windows 2000 and Windows XP. As both operating systems use multiple methods to access
modem settings this section provides only a brief summary of the most important steps.
Take care that the “usbmodem.inf” file delivered with MC75 is at hand. Connect the USB
cable to the MC75 host application (for example the evaluation board DSB75) and the PC.
Windows detects MC75 as a new USB modem, opens the Found New Hardware Wizard and
reports that it is searching for the “Siemens AG WM USB Modem” driver. Follow the
instructions on the screen and specify the path where the “usbmodem.inf” file is located.
Windows will copy the required software to your computer and configure the modem by
assigning a free COM port. If you are already using more than one COM port then the next
free one will be allocated. Click Finish to complete the installation.
Notes for Windows 2000 only:
• During the installation procedure you will be prompted for the “usbser.sys” driver. Make
sure the file is present before you start installing the above inf file.
The “usbser.sys” file is not delivered as a single file, but must be extracted from a
Windows 2000 cabinet file. This is either the file “driver.cab” located in the “I386” folder of
the original Windows 2000 CD or a later cabinet file inside the Service Pack. SP4 for
example includes the “sp4.cab” file which can be found in its “I386” folder. The
“usbser.sys” driver from the Service Pack has priority over one provided with the
standard Windows 2000 install CD.
• It is necessary to restart Windows 2000 to make the changes take effect.
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You can find the “Siemens AG WM
USB Modem” listed under Control
Panel | Phone and Modem Options |
Modems.
Troubleshooting for installation problems
If Windows fails to
assign the next free
COM port to MC75 and,
for example, allocates a
COM port already used
by another modem you
can manually select a
free port as follows:
Open the Windows
Device Manager, select
the installed “Siemens
AG WM USB Modem”,
click Properties, select
the Advanced tab and
click Advanced Port
settings. From the
listbox COM Port
Number choose a free
port. To make the
changes take effect
disconnect and re-
connect the USB cable.
If not yet successful,
also restart Windows.
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3.10 I2C Interface
I2C is a serial, 8-bit oriented data transfer bus for bit rates up to 400 kbps in Fast mode. It
consists of two lines, the serial data line I2CDAT and the serial clock line I2CCLK.
The MC75 module acts as a single master device, e.g. the clock I2CCLK is driven by
module. I2CDAT is a bi-directional line.
Each device connected to the bus is software addressable by a unique address, and simple
master/slave relationships exist at all times. The module operates as master-transmitter or as
master-receiver. The customer application transmits or receives data only on request of the
module. To configure and activate the I2C interface use the AT^SSPI command described in
[1].
The I2C interface can be powered from an external supply or via the VEXT line of MC75. If
connected to the VEXT line the I2C interface will be properly shut down when the module
enters the Power-down mode. If you prefer to connect the I2C interface to an external power
supply, take care that VCC of the application is in the range of VVEXT and that the interface is
shut down when the PWR_IND signal goes high. See figures below as well as Section 7 and
Figure 39.
In the application I2CDAT and I2CCLK lines need to be connected to a positive supply
voltage via a pull-up resistor.
For electrical characteristics please refer to Table 16.
GSM module
I2DAT
I2CCLK
GND
I2DAT
I2CCLK
GND
Application
VCC
R
p
R
p
wVEXT
Figure 15: I2C interface connected to VCC of application
GSM module
I2DAT
I2CCLK
GND
I2DAT
I2CCLK
GND
Application
VEXT
R
p
R
p
Figure 16: I2C interface connected to VEXT line of MC75
Note: Good care should be taken when creating the PCB layout of the host application: The
traces of I2CCLK and I2CDAT should be equal in length and as short as possible.
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3.11 SD Memory Card Interface
The SD card interface is compliant with the “SD Memory Card Specifications / Part 1
Physical Layer Specification, Version 1.01”.
The interface supports the following features:
• Data rates up to 3250 kByte/s.
• The read/write data rate depends on the clock rate.
• SD card insertion detection (at SD_D3-line) or via SD_DET line as option (CD switch in
SD card holder required)
• Write protect detection via SD_WP line is optional (WP switch in SD card holder required)
• Maximum capacity of SD cards compliant with the above SD Memory Card Specification
is 4 GByte.
The SD memory card interface can be powered from an external supply or via the VEXT line
of MC75. If connected to the VEXT line the SD memory card interface will be properly shut
down when the module enters the Power-down mode. If you prefer to connect the SD card
interface to an external power supply, take care that the interface is shut down when the
PWR_IND signal goes high. See also Section 7 and Figure 39.
Note: No guarantee can be given, nor any liability accepted, if loss of data is encountered
after removing the SD memory card during operation.
Table 8: SD card interface
Signal I/O Description Remark
SD_D0 I/O ---
SD_D1 I/O ---
SD_D2 I/O ---
SD_D3 I/O
4 bit data bus
Card detect at power on:
0 or open = Card removed
1 or 50k pullup = Card inserted
Note: This is no removal detection during card
operation!
SD_CMD O Command / Response
SD_CLK O Clock 25.4kHz …13MHz
Clock rise and fall time: max. 10ns
SD_WP I Write protect detection 0= unlocked
1= locked
(External pull-up resistor required)
SD_DET I Card detection
(optional)
0= card inserted
1= card removed
Power supply from external source or from
VEXT line
Required power supply: min. 2.7V, max. 3.6V.
Note: Good care should be taken when creating the PCB layout of the host application: The
traces of SD_CLK, SD_CMD, and SD_D(0..3) should be equal in length and as short
as possible.
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SD_CLK
SD_CMD
SD_WP
SD_D0
SD_D1
SD_D2
SD_D3
VEXT
8
7
6
5
4
3
2
1
9
DAT1
DAT0
GND
CLK
VDD
GND
CMD
CD/DAT3
DAT2
lock
unlock
Write
protect
slide
Card
detect
SD card holder
SD card
50k
1)
1) Internal switch is closed after power-up and
open during regular data transfer. Used for
card detection.
SD_DET
47k
GSM module
80 pole board-to-board connector
Baseband
controller
Analog
controller
Figure 17: SD card interface (example with power supply from module’s VEXT line)
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3.12 Audio Interfaces
MC75 comprises three audio interfaces available on the board-to-board connector:
• Two analog audio interfaces, both with balanced or single-ended inputs/outputs.
• Serial digital audio interface (DAI) designed for PCM (Pulse Code Modulation).
This means you can connect up to three different audio devices, although only one interface
can be operated at a time. Using the AT^SAIC command you can easily switch back and
forth.
Analog switch
Digital
Audio
Interface
Ai
r
Interface
DSP
MUX
X
D
A
MICN2
MICP2
MICN1
MICP1
USC6
USC5
USC4
USC3
USC2
AGND
USC0
USC1
D
A
EPP2
EPN2
EPP1
EPN1
VMIC
MUX
Figure 18: Audio block diagram
To suit different types of accessories the audio interfaces can be configured for different
audio modes via the AT^SNFS command. The electrical characteristics of the voiceband part
vary with the audio mode. For example, sending and receiving amplification, sidetone paths,
noise suppression etc. depend on the selected mode and can be altered with AT commands
(except for mode 1).
Both analog audio interfaces can be used to connect headsets with microphones or
speakerphones. Headsets can be operated in audio mode 3, speakerphones in audio
mode 2. Audio mode 5 can be used for a speech coder without signal pre or post processing.
When shipped from factory, all audio parameters of MC75 are set to interface 1 and audio
mode 1. This is the default configuration optimized for the Votronic HH-SI-30.3/V1.1/0
handset and used for type approving the Siemens reference configuration. Audio mode 1 has
fix parameters which cannot be modified. To adjust the settings of the Votronic handset
simply change to another audio mode.
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3.12.1 Speech Processing
The speech samples from the ADC or DAI are handled by the DSP of the baseband
controller to calculate e.g. amplifications, sidetone, echo cancellation or noise suppression
depending on the configuration of the active audio mode. These processed samples are
passed to the speech encoder. Received samples from the speech decoder are passed to
the DAC or DAI after post processing (frequency response correction, adding sidetone etc.).
Full rate, half rate, enhanced full rate, adaptive multi rate (AMR), speech and channel
encoding including voice activity detection (VAD) and discontinuous transmission (DTX) and
digital GMSK modulation are also performed on the GSM baseband processor.
3.12.2 Microphone Circuit
MC75 has two identical analog microphone inputs. There is no on-board microphone supply
circuit, except for the internal voltage supply VMIC and the dedicated audio ground line
AGND. Both lines are well suited to feed a balanced audio application or a single-ended
audio application.
The AGND line on the MC75 board is especially provided to achieve best grounding
conditions for your audio application. As there is less current flowing than through other GND
lines of the module or the application, this solution will avoid hum and buzz problems.
3.12.2.1 Single-ended Microphone Input
Figure 19 as well as Figure 39 show an example of how to integrate a single-ended
microphone input.
GSM module
R
B
V
Bias
C
K
AGND
MICNx
MICPx
VMIC
R
A
R
A
C
F
R
VMIC
RA = typ. 2k
RB = typ. 5k
RVMIC = typ. 470Ohm
Ck = typ. 100nF
CF = typ. 22µF
VMIC = typ. 2.5V
Vbias = 1.0V … 1.6V, typ. 1.5V
Figure 19: Single ended microphone input
RA has to be chosen so that the DC voltage across the microphone falls into the bias voltage
range of 1.0V to 1.6V and the microphone feeding current meets its specification.
The MICNx input is automatically self biased to the MICPx DC level. It is AC coupled via CK
to a resistive divider which is used to optimize supply noise cancellation by the differential
microphone amplifier in the module.
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The VMIC voltage should be filtered if gains larger than 20dB are used. The filter can be
attached as a simple first order RC-network (RVMIC and CF).
This circuit is well suited if the distance between microphone and module is kept short. Due
to good grounding the microphone can be easily ESD protected as its housing usually
connects to the negative terminal.
3.12.2.2 Differential Microphone Input
Figure 20 shows a differential solution for connecting an electret microphone.
GSM module
R
A
R
A
V
Bias
C
K
AGND
MICNx
MICPx
VMIC
C
F
R
VMIC
RA = typ. 1k
RVMIC = 470Ohm
CK = typ. 100nF
CF = typ. 22µF
VMIC = typ. 2.5V
Vbias = 1.0V … 1.6V, typ. 1.5V
Figure 20: Differential microphone input
The resulting DC voltage between MICPx and AGND should be in the range of 1.0V to 1.6V
to bias the input amplifier. MICNx is automatically self biased to the MICPx DC level. The
resulting AC differential voltage is then amplified in the GSM module.
The VMIC voltage should be filtered if gains larger than 20dB are used. The filter can be
attached as a simple first order RC-network (RVMIC and CF).
The advantage of this circuit is that it can be used if the application involves longer lines
between microphone and module.
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3.12.2.3 Line Input Configuration with OpAmp
Figure 21 shows an example of how to connect an opamp into the microphone circuit.
GSM module
R
V
Bias
C
K
AGND
MICNx
MICPx
VMIC
R
C
K
~
R
VMIC
C
F
RA = typ. 47k
RVMIC = 470Ohm
Ck = typ. 100nF
CF = typ. 22µF
VMIC = typ. 2.5V
Vbias = typ. ½ VMIC = 1.25V
Figure 21: Line input configuration with OpAmp
The AC source (e.g. an opamp) and its reference potential have to be AC coupled to the
MICPx resp. MICNx input terminals. The voltage divider between VMIC and AGND is
necessary to bias the input amplifier. MICNx is automatically self biased to the MICPx DC
level.
The VMIC voltage should be filtered if gains larger than 20dB are used. The filter can be
attached as a simple first order RC-network (RVMIC and CF). If a high input level and a lower
gain are applied the filter is not necessary.
If desired, MICNx via CK can also be connected to the inverse output of the AC source
instead of connecting it to the reference potential for differential line input.
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3.12.3 Loudspeaker Circuit
The GSM module comprises two analog speaker outputs: EP1 and EP2. Output EP1 is able
to drive a load of 8Ohms while the output EP2 can drive a load of 32Ohms. Each interface
can be connected in differential and in single ended configuration. See examples in Figure
22 and Figure 23.
GSM module
AGND
EPNx
EPPx
Figure 22: Differential loudspeaker configuration
Loudspeaker impedance
EPP1/EPN1
ZL = typ. 8Ohm
EPP2/EPN2
ZL = typ. 32Ohm
GSM module
AGND
EPNx
EPPx
+
C
k
Figure 23: Single ended loudspeaker configuration
Loudspeaker impedance
EPP1/EPN1
ZL = typ. 8Ohm
Ck = 220µF
EPP2/EPN2
ZL = typ. 32Ohm
Ck = 47µF
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3.12.4 Digital Audio Interface DAI
The DAI can be used to connect audio devices capable of PCM (Pulse Code Modulation), for
example a codec.
Table 9: Overview of USC pin functions
Signal name on
B2B connector
Function for PCM Interface Input/Output
USC0 (DAI0) REF_CLK_13M O
USC1 (DAI1) Reserved for future use I
USC2 (DAI2) REF_CLK_8K (Bit clock slave) O
USC3 (DAI3) BITCLK I
USC4 (DAI4) FS_IN (Frame sync slave) I
USC5 (DAI5) RXDAI I
USC6 (DAI6) TXDAI O
To clock input and output PCM samples the PCM interface requires a clock (BITCLK) which
is synchronous to the 26 MHz system clock. The customer application must be designed to
generate this bit clock by a PLL circuit or a divider controlled by one of the two following
reference clock signals:
• REF_CLK_13M that is equal to the system clock of 13 MHz.
• REF_CLK_8K that is an 8 kHz signal divided from the system clock.
The frequency of the bit clock can vary from 256 kHz to 2048 kHz. The PCM interface is
slave for the bit clock and the frame sync signals generated by the external codec.
PCM interface
of the GSM
module
BITCLK
FS_IN
REF_CLK8
TXDAI
bitclk
RXDAI
REF_CLK13
PLL or divider
+
frame sync logic
Codec
frame sync
RX_data
TX_data
e.g. 256kHz
Figure 24: PCM interface application
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The timing of a PCM short frame is shown in Figure 25. In PCM mode, 16-bit data are
transferred in both directions at the same time. The duration of a frame sync pulse is one
BITCLK period, starting at the rising edge of BITCLK. TXDAI data is shifted out at the next
rising edge of BITCLK. The most significant bit is transferred first. Data transmitted from
RXDAI of the internal application is sampled at the falling edge of BITCLK.
BITCLK
TXDAI
RXDAI
FS_IN
MSB LSB
116
125µs
Figure 25: PCM timing
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3.13 Control Signals
3.13.1 Synchronization Signal
The synchronization signal serves to indicate growing power consumption during the transmit
burst. The signal is generated by the SYNC pin (pin number 32). Please note that this pin
can adopt three different operating modes which you can select by using the AT^SSYNC
command: the mode AT^SSYNC=0 described below, and the two LED modes AT^SSYNC=1
or AT^SSYNC=2 described in [1] and Section 3.13.2.
The first function (factory default AT^SSYNC=0) is recommended if you want your
application to use the synchronization signal for better power supply control. Your platform
design must be such that the incoming signal accommodates sufficient power supply to the
MC75 module if required. This can be achieved by lowering the current drawn from other
components installed in your application.
The timing of the synchronization signal is shown below. High level of the SYNC pin
indicates increased power consumption during transmission.
Figure 26: SYNC signal during transmit burst
*) The duration of the SYNC signal is always equal, no matter whether the traffic or the
access burst are active.
Transmit burst
1 Tx 577 µs every 4.616 ms
2 Tx 1154 µs every 4.616 ms
300 µs
SYNC signal
*)
Transmit burst
1 Tx 577 µs every 4.616 ms
2 Tx 1154 µs every 4.616 ms
SYNC signal
*)
t = TBD
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3.13.2 Using the SYNC Pin to Control a Status LED
As an alternative to generating the synchronization signal, the SYNC pin can be configured
to drive a status LED that indicates different operating modes of the MC75 module. To take
advantage of this function the LED mode must be activated with the AT^SSYNC command
and the LED must be connected to the host application. The connected LED can be operated
in two different display modes (AT^SSYNC=1 or AT^SSYNC=2). For details please refer to
[1].
Especially in the development and test phase of an application, system integrators are
advised to use the LED mode of the SYNC pin in order to evaluate their product design and
identify the source of errors.
To operate the LED a buffer, e.g. a transistor or gate,
must be included in your application. A sample cicuit
is shown in Figure 27. Power consumption in the LED
mode is the same as for the synchronization signal
mode. For details see Table 16, SYNC pin.
Figure 27: LED Circuit (Example)
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4 Antenna Interface
The RF interface has an impedance of 50. MC75 is capable of sustaining a total mismatch
at the antenna connector or pad without any damage, even when transmitting at maximum
RF power.
The external antenna must be matched properly to achieve best performance regarding
radiated power, DC-power consumption, modulation accuracy and harmonic suppression.
Matching networks are not included on the MC75 PCB and should be placed in the host
application.
Regarding the return loss MC75 provides the following values in the active band:
Table 10: Return loss in the active band
State of module Return loss of module Recommended return loss of application
Receive > 8dB > 12dB
Transmit not applicable > 12dB
Idle < 5dB not applicable
The connection of the antenna or other equipment must be decoupled from DC voltage. This
is necessary because the antenna connector is DC coupled to ground via an inductor for
ESD protection.
4.1 Antenna Installation
To suit the physical design of individual applications MC75 offers two alternative approaches
to connecting the antenna:
• Recommended approach: U.FL-R-SMT antenna connector from Hirose assembled on
the component side of the PCB (top view on MC75). See Section 4.3 for details.
• Antenna pad and grounding plane placed on the bottom side. See Section 4.2.
The U.FL-R-SMT connector has been chosen as antenna reference point (ARP) for the
Siemens reference equipment submitted to type approve MC75. All RF data specified
throughout this manual are related to the ARP. For compliance with the test results of the
Siemens type approval you are advised to give priority to the connector, rather than using the
antenna pad.
IMPORTANT: Both solutions can only be applied alternatively. This means, whenever an
antenna is plugged to the Hirose connector, the pad must not be used. Vice versa, if the
antenna is connected to the pad, then the Hirose connector must be left empty.
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Module
A
ntenna o
r
measuremen
t
equipmen
t
50Ohm
50Ohm
U.FL
PAD
Z
Module Antenna or
measurement
equipment
50Ohm 50Ohm
U.FL
Z
PAD
Antenna connected to Hirose connector:
Antenna connected to pad:
Figure 28: Never use antenna connector and antenna pad at the same time
No matter which option you choose, ensure that the antenna pad does not come into contact
with the holding device or any other components of the host application. It needs to be
surrounded by a restricted area filled with air, which must also be reserved 0.8 mm in height.
PCB
U.FL antenna connector
RF section
A
ntenna pad Restricted area
Figure 29: Restricted area around antenna pad
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4.2 Antenna Pad
The antenna can be soldered to the pad, or attached via contact springs. For proper
grounding connect the antenna to the ground plane on the bottom of MC75 which must be
connected to the ground plane of the application.
When you decide to use the antenna pad take into account that the pad has not been
intended as antenna reference point (ARP) for the Siemens MC75 type approval. The
antenna pad is provided only as an alternative option which can be used, for example, if the
recommended Hirose connection does not fit into your antenna design.
Also, consider that according to the GSM recommendations TS 45.005 and TS 51.010-01 a
50 connector is mandatory for type approval measurements. This requires GSM devices
with an integral antenna to be temporarily equipped with a suitable connector or a low loss
RF cable with adapter.
To prevent damage to the module and to obtain long-term solder joint properties you are
advised to maintain the standards of good engineering practice for soldering.
MC75 material properties:
MC75 PCB: FR4
Antenna pad: Gold plated pad
4.2.1 Suitable Cable Types
For direct solder attachment, we suggest to use the following cable types:
• RG316/U 50 Ohm coaxial cable
• 1671A 50 Ohm coaxial cable
Suitable cables are offered, for example, by IMS Connector Systems. For further details and
other cable types please contact http://www.imscs.com.
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4.3 Antenna Connector
MC75 uses an ultra-miniature SMT antenna connector supplied
from Hirose Ltd. The product name is:
U.FL-R-SMT
The position of the antenna connector on the MC75 board can be
seen in Figure 30.
Figure 30: Mechanical dimensions of U.FL-R-SMT connector
Table 11: Product specifications of U.FL-R-SMT connector
Item Specification Conditions
Ratings
Nominal impedance 50 Ω
Rated frequency DC to 3 GHz
Operating temp:-40°c to + 90°C
Operating humidity: max. 90%
Mechanical characteristics
Female contact holding
force
0.15 N min Measured with a ∅ 0.475 pin
gauge
Repetitive operation Contact resistance:
Center 25 mΩ
Outside 15mΩ
30 cycles of insertion and
disengagement
Vibration No momentary disconnections of
1 µs;
No damage, cracks and looseness
of parts
Frequency of 10 to 100 Hz,
single amplitude of 1.5 mm,
acceleration of 59 m/s2, for 5
cycles in the direction of each of
the 3 axes
Shock No momentary disconnections of
1 µs.
No damage, cracks and looseness
of parts.
Acceleration of 735 m/s2, 11 ms
duration for 6 cycles in the
direction of each of the 3 axes
Environmental characteristics
Humidity resistance No damage, cracks and looseness
of parts.
Insulation resistance:
100 MΩ min. at high humidity
500 MΩ min when dry
Exposure to 40°C, humidity of
95% for a total of 96 hours
Temperature cycle No damage, cracks and looseness
of parts.
Contact resistance:
Center 25 mΩ
Outside 15mΩ
Temperature: +40°C → 5 to 35°C
→ +90°C → 5 to 35°C
Time: 30 min. → within 5 min. →
30 min. within 5 min
Salt spray test No excessive corrosion 48 hours continuous exposure to
5% salt water
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Table 12: Material and finish of U.FL-R-SMT connector and recommended plugs
Part Material Finish
Shell Phosphor bronze Silver plating
Male center contact Brass Gold plating
Female center contact Phosphor bronze Gold plating
Insulator Plug: PBT
Receptacle: LCP
Black
Beige
Mating plugs and cables can be chosen from the Hirose U.FL Series. Examples are shown
below and listed in Table 13. For latest product information please contact your Hirose dealer
or visit the Hirose home page, for example http://www.hirose.com.
Figure 31: U.FL-R-SMT connector with U.FL-LP-040 plug
Figure 32: U.FL-R-SMT connector with U.FL-LP-066 plug
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In addition to the connectors illustrated above, the U.FL-LP-(V)-040(01) version is offered as
an extremely space saving solution. This plug is intended for use with extra fine cable (up to
∅ 0.81 mm) and minimizes the mating height to 2 mm. See Figure 33 which shows the
Hirose datasheet.
Figure 33: Specifications of U.FL-LP-(V)-040(01) plug
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Table 13: Ordering information for Hirose U.FL Series
Item Part number HRS number
Connector on MC75 U.FL-R-SMT CL331-0471-0-10
Right-angle plug shell for
∅ 0.81 mm cable
U.FL-LP-040 CL331-0451-2
Right-angle plug for
∅ 0.81 mm cable
U.FL-LP(V)-040 (01) CL331-053-8-01
Right-angle plug for
∅ 1.13 mm cable
U.FL-LP-068 CL331-0452-5
Right-angle plug for
∅ 1.32 mm cable
U.FL-LP-066 CL331-0452-5
Extraction jig E.FL-LP-N CL331-04441-9
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5 Electrical, Reliability and Radio Characteristics
5.1 Absolute Maximum Ratings
The absolute maximum ratings stated in Table 14 are stress ratings. Stresses beyond any of
these limits will cause permanent damage to MC75.
Table 14: Absolute maximum ratings
Parameter Min Max Unit
Supply voltage BATT+ -0.3 5.5 V
Voltage at digital pins -0.3 3.05 V
Voltage at analog pins -0.3 3.0 V
Voltage at digital / analog pins in Power-down mode TBD TBD V
Voltage at VCHARGE pin -0.3 5.5 V
Voltage at CHARGEGATE pin -0.3 5.5 V
VUSB_IN -0.3 5.5
V
VSENSE 5.5
V
ISENSE 5.5
V
5.2 Operating Temperatures
Test conditions were specified in accordance with IEC 60068-2 (still air). The values stated
below are in compliance with GSM recommendation TS 51.010-01.
Table 15: Operating temperatures
Parameter Min Typ Max Unit
Ambient temperature (according to GSM 11.10) -30 +25 +65 °C
Automatic shutdown
MC75 board temperature
Battery temperature
-30
-20
---
---
+90
+60
°C
Ambient temperature for charging (software controlled fast
charging)
0 --- +45 °C
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5.3 Pin Assignment and Signal Description
The Molex board-to-board connector on MC75 is an 80-pin double-row receptacle. The
names and the positions of the pins can be seen from Figure 1 which shows the top view of
MC75.
1 GND GND 80
2 nc Do not use 79
3 nc PWR_IND 78
4 GND Do not use 77
5 Do not use Do not use 76
6 SD_WP Do not use 75
7 Do not use SD_D3 74
8 SD_DETECT SD_D2 73
9 SD_CMD SD_D1 72
10 SD_CLK SD_D0 71
11 I2CCLK I2CDAT 70
12 VUSB_IN USB_DP 69
13 USC5 USB_DN 68
14 ISENSE VSENSE 67
15 USC6 VMIC 66
16 CCCLK EPN2 65
17 CCVCC EPP2 64
18 CCIO EPP1 63
19 CCRST EPN1 62
20 CCIN MICN2 61
21 CCGND MICP2 60
22 USC4 MICP1 59
23 USC3 MICN1 58
24 USC2 AGND 57
25 USC1 IGT 56
26 USC0 EMERG_RST 55
27 BATT_TEMP DCD0 54
28 SYNC CTS1 53
29 RXD1 CTS0 52
30 RXD0 RTS1 51
31 TXD1 DTR0 50
32 TXD0 RTS0 49
33 VDDLP DSR0 48
34 VCHARGE RING0 47
35 CHARGEGATE VEXT 46
36 GND BATT+ 45
37 GND BATT+ 44
38 GND BATT+ 43
39 GND BATT+ 42
40 GND BATT+ 41
Figure 34: Pin assignment (component side of MC75)
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Please note that the reference voltages listed in Table 16 are the values measured directly
on the MC75 module. They do not apply to the accessories connected.
Table 16: Signal description
Function Signal name IO Signal form and level Comment
VImax = 4.3V
VItyp = 3.8V
VImin = 3.2V during Tx burst on board
I 2A, during Tx burst
Power
supply
BATT+ I
n Tx = n x 577µs peak current every
4.616ms
Five pins of BATT+ and GND
must be connected in parallel
for supply purposes because
higher peak currents may
occur.
Minimum voltage must not fall
below 3.2V including drop,
ripple, spikes.
Power
supply
GND Ground Application Ground
VCHARGE I
VImin = 1.015 * VBATT+
VImax = 5.45V
This line signalizes to the
processor that the charger is
connected.
If unused keep pin open.
BATT_TEMP I
Connect NTC with RNTC 10kΩ @ 25°C to
ground. See Section 3.4.1 for B value of
NTC.
Battery temperature
measurement via NTC
resistance.
NTC should be installed
inside or near battery pack to
enable proper charging and
deliver temperature values.
If unused keep pin open.
ISENSE I
VImax = 4.65V
∆VImax to VBATT+ = +0.3V at normal
condition
ISENSE is required for
measuring the charge current.
For this purpose, a shunt
resistor for current
measurement needs to be
connected between ISENSE
and VSENSE.
If unused connect pin to
VSENSE.
VSENSE I
VImax = 4.5V VSENSE must be directly
connected to BATT+ at
battery connector or external
power supply.
Charge
Interface
CHARGEGATE O VOmax = 5.5V
IOmax = 1mA
Control line to the gate of
charge FET
If unused keep pin open.
External
supply
voltage
VEXT O
Normal mode:
VOmin = 2.75V
VOtyp = 2.93V
VOmax = 3.05V
IOmax = -50mA
VEXT may be used for
application circuits, for
example to supply power for
an SD Card.
If unused keep pin open.
Not available in Power-down
mode. The external digital
logic must not cause any
spikes or glitches on voltage
VEXT.
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Function Signal name IO Signal form and level Comment
Power
indicator
PWR_IND
[SE10]
O VIHmax = 10V
VOLmax = 0.4V at Imax = 2mA
PWR_IND (Power Indicator)
notifies the module’s on/off
state.
PWR_IND is an open
collector that needs to be
connected to an external pull-
up resistor. Low state of the
open collector indicates that
the module is on. Vice versa,
high level notifies the Power-
down mode.
Therefore, the pin may be
used to enable external
voltage regulators which
supply an external logic for
communication with the
module, e.g. level converters.
Ignition IGT I
RI 30kΩ, CI 10nF
VILmax = 0.8V at Imax = -150µA
VOHmax = 4.5V (VBATT+)
ON ~~~|____|~~~ Active Low ≥ 300ms
This signal switches the
mobile on.
This line must be driven low
by an open drain or open
collector driver.
Emergency
reset
EMERG_RST I
RI 5kΩ
VILmax = 0.2V at Imax = -0.5mA
VOHmin = 1.75V
VOHmax = 3.05V
Signal ~~~|______|~~~ Pull down ≥ 10ms
Falling edge resets module.
Reset function in case of
emergency: Pull down and
release EMERG_RST. Falling
edge will reset the module.
Data stored in the volatile
memory will be lost. For
orderly software controlled
reset rather use the
AT+CFUN command (e.g.
AT+CFUN=,1).
This line must be driven by
open drain or open collector.
If unused keep pin open.
VOLmax = 0.3V at I = 0.1mA
VOHmin = 2.3V at I = -0.1mA
VOHmax = 0.05V
Synchroni-
zation
SYNC O
n Tx = n x 577µs impulse each 4.616ms,
with ___µs forward time.
There are two alternative
options for using the SYNC
pin:
a) Indicating increased
current consumption during
uplink transmission burst.
Note that the timing of the
signal is different during
handover.
b) Driving a status LED to
indicate different operating
modes of MC75. The LED
must be installed in the host
application.
If unused keep pin open.
RTC backup VDDLP I/O RI 1k
VOmax = 4.5V
VBATT+ = 4.3V:
VO = 3.2V at IO = -500µA
VBATT+ = 0V:
VI = 2.7V…4.5V at Imax= 15µA
If unused keep pin open.
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Function Signal name IO Signal form and level Comment
CCIN I
RI 100kΩ
VILmax = 0.6V at I = -25µA
VIHmin = 2.1V at I = -10µA,
VOmax= 3.05V
CCRST O
RO 47Ω
VOLmax = 0.25V at I = +1mA
VOHmin = 2.5V at I = -0.5mA
VOHmax = 2.95V
CCIO I/O
RI 4.7kΩ
VILmax = 0.75V
VILmin = -0.3V
VIHmin = 2.1V
VIHmax = CCVCCmin + 0.3V = 3.05V
RO 100Ω
VOLmax = 0.3V at I = +1mA
VOHmin = 2.5V at I = -0.5mA
VOHmax = 2.95V
CCCLK O
RO 100Ω
VOLmax = 0.3V at I = +1mA
VOHmin = 2.5V at I = -0.5mA
VOHmax = 2.95V
CCVCC O VOmin = 2.75V,
VOtyp = 2.85V
VOmax = 2.95V
IOmax = -20mA
SIM interface
specified for
use with 3V
SIM card
CCGND Ground
CCIN = Low, SIM card holder
closed
Maximum cable length or
copper track 100mm to SIM
card holder.
All signals of SIM interface
are protected against ESD
with a special diode array.
Usage of CCGND is
mandatory.
CCIN I
RI 100kΩ
VILmax = 0.6V at I = -25µA
VIHmin = 2.1V at I = -10µA,
VOmax= 3.05V
CCRST O
RO 47Ω
VOLmax = 0.25V at I = +1mA
VOHmin = 1.45V at I = -0.5mA
VOHmax = 1.90V
CCIO I/O
RI 4.7kΩ
VILmax = 0.45V
VIHmin = 1.35V
VIHmax = CCVCCmin + 0.3V = 2.00V
RO 100Ω
VOLmax = 0.3V at I = +1mA
VOHmin = 1.45V at I = -0.5mA
VOHmax = 1.90V
CCCLK O
RO 100Ω
VOLmax = 0.3V at I = +1mA
VOHmin = 1.45V at I = -0.5mA
VOHmax = 1.90V
CCVCC O VOmin = 1.70V,
VOtyp = 1.80V
VOmax = 1.90V
IOmax = -20mA
SIM interface
specified for
use with
1.8V SIM
card
CCGND Ground
CCIN = Low, SIM card holder
closed
Maximum cable length or
copper track 100mm to SIM
card holder.
All signals of SIM interface
are protected against ESD
with a special diode array.
Usage of CCGND is
mandatory.
ASC0
Serial
interface
RXD0
TXD0
CTS0
RTS0
DTR0
DCD0
DSR0
RING0
O
I
O
I
I
O
O
O
VOLmax = 0.2V at I = 2mA
VOHmin = 2.55V at I = -0.5mA
VOHmax = 3.05V
VILmax = 0.8V
VIHmin = 2.0V,
VIHmax = VEXTmin + 0.3V = 3.05V
Serial interface for AT
commands or data stream.
If lines are unused keep pins
open.
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Function Signal name IO Signal form and level Comment
ASC1
Serial
interface
RXD1
TXD1
CTS1
RTS1
O
I
O
I
VOLmax = 0.2V at I = 2mA
VOHmin = 2.55V at I = -0.5mA
VOHmax = 3.05V
VILmax = 0.8V
VIHmin = 2.0V
VIHmax = VEXTmin + 0.3V = 3.05V
Serial interface for AT
commands or data stream.
If lines are unused keep pins
open.
I2CCLK O VOLmax = 0.2V at I = 2mA
VOHmin = 2.55V at I = -0.5mA
VOHmax = 3.05V
I2C interface
I2CDAT I/O VOLmax = 0.2V at I = 2mA
VILmax = 0.8V
VIHmin = 2.0V
VIHmax = VEXTmin + 0.3V = 3.05V
I2CDAT is configured as
Open Drain and needs a pull-
up resistor in the host
application.
According to the I2C Bus
Specification Version 2.1
for the fast mode a rise
time of max. 300ns is
permitted. There is also a
maximum VOL=0.4V at
3mA specified.
The value of the pull-up
depends on the capacitive
load of the whole system
(I2C Slave + lines). The
maximum sink current of
I2CDAT and I2CCLK is
4mA.
If lines are unused keep pins
open.
VUSB_IN I VINmin = 4.0V
VINmax = 5.25V
USB_DN I/O
USB
USB_DP I/O
Differential Output Crossover voltage
Range
VCRSmin = 1.5V, VCRSmax = 2.0V
Driver Output Resistance
ZDRVtyp = 32 Ohm
If lines are unused keep pins
open.
SD_D0
SD_D1
SD_D2
SD_D3
I/O
SD_CLK O
SD_WP I
SD_CMD O
SD card
interface
SD_DETECT I
VOLmax = 0.2V at I = 2mA
VOHmin = 2.55V at I = -0.5mA
VOHmax = 3.05V
VILmax = 0.8V
VIHmin = 2.0V
VIHmax = VEXTmin + 0.3V = 3.05V
SD card interface can be
connected to VEXT of MC75
or to external power supply.
Rise and fall time of SD_CLK
signal: max. 10ns.
If lines are unused keep pins
open.
USC0 (DAI0) O
USC1 (DAI1) I
USC2 (DAI2) O
USC3 (DAI3) I
USC4 (DAI4) I
USC5 (DAI5) I
Digital Audio
interface
USC6 (DAI6) O
VOLmax = 0.2V at I = 2mA
VOHmin = 2.55V at I = -0.5mA
VOHmax = 3.05V
VILmax = 0.8V
VIHmin = 2.0V
VIHmax = VEXTmin + 0.3V = 3.05V
See Table 9 for details.
If unused keep pins open.

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