Telit Wireless Solutions GL865 QUAD, GL865 DUAL Hardware User's Manual

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GL865 Hardware User Guide

1vv0300910 Rev.3 – 2011-10-03

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GL865 Hardware User Guide

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APPLICABILITY TABLE

PRODUCT

GL865 QUAD

GL865 DUAL

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SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE

Notice

While reasonable efforts have been made to assure the accuracy of this document, Telit assumes no liability resulting from any inaccuracies or omissions in this document, or from use of the information obtained herein. The information in this document has been carefully checked and is believed to be entirely reliable. However, no responsibility is assumed for inaccuracies or omissions. Telit reserves the right to make changes to any products described herein and reserves the right to revise this document and to make changes from time to time in content hereof with no obligation to notify any person of revisions or changes. Telit does not assume any liability arising out of the application or use of any product, software, or circuit described herein; neither does it convey license under its patent rights or the rights of others.

It is possible that this publication may contain references to, or information about Telit products (machines and programs), programming, or services that are not announced in your country. Such references or information must not be construed to mean that Telit intends to announce such Telit products, programming, or services in your country.

Copyrights

This instruction manual and the Telit products described in this instruction manual may be, include or describe copyrighted Telit material, such as computer programs stored in semiconductor memories or other media. Laws in the Italy and other countries preserve for Telit and its licensors certain exclusive rights for copyrighted material, including the exclusive right to copy, reproduce in any form, distribute and make derivative works of the copyrighted material. Accordingly, any copyrighted material of Telit and its licensors contained herein or in the Telit products described in this instruction manual may not be copied, reproduced, distributed, merged or modified in any manner without the express written permission of Telit. Furthermore, the purchase of Telit products shall not be deemed to grant either directly or by implication, estoppel, or otherwise, any license under the copyrights, patents or patent applications of Telit, as arises by operation of law in the sale of a product.

Computer Software Copyrights

The Telit and 3rd Party supplied Software (SW) products described in this instruction manual may include copyrighted Telit and other 3rd Party supplied computer programs stored in semiconductor memories or other media. Laws in the Italy and other countries preserve for Telit and other 3rd Party supplied SW certain exclusive rights for copyrighted computer programs, including the exclusive right to copy or reproduce in any form the copyrighted computer program. Accordingly, any copyrighted Telit or other 3rd Party supplied SW computer programs contained in the Telit products described in this instruction manual may not be copied (reverse engineered) or reproduced in any manner without the express written permission of Telit or the 3rd Party SW supplier. Furthermore, the purchase of Telit products shall not be deemed to grant either directly or by implication, estoppel, or otherwise, any license under the copyrights, patents or patent applications of Telit or other 3rd Party supplied SW, except for the normal non-exclusive, royalty free license to use that arises by operation of law in the sale of a product.

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Usage and Disclosure Restrictions License Agreements

The software described in this document is the property of Telit and its licensors. It is furnished by express license agreement only and may be used only in accordance with the terms of such an agreement.

Copyrighted Materials

Software and documentation are copyrighted materials. Making unauthorized copies is prohibited by law. No part of the software or documentation may be reproduced, transmitted, transcribed, stored in a retrieval system, or translated into any language or computer language, in any form or by any means, without prior written permission of Telit

High Risk Materials

Components, units, or third-party products used in the product described herein are NOT faulttolerant and are NOT designed, manufactured, or intended for use as on-line control equipment in the following hazardous environments requiring fail-safe controls: the operation of Nuclear Facilities, Aircraft Navigation or Aircraft Communication Systems, Air Traffic Control, Life Support, or Weapons Systems (High Risk Activities"). Telit and its supplier(s) specifically disclaim any expressed or implied warranty of fitness for such High Risk Activities.

Trademarks

TELIT and the Stylized T Logo are registered in Trademark Office. All other product or service names are the property of their respective owners.

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Contents

1. INTRODUCTION ........................................................................................................................................................... 7

1.1. SCOPE ....................................................................................................................................................................... 7

1.2. AUDIENCE ................................................................................................................................................................. 7

1.3. CONTACT INFORMATION, SUPPORT ........................................................................................................................... 7

1.4. DOCUMENT ORGANIZATION ..................................................................................................................................... 8

1.5. TEXT CONVENTIONS ................................................................................................................................................. 9

1.6. RELATED DOCUMENTS ............................................................................................................................................. 9

2. OVERVIEW .................................................................................................................................................................. 10

3. GL865 MECHANICAL DIMENSIONS ..................................................................................................................... 11

4. GL865 MODULE CONNECTIONS ........................................................................................................................... 12

4.1. PIN-OUT ................................................................................................................................................................ 12

4.2. PIN LAYOUT ............................................................................................................................................................ 15

5. HARDWARE COMMANDS ....................................................................................................................................... 16

5.1. AUTO-TURNING ON THE GL865 ............................................................................................................................. 16

5.2. TURNING OFF THE GL865 ...................................................................................................................................... 18

5.3. RESETTING THE GL865 ........................................................................................................................................... 20

5.3.1. Hardware Unconditional restart ................................................................................................................... 20

6. POWER SUPPLY ......................................................................................................................................................... 22

6.1. POWER SUPPLY REQUIREMENTS ............................................................................................................................. 22

6.2. POWER CONSUMPTION ............................................................................................................................................ 22

6.3. GENERAL DESIGN RULES ........................................................................................................................................ 23

6.3.1. Electrical Design Guidelines ......................................................................................................................... 24

6.3.2. Thermal Design Guidelines ........................................................................................................................... 28

6.3.3. Power Supply PCB layout Guidelines ........................................................................................................... 29

7. ANTENNA ..................................................................................................................................................................... 30

7.1. GSM ANTENNA REQUIREMENTS ............................................................................................................................ 30

7.1.1. GL865 Antenna – PCB line Guidelines ......................................................................................................... 30

7.2. PCB GUIDELINES IN CASE OF FCC CERTIFICATION ................................................................................................. 31

7.2.1. Transmission line design ............................................................................................................................... 31

7.2.2. Transmission line measurements ................................................................................................................... 32

7.3. GSM ANTENNA - INSTALLATION GUIDELINES ........................................................................................................ 35

8. LOGIC LEVEL SP ECIFICATIONS .......................................................................................................................... 36

8.1. RESET SIGNAL ......................................................................................................................................................... 37

9. SERIAL PORTS ........................................................................................................................................................... 38

9.1. MODEM SERIAL PORT ....................................................................................................................................... 38

9.2. RS232 LEVEL TRANSLATION ................................................................................................................................... 40

9.3. ....................................................................................................................................................................................... 42

9.4. 5V UART LEVEL TRANSLATION ............................................................................................................................. 43

10. AUDIO SECTION OVERVIEW ............................................................................................................................ 45

10.1. ELECTRICAL CHARACTERISTICS ............................................................................................................................. 48

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10.1.1. Input Lines ..................................................................................................................................................... 48

10.1.2. Output Lines .................................................................................................................................................. 49

11. GENERAL PURPOSE I/O ...................................................................................................................................... 50

11.1. GPIO LOGIC LEVELS ............................................................................................................................................... 51

11.2. USING A GPIO PAD AS INPUT ............................................................................................................................... 51

11.3. USING A GPIO PAD AS OUTPUT ........................................................................................................................... 52

11.4. USING THE RF TRANSMISSION CONTROL GPIO4 .................................................................................................... 52

11.5. USING THE RFTXMON OUTPUT GPIO5 ................................................................................................................ 52

11.6. USING THE ALARM OUTPUT GPIO6 ........................................................................................................................ 53

11.7. USING THE BUZZER OUTPUT GPIO7 ....................................................................................................................... 53

11.8. MAGNETIC BUZZER CONCEPTS ............................................................................................................................... 53

1.1.1 Short Description ................................................................................................................................................... 53

11.8.1. Frequency Behaviour .................................................................................................................................... 54

11.8.2. Power Supply Influence ................................................................................................................................. 54

11.8.3. Working Current Influence ............................................................................................................................ 55

11.9. STAT LED INDICATION OF NETWORK SERVICE AVAILABILITY............................................................................... 55

11.10. SIMIN DETECT FUNCTION .................................................................................................................................. 57

11.11. RTC BYPASS OUT ............................................................................................................................................... 58

11.12. SIM HOLDER IMPLEMENTATION ........................................................................................................................ 58

12. DAC AND ADC SECTION ..................................................................................................................................... 59

12.1. DAC CONVERTER ................................................................................................................................................... 59

12.1.1. Description .................................................................................................................................................... 59

12.1.2. Enabling DAC ............................................................................................................................................... 60

12.1.3. Low Pass Filter Example ............................................................................................................................... 60

12.2. ADC CONVERTER ................................................................................................................................................... 61

12.2.1. Description .................................................................................................................................................... 61

12.2.2. Using ADC Converte r ................................................................................................................................... 61

12.3. DEBUG OF THE GL865 IN PRODUCTION ................................................................................................................... 62

13. MOUNTING THE GL865 ON YOUR BOARD .................................................................................................... 63

13.1. GENERAL ................................................................................................................................................................ 63

13.2. MODULE FINISHING & DIMENSIONS ........................................................................................................................ 63

13.3. RECOMMENDED FOOT PRINT FOR THE APPLICATION ................................................................................................ 64

13.4. SOLDER PASTE ........................................................................................................................................................ 65

13.4.1. GL865 Solder reflow ..................................................................................................................................... 65

14. PACKING SYSTEM ................................................................................................................................................ 67

14.1. MOISTURE SENSIBILITY ........................................................................................................................................... 68

15. CONFORMITY ASSESSMENT ISSUES .............................................................................................................. 69

16. SAFETY RECOMMANDATIONS ......................................................................................................................... 70

17. DOCUMENT HISTO RY ......................................................................................................................................... 71

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1. Introduction

1.1. Scope

The aim of this document is the description of some hardware solutions useful for developing a product with the Telit GL865 module.

1.2. Audience

This document is intended for Telit customers, who are integrators, about to implement their applications using our GL865 modules.

1.3. Contact Information, Support

For general contact, technical support, to report documentation errors and to order manuals, contact Telit’s Technical Suppor t Center ( TTSC) at :

TS-EMEA@telit.com TS-NORTHAMERICA@telit.com TS-LATINAMERICA@telit.com TS-APAC@telit.com

Alternatively, use:

http://www.telit.com/en/products/technical-support-center/contact.php

For detailed information about where you can buy the Telit modules or for recommendations on accessories and components visit:

http://www.telit.com

To register for product news and announcements or for product questions contact Telit’s Technical Support Center (TTSC). Our aim is to make this guide as helpful as possible. Keep us informed of your comments and suggestions for improvements. Telit appreciates feedback from the users of our information.

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1.4. Document Organization

This document contains the following chapters:

Chapter 1: “Introduction”

provides a scope for this document, target audience, contact and

support information, and text conventions.

Chapter 2: “Overview”

provides an overview of the document.

Chapter 3: “GL865 Mechanical Dimensions”

Chapter 4: “GL865 Module Connections

” deals with the pin out configuration and layout.

Chapter 5: “Hardware Commands”

How to operate on the module via hardware.

Chapter 6: “Power supply”

Power supply requirements and general design rules.

Chapter 7: “Antenna”

The antenna connection and board layout design are the most important

parts in the full product design.

Chapter 8: “Logic Level specifications”

Specific values adopted in the implementation of logic

levels for this module.

Chapter 9: “Serial ports”

The serial port on the Telit GL865 is the core of the interface between

the module and OEM hardware

Chapter 10: “Audio Section overview”

Refers to the audio blocks of the Base Band Chip of the

GL865 Telit Modules.

Chapter 11: “General Purpose I/O”

How the general purpose I/O pads can be configured.

Chapter 12 “DAC and ADC Section”

Deals with these two kind of converters.

Chapter 13: “Mounting the GL865 on the application board”

Recommendations and specifics on

how to mount the module on the user’s board.

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1.5. Text Conventions

Danger – This information MUST be followed or catastrophic equipment failure or bodily injury may occur.

Caution or Warning – Alerts the user to important points about integrating the module, if these points are not followed, the module and end user equipment may fail or malfunction.

Tip or Information – Provides advice and suggestions that may be useful when integrating the module.

All dates are in ISO 8601 format, i.e. YYYY-MM-DD.

1.6. Related Documents

• Telit's GSM/GPRS Family Software User Guide, 1vv0300784

• Audio settings application note , 80000NT10007a

• Digital Voice Interface Application Note, 80000NT10004a

• GL865 Product description, 80370ST10080a

• SIM Holder Design Guides, 80000NT10001a

• AT Commands Reference Guide, 80000ST10025a

• Telit EVK2 User Guide, 1vv0300704

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2. Overview

The aim of this document is the description of some hardware solutions useful for developing a product with the Telit GL865 module. In this document all the basic functions of a mobile phone will be taken into account; for each one of them a proper hardware solution will be suggested and eventually the wrong solutions and common errors to be avoided will be evidenced. Obviously this document cannot embrace the whole hardware solutions and products that may be designed. The wrong solutions to be avoided shall be considered as mandatory, while the suggested hardware configurations shall not be considered mandatory, instead the information given shall be used as a guide and a starting point for properly developing your product with the Telit GL865 module. For further hardware details that may not be explained in this document refer to the Telit GL865 Product De scri pti on document where all the hardware information is reported.

NOTICE:

The integration of the GSM/GPRS GL865 cellular module within user application shall be done according to the design rules described in this manual.

The information presented in this document is believed to be accurate and reliable. However, no responsibility is assumed by Telit Communications S.p.A. for its use, nor any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent rights of Telit Communications S.p.A. other than for circuitry embodied in Telit products. This document is subject to change without notice.

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3. GL865 Mechanical Dim ensions

The GL865 overall dimensions are:

• Length: 24.4 mm

• Width: 24.4 mm

• Thickness: 2.7 mm

• Weight 2.48 g

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4. GL865 module connections

4.1. PIN-OUT

Pad Signal I/O Function Note Type

Audio

EAR- AO Earphone signal output, phase - Audio

EAR+ AO Earphone signal output , phase + Audio

MIC- AI Mic.signal input; phase- Audio

MIC+ AI Mic.signal input; phase+ Audio

AGND - Analog Ground -

SIM card interface

SIMVCC - External SIM signal – Power supply for the SIM 1,8 / 3V

SIMRST O External SIM signal – Reset 1,8 / 3V

SIMCLK O External SIM signal – Clock 1,8 / 3V

SIMIO I/O External SIM signal – Data I/O

4.7K Pull up

1,8 / 3V

All GPI0

can be

program

med

SIMIN I

Presence SIM input

(See para 11.9)

CMOS 2.8V

Trace

RX_AUX I Auxiliary UART (RX Data) CMOS 2.8V

TX_AUX O Auxiliary UART (TX Data) CMOS 2.8V

Prog. / Data + HW Flow Control

C109/DCD/GPO O

Output for Data carrier detect signal (DCD) to DTE

/ GP output

CMOS 2.8V

C125/RING/GPO O

Output for Ring indicator signal (RI) to DTE

/ GP output

CMOS 2.8V

C107/DSR/GPO O

Output for Data set ready signal (DSR) to DTE

/ GP output

CMOS 2.8V

C108/DTR/GPI I

Input for Data terminal ready signal (DTR) from DTE

/ GP input

CMOS 2.8V

C105/RTS/GPI I

Input for Request to send signal (RTS) from DTE

/ GP input

CMOS 2.8V

C106/CTS/GPO O

Output for Clear to send si gnal (CTS) to DTE

/ GP output

CMOS 2.8V

C103/TXD I Serial data input (TXD) from DTE CMOS 2.8V

C104/RXD O Serial data output to DTE CMOS 2.8V

DAC and ADC

ADC_IN1 AI Analog/Digit al converter input A/D

ADC_IN2 AI Analog/Digit al converter input A/D

DAC_OUT AO Digital/Analog converter output D/A

Miscellaneous Functions

VRTC AO VRTC Backup Power

RESET* I Reset input CMOS 1.8V

V_AUX / PWRMON O

2.8V stabilized output Imax=100mA

/ Power ON monitor

Power Out 2.8V

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Pad Signal I/O Function Note Type

Antenna O Antenna output – 50 Ω RF

GPIO

GPIO_01 / DVI_WA0 I/O

GPIO01 Configurable GPIO / Digital Audio Interface (WA0)

CMOS 2.8V

GPIO_02 / JDR /

DVI_RX

I/O

GPIO02 Configurable GPIO / Jammer Det ect Report

/ Digital Audio Interface (RX)

CMOS 2.8V

GPIO_03 / DVI_TX I/O

GPIO03 Configurable GPIO

/ Digital Audio Interface (TX)

CMOS 2.8V

GPIO_04 / TX Disable

/ DVI_CLK

I/O

GPIO04 Configurable GPIO / TX Disable input / Digital Audio Interface (CLK)

CMOS 2.8V

GPIO_05 / RFTXMON I/O

GPIO05 Configurable GPIO

/ Transmitter ON monitor

CMOS 2.8V

GPIO_06 / ALARM I/O

GPIO06 Configurable GPIO

/ ALARM

CMOS 2.8V

GPIO_07 / BUZZER I/O

GPIO07 Configurable GPIO / Buzzer

CMOS 2.8V

GPIO_08 / STAT_LED I/O

GPIO08 Configurable GPIO / STAT LED

CMOS 2.8V

Power Supply

VBATT - Main power supply (Baseband) Power

VBATT_PA - Main power supply (Radio PA) Power

AGND - AF Signal Ground (see audio section) AF Signal

GND - Ground Power

RESERVED

WARNING:

Reserved pins must not be connected.

NOTE:

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If not used, almost all pins should be left disconnected. The only exceptions are the following pins:

signal

38, 37

VBATT & VB ATT_PA

32, 33, 35, 36, 46

GND

AGND

TXD

8 RXD

RTS

V_AUX / PWRMON

RESET*

TX_AUX

RX_AUX

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4.2. Pin Layout

TOP VIEW

NOTE:

The pin defined as NC/RFU has to be considered RESERVED and don’t connect on any pin in the application.

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5. Hardware Commands

5.1. Auto-Turning ON the GL865

To Auto-turn on the GL865, the power supply must be applied on the power pins VBATT and VBATT_PA, after 1000 m-seconds, the

V_AUX / PWRMON pin will be at the high logic level

and the module can be consider fully operating.

When the power supply voltage is lower than 3.4V, after 5000 m-seconds, the

V_AUX /

PWRMON

pin will be at the high logic level and the module can be consider fully operating.

The following flow chart shows the proper turn on procedure:

Modem ON Proc

PWR supply = ON?

Delay 1s - 5s for Low

Voltage Operating

Modem Reset Proc.

AT init sequence

Start AT CMD

PWMON = ON?

Delay 300mS

Enter AT<CR>

AT answer in

1second ?

Delay 1s

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NOTE:

The power supply on the pins VBATT and VBATT_PA must be applied at the same time or for the special application in the first apply the VBATT_PA and in second time apply VBATT, never vice versa in this case can be damage the unit.

NOTE:

In order to avoid a back powering effect it is recommended to avoid having any HIGH logic level signal applied to the digital pins of the GL865 when the module is powered OFF or during an ON/OFF transition.

A flow chart showing the AT command managing procedure is displayed b elow:

Modem ON Proc.

Disconnect PWR

supply

AT init

sequence.

Delay 300mS

Enter AT<CR>

AT answer in

1second ?

Start AT CMD

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5.2. Turning OFF the GL865

Turning off of the device can be done in two ways:

• General turn OFF

• Processor turn OFF

General turn OFF – disconnect the power supply from the both power pins VBATT and VBATT_PA at the same time. In this case all parts of the module are in OFF condition, any power consumption is present. Processor turn OFF – disconnect the power supply only from the power pin VBATT, the power pin VBATT_PA can be connected to power supply, in this case a low, typical 2uA max 20uA, power consumption is present. Before any of both OFF procedure will be applied, the AT#SYSHALT AT command must be send (see AT Commands Reference Guide, 80000ST10025a), after the OK response message, check the

V_AUX / PWRMON pin, when the logic level is low the module can be consider fully

not operating and at this moment is possible disconnect the Power Supply. The following flow chart shows the proper turnoff procedure:

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TIP: To check if the device has been powered off, the hardware line PWRMON must be monitored.

The device is powered off when PWRMON goes low.

NOTE:

Modem OFF

Proc.

PWRMON = OFF?

Place AT command

AT#SYSHALT

Disconnect PWR

supply

Disconnect PWR

supply

Wait

PWRMON =OFF

15s timeout

Modem ON Proc

Delay 1.5s

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5.3. Resetting the GL865

5.3.1. Hardware Uncondit ional restar t

WARNING:

The hardware unconditional Restart must not be used during normal operation of the device since it does not detach the device from the network. It shall be kept as an emergency exit procedure to be done in the rare case that the device gets stacked waiting for some network or SIM responses.

To unconditionally reboot the GL865, the pad RESET* must be tied low for at least 200 milliseconds and then released.

NOTE: Do not use any pull up resistor on the RESET* line nor any totem pole digital output. Using pull

up resistor may bring to latch up problems on the GL865 power regulator and improper functioning of the module. The line RESET* must b e connected only in open collector configuration; the transistor must be connected as close as possible to the RESET* pin.

TIP: The unconditional hardware restart must always be implemented on the boards and the software

must use it as an emergency exit procedure.

A simple circuit to do it is:

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In the following flow chart is detailed the proper restart procedure:

NOTE:

Modem Reset

Proc.

Reset = LOW

Delay 200ms

Reset = HIGH

PWRMON =

OFF

Delay 1s

Start AT CMD

Modem ON

Proc.

Delay 1,5s

Disconnect PWR

supply

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6. Power Supply

The power supply circuitry and board layout are a very important part in the full product design and they strongly reflect on the product overall performances, hence read carefully the requirements and the guidelines that will follow for a proper design.

6.1. Power Supply Requirements

The external power supply must be connected to VBATT & VBATT_PA signals and must fulfill the following require ments:

POWER SUPPLY

Nominal Supply Voltage

3.8 V

Normal Operating Voltage Range

3.4 V÷ 4.20 V

Extended Operating Voltage Range

3.22 V÷ 4.50 V

NOTE:

The Operating Voltage Range MUST never be exceeded; care must be taken in order to fulfil min/max voltage requirement.

NOTE:

Overshoot voltage (regarding MAX Extended Operating Voltage) and drop in voltage (regarding MIN Extended Operating Voltage) MUST never be exceeded;

The “Extended Operating Voltage Range” can be used only with completely assumption and application of the HW User guide suggestions.

NOTE:

When the power supply voltage is lower than 3.4V, after 4000 m-seconds, the V_AUX /

PWRMON

pin will be at the high logic level and the module can be consider fully operating. See

para 6.1

6.2. Power Consumption

The GL865 power consumptions are:

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GL 865

Mode

Average

(mA)

Mode description

SWITCHED OFF

Module power supplied only on VBATT_PA pin, the VBATT pin is not power supplied.

Switched Off

Typical 2uA

max 20uA

Switched Off with

AT#SYSHALT

<650uA

Module power supplied on VBATT_PA pin and VBATT pin, the at

command AT#SYSHALT is applied.

IDLE mode

AT+CFUN=1

21,0

Normal mode: full functionality of the module

AT+CFUN=4

18,0

Disabled TX and RX; module is not registered on the network

AT+CFUN=0 or =5

3,9

Paging Mult i frame 2

2,5

Paging Mult i frame 3

2,4

Paging Mult i frame 4

1,5

Paging Mult i frame 9

CSD TX and RX mode

GSM VOICE CALL

GSM900 CSD PL5

230

DCS1800 CSD PL0

180

GPRS (class 8) 1TX

GPRS Sending data mode

GSM900 PL5

225

DCS1800 PL0

175

GPRS (class 10) 2TX

GPRS Sending data mode

GSM900 PL5

360

DCS1800 PL0 300

The GSM system is made in a way that the RF transmission is not continuous, else it is packed into bursts at a base frequency of about 216 Hz, and the relative current peaks can be as high as about 2A. Therefore the power supply has to be designed in order to withstand with these current peaks without big voltage drops; this means that both the electrical design and the board layout must be designed for this current flow. If the layout of the PCB is not well designed a strong noise floor is generated on the ground and the supply; this will reflect on all the audio paths producing an audible annoying noise at 216 Hz; if the voltage drop during the peak current absorption is too much, then the device may even shutdown as a consequence of the supply voltage drop.

NOTE:

The electrical design for the Power supply should be made ensuring it will be capable of a peak current output of at least 2 A.

6.3. General Design Rules

The principal guidelines for the Power Supply Design embrace three different design steps:

• the electrical design

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• the therm al des ig n

• the PCB layout.

6.3.1. Electrical Design Guidelines

The electrical design of the power supply depends strongly from the power source where this power is drained. We will distinguish them into three categories:

• +5V input (typically PC internal regulator output)

• +12V input (typically automotive)

• Battery

6.3.1.1. + 5V input Source Power Supply Design Guidelines

The desired output for the power supply is 3.8V, hence there's not a big difference between the input source and the desired output and a linear regulator can be used. A switching power supply will not be suited because of the low drop out requirements. When using a linear regulator, a proper heat sink shall be provided in order to dissipate the power generated. A Bypass low ESR capacitor of adequate capacity must be provided in order to cut the current absorption peaks close to the GL865, a 100μF tantalum capacitor is usually suited. Make sure the low ESR capacitor on the power supply output (usually a tantalum one) is rated at least 10V. A protection diode should be inserted close to the power input, in order to save the GL865 from power polarity inversion.

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An example of linear regulator with 5V input is:

6.3.1.2. + 12V input Source Power Supply Design Guidelines

The desired output for the power supply is 3.8V, hence due to the big difference between the input source and the desired output, a linear regulator is not suited and shall not be used. A switching power supply will be preferable because of its better efficiency especially with the 2A peak current load represented by the GL865. When using a switching regulator, a 500kHz or more switching frequency regulator is preferable because of its smaller inductor size and its faster transient response. This allows the regulator to respond quickly to the current peaks absorption. In any case the frequency and Switching design selection is related to the application to be developed due to the fact the switching frequency could also generate EMC interferences. For car PB battery the input voltage can rise up to 15,8V and this should be kept in mind when choosing components: all components in the power supply must withstand this voltage. A Bypass low ESR capacitor of adequate capacity must be provided in order to cut the current absorption peaks, a 100μF tantalum capacitor is usually suited. Make sure the low ESR capacitor on the power supply output (usually a tantalum one) is rated at least 10V. For Car applications a spike protection diode should be inserted close to the power input, in order to clean the supply from spikes. A protection diode should be inserted close to the power input, in order to save the GL865 from power polarity inversion. This can be the same diode as for spike protection.

An example of switching regulator with 12V input is in the below schematic (split in 2 parts):

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6.3.1.3. Battery Source Power Supply Design Guidelines

The desired nominal output for the power supply is 3.8V and the maximum voltage allowed is

4.2V, hence a single 3.7V Li-Ion cell battery type is suited for supplying the power to the Telit GL865 module.

WARNING:

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The three cells Ni/Cd or Ni/MH 3,6 V Nom. battery types or 4V PB types MUST NOT BE USED DIRECTLY since their maximum voltage can rise over the absolute maximum voltage

for the GL865 and damage it.

NOTE:

DON'T USE any Ni-Cd, Ni-MH, and Pb battery types directly connected with GL865. Their use can lead to overvoltage on the GL865 and damage it. USE ONLY Li-Ion battery types.

A Bypass low ESR capacitor of adequate capacity must be provided in order to cut the current absorption peaks, a 100μF tantalum capacitor is usually suited. Make sure the low ESR capacitor (usually a tantalum one) is rated at least 10V. A protection diode should be inserted close to the power input, in order to save the GL865 from power polarity inversion. Otherwise the battery connector should be done in a way to avoid polarity inversions when connecting the battery. The battery capacity must be at least 500mAh in order to withstand the current peaks of 2A; the suggested capacity is from 500mAh to 1000mAh.

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6.3.2. Thermal Design Guidelines

The thermal design for the power supply heat sink should be done with the following specifications: See para 7.2 Power Consumption

NOTE:

The average consumption during transmissions depends on the power level at which the device is requested to transmit by the network. The average current consumption hence varies significantly.

Considering the very low current during idle, especially if Power Saving function is enabled, it is possible to consider from the thermal point of view that the device absorbs current significantly only during calls. For the heat generated by the GL865, you can consider it to be during transmission 1W max during CSD/VOICE calls and 2W max during class10 GPRS upload. This generated heat will be mostly conducted to the ground plane under the GL865; you must ensure that your application can dissipate it.

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6.3.3. Power Supply PCB layout Guidelines

As seen on the electrical design guidelines the power supply shall have a low ESR capacitor on the output to cut the current peaks and a protection diode on the input to protect the supply from spikes and polarity inversion. The placement of these components is crucial for the correct working of the circuitry. A misplaced component can be useless or can even decrease the power supply performances.

The Bypass low ESR capacitor must be placed close to the Telit GL865 power input pads or in the case the power supply is a switching type it can be placed close to the inductor to cut the ripple provided the PCB trace from the capacitor to the GL865 is wide enough to ensure a dropless connection even during the 2A current peaks. The protection diode must be placed close to the input connector where the power source is drained. The PCB traces from the input connector to the power regulator IC must be wide enough to ensure no voltage drops occur when the 2A current peaks are absorbed. Note that this is not made in order to save power loss but especially to avoid the voltage drops on the power line at the current peaks frequency of 216 Hz that will reflect on all the components connected to that supply, introducing the noise floor at the burst base frequency. For this reason while a voltage drop of 300-400 mV may be acceptable from the power loss point of view, the same voltage drop may not be acceptable from the noise point of view. If your application doesn't have audio interface but only uses the data feature of the Telit GL865, then this n oise is not so di sturbing and power supply layout design can be more forgiving. The PCB traces to the GL865 and the Bypass capacitor must be wide enough to ensure no significant voltage drops occur when the 2A current peaks are absorbed. This is for the same reason as previous point. Try to keep this trace as short as possible. The PCB traces connecting the Switching output to the inductor and the switching diode must be kept as short as possible by placing the inductor and the diode very close to the power switching IC (only for switching power supply). This is done in order to reduce the radiated field (noise) at the switching frequency (100-500 kHz usually). The use of a good common ground plane is suggested. The placement of the power supply on the board should be done in such a way to guarantee that the high current return paths in the ground plane are not overlapped to any noise sensitive circuitry as the microphone amplifier/buffer or earphone amplifier. The power supply input cables should be kept separate from noise sensitive lines such as microphone/earphone cables.

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7. Antenna

The antenna connection and board layout design are the most important aspect in the full product design as they strongly affect the product overall performances, hence read carefully and follow the requirements and the guidelines for a proper design.

7.1. GSM Antenna Requirements

As suggested on the Product Description the antenna and antenna transmission line on PCB for a Telit GL865 device shall fulfil the following requirements:

ANTENNA REQUIREMENTS QUAD

DUAL

Frequency r ange

824-894 MHz GSM850 band

880-960 MHz GSM900 band 1710-1885MHz DCS1800 band

1850-1990MHz PCS1900 band

880-960 MHz GSM900 band 1710-1885MHz MHz DCS1800 band

Gain

1.4dBi @ GSM900 and 3dBi @

DCS1800

1.4dBi @ GSM850 and 3dBi @ PCS1900

1.4dBi @ GSM900 and 3dBi @ DCS1800

Impedance

50 Ohm

Input power

> 2 W

VSWR absolute max

≤ 10:1 (limit to avoid permanent damage)

VSWR recommended

≤ 2:1 (limit to fulfil all regulatory

requirements)

≤ 2:1 (limit to fulfil all regulatory

requirements)

Furthermore if the devices are developed for the US market and/or Canada market, they shall comply to the FCC and/or IC approval requirements:

Those devices are to be used only for mobile and fixed application. The antenna(s) used for this transmitter must be installed to provide a separation distance of at least 20 cm from all persons and must not be co-located or operating in conjunction with any other antenna or transmitter. End-Users must be provided with transmitter operation conditions for satisfying RF exposure compliance. OEM integrators must ensure that the end user has no manual instructions to remove or install the GL865. Antennas used for those OEM modules must not exceed 3dBi gain for mobile and fixed operating configurations.

7.1.1. GL865 Antenna – PCB line Guidelines

When using the Telit GL865 module, since there's no antenna connector on the module, the antenna must be connected to the GL865 through the PCB with the antenna pad (pin 34).

In the case that the antenna is not directly developed on the same PCB, hence directly connected at the antenna pad of the GL865, then a PCB line is needed in order to connect with it or with its connector.

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This line of transmission shall fulfill the following requirements:

ANTENNA LINE ON PCB REQUIREMENTS

Impedance

50 ohm

Max Attenuation

0,3 dB

No coupling with other signals allowed

Cold End (Ground Plane) of antenna shall be equipotential to the

GL865 ground pins

This transmission line should be designed according to the following guidelines:

• Ensure that the antenna line impedance is 50 ohm;

• Keep the antenna line on the PCB as short as possible, since the antenna line loss shall

be less than 0,3 dB;

• Antenna line must have uniform characteristics, constant cross section, avoid meanders

and abrupt curves;

• Keep, if possible, one layer of the PCB used only for the Ground plane;

• Surround (on the sides, over and under) the antenna line on PCB with Ground, avoid

having other signal tracks facing directly the antenna line track;

• The ground around the antenna line on PCB has to be strictly connected to the Ground

Plane by placing vias once per 2mm at least;

• Place EM noisy devices as far as possible from GL865 antenna line;

• Keep the antenna line far away from the GL865 power supply lines;

• If you have EM noisy devices around the PCB hosting the GL865, such as fast

switching ICs, take care of the shielding of the antenna line by burying it inside the layers of PCB and surround it with Ground planes, or shield it with a metal frame cover.

• If you don't have EM noisy devices around the PCB of GL865, by using a strip-line on

the superficial copper layer for the antenna line, the line attenuation will be lower than a buried one;

7.2. PCB Guidelines in case of FCC certification

In the case FCC certification is required for an application using GL865, according to FCC KDB 996369 for modular approval requirements, the transmission line has to be similar to that implemented on GL865 interface board and described in the following chapter.

7.2.1. Transmission line design

During the design of the GL865 interface board, the placement of components has been chosen properly, in order to keep the line length as short as possible, thus leading to lowest power losses

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possible. A Grounded Coplanar Waveguide (G-CPW) line has been chosen, since this kind of transmission line ensures good impedance control and can be implemented in an outer PCB layer as needed in this case. A SMA female connector has been used to feed the line. The interface board is realized on a FR4, 4-layers PCB. Substrate material is characterized by relative permittivity ε

= 4.6 ± 0.4 @ 1 GHz, TanD= 0.019 ÷ 0.026 @ 1 GHz. A characteristic impedance of nearly 50 Ω is achieved using trace width = 1.1 mm, clearance from coplanar ground plane = 0.3 mm each side. The line uses reference ground plane on layer 3, while copper is removed from layer 2 underneath the line. Height of trace above ground plane is 1.335 mm. Calculated characteristic impedance is 51.6 Ω, estimated line loss is less than 0.1 dB. The line geometry is shown below:

7.2.2. Transmission line measurements

HP8753E VNA (Full-2-port calibration) has been used in this measurement session. A calibrated coaxial cable has been soldered at the pad corresponding to GL865 RF output; a SMA connector has been soldered to the board in order to characterize the losses of the transmission line including the connector itself. During Return Loss / impedance measurements, the transmission line has been terminated to 50 Ω load.

Return Loss plot of line under test is shown below:

0 . 3 mm

0. 035 m m

0 . 3 mm

6 . 2 mm

FR4

0. 035 m m

1. 335 m m

0. 2 m m

1. 1 m m

1 . 1 mm

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Line input impedance (in Smith Chart format, once the line has been terminated to 50 Ω load) is shown in the following figure:

Insertion Loss of G-CPW line plus

SMA connector is shown below:

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7.3. GSM Antenna - Installation Guidelines

• Install the antenna in a place covered by the GSM signal.

• The Antenna must be installed to provide a separation distance of at least 20 cm

from all persons and must not be co-located or operating in conjunction with any other antenna or transmitter;

• Antenna shall not be installed inside metal cases

• Antenna shall be installed also according Antenna manufacturer instructions.

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8. Logic level specifications

Where not specifically stated, all the interface circuits work at 2.8V CMOS logic levels. The following table shows the logic level specifications used in the GL865 interface circuits:

Absolute Maximum Ratings -Not Functional

Parameter

Min

Max

Input level on any digital pin (CMOS

2.8) when on

-0.3V

+3.1V

Input level on any digital pin (CMOS

1.8) when on

-0.3V

+2.1V Input voltage on analog p ins when on

-0.3V

+3.0 V

Operating Range - Interface levels (2.8V CMOS)

Level

Min

Max

Input high level

2.1V

3.1V

Input low level

0.5V

Output high level

2.2V

3.1V

Output low level

0.35V

For 1.8V signals: Operating Range - Interface levels (1.8V CMOS)

Level

Min

Max

Input high level

1.6V

2.0V

Input low level

0.4V

Output high level

1,65V

2.0V

Output low level

0.35V

Current characteristics

Level

Typical

Output Current

1mA

Input Current

1uA

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8.1. Reset signal

Signal

Function

I/O

RESET*

Phone reset

RESET* i s used to reset the GL865. Whenever this signal is pulled low, the GL865 is reset. When the device is reset it stops any operation. After the release of the reset GL865 is unconditionally shut down, without doing any detach operation from the network where it is registered. This behaviour is not a proper shut down because any GSM device is requested to issue a detach request on turn off. For this reason the Reset signal must not be used to normally shutting down the device, but only as an emergency exit in the rare case the device remains stuck waiting for some network response.

The RESET* is internally controlled on start-up to achieve always a proper power-on reset sequence, so there's no need to control this pin on start-up. It may only be used to reset a device already on that is not responding to any command.

NOTE:

Do not use this signal to power OFF the GL865. Use the ON/OFF procedure to perform this function.

Reset Signal Operating levels:

Signal

Min

Max

RESET* Input high

1.8V(NOTE1)

2.1V

RESET* Input low

0.2V

(NOTE1) this signal is internally pulled up so the pin can be left floating if not used.

If unused, this signal may be left unconnected. If used, then it must always be connected with an open collector transistor, to permit to the internal circuitry the power on reset and under voltage lockout functions.

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9. Serial Ports

The serial port on the GL865 is the core of the interface between the module and OEM hardware. 2 serial ports are available on the module: MODEM SERIAL PORT 1 (MAIN)  for AT commands and Data MODEM SERIAL PORT 2 (AUX)  for AT commands or Debug

9.1. MODEM SERIAL PORT

Several configurations can be designed for the serial port on the OEM hardware, but the most common are: RS232 PC com port microcontroller UART @ 2.8V - 3V (Universal Asynchronous Receive Transmit) microcontroller UART @ 5V or other voltages different from 2.8V

Depending from the type of serial port on the OEM hardware a level translator circuit may be needed to make the system work. The only configuration that doesn't need a level translation is the 2.8V UART. The serial port on the GL865 is a +2.8V UART with all the 7 RS232 signals. It differs from the PC-RS232 in the signal polarity (RS232 is reversed) and levels. The levels for the GL865 UART are the CMOS levels:

Absolute Maximum Rating s -Not Functional

Parameter

Min

Max

Input level on any digital

pad when on

-0.3V

+3.1V

Input voltage on analog

pads when on

-0.3V

+3.1V

Operating Range - Interface levels (2.8V CMOS)

Level

Min

Max

Input high level VIH

2.1V

3.1 V

Input low level VIL

0.5V

Output high level VOH

2.2V

3.1V

Output low level VOL

0.35V

The signals of the GL865 serial port are:

RS232 Pin

Number

Signal

GL865

Pad Number

Name

Usage

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1 DCD - dcd_uart 1 Data Carrier Detect

Output from the GL865 that indicate s the carrier presence

RXD - tx_uart

Transmit line *see Note

Output transmit line of GL865 UART

TXD - rx_uart

Receive line *see Note

Input receive of the GL865 UART

4 DTR - dtr_uart 4 Data Terminal Ready

Input to the GL865 that controls the DTE READY condition

5 GND

32, 33, 35, 36,

Ground ground

6 DSR - dsr_uart 3 Data Set Ready

Output from the GL865 that indicate s the

module is ready

7 RTS -rts_uart 5 Request to Send

Input to the GL865 that controls the Hardware flow control

8 CTS - cts_uart 6 Clear to Send

Output from the GL865 that controls the

Hardware flow control

9 RI - ri_uart 2 Ring Indicator

Output from the GL865 that indicate s the incoming call condition

NOTE:

According to V.24, RX/TX signal names are referred to the application side, therefore on the GL865 side these signal are on the opposite direction: TXD on the application side will be connected to the receive line (here named TXD/ rx_uart ) of the GL865 serial port and viceversa for RX.

NOTE:

For a minimum implementation, only the TXD and RXD lines can be connected, the other lines can be left open provided a software flow control is implemented.

NOTE:

In order to avoid a back powering effect it is recommended to avoid having any HIGH logic level signal applied to the digital pins of the GE865 when the module is powered off or during an ON/OFF transition.

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9.2. RS232 level translation

In order to interface the GL865 with a PC com port or a RS232 (EIA/TIA-232) application a level translator is required. This level translator must:

• invert the electrical signal in both directions;

• change the level from 0/2.8V to +15/-15V .

Actually, the RS232 UART 16450, 16550, 16650 & 16750 chipsets accept signals with lower levels on the RS232 side (EIA/TIA-562), allowing a lower voltage-multiplying ratio on the level translator. Note that the negative signal voltage must be less than 0V and hence some sort of level translation is always required. The simplest way to translate the levels and invert the signal is by using a single chip level translator. There are a multitude of them, differing in the number of drivers and receivers and in the levels (be sure to get a true RS232 level translator not a RS485 or other standards). By convention the driver is the level translator from the 0-2.8V UART to the R S232 l evel . The receiver is the translator from the RS232 level to 0-2.8V UART. In order to translate the whole set of control lines of the UART you will need:

• 5 drivers

• 3 receivers

NOTE:

The digital input lines working at 2.8V CMOS have an absolute maximum input voltage of

3.0V; therefore the level translator IC shall not be powered by the +3.8V supply of the module. Instead, it must be powered from a +2.7V / +2.9V (dedicated) power supply.

This is because in this way the level translator IC outputs on the module side (i.e. GL865 inputs) will work at +3.8V interface levels, damaging the module inputs.

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An example of level translation circuitry of this kind is:

The example is done with a MAXIM MAX3237 Transceiver that could accept supply voltages of 3V DC. Not exceeded with supply voltage higher then 3.1VDC because this is the higher voltage limit of module’s inputs.

NOTE:

In this case Vin has to be set with a value compatible with the logic levels of the module. (Max

3.1V DC)

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Second solution could be done using a MAXIM transceiver (MAX218) In this case the compliance with RS232 (+-5V) is possible.

Another level adapting method could be done using a standard RS232 Transceiver (MAX3237EAI) adding some resistors to adapt the levels on the GL865 Input lines.

NOTE: In this case has to be taken in account the length of the lines on the application to avoid problems in case of High-speed rates on RS232.

The RS232 serial port lines are usually connected to a DB9 connector with the following layout:

9.3.

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9.4. 5V UART level translation

If the OEM application uses a microcontroller with a serial port (UART) that works at a voltage different from 2.8 - 3V, then a circuitry has to be provided to adapt the different levels of the two set of signals. As for the RS232 translation there are a multitude of single chip translators. For example a possible translator circuit for a 5V TRANSMITTER/RECEIVER can be:

TIP:

Note that the TC7SZ07AE has open drain output; therefore the resistor R2 is mandatory.

NOTE:

The UART input line TXD (rx_uart) of the GL865 is NOT internally pulled up with a resistor, so there may be the need to place an external 47KΩ pull-up resistor, either the DTR (dtr_uart) and RTS (rts_uart) input lines are not pulled up internally, so an external pull-up resistor of 47KΩ may be required.

NOTE:

The input lines working at 2.8VCMOS can be pulled-up with 47KΩ

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In case of reprogramming of the module has to be considered the use of the RESET line to start correctly the ac tiv ity.

The preferable configuration is having an external supply for the buffer.

NOTE:

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10. Audio Section Overview

The Base Band Chip of the GL865 provides one input for audio to be transmitted (Uplink), that can be connected directly to a microphone or an audio source. The bias for the microphone is already provided by the product; so the connection can be done in both following ways:

For more information refer to Telit document : “ 80000NT10007a Audio Settings Application Note “.

MIC connection

220n

MIC/AF_IN+

MIC/AF_IN-

AGND

MODULE

INPUT

ADC

Vmic

Wire Or Ground Plane

220n

2.2K

÷10u

MODULE

INPUT

ADC

Vmic

MIC/AF_IN+

MIC/AF_IN

AGND

Integral Ground Plane

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TIP: Since the J-FET transistor inside the microphone acts as RF-detector-amplifier, ask vendor for a microphone with anti-EMI capacitor (usually a 33pF or a 10pF capacitor placed across the output terminals inside the case).

LINE-IN connection

If the audio source is not a mike but a different device, the following connections can be done. Place a 1Kohm resistor to ground on the negative input, in order to get balanced the input; than connect the source via 1uF capacitor, so the DC current is blocked. Since the input is differential, the common mode voltage noise between the two (different) ground is rejected, provided that both AF_IN+ & AF_IN- are connected directly onto the source.

220n

AF_IN+

MIC/AF_IN+

MIC/A F_IN-

AGND

MODULE

INPUT

ADC

Vmic

AF_IN-

220n

1K 1K 1u 1u

AF_IN+

MIC/AF_IN+

MIC/AF_IN

AGND

MODULE

INPUT

ADC

Vmic

Remote_GND

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EAR connection connection

The audio output of the GL865 is balanced, this is helpful to double the level and to reject common mode (click and pop are common mode and therefore rejected). These outputs can drive directly a small loudspeaker with electrical impedance not lower than 8Ohm.

TIP: in order to get the maximum audio level at a given output voltage level (dBspl/Vrms), the following breaking through procedure can be used. Have the loudspeaker as close as you can to the listener (this simplify also the echo cancelling); choose the loudspeaker with the higher sensitivity (dBspl per W); choose loudspeakers with the impedance close to the limit (ex: 16 or 8 Ohm), in order to feed more power inside the transducer (it increases the W/Vrms ratio). If this were not enough, an external amplifier should be used.

EAR+

EAR-

MODULE

OUTPUT

DAC

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10.1. Electrical Characteristics

10.1.1. Input Lines

Microphone/Line-in path

Line Type Differential Coupling capacitor ≥ 1μF Differential input resistance 1kΩ/2kΩ/2.2kΩ

Levels

To have 0dBm0 @1KHz (*) Differential input voltage AT#HFMICG=0 290mVrms AT#HFMICG=1 (+6dB) 145mVrms AT#HFMICG=2 (+12dB) 72mVrms AT#HFMICG=3 (+18dB) 36mVrms AT#HFMICG=4 (+24dB) 18mVrms AT#HFMICG=5 (+30dB) 9mVrms AT#HFMICG=6 (+36dB) 4.5mVrms AT#HFMICG=7 (+42dB) 2.25mVrms

(*) 0 dBm0 in the network are -3.14 dBfs

TIP: The Electrect microphone is internally amplified by a J-Fet transistor, thus the sound is carried out as saturation drain current; this means that the norton equivalence has to be considered. The signal is converted to voltage on the 2.2KOhm resistance, from there on circuitry has to be routed in order to not pick up common mode noise; beware of the return path (ground).

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10.1.2. Output Lines

EAR/Line-out Output

Differential line coupling

Direct connection (VDC=1.3÷1.6V)

Single-ended line coupling

One EAR terminal connected via a

DC-block capacitor, the other one left

open

output load resistance

≥ 8 Ω

internal output resistance

4 Ω (typ.)

signal bandwidth

250÷3400Hz (@ -3dB with default filter)

max. differential output voltage

1120mVpp @3.14dBm0 (*)

differential output voltage

550mV

rms

@0dBm0 (*)

volume increment 2dB per step volume steps 0..10

(*) in default condition: AT+CLVL=10, AT#HFRECG=0

TIP : We suggest driving the load differentially; this kills all the common mode noises (click and pop, for example), the output swing will double (+6dB) and the big output coupling capacitor will be avoided.

However if particular OEM application needs, also a Single Ended (S.E) circuitry can be implemented. The OEM circuitry shall be designed to reduce the common mode noise typically generated by the return path of the big currents.

In order to get the maximum power output from the device, the resistance of the tracks has to be negligible in comparison to the load.

WARNING. When in Single Ended configuration, the unused output line must be left open: if this constraint is not respected, the output stage will be damaged.

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11. General Purpose I/O

The general purpose I/O pads can be configured to act in three different ways:

• input

• output

• alternate function (

internally controlled)

Input pads can only be read; they report the digital value (

high or low) present on the pad at the

read time . Output pads can only be written or queried and set the value of the pad output. An alternate function pad is internally controlled by the GL865 firmware and acts depending on the function implemented.

For Logic levels please re fe r to chapte r 8.

The following table shows the available GPIO on the GL865.

Signal

I/O

Function

Type

Input /

output

current

Default

State

ON_OFF

state

State

during

Reset

Note

42 GPIO_01 I/O Configurable GPIO

CMOS

2.8V

1uA/1mA INPUT 0 0

Alternate function

DVI_WA0

41 GPIO_02 I/O Configurable GPIO

CMOS

2.8V

1uA/1mA INPUT 0 0

Alternate function JDR and DVI_RX

40 GPIO_03 I/O Configurable GPIO

CMOS

2.8V

1uA/1mA INPUT 0 0

Alternate function

DVI_TX

39 GPIO_04 I/O Configurable GPIO

CMOS

2.8V

1uA/1mA INPUT 0 0

Alternate function

TX disable and

DVI_CLK

29 GPIO_05 I/O Configurable GPIO

CMOS

2.8V

1uA/1mA INPUT 0 0

Alternate function

RFTXMON

28 GPIO_06 I/O Configurable GPIO

CMOS

2.8V

1uA/1mA INPUT 0 0

Alternate function

ALARM

27 GPIO_07 I/O Configurable GPIO

CMOS

2.8V

1uA/1mA INPUT 0 0

Alternate function

BUZZER

26 GPIO_08 I/O Configurable GPIO

CMOS

2.8V

1uA/1mA INPUT 0 0

Alternate function

STAT_LED

Also the UART‘s control flow pins can be unable as GPI/O.

Signal

I/O

Function

Type

Input / output

Default

State

ON_OFF

state

State

during

Note

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current Reset

1 GPO_A O Configurable GPO

CMOS

2.8V

1uA/1mA INPUT 0 0

Alternate function

C109/DCD

2 GPO_B O Configurable GPO

CMOS

2.8V

1uA/1mA INPUT 0 0

Alternate function C125/RING

3 GPO_C O Configurable GPO

CMOS

2.8V

1uA/1mA INPUT 0 0

Alternate function

C107/DSR

4 GPI_E I Configurable GPI

CMOS

2.8V

1uA/1mA INPUT 0 0

Alternate function C108/DTR

5 GPI_F I Configurable GPI

CMOS

2.8V

1uA/1mA INPUT 0 0

Alternate function C105/RTS

6 GPO_D O Configurable GPO

CMOS

2.8V

1uA/1mA INPUT 0 0

Alternate function C106/CTS

11.1. GPIO Logic levels

Where not specifically stated, all the interface circuits work at 2.8V CMOS logic levels. The following table shows the logic level specifications used in the GL865 interface circuits:

Absolute Maximum Ratings -Not Functional

Parameter

Min

Max

Input level on any digital pin when on (CMOS 2.8)

-0.3V

+3.1V

Input level on any digital pin when on (CMOS 1.8)

-0.3V

+2.1V

Input voltage on analog pins when on

-0.3V

+3.0V

Operating Range - Interface levels (2.8V CMOS)

Level

Min

Max

Input high level 2.1V 3.1V Input low level 0V 0.5V Output high level 2.2V 3.1V Output low level 0V 0.35V

11.2. Using a GPIO Pad as INPUT

The GPIO pads, when used as inputs, can be connected to a digital output of another device and report its status, provided this device has interface levels compatible with the 2.8V CMOS levels of the GPIO.

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If the digital output of the device to be connected with the GPIO input pad has interface levels different from the 2.8V CMOS, then it can be buffered with an open collector transistor with a 47K pull up to 2.8V.

NOTE:

TIP:

The V_AUX / PWRMON pin can be used for input pull up reference or/and for ON/OFF monitoring.

11.3. Using a GPIO Pad as OUTPUT

The GPIO pads, when used as outputs, can drive 2.8V CMOS digital devices or compatible hardware. When set as outputs, the pads have a push-pull output and therefore the pull-up resistor may be omitted.

11.4. Using the RF Transmission Control GPIO4

The GPIO4 pin, when configured as RF Transmission Control Input, permits to disable the Transmitter when the GPIO is set to Low by the application. In the design is necessary to add a resistor 47K pull up to 2.8V, this pull up must be switched off when the module is in off condition.

11.5. Using the RFTXMON Output GPIO5

The GPIO5 pin, when configured as RFTXMON Output, is controlled by the GL865 module and will rise when the transmitter is active and fall after the transmitter activity is completed.

There are 2 different modes for this function:

1) Active during all the Call: For example, if a call is started, the line will be HIGH during all the conversation and it will be again LOW after hanged up. The line rises up 300ms before first TX burst and will became again LOW from 500ms to 1s after last TX burst.

2) Active during all the TX activity: The GPIO is following the TX bursts

Please refer to the AT User interface manual for additional information on how to enable this function.

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11.6. Using the Alarm Output GPIO6

The GPIO6 pad, when configured as Alarm Output, is controlled by the GL865 module and will rise when the alarm starts and fall after the issue of a dedicated AT command. This output can be used to controlling microcontroller or application at the alarm time.

11.7. Using the Buzzer Output GPIO7

The GPIO7 pad, when configured as Buzzer Output, is controlled by the GL865 module and will drive a Buzzer driver with appropriate square waves. This permits to your application to easily implement Buzzer feature with ringing tones or melody played at the call incoming, tone playing on SMS incoming or simply playing a tone or melody when needed.

A sample interface scheme is included below to give you an idea of how to interface a Buzzer to the GPIO7:

TR1 BCR141W

TR2

SMBT2907A

4,7K

R2 1K

D1N4148

33pF

+V buzzer

GPIO7

NOTE:

To correctly drive a buzzer a driver must be provided, its characteristics depend on the Buzzer and for them refer to your buzzer vendor.

11.8. Magnetic Buzzer Concepts

1.1.1 Short Description

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A magnetic Buzzer is a sound-generating device with a coil located in the magnetic circuit consisting of a permanent magnet, an iron core, a high permeable metal disk and a vibrating diaphragm.

Drawing of the Magnetic Buzzer.

The disk and diaphragm are attracted to the core by the magnetic field. When an oscillating signal is moved through the coil, it produces a fluctuating magnetic field which vibrates the diaphragm at a frequency of the drive signal. Thus the sound is produced relative to the frequency applied.

Diaphra g m moveme nt.

11.8.1. Frequency Behaviour

The frequency behaviour represents the effectiveness of the reproduction of the applied signals. Because performance is related to a square driving waveform (whose amplitude varies from 0V to V

), if you modify the waveform (e.g. from square to sinus) the frequency response will change.

11.8.2. Power Supply Influence

Applying a signal whose amplitude is different from that suggested by the manufacturer, the performance change following the rule “if resonance frequency f

increases, amplitude

decreases”.

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Because resonance frequency depends on acoustic design, by lowering the amplitude of the driving signal the response bandwidth tends to become narrow, and vice versa. Summarizing: V

↑  fo ↓ Vpp ↓ fo ↑

The risk is that the f

could easily fall outside of new bandwidth; consequently the SPL could be

much lower than the expected.

11.8.3. Working Current Influence

In the component data sheet you will find the value of MAX CURRENT: this represents the maximum average current that can flow at nominal voltage without current limitation. In other words it is not the peak current, which could be twice or three times higher. If driving circuitry does not support these peak values, the SPL will never reach the declared level or the oscillations will stop.

11.9. STAT LED Indication of network service availability

The STAT_LED pin status shows information on the network service availability and Call status. In the GL865 modules, the STAT_LED usually needs an external transistor to drive an external LED. Therefore, the status indicated in the following table is reversed with respect to the pin status. The AT command to enable the function is AT#SLED=2, in order to save the function use the AT command AT#SLEDSAV, the AT command AT#SLED=0 disable the function and the functionality of GPIO8 can be used. (see AT Command user guide)

LED status

Device Status

Permanently off Device off

Fast blinking

(Period 1s, Ton 0,5s)

Net search / Not registered /

turning off

Slow blinking

(Period 3s, Ton 0,3s)

Registered full service

Permanently on a call is active

WARNING:

It is very important to respect the sense of the applied voltage: never apply to the "-" pin

voltage more positive than the "+" pin

: if this happens, the diaphragm vibrates in the opposite

direction with a high probability to be expelled from its phys

ical position. This damages the

device permanently.

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NOTE:

Don’t use the STAT LED function if the GPIO 8 function is enabled and vice versa!

A schematic example could be:

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11.10. SIMIN detect function

All the GPIO pins can be used as SIM DETECT input. The AT Command used to enable the function is:

#SIMINCFG– SIMIN pin configuration

SELINT 2

AT#SIMINCFG = <GPIO_ pin>

The command enable the function on the general

purpose I/O pin GPIO<pin> Parameters: <GPIO_pin> - GPIO pin number; supported range is

from 1 to 8 (see chapter 11)

AT#SIMINCFG?

Read command reports the selected I/O pin in the

format:

#SIMINCFG: 1

AT#SIMINCFG =?

Test command reports supported range of values for

parameters in the format: #SIMINCFG : (0 – 8) 0 = disabled

Use the AT command AT#SIMDET=2 to enable the SIMIN detection Use the AT command AT&W0 and AT&P0 to store the SIMIN detection in the common

profile (See AT Command user guide)

NOTE:

Don’t use the SIM IN function on the same pin where the GPIO function is enabled and vice versa!

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11.11. RTC Bypass out

The VRTC pin brings out the Real Time Clock supply, which is separate from the re st of the digital part, allowing having only RTC going on when all the other parts of the device are off. To this power output a backup battery can be added in order to increase the RTC autonomy during power off of the main battery (power supply). NO Devices must be powered from this pin.

11.12. SIM Holder Implementation

Please refer to the related User Guide (SIM Holder Design Guides, 80000NT10001a).

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12. DAC and ADC section

12.1. DAC Converter

12.1.1. Description

The GL865 provides a Digital to Analog Converter. The signal (named DAC_OUT) is available on pin 15 of the GL865. The on board DAC is a 10 bit converter, able to generate a analogue value based a specific input in the range from 0 up to 1023. However, an external low-pass filter is necessary

Min

Max

Units

Voltage range (filtered)

2,6

Volt

Range

1023

Steps

The precision is 10 bits so, if we consider that the maximum voltage is 2V, the integrated voltage could be calculated with the following formula:

Integrated output voltage = (2 *value) / 1023

DAC_OUT line must be integrated (for example with a low band pass filter) in order to obtain an analog voltage.

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12.1.2. Enabling DAC

An AT command is available to use the DAC function. The command is: AT#DAC= [<enable> [, <value>]]

<value> - scale factor of the integrated output voltage (0..1023 - 10 bit precision) it must be present if <enable>=1

Refer to SW User Guide or AT Commands Reference Guide for the full description of this function.

NOTE:

The DAC frequency is selected internally. D/A converter must not be used during POWERSAVING.

12.1.3. Low Pass Filter Example

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12.2. ADC Converter

12.2.1. Description

The on board A/D are 11-bit converter. They are able to read a voltage level in the range of 0÷2 volts applied on the ADC pin input, store and convert it into 11 bit word.

Min

Max

Units

Input Voltage range

Volt

AD conversion

bits

Resolution

< 1

The GL865 module provides 2 Analog to Digital Converters. The input lines are:

ADC_IN1 available on pin 13

ADC_IN2 available on pin 14

12.2.2. Using ADC Converter

An AT command is available to use the ADC function.

The command is AT#ADC=1,2

The read value is expressed in mV

Refer to SW User Guide or AT Commands Reference Guide for the full description of this function.

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12.3. Debug of the GL865 in production

To test and debug the mounting of the GL865, we strongly recommend to foreseen test pads on the host PCB, in order to check the connection between the GL865 itself and the application and to test the performance of the module connecting it with an external computer. Depending by the customer application, these pads include, but are not limited to the following signals:

signal

38, 37

VBATT & VBATT_PA

32, 33, 35, 36, 46

GND

TXD

RXD

RTS

V_AUX / PWRMON

RESET*

TX_AUX

RX_AUX

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13. Mounting the GL865 on your Board

13.1. General

The GL865 modules have been designed in order to be compliant with a standard lead-free SMT process.

13.2. Module finishing & dimensions

Lead-free Alloy:

Surface finishing Ni/Au for all solder pads

Pin 1

Bottom View

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13.3. Recommended foot print for the application

In order to easily rework the GE865 is suggested to consider on the application a 1.5 mm placement inhibit area around the module. It is also suggested, as common rule for an SMT component, to avoid having a mechanical part of the application in direct contact with the module.

NOTE: In the customer application, the region under WIRING INHIBIT (see figure) must be clear from signal or ground paths.

Top View

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13.4. Solder paste

Lead free

Solder paste

Sn/Ag/Cu

We recommend to use only “no clean” solder paste in order to avoid the cleaning of the modules after assembly

13.4.1. GL865 Solder reflow

The following is the recommended solder reflow profile

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Profile Feature

Pb-Free Assembly

Average ramp-up rate (TL to TP)

3°C/second max

Preheat

– Temperature Min (Tsmin) – Temperature Max (Tsmax)

– Time (min to max) (ts)

150°C 200°C

60-180 seconds

Tsmax to TL

– Ramp-up Rate

3°C/second max

Time maintained above:

– Temperature (TL) – Time (tL)

217°C 60-150 seconds

Peak Temperature (Tp)

245 +0/-5°C

Time within 5°C of actual Peak Temperature (tp)

10-30 seconds Ramp-down Rate

6°C/second max.

Time 25°C to Peak Temperature

8 minutes ma x.

NOTE:

All temperatures refer to topside of the package, measured on the package body surface

WARNING:

The GL865 module withstands one reflow process only.

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14. Packing system

The GL865 modules are packaged on trays of 20 pieces each. This is especially suitable for the GL865 according to SMT processes for pick & place movement requirements.

NOTE:

All temperatures refer to topside of the package, measured on the package body surface

WARNING:

These trays can withstand at the maximum temperature of 65° C.

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14.1. Moisture sensibility

The level of moisture sensibility of the Product is “3”, according with standard IPC/JEDEC JSTD-020, take care of all the relative requirements for using this kind of components. Moreover, the customer has to take care of the following conditions: a) The shelf life of the Product inside of the dry bag must be 12 months from the bag seal date, when stored in a non-condensing atmospheric environment of <40°C / 90% RH b) Environmental condition during the production: <= 30°C / 60% RH according to IPC/JEDEC J-STD-033A paragraph 5

c) The maximum time between the opening of the sealed bag and the reflow process must be 168 hours if condition b) “IPC/JEDEC J-STD-033A paragraph 5.2” is respected d) Baking is required if conditions b) or c) are not respected e) Baking is required if the humidity indicator inside the bag indicates 10% RH or more

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15. Conformity Assessment Issues

The Telit GL865 Module has been assessed in order to satisfy the essential requirements of the R&TTE Directive 1999/05/EC (Radio Equipment & Telecommunications Terminal Equipments) to demonstrate the conformity against the harmonised standards with the final involvement of a Notified Body.

If the module is installed in conformance to the Telit installation manuals, no further evaluation under Article 3.2 of the R&TTE Directive and do not require further involvement of a R&TTE Directive Notified Body for the final product.

In all other cases, or if the manufacturer of the final product is in doubt, then the equipment integrating the radio module must be assessed ag ains t A rticle 3.2 of the R&TTE Directive.

In all cases the assessment of the final product must be made against the Essential requirements of the R&TTE Directive Articles 3.1(a) and (b), Safety and EMC respectively, and any relevant Article 3.3 requirements.

This Hardware User Guide contains all the information you may need for developing a product meeting the R&TTE Directive.

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16. SAFETY RECOMMANDAT IO NS

READ CAREFULLY

Be sure the use of this product is allowed in the country and in the environment required. The use of this product may be dangerous and has to be avoided in the following areas:

• Where it can interfere with other electronic devices in environments such as hospitals,

airports, aircrafts, etc.

• Where there is risk of explosion such as gasoline stations, oil refineries, etc. It is

responsibility of the user to enforce the country regulation and the specific environment

regulation. Do not disassemble the product; any mark of tampering will compromise the warranty validity. We recommend following the instructions of the hardware user guides for a correct wiring of the product. The product has to be supplied with a stabilized voltage source and the wiring has to be conforming to the security and fire prevention regulations. The product has to be handled with care, avoiding any contact with the pins because electrostatic discharges may damage the product itself. Same cautions have to be taken for the SIM, checking carefully the instruction for its use. Do not insert or remove the SIM when the product is in power saving mode. The system integrator is responsible of the functioning of the final product; therefore, care has to be taken to the external components of the module, as well as of any project or installation issue, because the risk of disturbing the GSM network or external devices or having impact on the security. Should there be any doubt, please refer to the technical documentation and the regulations in force. Every module has to be equipped with a proper antenna with specific characteristics. The antenna has to be installed with care in order to avoid any interference with other electronic devices and has to guarantee a minimum distance from the body (20 cm). In case of this requirement cannot be satisfied, the system integrator has to assess the final product against the SAR regulation.

The European Community provides some Directives for the electronic equipments introduced on the market. All the relevant information’s are available on the European Community website:

http://ec.europa.eu/enterprise/sectors/rtte/documents/

The text of the Directive 99/05 regarding telecommunication equipments is available, while the applicable Directives (Low Voltage and EMC) are available at:

http://ec.europa.eu/enterprise/sectors/electrical/

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17. Document History

RReevviissiioonn

DDaattee

CChhaannggeess

Rev.0

2011-01-05

First ISSUE

Rev.1

2011-03-10

VBATT_PA power consumption specification

Page 18 typical 2uA max 20uA Page 23 typical 2uA max 20uA AUX serial port naming

from RXD_AUX; TXD_AUX to RX_AUX; TX_AUX

Rev.2

2011-08-24

Added chapter 7.2 PCB guidelines in case of FCC certifications –

updated with FCC requirements Added chapter 16. Safety Recommendations – updated with FCC and IC

requirements

Rev.3

2011-10-03

Add chapter 11.4 Using the RF Transmission Control GPIO4

Add chapter 14.1 Moisture sensibility – add details Updated Chapter 5.1 Auto-Turning ON the GL865 – 5 second with VBATT< 3,4V

Telit Wireless Solutions GL865 QUAD, GL865 DUAL Hardware User's Manual

Specifications and Main Features

Frequently Asked Questions

User Manual