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

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1vv0300910

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1 – 2011-07-22

GL865 Hardware User Guide

1vv0300910 Rev.1 – 2011-07-22

APPLICABILITY TABLE

PRODUCT

GL865 QUAD GL865 DUAL

GL865 Hardware User Guide

1vv0300910 Rev.1 – 2011-07-22

DISCLAIMER

The information contained in this document is the proprietary information of Telit Communications S.p.A. and its affiliates (“TELIT”). The contents are confidential and any disclosure to persons other than the officers, employees, agents or subcontractors of the owner or licensee of this document, without the prior written consent of Telit, is strictly prohibited.

Telit makes every effort to ensure the quality of the information it makes available. Notwithstanding the foregoing, Telit does not make any warranty as to the information contained herein, and does not accept any liability for any injury, loss or damage of any kind incurred by use of or reliance upon the information.

Telit disclaims any and all responsibility for the application of the devices characterized in this document, and notes that the application of the device must comply with the safety standards of the applicable country, and where applicable, with the relevant wiring rules.

Telit reserves the right to make modifications, additions and deletions to this document due to typographical errors, inaccurate information, or improvements to programs and/or equipment at any time and without notice. Such changes will, nevertheless be incorporated into new editions of this application note.

GL865 Hardware User Guide

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Contents

1. INTRODUCTION ......................................................................................................................................................... 6

1.1. S

1.2. A

1.3. C

1.4. D

1.5. T

1.6. R

1.7. D

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

3. GL865 MECHANICAL DIMENSIONS .......................................................................................................................... 12

4. GL865 MODULE CONNECTIONS ............................................................................................................................... 13

4.1. PIN-OUT .................................................................................................................................................................. 13

4.2. P

5. HARDWARE COMMANDS ........................................................................................................................................ 17

5.1. A

5.2. T

5.3. R

6. POWER SUPPLY ....................................................................................................................................................... 23

6.1. P

6.2. P

6.3. G

COPE

......................................................................................................................................................................... 6

UDIENCE

.................................................................................................................................................................... 6

ONTACT INFORMATION, SUPPORT

OCUMENT ORGANIZATION

EXT CONVENTIONS

ELATED DOCUMENTS

OCUMENT HISTORY

IN LAYOUT

UTO-TURNING ON THE

URNING

ESETTING THE

5.3.1.

OWER SUPPLY REQUIREMENTS

OWER CONSUMPTION

ENERAL DESIGN RULES

6.3.1.

6.3.2.

6.3.3.

............................................................................................................................................................... 16

OFF

THE

GL865 ................................................................................................................................................ 21

Hardware Unconditional restart .................................................................................................................... 21

Electrical Design Guidelines ........................................................................................................................... 25

Thermal Design Guidelines ............................................................................................................................ 29

Power Supply PCB layout Guidelines ............................................................................................................. 30

.................................................................................................................................. 6

............................................................................................................................................ 6

....................................................................................................................................................... 7

................................................................................................................................................... 8

..................................................................................................................................................... 8

GL865 ................................................................................................................................... 17

GL865 ........................................................................................................................................... 19

..................................................................................................................................... 23

................................................................................................................................................ 24

............................................................................................................................................... 25

7. ANTENNA ................................................................................................................................................................ 32

7.1. GSM A

7.2. GSM A

7.3. GSM A

8. LOGIC LEVEL SPECIFICATIONS .................................................................................................................................. 38

8.1. R

9. SERIAL PORTS .......................................................................................................................................................... 41

9.1. MODEM SERIAL PORT ............................................................................................................................................. 41

9.2. RS232

9.3. ................................................................................................................................................................................ 46

9.4. 5V UART

10. AUDIO SECTION OVERVIEW ................................................................................................................................ 49

NTENNA REQUIREMENTS

NTENNA -

NTENNA - INSTALLATION GUIDELINES

ESET SIGNAL

LEVEL TRANSLATION

PCB

LINE GUIDELINES

............................................................................................................................................................. 39

LEVEL TRANSLATION

.................................................................................................................................... 32

.......................................................................................................................... 33

................................................................................................................... 37

.......................................................................................................................................... 43

...................................................................................................................................... 47

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10.1. E

LECTRICAL CHARACTERISTICS

10.1.1. Input Lines ..................................................................................................................................................... 52

10.1.2. Output Lines................................................................................................................................................... 53

........................................................................................................................................ 52

11. GENERAL PURPOSE I/O ....................................................................................................................................... 55

11.1. GPIO L

11.2. U

11.3. U

11.4. U

11.5. U

11.6. U

11.7. M

1.1.1 Short Description .................................................................................................................................................... 59

11.7.1. Frequency Behaviour ..................................................................................................................................... 60

11.7.2. Power Supply Influence .................................................................................................................................. 60

11.7.3. Working Current Influence ............................................................................................................................. 61

11.8. STAT LED I

11.9. SIMIN

11.10. RTC B

11.11. SIM H

12. DAC AND ADC SECTION ....................................................................................................................................... 65

12.1. DAC C

12.1.1. Description ..................................................................................................................................................... 65

12.1.2. Enabling DAC ................................................................................................................................................. 66

12.1.3. Low Pass Filter Example................................................................................................................................. 66

12.2. ADC C

12.2.1. Description ..................................................................................................................................................... 67

12.2.2. Using ADC Converter ..................................................................................................................................... 67

12.3. D

OGIC LEVELS

SING A

GPIO P

SING A

GPIO P

SING THE

SING THE ALARM OUTPUT

SING THE BUZZER OUTPUT

AGNETIC BUZZER CONCEPTS

DETECTION

YPASS OUT

OLDER IMPLEMENTATION

ONVERTER

EBUG OF THE

..................................................................................................................................................... 56

AD AS

INPUT ...................................................................................................................................... 57

AD AS

OUTPUT .................................................................................................................................. 57

RFTXMON O

NDICATION OF NETWORK SERVICE AVAILABILITY

GL865

UTPUT

...................................................................................................................................................... 62

.................................................................................................................................................... 64

........................................................................................................................................................ 65

........................................................................................................................................................ 67

IN PRODUCTION

GPIO5 ......................................................................................................................... 57

GPIO6 ............................................................................................................................... 58

GPIO7 ............................................................................................................................... 58

....................................................................................................................................... 59

................................................................................................. 61

................................................................................................................................ 64

........................................................................................................................... 67

13. MOUNTING THE GL865 ON YOUR BOARD ........................................................................................................... 69

13.1. G

13.2. M

13.3. R

13.4. S

14. PACKING SYSTEM ................................................................................................................................................ 73

14.1. M

15. CONFORMITY ASSESSMENT ISSUES ..................................................................................................................... 75

16. SAFETY RECOMMANDATIONS ............................................................................................................................. 76

ENERAL

................................................................................................................................................................... 69

ODULE FINISHING & DIMENSIONS

ECOMMENDED FOOT PRINT FOR THE APPLICATION

OLDER PASTE

13.4.1. GL865 Solder reflow ....................................................................................................................................... 71

OISTURE SENSIBILITY

............................................................................................................................................................ 71

................................................................................................................................................. 74

................................................................................................................................ 69

........................................................................................................... 70

GL865 Hardware User Guide

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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 Support 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.

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.

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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.

1.5. Text Conventions

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

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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

1.7. Document History

RReevviissiioon

ISSUE#0 ISSUE#1

DDaattee CChhaannggeess

2011-01-05 2011-07-22

First ISSUE Add FCC IC note in Safety recommendations

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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 Description document where all the hardware information is reported.

NOTICE:

(

EN) The integration of the GSM/GPRS GL865 cellular module within

user application shall be done according to the design rules described in this manual.

(IT) L’integrazione del modulo cellulare GSM/GPRS dell’applicazione dell’utente dovrà rispettare le indicazioni progettuali descritte in questo manuale.

(DE) Die Integration des muß gemäß der in diesem Dokument beschriebenen Kunstruktionsregeln erfolgen.

(SL) Integracija GSM/GPRS morala upoštevati projektna navodila, opisana v tem piročniku.

(SP) La utilización del modulo GSM/GPRS usos para los cuales ha sido deseñado descritos en este manual del usuario.

(FR) L’intégration du module cellulaire GSM/GPRS l’application de l’utilisateur sera faite selon les règles de conception décrites dans ce manuel.

(HE)

GL865

GSM/GPRS Mobilfunk-Moduls in ein Gerät

modula v uporabniški aplikaciji bo

GL865

The information presented in this document is believed to be accurate and reliable. However, no responsibility is assumed by

GL865

debe ser conforme a los

GL865

all’interno

dans

GL865 Hardware User Guide

1vv0300910 Rev.1 – 2011-07-22

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 Dimensions

The GL865 overall dimensions are:

• Length: 24.4 mm

• Width: 24.4 mm

• Thickness: 2.7 mm

• Weight 2.48 g

can be

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4. GL865 module connections

4.1. PIN-OUT

Pad Signal

20 21 22 24 23

10 11

All

GPI0

program

med

44 45

7 8

13 14 15

EAR- AO EAR+ AO MIC- AI MIC+ AI AGND - Analog Ground -

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

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

SIMIO

SIMIN I

RXD_AUX I Auxiliary UART (RX Data) CMOS 2.8V TXD_AUX O Auxiliary UART (TX Data) CMOS 2.8V

C109/DCD/GPO O

C125/RING/GPO O

C107/DSR/GPO O

C108/DTR/GPI I

C105/RTS/GPI I

C106/CTS/GPO O

C103/TXD I Serial data input (TXD) from DTE CMOS 2.8V C104/RXD O Serial data output to DTE CMOS 2.8V

ADC_IN1 AI ADC_IN2 AI DAC_OUT AO

Earphone signal output, phase - Audio Earphone signal output, phase + Audio

Mic.signal input; phase- Audio Mic.signal input; phase+ Audio

SIM card interface

External SIM signal – Power supply for

External SIM signal – Data I/O

Prog. / Data + HW Flow Control

Output for Data carrier detect signal

Output for Ring indicator signal (RI)

Output for Data set ready signal (DSR)

Input for Data terminal ready signal

Input for Request to send signal (RTS)

Output for Clear to send signal (CTS)

Analog/Digital converter input A/D Analog/Digital converter input A/D

Digital/Analog converter output D/A

Function Note Type

Audio

the SIM

Presence SIM input

(See para 11.9)

Trace

(DCD) to DTE

/ GP output

to DTE

/ GP output

to DTE

/ GP output

(DTR) from DTE

/ GP input

from DTE

/ GP input

to DTE

/ GP output

DAC and ADC

1,8 / 3V

4.7K

Pull up

CMOS 2.8V

1,8 / 3V

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Pad Signal

30 47

43 34

38 37 23 32 33 35 36 46

48 16 17 18 19 25 31

VRTC AO

RESET* I Reset input CMOS 1.8V

V_AUX / PWRMON O

Antenna O Antenna output – 50 Ω RF

GPIO_01 /

DVI_WA0

GPIO_02 / JDR /

DVI_RX

GPIO_03 /

DVI_TX

GPIO_04 / TX

Disable /

DVI_CLK

GPIO_05 /

RFTXMON

GPIO_06 / ALARM

GPIO_07 /

BUZZER

GPIO_08 /

STAT_LED

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 GND - Ground Power GND - Ground Power GND - Ground Power GND - Ground Power

Miscellaneous Functions

2.8V stabilized output Imax=100mA

I/O GPIO01 Configurable GPIO

/ Digital Audio Interface (WA0) GPIO02 Configurable GPIO / Jammer

Detect Report

/ Digital Audio Interface (RX)

I/O GPIO03 Configurable GPIO

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

input

/ Digital Audio Interface (CLK)

I/O GPIO05 Configurable GPIO

/ Transmitter ON monitor

I/O GPIO06 Configurable GPIO

/ ALARM

I/O GPIO07 Configurable GPIO

/ Buzzer

I/O GPIO08 Configurable GPIO

/ STAT LED

Function Note Type

VRTC Backup Power

/ Power ON monitor

GPIO

Power Supply

RESERVED

CMOS 2.8V

Power Out

2.8V

WARNING:

Reserved pins must not be connected.

pin signal

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NOTE:

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

38, 37 VBATT & VBATT_PA

32, 33, 35, 36, 46 GND

23 AGND

7 TXD 8 RXD

5 RTS 43 V_AUX / PWRMON 47 RESET* 45 TXD_AUX 44 RXD_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.

Modem Reset Proc

AT init sequence

Start AT CMD

PWMON = ON?

Enter AT<CR>

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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

can be consider fully operating.

When the power supply voltage is lower than 3.4V, after 4000 mseconds, the and the module can be consider fully operating.

The following flow chart shows the proper turn on procedure:

Modem ON Proc.

pin will be at the high logic level and the module

V_AUX / PWRMON

pin will be at the high logic level

PWR supply =

Delay 300mS

ON?

AT answer in

1second ?

Delay 1s - 4s

for Low Voltage

Delay 1s

Modem ON Proc.

Disconnect PWR

AT init

Enter AT<CR>

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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 below:

Start AT CMD.

Delay 300mS

AT answer in

1second ?

sequence.

supply

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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, about 30uA, 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

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:

V_AUX /

Modem OFF

Disconnect PWR

Modem ON

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Proc.

PWRMON = OFF?

supply

Place AT command

AT#SYSHALT

Wait

PWRMON =OFF

15s timeout

supply

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:

Delay 1.5s

Proc.

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5.3. Resetting the GL865

5.3.1. Hardware Unconditional restart

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 be 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:

Reset = LOW

Delay 200ms

Reset = HIGH

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

Modem Reset

Proc.

PWRMON =

Delay 1s

Delay 1,5s

Start AT

CMD.

Disconnect PWR

supply

Modem ON

Proc.

NOTE:

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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 requirements:

POWER SUPPLY

Nominal Supply Voltage Normal Operating Voltage Range Extended Operating Voltage Range

3.8 V

3.4 V÷ 4.20 V

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 mseconds, the

V_AUX / PWRMON

pin will be at the high logic level

and the module can be consider fully operating. See para 5.1.

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6.2. Power Consumption

The GL865 power consumptions are:

GL 865

Mode

SWITCHED OFF

Switched Off <5uA Switched Off with

AT#SYSHALT

IDLE mode

AT+CFUN=1

AT+CFUN=4

AT+CFUN=0 or =5

CSD TX and RX mode

GSM900 CSD PL5 DCS1800 CSD PL0

GPRS (class 8) 1TX

DCS1800 PL0

GPRS (class 10) 2TX

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.

Average

(mA)

<650uA

21,0

18,0

3,9 2,5 2,4 1,5

230

180

225 175

Mode description

Module power supplied only on VBATT_PA pin, the VBATT pin is not power supplied. Module power supplied on VBATT_PA pin and VBATT pin, the at command applied.

AT#SYSHALT

Normal mode: full functionality of the module Disabled TX and RX; module is not registered on the network Paging Multiframe 2 Paging Multiframe 3 Paging Multiframe 4 Paging Multiframe 9

GSM VOICE CALL

GPRS Sending data mode GSM900 PL5

GPRS Sending data mode

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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

• the thermal design

• 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.

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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):

6.3.1.3. Battery Source Power Supply Design Guidelines

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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:

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 noise is not so disturbing 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.

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The power supply input cables should be kept separate from noise sensitive lines such as microphone/earphone cables.

QUAD

1850

1990MHz PCS1900 band

2:1 (limit to fulfil all

Impedance

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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

DUAL

824-894 MHz GSM850 band

Frequency range

Gain

Impedance 50 Ohm 50 Ohm Input power > 2 W > 2 W VSWR absolute max

VSWR recommended

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

1.4dBi @ GSM900 and 3dBi @ DCS1800

1.4dBi @ GSM850 and 3dBi @ PCS1900

≤ 10:1 (limit to avoid permanent damage) ≤ regulatory requirements)

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

1.4dBi @ GSM900 and 3dBi @ DCS1800

≤ 10:1 (limit to avoid permanent damage) ≤ regulatory requirements)

When using the GL865, since there's no antenna connector on the module, the antenna must be connected to the GL865 antenna pad (pin 34) by means of a transmission line implemented on the PCB.

In the case the antenna is not 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.

This line of transmission shall fulfill the following requirements:

ANTENNA LINE ON PCB REQUIREMENTS

Characteristic

Max Attenuation 0,3 dB

50 Ohm

equipotential to the

GL865

ground pins

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Coupling with other signals shall be avoided Cold End (Ground Plane) of antenna shall be

7.2. GSM Antenna - PCB line Guidelines

Make sure that the transmission line’s characteristic impedance is 50Ω; Keep the length of line on the PCB as short as possible, since the antenna line loss shall be less than about 0,3 dB; Line geometry should have uniform characteristics, constant cross section, avoid meanders and abrupt curves; Any kind of suitable geometry / structure (Microstrip, Stripline, Coplanar, Grounded Coplanar Waveguide...) can be used for implementing the printed transmission line afferent the antenna; If a Ground plane is required in line geometry, that plane has to be continuous and sufficiently extended, so the geometry can be as similar as possible to the related canonical model; Keep, if possible, at least one layer of the PCB used only for the Ground plane. If possible, use this layer as reference Ground plane for the transmission line; It is wise to surround (on both sides) the PCB transmission line with Ground, avoid having other signal tracks facing directly the antenna line track. Avoid crossing any un-shielded transmission line footprint with other signal tracks on different layers; The ground surrounding the antenna line on PCB has to be strictly connected to the main Ground Plane by means of via holes (once per 2mm at least), placed close to the ground edges facing line track; 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 EM noisy devices are present on 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 EM noisy devices are not present around the line, the use of geometries like Microstrip or Grounded Coplanar Waveguide has to be preferred, since they typically ensure less attenuation if compared to a Stripline having same length;

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7.3. 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.

7.3.1. 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 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 εr = 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:

1.1 mm

m m 5

FR4

0.3 mm

m m 2

m m 5

m m 1

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7.3.2. 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:

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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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7.4. GSM Antenna - Installation Guidelines

Install the antenna in a place covered by the GSM signal. Antenna shall not be installed inside metal cases Antenna shall be installed also according Antenna manufacturer instructions.

pins when on

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

Operating Range - Interface levels (2.8V CMOS)

Level Min Max

Input high level Input low level Output high level Output low level

2.1V 3.1V 0V 0.5V

2.2V 3.1V 0V 0.35V

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

Level Min Max

Input high level Input low level Output high level Output low level

1.6V 2.0V 0V 0.4V 1,65V 2.0V 0V 0.35V

Current characteristics

Level Typical

Output Current 1mA Input Current 1uA

-0.3V +3.1V

-0.3V +2.1V

-0.3V +3.0 V

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8.1. Reset signal

Signal Function I/O pin

RESET* Phone reset I 47

RESET* is 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(NOTE

RESET* Input low 0V 0.2V

2.1V

(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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gh level

Input low level

VOL

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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 Ratings -Not Functional

Parameter Min Max Input level on any

digital pad when on Input voltage on analog pads when on

Operating Range - Interface levels (2.8V CMOS)

Level Min Max Input hi

VIH

VIL Output high level VOH Output low level

-0.3V +3.1V

2.1V 3.1 V

0V 0.5V

2.2V 3.1V

0V 0.35V

Transmit line *see

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The signals of the GL865 serial port are:

RS232

Number

1 DCD - dcd_uart

2 RXD - tx_uart 8

3 TXD - rx_uart 7

4 DTR - dtr_uart

5 GND

6 DSR - dsr_uart

7 RTS -rts_uart 5 Request to Send

8 CTS - cts_uart

9 RI - ri_uart 2 Ring Indicator

Signal GL865

Pad Number

32, 33,

35, 36, 46

3 Data Set Ready

6 Clear to Send

Name Usage

Data Carrier

Detect

Note

Receive line *see

Note

Data Terminal

Ready

Ground ground

Output from the GL865 that indicates the carrier presence Output transmit line of GL865 UART Input receive of the GL865 UART Input to the GL865 that controls the DTE READY condition

Output from the GL865 that indicates the module is ready Input to the GL865 that controls the Hardware flow control Output from the GL865 that controls the Hardware flow control Output from the GL865 that indicates 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:

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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.

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 RS232 level. 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.

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NOTE:

The input lines working at 2.8VCMOS can be pulled-up with 47KΩ In case of reprogramming of the module has to be considered the

use of the RESET line to start correctly the activity. The preferable configuration is having an external supply for

the buffer.

NOTE:

220n

MIC/AF_IN+

MIC/AF_IN

AGND

MODULE

INPUT

ADC

Vmic

220n

2.2K

MODULE

INPUT

ADC

Vmic

MIC/AF_IN+

AGND

Integral Ground Plane

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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

÷10u

1 u

MIC/AF_IN-

220n

Wire Or Ground Plane

TIP: Since the J-FET transistor inside the microphone acts as RF-detector-amplifier, ask vendor for a microphone with anti-EMI

AF_IN+

AGND

MODULE

INPUT

ADC

AF_IN

220n

AF_IN+

MIC/AF_IN+

MIC/AF_IN

AGND

MODULE

Vmic

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capacitor (usually a 33pF or a 10pF capacitor placed across the output terminals inside the case).

LINE-IN connection

Vmic

220n

MIC/AF_IN+

MIC/AF_IN-

INPUTADC

Remote_GND

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.

EAR+

EAR

MODULE

OUTPUT

DAC

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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.

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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

Levels

To have 0dBm0 @1KHz

(*)

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 JFet 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).

1kΩ/2kΩ/2.2kΩ

Differential input

voltage

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10.1.2. Output Lines

EAR/Line-out Output

Differential line coupling

Single-ended line coupling

output load resistance ≥ 8 Ω internal output

resistance signal bandwidth 250÷3400Hz

max. differential output

Direct connection (VDC=1.3÷1.6V) One EAR terminal connected via a DC-block capacitor, the other one left open

4 Ω (typ.)

(@ -3dB with default filter)

1120mVpp @3.14dBm0 (*)

differential output voltage

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

550mV

@0dBm0 (*)

rms

(*) 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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Pin Signal

I/O Function

Type

Input /

Default

ON_OFF

State

Note

function JDR

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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 (

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

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 refer to chapter 8.

The following table shows the available GPIO on the GL865.

internally controlled

)

high

42 GPIO_01 I/O

41 GPIO_02 I/O

40 GPIO_03 I/O

39 GPIO_04 I/O

29 GPIO_05 I/O

28 GPIO_06 I/O

27 GPIO_07 I/O

26 GPIO_08 I/O

Configurable GPIO

CMOS

2.8V

CMOS

2.8V

CMOS

2.8V

CMOS

2.8V

CMOS

2.8V

CMOS

2.8V

CMOS

2.8V

CMOS

2.8V

output

current

1uA/1mA INPUT 0 0

State

state

during

Reset

Alternate

function

DVI_WA0

Alternate

and DVI_RX

Alternate

function

DVI_TX

Alternate function TX disable and

DVI_CLK

Alternate

function

RFTXMON

Alternate

function

ALARM

Alternate

function

BUZZER

Alternate

function STAT_LED

Signal

I/O F

unction

Type

Input /

Default

ON_OFF

State

Note

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

output

current

1 GPO_A O

2 GPO_B O

3 GPO_C O

4 GPI_E I

5 GPI_F I

6 GPO_D O

Configurable GPO

Configurable GPI

Configurable GPO

CMOS

2.8V

CMOS

2.8V

CMOS

2.8V

CMOS

2.8V

CMOS

2.8V

CMOS

2.8V

1uA/1mA INPUT 0 0

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) Input level on any digital pin when on (CMOS 1.8) Input voltage on analog pins when on

Operating Range - Interface levels (2.8V CMOS)

Level Min Max

State

state

-0.3V +3.1V

-0.3V +2.1V

-0.3V +3.0V

during

Reset

Alternate

function C109/DCD Alternate function C125/RING Alternate function C107/DSR Alternate function C108/DTR Alternate function C105/RTS Alternate function C106/CTS

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Input high level 2.1V 3.1V Input low level 0V 0.5V

Output high level

Output low level

2.2V 3.1V 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. 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 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:

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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.

11.5. 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.

11.6. 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:

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+V buzzer

TR2

SMBT2907A

4,7K

GPIO7

TR1

BCR141W

D1N4148

33pF

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.

11.7. Magnetic Buzzer Concepts

1.1.1 Short Description

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.

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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.

Diaphragm movement.

11.7.1. 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 Vpp), if you modify the waveform (

sinus

) the frequency response will change.

e.g. from square to

11.7.2. 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 fo increases, amplitude decreases”.

It is very important to respect the sense of the applied

a voltage more positive than

: if this happens, the diaphragm vibrates in the

obability to be expelled from

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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: Vpp ↑  fo ↓ Vpp ↓ fo ↑

The risk is that the fo could easily fall outside of new bandwidth; consequently the SPL could be much lower than the

WARNING:

voltage: never apply to the "-" pin the "+" pin opposite direction with a high pr its physical position. This damages the device permanently.

expected.

11.7.3. 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.

11.8. 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)

0,5s)

off

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LED status Device Status

Permanently off Device off Fast blinking

(Period 1s, Ton

Net search / Not registered / turning

NOTE:

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

A schematic example could be:

Slow blinking (Period 3s, Ton 0,3s)

Permanently on a call is active

Registered full service

11.9. 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;

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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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11.10. RTC Bypass out

The VRTC pin brings out the Real Time Clock supply, which is separate from the rest 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.

11.11. 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

Voltage range

(filtered)

Range 0 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.

Min Max Units

0 2,6 Volt

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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

Input Voltage

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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.

range AD conversion Resolution

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

Min Max Units

0 2

- 11

- < 1

Volt

bits mV

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.

12.3. Debug of the GL865 in production

44 RXD_AUX

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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:

32, 33, 35, 36,

pin signal

38, 37 VBATT & VBATT_PA

GND

7 TXD 8 RXD

5 RTS 43 47 RESET* 45 TXD_AUX

V_AUX / PWRMON

Lead

free Alloy:

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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

Bottom

Surface finishing Ni/Au for all solder pads

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13.3. Recommended foot print for the application

Top View

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.

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13.4. Solder paste

Solder paste

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

Lead free

Sn/Ag/Cu

– Time (min to max) (ts)

60-180 seconds

– Time (tL)

60-150 seconds

Peak Temperature (Tp)

245 +0/

5°C

Time within 5°C of actual

Temperature (tp)

Ramp

down Rate

6°C/second max.

Time 25°C to Peak

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Profile Feature Pb-Free Assembly

Average ramp-up rate (T to TP) Preheat – Temperature Min (Tsmin) – Temperature Max (Tsmax)

3°C/second max

150°C 200°C

Tsmax to TL – Ramp-up Rate Time maintained above: – Temperature (TL)

Peak

Temperature

3°C/second max

217°C

10-30 seconds

8 minutes max.

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 GL865 is “3”, in according with standard IPC/JEDEC J-STD-020, take care all the relatives requirements for using this kind of components.

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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 against Article 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 RECOMMANDATIONS

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.

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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

FCC Regulatory Requirements

This device complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) this device may not cause harmful interference, and (2) this device must accept any interference received, including interference that may cause undesired operation. RF Exposure: The antenna(s) used for this transmitter must be installed to provide a separation distance of at least 20 cm from all the persons and must not be co-located or operating in conjunction with any other antenna or transmitter. The system antenna(s) used for this module must not exceed 1,4dBi (850MHz) and 3.0dBi (1900MHz) for mobile and fixed or mobile operating configurations.

Users and installers must be provided with antenna installation instructions and transmitter operating conditions for satisfying RF exposure compliance.

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IC Regulatory Requirements

This device complies with Industry Canada license-exempt RSS standard(s). Operation is subject to the following two conditions: (1) this device may not cause interference, and (2) this device must accept any interference, including interference that may cause undesired operation of the device.

Le présent appareil est conforme aux CNR d'Industrie Canada applicables aux appareils radio exempts de licence. L'exploitation est autorisée aux deux conditions suivantes : (1) l'appareil ne doit pas produire de brouillage, et (2) l'utilisateur de l'appareil doit accepter tout brouillage radioélectrique subi, même si le brouillage est susceptible d'en compromettre le fonctionnement.

Under Industry Canada regulations, this radio transmitter may only operate using an antenna of a type and maximum (or lesser) gain approved for the transmitter by Industry Canada. To reduce potential radio interference to other users, the antenna type and its gain should be so chosen that the equivalent isotropically radiated power (e.i.r.p.) is not more than that necessary for successful communication.

Conformément à la réglementation d'Industrie Canada, le présent émetteur radio peut fonctionner avec une antenne d'un type et d'un gain maximal (ou inférieur) approuvé pour l'émetteur par Industrie Canada. Dans le but de réduire les risques de brouillage radioélectrique à l'intention des autres utilisateurs, il faut choisir le type d'antenne et son gain de sorte que la puissance isotrope rayonnée équivalente (p.i.r.e.) ne dépasse pas l'intensité nécessaire à l'établissement d'une communication satisfaisante.

The GL865-QUAD has been designed to comply with safety requirements for exposure to radio waves (SAR) in accordance with RSS-102. Please follow the instructions included in the user guide for product installation and use.

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This radio transmitter GL865-QUAD has been approved by Industry Canada to operate with antennas with maximum permissible gain not exceeding 1,4dBi (850MHz) and 3.0dBi (1900MHz). Antenna types having a gain greater than the maximum gain indicated are strictly prohibited for use with this device.

Le GL865-QUAD a été conçu pour se conformer aux exigences de sécurité pour l'exposition aux ondes radio (SAR) en conformité avec RSS-102. S'il vous plaît suivez les instructions incluses dans le guide utilisateur pour l'installation du produit et son utilisation.

Cet émetteur radio (numéro de modèle) a été approuvé par Industrie Canada pour fonctionner avec des antennes avec un gain maximal admissible de 1.4 dBi (850MHz) et 3.0dBi (1900MHz). Types d'antenne ayant un gain supérieur au gain maximal indiqué est strictement interdit pour une utilisation avec cet appareil.

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

Specifications and Main Features

Frequently Asked Questions

User Manual