Telit Communications S p A HE920NA Wireless module User Manual HW User Guide

Telit Communications S.p.A. Wireless module HW User Guide

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HE920
Hardware User Guide
1vv0301014 Rev.9 – 2014-01-23
HE920 Hardware User Guide
1vv0301014 Rev.9 – 2014-01-23
APPLICABILITY TABLE
PRODUCT
HE920-EU
HE920-NA
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HE920 Hardware User Guide
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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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HE920 Hardware User Guide
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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
fault-tolerant 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.
Copyright © Telit Communications S.p.A. 2013.
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HE920 Hardware User Guide
1vv0301014 Rev.9 – 2014-01-23
Contents
1.
Introduction ................................................. 9
1.1.
Scope ..................................................... 9
1.2.
Audience .................................................. 9
1.3.
Contact Information, Support .............................. 9
1.4.
Document Organization .................................... 10
1.5.
Text Conventions ......................................... 11
1.6.
Related Documents ........................................ 11
2.
General Product Description ................................. 12
2.1.
Overview ................................................. 12
2.2.
HE920 Mechanical Dimensions .............................. 13
2.3.
Weight ................................................... 13
2.4.
Environmental requirements ............................... 14
2.4.1.
2.4.2.
2.5.
3.
Operating Frequency ...................................... 14
HE920 Module Connections .................................... 16
3.1.
PIN-OUT .................................................. 16
3.1.1.
4.
Temperature range .......................................... 14
RoHS compliance ............................................ 14
LGA Pads Layout ............................................ 23
Hardware Commands ........................................... 25
4.1.
Turning ON the HE920 ..................................... 25
4.2.
Initialization and Activation state ...................... 25
4.3.
Turning OFF the HE920 .................................... 27
4.3.1.
4.3.2.
Shutdown by Software Command ............................... 28
Hardware Shutdown .......................................... 29
4.4.
Hardware Unconditional Restart (RESET) ................... 30
4.5.
Hardware Unconditional Shutdown (Power Off) .............. 31
4.6.
Summary of Turning ON and OFF the module ................. 32
5.
Power Supply ................................................ 33
5.1.
Power Supply Requirements ................................ 33
5.2.
General Design Rules ..................................... 35
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HE920 Hardware User Guide
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5.2.1. Electrical Design Guidelines ...............................
5.2.1.1. + 5V Input Source Power Supply Design Guidelines ........
5.2.1.2. + 12V Input Source Power Supply Design Guidelines .......
5.2.1.3. Battery Source Power Supply Design Guidelines ...........
5.2.2. Thermal Design Guidelines ..................................
5.2.3. Power Supply PCB Layout Guidelines .........................
6.
35
35
36
38
39
40
Antenna(s) .................................................. 42
6.1.
GSM/WCDMA Antenna Requirements ........................... 42
6.2.
GSM/WCDMA Antenna – PCB line Guidelines .................. 43
6.3.
GSM/WCDMA Antenna – Installation Guidelines .............. 44
6.4.
Antenna Diversity Requirements ........................... 44
6.5.
GPS/GNSS Antenna Requirements ............................ 45
6.5.1.
6.5.2.
6.5.3.
6.5.4.
6.5.5.
7.
Combined GPS/GNSS Antenna ..................................
Linear and Patch GPS/GNSS Antenna ..........................
LNA and Front End Design Considerations ....................
GPS/GNSS Antenna - PCB Line Guidelines .....................
GPS/GNSS Antenna – Installation Guidelines .................
45
45
45
47
48
Logic Level Specifications .................................. 49
7.1.
Reset Signal(Module Restart) ............................. 50
8.
USB Port .................................................... 51
9.
Serial Ports ................................................ 52
9.1.
Modem Serial Port 1 ...................................... 53
9.2.
Modem Serial Port 2 ...................................... 54
9.3.
RS232 Level Translation .................................. 54
10. Audio Section Overview ...................................... 56
10.1.
Analog Audio ........................................... 56
10.2.
Digital Audio .......................................... 56
10.2.1.
CODEC Example ............................................ 56
11. General Purpose I/O ......................................... 57
11.1.
Logic Level Specifications ............................. 58
11.2.
Using a GPIO Pad as Input .............................. 58
11.3.
Using a GPIO Pad as Output ............................. 59
11.4.
Using the Temperature Monitor Function ................. 60
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11.4.1.
Short Description ........................................ 60
11.5.
Indication of Network Service Availability ............. 60
11.6.
RTC Bypass Out ......................................... 61
11.7.
VAUX Power Output ...................................... 61
12. DAC and ADC section ......................................... 62
12.1.
DAC Converter .......................................... 62
12.1.1.
12.1.2.
12.1.3.
12.2.
Description .............................................. 62
Enabling DAC ............................................. 62
Low Pass Filter Example .................................. 63
ADC Converter .......................................... 63
12.2.1.
12.2.2.
Description .............................................. 63
Using ADC Converter ...................................... 63
13. Mounting the module on your board ........................... 64
13.1.
General ................................................ 64
13.2.
Module Finishing & Dimensions .......................... 65
13.3.
Recommended foot print for the application ............. 66
13.4.
Stencil ................................................ 67
13.5.
PCB Pad Design ......................................... 67
13.6.
Recommendations for PCB Pad Dimensions (mm) ............ 68
13.7.
Solder Paste ........................................... 70
13.7.1.
Solder Reflow ............................................ 70
14. Application guide ........................................... 72
14.1.
Debug of the HE920 in production ....................... 72
14.2.
Bypass capacitor on Power supplies ..................... 73
14.3.
SIM interface .......................................... 74
14.3.1.
SIM schematic example .................................... 74
14.4.
EMC recommendations .................................... 75
14.5.
Download and Debug Port ................................ 76
15. Packing system .............................................. 77
15.1.
Tray Drawing ........................................... 77
15.2.
Moisture Sensibility ................................... 77
16. Conformity Assessment Issues ................................ 79
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HE920 Hardware User Guide
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16.1.
1999/5/EC Directive .................................... 79
16.2.
FCC/IC Regulatory notices .............................. 81
17. Safety Recommendations ...................................... 83
18. Document History ............................................ 84
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HE920 Hardware User Guide
1vv0301014 Rev.9 – 2014-01-23
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 HE920-EU/NA module. All the features and solutions detailed are
applicable to all HE920, whereas “HE920” is intended the modules listed in the applicability
table.
When a specific feature is applicable to a specific product, it will be clearly highlighted.
1.2.
Audience
This document is intended for Telit customers, who are integrators, about to implement their
applications using our HE920 module.
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.
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HE920 Hardware User Guide
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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: “General Product Description” gives an overview of the features of the product.
Chapter 3: “HE920 Module Connections” deals with the pin out configuration and layout.
Chapter 4: “Hardware Commands” How to control the module via hardware
Chapter 5: “Power Supply” deals on supply and consumption.
Chapter 6: “Antenna” The antenna connection and board layout design are the most important
parts in the full product design
Chapter 7: “Logic Level specifications” Specific values adopted in the implementation of
logic levels for this module.
Chapter 8: “USB Port”
Chapter 9: “Serial Ports”
Chapter 10: “Audio Section Overview”
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 module on your board”
Chapter 14: “Application Guides”
Chapter 15: “Packing System”
Chapter 16: “Conformity Assessments Issues”
Chapter 17: “Safety Recommendations”
Chapter 18: “Document History”
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HE920 Hardware User Guide
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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

HE920 Product Description, 80404ST10112A

HE920 Software User guide, 1vv0301015

HE920 AT command reference guide, 80404ST10113A

xE920_Audio_Settings_Application_Note, 80404NT10095A

Telit_UE_HE910V2_DE_CE910_HE920_DVI_Application_Note, 8000010101A

Telit EVK2 User Guide, 1vv0300704
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HE920 Hardware User Guide
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2. General Product Description
2.1.
Overview
The aim of this document is the description of some hardware solutions useful for developing
a product with the Telit HE920 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 must be considered as mandatory, while the suggested hardware
configurations must not be considered mandatory, instead the information given must be used
as a guide and a starting point for properly developing your product with the Telit HE920
module.
NOTICE:
The integration of the GSM/GPRS/EGPRS/WCDMA/HSPA+ HE920 cellular module within
user application must 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 Communication S.p.A. for its use, such as 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 Communication
S.p.A. other than for circuitry embodied in Telit products. This document is subject to change
without notice.
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HE920 Hardware User Guide
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2.2.
HE920 Mechanical Dimensions
The Telit HE920 module overall dimensions are:
2.3.
•
Length:
34 mm
•
Width:
40 mm
•
Thickness:
2.8 mm
Weight
The module weight of HE920-EU/NA is about 9.0 gram.
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HE920 Hardware User Guide
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2.4.
Environmental requirements
2.4.1. Temperature range
Note
Operating Temperature
Range
Storage and non-operating
Temperature Range
–20°C ~ +55°C
The module is fully functional(*) in all the
temperature range, and it fully meets the ETSI
specifications.
–40°C ~ +85°C
The module is fully functional(*) in all the
temperature range. Temperatures outside of
the range –20°C ÷ +55°C might slightly
deviate from ETSI specifications.
–40°C ~ +90°C
(*)Functional: the module is able to make and receive voice calls, data calls and SMS.
2.4.2. RoHS compliance
As a part of Telit’s corporate policy of environmental protection, the HE920 complies with
the RoHS (Restriction of Hazardous Substances) directive of the European Union (EU
directive 2011/65/EU).
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HE920 Hardware User Guide
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2.5.
Operating Frequency
The operating frequencies in GSM850, EGSM900, DCS1800, PCS1900, WCDMA modes are
conformed to the 3GPP specifications.
Mode
Freq. TX (MHz)
Freq. RX (MHz)
Channels
TX - RX offset
GSM850
824.2 ~ 848.8
869.2 ~ 893.8
128 ~ 251
45 MHz
890.0 ~ 914.8
935.0 ~ 959.8
0 ~ 124
45 MHz
880.2 ~ 889.8
925.2 ~ 934.8
975 ~ 1023
45 MHz
DCS1800
1710.2 ~ 1784.8
1805.2 ~ 1879.8
512 ~ 885
95MHz
PCS1900
1850.2 ~ 1909.8
1930.2 ~ 1989.8
512 ~ 810
80MHz
826.4 ~ 846.6
871.4 ~ 891.6
882.4 ~ 912.6
927.4 ~ 957.6
1712.4 ~ 1752.6
2112.4 ~ 2152.6
1852.4 ~ 1907.6
1932.4 ~ 1987.6
1922.4 ~ 1977.6
2112.4 ~ 2167.6
EGSM900
WCDMA850
WCDMA900
(HE920-EU only)
WCDMA(AWS)
(HE920-NA only)
WCDMA1900
(HE920-NA only)
WCDMA2100
(HE920-EU only)
Tx: 4132 ~ 4233
Rx: 4357 ~ 4458
Tx: 2712 ~ 2863
Rx: 2937 ~ 3088
Tx: 1312 ~ 1513
Rx: 1537 ~ 1738
Tx: 9262 ~ 9538
Rx: 9662 ~ 9938
Tx: 9612 ~ 9888
Rx: 10562 ~ 10838
45MHz
45MHz
400MHz
80MHz
190MHz
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HE920 Hardware User Guide
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3. HE920 Module Connections
3.1.
PIN-OUT
PAD
Signal
I/O
Function
USB HS 2.0 Communication Port
I/O USB differential Data(+)
D19 USB_D+
USB_DI/O USB differential Data(-)
F19
Analog input used to sense whether a peripheral device
AI is connected, and determine the peripheral type, a host
B19 USB_ID(TBD)
or a peripheral
AI Power sense for the internal USB transceiver
A18 USB_VBUS
Asynchronous UART – Prog. / data +HW Flow Control
Serial data input (TXD) from DTE
AH19 C103/TXD
O Serial data output to DTE
AF19 C104/RXD
Input for Data terminal ready signal (DTR) from DTE
AC18 C108/DTR
Input for Request to send signal (RTS) from DTE
AA18 C105/RTS
O Output for Clear to send signal (CTS) to DTE
AK19 C106/CTS
O Output for Data carrier detect signal (DCD) to DTE
AE18 C109/DCD
O Output for Data set ready signal (DSR) to DTE
AG18 C107/DSR
O Output for Ring indicator signal (RI) to DTE
AJ18 C125/RING
Asynchronous Auxiliary UART
O Auxillary UART (TX Data to DTE)
AB19 TXD_AUX
Auxillary UART (RX Data from DTE)
AD19 RXD_AUX
SIM Card Interface
O External SIM signal – Clock
A10 SIMCLK
O External SIM signal – Reset
B11 SIMRST
SIMIO
I/O External SIM signal - Data I/O
B9
SIMIN
External SIM signal - Presence (active low)
B7
SIMVCC
External SIM signal – Power supply for the SIM
A8
Audio
EAR1_MT+
AO Earphone signal output1, phase +
B5
EAR1_MTAO Earphone signal output1, phase A4
MIC1_MT+
AI Mic signal input1, phase +
B3
MIC1_MTAI Mic signal input1, phase A2
EAR2_MT+
AO Earphone signal output2, phase +
E2
EAR2_MTAO Earphone signal output2, phase D1
MIC2_MT+
AI Mic signal input2, phase +
C2
MIC2_MTAI Mic signal input2, phase B1
Digital Voice interface (DVI)
I/O Digital Voice interface (WA0)
D11 DVI_WA0
Type
COMMENT
Analog
5V
1.8V
1.8V
1.8V
1.8V
1.8V
1.8V
1.8V
1.8V
1.8V
1.8V
1.8/2.85V
1.8/2.85V
1.8/2.85V
1.8V
1.8/2.85V
Audio
Audio
Audio
Audio
Audio
Audio
Audio
Audio
1.8V
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PAD
Signal
DVI_RX
C8
DVI_TX
D9
C10 DVI_CLK
Digital IO
GPIO_01
F9
E10 GPIO_02
GPIO_03
F11
E12 GPIO_04
GPIO_05
F13
E14 GPIO_06
R18 GPIO_07
GPIO_08
S19
U19 GPIO_09
W19 GPIO_10
RF Section
AD1 Antenna
AU9 ANT_DIV
GPS Section
ANT_GPS
S1
GPS_LNA_EN
V2
Miscellaneous Function
AP1 RESET*
AS1 ON_OFF*
I/O
Function
I/O Digital Voice interface (RX)
I/O Digital Voice interface (TX)
I/O Digital Voice interface (CLK)
Type
1.8V
1.8V
1.8V
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
1.8V
1.8V
1.8V
1.8V
1.8V
1.8V
1.8V
1.8V
1.8V
1.8V
I/O GSM/EDGE/UMTS Antenna (50Ohm)
UMTS Antenna Diversity Input (50Ohm)
RF
RF
GPS Antenna (50Ohm)
Output enable for External LNA supply
RF
1.8V
Reset Input
Input Command for Power ON/OFF
1.8V
1.8V
F17
VRTC
P17
VAUX/PWRMON O
ADC_IN1
D5
ADC_IN2
E6
AU3 STAT_LED
AN10 SW_RDY
AN12 SHDN*
M17 LED_DRV_EN
Power Supply
AP17 VBATT
AP19 VBATT
AR18 VBATT
AS17 VBATT_PA
AS19 VBATT_PA
AT18 VBATT_PA
GPIO_01
GPIO_02
GPIO_03
GPIO_04
GPIO_05
GPIO_06 / DAC_OUT(PDM)
GPIO_07
GPIO_08
GPIO_09
GPIO_10
AI VRTC Backup Capacitor
Power
COMMENT
Active Low
Active Low
To be used to
back up the
RTC section
Supply Output for External Accessories / Power ON
1.8V
Monitor
AI Analog/Digital Converter Input 1
Analog
AI Analog/Digital Converter Input 2
Analog
O Status Indicator LED
1.8V
O Indicates that the boot sequence completed successfully 1.8V
Unconditional Shut down Input
1.8V
O Enable for the external LED Driver circuit
1.8V
Main Power Supply (Baseband)
Main Power Supply (Baseband)
Main Power Supply (Baseband)
Main Power Supply (PAM)
Main Power Supply (PAM)
Main Power Supply (PAM)
Power
Power
Power
Power
Power
Power
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HE920 Hardware User Guide
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PAD
AU17
AU19
A6
A12
B13
B15
B17
C4
C6
D3
D7
E18
F1
G18
H19
M1
N2
P1
P3
R2
T2
T18
U1
V18
W1
X2
X18
Y1
Y19
AA2
AB1
AC2
AE2
AF1
AG2
AH1
AJ2
AK1
AK17
AL18
AM17
Signal
VBATT_PA
VBATT_PA
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
I/O
Function
Main Power Supply (PAM)
Main Power Supply (PAM)
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Type
Power
Power
COMMENT
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PAD
Signal
AM19 GND
AN16 GND
AN18 GND
AP3 GND
AP5 GND
AP7 GND
AP9 GND
AP11 GND
AP13 GND
AP15 GND
AR2 GND
AR4 GND
AR6 GND
AR8 GND
AR10 GND
AR12 GND
AR14 GND
AR16 GND
AS5 GND
AS7 GND
AS9 GND
AS11 GND
AS13 GND
AS15 GND
AT4 GND
AT6 GND
AT8 GND
AT10 GND
AT12 GND
AT14 GND
AT16 GND
AU1 GND
AU5 GND
AU7 GND
AU11 GND
AU15 GND
Reserved
A14 Reserved
A16 Reserved
C12 Reserved
C14 Reserved
I/O
Function
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Ground
Reserved
Reserved
Reserved
Reserved
Type
COMMENT
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PAD
C16
C18
D13
D15
D17
E4
E8
E16
F3
F5
F7
F15
G2
H1
H3
H17
J2
J18
K1
K3
K17
K19
L2
L18
M3
M19
N18
P19
S3
S17
U3
U17
W3
W17
Y3
Y17
AB3
AB17
AD3
AD17
AF3
Signal
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
I/O
Function
Type
COMMENT
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
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PAD
AF17
AH3
AH17
AK3
AL2
AM1
AM3
AN2
AN4
AN6
AN8
AN14
AS3
AT2
AU13
Signal
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
I/O
Function
Type
COMMENT
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
NOTE:
DTR pin must be connected in order to enter HE920’s power saving mode.
NOTE:
RI pin must be connected in order to wake up the host when a call is coming in sleep mode of
host.
NOTE:
RESERVED pins must not be connected
RTS must be connected to the GND (on the module side) if flow control is not used
NOTE:
If not used, almost all pins must be left disconnected. The only exceptions are the following:
PAD
AP17,AP19,AR18,AS17,AS19,AT18,AU17,AU19
A6,A12,B13,B15,B17,C4,C6,D3,D7,E18,F1,G18,H19,
M1,N2,P1,P3,R2,T2,T18,U1,V18,W1,X2,X18,Y1,Y19,
AA2,AB1,AC2,AE2,AF1,AG2,AH1,AJ2,AK1,AK17,
AL18,AM17,AM19,AN16,AN18,AP3,AP5,AP7,AP9,
AP11,AP13,AP15,AR2,AR4AR6,AR8,AR10,AR12,
AR14,AR16,AS5,AS7,AS9,AS11,AS13,AS15,AT4,
AT6,AT8,AT10,AT12,AT14,AT16,AU1,AU5,AU7,
AU11,AU15
Signal
VBATT & VBATT_PA
GND
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AS1
AP1
D19
F19
A18
AH19
AF19
AA18
AK19
AB19
AD19
ON/OFF*
RESET*
USB_D+
USB_DUSB_VBUS
C103/TXD
C104/RXD
C105/RTS
C106/CTS
TXD_AUX
RXD_AUX
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3.1.1.
LGA Pads Layout
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NOTE:
The pin defined as RES has to be considered RESERVED and not
connected on any pin in the application. The related area on
the application has to be kept empty.
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4. Hardware Commands
4.1.
Turning ON the HE920
To turn on HE920, the pad ON_OFF* must be tied low for at least 1 second and then released.
The maximum current that can be drained from the ON_OFF* pad is 0.1 mA.
A simple circuit to power on the module is illustrated below:
4.2.
Initialization and Activation state
Upon turning on HE920 module, The HE920 is not activated yet because the boot sequence of
HE920 is still going on internally. It takes about 10 seconds to complete the initializing the
module internally.
For this reason, it would be useless to try to access HE920 during the Initialization state as
below. To get the desirable stability, The HE920 needs at least 10 seconds after the
PWRMON goes High to become operational by reaching the activation state.
During the Initialization state, any kind of AT-command is not available. DTE must be
waiting for the Activation state to communicate with HE920.
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NOTE:
To check if the HE920 has powered on, the hardware line PWRMON must be monitored.
When PWRMON goes high, the module has powered on.
NOTE:
Do not use any pull up resistor on the ON_OFF* line, it is internally pulled up. Using pull up
resistor may bring to latch up problems on the HE920 power regulator and improper power
on/off of the module. The line ON_OFF* must be connected only in open collector
configuration.
NOTE:
In this document all the lines are inverted. Active low signals are labeled with a name that
ends with "#", "*" or with a bar over the name.
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 module when is powered OFF or during an
ON/OFF transition.
For example:
1- Let us assume you need to drive the ON_OFF* pad with a totem pole output of a +1.8/5
V microcontroller (uP_OUT1):
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4.3.
Turning OFF the HE920
Turning off the device can be done in two ways:

by software command (see HE920 Software User Guide)

by Hardware shutdown(pad ON_OFF*)
When the device is shut down by software command or by hardware shutdown(pad
ON_OFF*), it issues to the network a detach request that informs the network that the device
will not be reachable any more.
TIP:
To check if the device has powered off, hardware line PWRMON must be monitored. When
PWRMON goes low it can be considered the device has powered off.
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 module when is powered OFF or during an
ON/OFF transition.
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4.3.1.
Shutdown by Software Command
HE920 can be shut down by a software command.
When a shut down command is sent, HE920 goes into the finalization state and finally will
shut down PWRMON at the end of this state.
The period of the finalization state can differ according to the situation in which the HE920 is
so it cannot be fixed definitely.
Normally it will be above 10 seconds later from sending a shut down command and DTE
should monitor the status of PWRMON to see the actual power off.
TIP:
To check if the device has powered off, hardware line PWRMON must be monitored. When
PWRMON goes low, the device has powered off.
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4.3.2.
Hardware Shutdown
To turn OFF HE920 the pad ON_OFF* must be tied low for at least 2 seconds and then
released. Same circuitry and timing for the power on must be used.
When the hold time of ON_OFF* is above 2 seconds, HE920 goes into the finalization state
and finally will shut down PWRMON at the end of this state.
The period of the finalization state can differ according to the situation in which the HE920 is
so it cannot be fixed definitely.
Normally it will be above 10 seconds later from releasing ON_OFF* and DTE should
monitor the status of PWRMON to see the actual power off.
TIP:
To check if the device has powered off, hardware line PWRMON must be monitored. When
PWRMON goes low, the device has powered off.
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4.4.
Hardware Unconditional Restart (RESET)
To unconditionally restart HE920, the pad RESET* must be tied low for at least 200
milliseconds and then released.
A simple circuit to do it is:
RESET#
Unconditional Restart
impulse
GND
NOTE:
Do not use any pull up resistor on the RESET* line or any totem pole digital output. Using
pull up resistor may bring to latch up problems on the HE920 power regulator and improper
functioning of the module. The line RESET* must be connected only in open collector
configuration.
TIP:
The unconditional hardware Restart must always be implemented on the boards and the
software must use it as an emergency exit procedure.
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For example:
10k
1- Let us assume you need to drive the RESET* pad with a totem pole output of a +1.8/5 V
microcontroller (uP_OUT2):
+1.8 / 5V
4.5.
Hardware Unconditional Shutdown (Power Off)
The Unconditional Shutdown of the module could be activated using the SHDN* line (pad
AN12).
WARNIG:
The hardware unconditional Shutdown 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 unconditionally shutdown the HE920, the pad SHDN* must be tied low for at least 200
milliseconds and then released.
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NOTE:
Do not use any pull up resistor on the SHDN* line nor any totem pole digital output. Using
pull up resistor may bring to latch up problems on the HE920 power regulator and improper
functioning of the module. The line SHDN* must be connected only in open collector
configuration.
The SHDN* is generating an unconditional shutdown(power off) of the module without an
automatic restart.
The module will shutdown, but will NOT perform the detach from the cellular network.
To proper power on again the module please refer to the related paragraph (“Turning ON the
HE920”)
TIP:
The unconditional hardware shutdown must always be implemented on the boards and should
be used only as an emergency exit procedure.
4.6.
Summary of Turning ON and OFF the module
Below chart describes the overall sequences for Turning ON and OFF.
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5. 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. Read carefully the
requirements and the guidelines that will follow for a proper design.
5.1.
Power Supply Requirements
The HE920 power requirements are:
Power Supply
Nominal Supply Voltage
Max Supply Voltage
Supply Voltage Range
3.8V
4.2V
3.4V – 4.2V
HE920
Mode
IDLE mode
WCDMA
AT+CFUN=1
GSM
WCDMA
AT+CFUN=4
GSM
Average(mA)
15
15
13
13
WCDMA
3.2/1.0*
GSM
3.2/1.3*
AT+CFUN=0 or
AT+CFUN=5
WCDMA TX and RX mode
WCDMA Voice
630
HSPA
640
GSM TX and RX mode
GSM Voice
260
GPRS Class33
680
EDGE Class33
380
GPRS Class10
490
EDGE Class10
280
Mode Description
Standby mode; no call in progress
Normal mode; full functionality of the module
Disabled TX and RX; modules is not registered on the
network
Power saving; CFUN=0 module registered on the
network and can receive voice call or an SMS; but it is
not possible to send AT commands; module wakes up with
an unsolicited code (call or SMS) or rising RTS line.
CFN=5 full functionality with power saving;
Module registered on the network can receive
incoming call sand SMS
WCDMA voice channel
HSPA data channel
GSM voice channel
GPRS data channel
EDGE data channel
GPRS data channel
EDGE data channel
* Worst/best case depends on network configuration and is not under module control.
TIP:
The electrical design for the Power supply must be made ensuring that it will be capable of a
peak current output of at least 2A.
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In GSM/GPRS mode, RF transmission is not continuous and 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 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; this will reflect on all the audio paths producing an audible
annoying noise at 216 Hz; if the voltage drops during the peak, current absorption is too much.
The device may even shut down as a consequence of the supply voltage drop.
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5.2.
General Design Rules
The principal guidelines for the Power Supply Design embrace three different design steps:
5.2.1.

the electrical design

the thermal design

the PCB layout
Electrical Design Guidelines
The electrical design of the power supply depends strongly on the power source where this
power is drained. We will distinguish them into three categories:
5.2.1.1.

+5V input (typically PC internal regulator output)

+12V input (typically automotive)

battery
+ 5V Input Source Power Supply Design Guidelines

The desired output for the power supply is 3.8V, hence there is 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 must 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 HE920, 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 must be inserted close to the power input, in order to save
HE920 from power polarity inversion.
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An example of linear regulator with 5V input is:
5.2.1.2.
+ 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 must not be used. A switching power supply will be preferable because of its
better efficiency especially with the 2A peak current load represented by HE920.

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 must 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 for
this.

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 must be inserted close to the power
input, in order to clean the supply from spikes.

A protection diode must be inserted close to the power input, in order to save
HE920 from power polarity inversion. This can be the same diode as for spike
protection.
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An example of switching regulator with 12V input is in the below schematic (it is split in 2
parts):
Switching regulator
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5.2.1.3.
Battery Source Power Supply Design Guidelines

The desired nominal output for the power supply is 3.8V and the maximum
allowed voltage is 4.2V, hence a single 3.7V Li-Ion cell battery type is suited for
supplying the power to the Telit HE920 module. 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 HE920 and
damage it.
NOTE:
Do not use any Ni-Cd, Ni-MH, and Pb battery types directly connected with HE920. Their
use can lead to overvoltage on HE920 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 must be inserted close to the power input, in order to save
HE920 from power polarity inversion. Otherwise the battery connector must 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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5.2.2.
Thermal Design Guidelines
The thermal design for the power supply heat sink must be done with the following
specifications:

Average current consumption during HSPA transmission @PWR level max in
HE920: 640mA

Average current consumption during class33 GPRS transmission @PWR level
max: 680mA

Average current consumption during class10 GPRS transmission @PWR level
max: 490mA

Average GPS current during GPS ON (Power Saving disabled) : 65mA
NOTE:
The average consumption during transmissions depends on the power level at which the
device is requested to transmit via the network. The average current consumption hence varies
significantly.
NOTE:
The thermal design for the Power supply must be made keeping an average consumption at
the max transmitting level during calls of 640mA(HSPA)/680mA(GPRS) rms plus 65mA rms
for GPS in tracking mode.
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.
If we assume that the device stays in transmission for short periods of time (let us say few
minutes) and then remains for quite a long time in idle (let us say one hour), then the power
supply has always the time to cool down between the calls and the heat sink could be smaller
than the calculated for 640mA (HSPA)/680mA (GPRS) maximum RMS current. There could
even be a simple chip package (no heat sink).
Moreover in average network conditions the device is requested to transmit at a lower power
level than the maximum and hence the current consumption will be less than 640mA (HSPA)
/680mA (GPRS) (being usually around 250mA).
For these reasons the thermal design is rarely a concern and the simple ground plane where
the power supply chip is placed can be enough to ensure a good thermal condition and avoid
overheating.
For the heat generated by the HE920, you can consider it to be during transmission 2W max
during class33 GPRS upload. This generated heat will be mostly conducted to the ground
plane under the HE920; you must ensure that your application can dissipate heat.
In the WCDMA/HSPA mode, since HE920 emits RF signals continuously during
transmission, you must pay special attention how to dissipate the heat generated.
The current consumption will be up to about 640mA in HSPA (630mA in WCDMA)
continuously at the maximum TX output power (23dBm). Thus, you must arrange the PCB
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area as large as possible under HE920 which you will mount. You must mount HE920 on the
large ground area of your application board and make many ground vias to dissipate the heat.
The peak current consumption in the GSM mode is higher than that in WCDMA. However,
considering the heat sink is more important in case of WCDMA.
As mentioned before, a GSM signal is bursty, thus, the temperature drift is more insensible
than WCDMA. Consequently, if you prescribe the heat dissipation in the WCDMA mode,
you don’t need to think more about the GSM mode.
5.2.3.
Power Supply PCB Layout Guidelines
As seen in the electrical design guidelines, the power supply must 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 HE920 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 if the PCB trace from the capacitor to
HE920 is wide enough to ensure a drop-less 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 to 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 (also
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 does not have audio interface but only uses the data feature of
the Telit HE920, then this noise is not so disturbing and power supply layout
design can be more forgiving.

The PCB traces to HE920 and the Bypass capacitor must be wide enough to
ensure no significant voltage drops to occur when the 2A current peaks are
absorbed. This is a must for the same above-mentioned reasons. 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 (usually 100-500 kHz).

The use of a good common ground plane is suggested.

The placement of the power supply on the board must be done in a way to
guarantee that the high current return paths in the ground plane are not
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overlapped to any noise sensitive circuitry as the microphone amplifier/buffer or
earphone amplifier.

The power supply input cables must be kept separately from noise sensitive lines
such as microphone/earphone cables.
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6. Antenna(s)
The antenna connection and board layout design are the most important parts in the full
product design and they strongly reflect on the product’s overall performances. Read carefully
and follow the requirements and the guidelines for a proper design.
6.1.
GSM/WCDMA Antenna Requirements
The antenna for a Telit HE920 device must fulfill the following requirements:
GSM / WCDMA Antenna Requirements
Frequency
range
Bandwidth
Impedance
Input power
Depending by frequency band(s) provided by the network operator, the
customer must use the most suitable antenna for that/those band(s)
HE920-EU
HE920-NA
GSM850 : 70 MHz
GSM850 : 70 MHz
GSM900 : 80 MHz
GSM900 : 80 MHz
GSM1800(DCS) : 170 MHz
GSM1800(DCS) : 170 MHz
GSM1900(PCS) : 140 MHz
GSM1900(PCS) : 140 MHz
WCDMA band I(2100) : 250 MHz
WCDMA band II(1900) : 140 MHz
WCDMA band V(850) : 70 MHz
WCDMA band IV(AWS) : 445 MHz
WCDMA band VIII(900) : 80 MHz
WCDMA band V(850) : 70 MHz
50 Ohm
> 33dBm(2 W) peak power in GSM
> 24dBm Average power in WCDMA
<= 5:1(limit to avoid permanent damage)
VSWR
absolute max
<= 2:1(limit to fulfill all regulatory requirements)
VSWR
recommended
When using the Telit HE920, since there’s no antenna connector on the module, the antenna
must be connected to the HE920 antenna pad (AD1) by means of a transmission line
implemented in the PCB.
In the case that the antenna is not directly connected at the antenna pad of the HE920, then a
PCB line is required in order to connect with it or with its connector.
This transmission line shall fulfill the following requirements:
Antenna Line on PCB Requirements
Characteristic Impedance
50Ohm
Max Attenuation
0.3dB
Coupling with other signals shall be avoided
Cold End (Ground Plane) of antenna shall be equipotential to the HE920 ground pads
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Furthermore if the device is developed for the US and/or Canada market, it must comply with
the FCC and/or IC approval requirements:
This device is to be used only for mobile and fixed application. In order to re-use the Telit
FCC/IC approvals 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. If antenna is installed with a separation
distance of less than 20 cm from all persons or is co-located or operating in conjunction with
any other antenna or transmitter then additional FCC/IC testing may be required. 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 HE920 module. Antennas used for this OEM module must not exceed 6.79dBi gain for
850MHz bands, 3.01dBi gain for 1900MHz bands and 2.7dBi for 1700MHz bands for mobile
and fixed operating configurations.
6.2.
GSM/WCDMA Antenna – PCB line Guidelines













Make sure that the transmission line’s characteristic impedance is 50ohm.
Keep line on the PCB as short as possible since the antenna line loss shall be less than
around 0.3dB.
Line geometry should have uniform characteristics, constant cross section, avoid
meanders and abrupt curves.
Any kind of suitable geometry/structure 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) of 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 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 HE920 antenna line.
Keep the antenna line far away from the HE920 power supply lines.
If EM noisy devices are present on the PCB hosting the HE920, such as fast switching
ICs, take care of shielding them with a metal frame cover.
If EM noisy devices are not present around the line use of geometries like Micro strip
or Grounded Coplanar Waveguide are preferred since they typically ensure less
attenuation when compared to a Strip line having same length.
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6.3.
6.4.
GSM/WCDMA Antenna – Installation Guidelines

Install the antenna in a place covered by the GSM/WCDMA signal.

The Antenna shall 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;

If the device antenna is located greater then 20cm from the human body and there
are no co-located transmitter then the Telit FCC/IC approvals can be re-used by
the end product.

If the device antenna is located less then 20cm from the human body or there are
no co-located transmitter then the additional FCC/IC testing may be required for
the end product (Telit FCC/IC approvals cannot be reused)

Antenna shall not be installed inside metal cases;

Antenna shall be installed also according Antenna manufacturer instructions.
Antenna Diversity Requirements
This product is including an input for a second RX antenna to improve the radio sensitivity.
The function is called Antenna Diversity.
ANTENNA REQUIREMENTS
Frequency range
Bandwidth
Impedance
Depending by frequency band(s) provided by the network operator, the
customer shall use the most suitable antenna for that/those band(s)
HE920-EU
HE920-NA
WCDMA band I(2100) : 60 MHz
WCDMA band II(1900) : 60 MHz
WCDMA band V(850) : 25 MHz
WCDMA band IV(AWS) : 45 MHz
WCDMA band VIII(900) : 35 MHz WCDMA band V(850) : 25 MHz
50Ω
When using the Telit HE920, since there’s no antenna connector on the module, the antenna
must be connected to the HE920 antenna pad (AU9) by means of a transmission line
implemented on the PCB.
In the case that the antenna is not directly connected at the antenna pad of the HE920, then a
PCB line is required in order to connect with it or with its connector.
The second Rx antenna should not be located in the close vicinity of main antenna. In order to
improve Diversity Gain, Isolation and reduce mutual interaction, the two antennas should be
located at the maximum reciprocal distance possible, taking into consideration the available
space into the application.
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NOTE:
If the RX Diversity is not used/connected, disable the Diversity functionality using the
AT#CRXD command and leave the pad AU9 unconnected. Please refer to the AT command
User Guide in detail.
6.5.
GPS/GNSS Antenna Requirements
The use of an active GPS/GNSS antenna is required to achieve better performance.
The module is provided with a Digital Output signal to enable the external LNA (pad V2).
Parameter
Output high level
Output low level
6.5.1.
Min
1.35V
0V
Max
1.8V
0.45V
Combined GPS/GNSS Antenna
The use of combined RF/GPS/GNSS antenna is NOT recommended. This solution could
generate extremely poor GPS/GNSS reception and also the combined antenna requires
additional diplexer and adds a loss in the RF route.
In addition, the combination of antennas requires an additional diplexer, which adds
significant power losses in the RF path.
6.5.2.
Linear and Patch GPS/GNSS Antenna
Using this type of antenna introduces at least 3dB of loss if compared to a circularly polarized
(CP) antenna. Having a spherical gain response instead of a hemispherical gain response
could aggravate the multipath behaviour & create poor position accuracy.
6.5.3.
LNA and Front End Design Considerations
Depending on the characteristics and requirements unique to the customer’s designs, the use
of an external LNA or an external active antenna may be required to achieve best
performance.
The optional external LNA should be dimensioned to avoid an excessive LNA gain that can
introduce jamming, spurious, degrade IIP3, and saturate the receiver.
The configurations of an external device must fulfill the following requirements:



An external passive antenna (GPS only)
An external active antenna (GPS or GNSS)
An external passive antenna, GNSS pre-Filter and GNSS LNA (GPS or GNSS)
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NOTE:
The external GNSS LNA and GNSS pre-Filter shall be required for GLONASS application.
GNSS LNA requirement shall fulfill the following specifications.
 Frequency = 1565 – 1606MHz
 Power Gain|S21|2 = 14 – 17dB
 NF < 1dB
GNSS pre-Filter requirement shall fulfill the following requirements.
 Source and Load Impedance = 50Ohm
 Insertion Loss (1575.42 – 1576.42MHz) = 1.4dB (Max)
 Insertion Loss (1565.42 – 1585.42MHz) = 2.0dB (Max)
 Insertion Loss (1597.5515 – 1605.886MHZ) = 2.0dB (Max)
WARNING:
The HE920 software is implemented differently depending on the configurations of an
external device. Please refer to the AT command User Guide in detail.
The external active antenna for the Telit HE920 device must fulfill the following
requirements:
ACTIVE GPS/GNSS Antenna Requirements
Frequency range
Bandwidth
Impedance
LNA NF
LNA Gain
LNA Input Voltage
GNSS(GPS L1 & GLONASS) : 1565 MHz ~ 1606 MHz
GPS L1 : 1575.42MHz
GLONASS : 1597.55 – 1605.89MHz
GPS L1 : +/- 1.023MHz
GLONASS : 8.34MHz
50 Ohm
< 1dB
14 ~ 17dB
3.0V or 5.0V
NOTE:
The maximum DC voltage applicable to ANT_GPS pin is 5V. In case this is exceeded, a
series capacitor has to be included in the design to avoid exceeding the maximum input DC
level.
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An example of GNSS antenna supply circuit is shown in the following image:
When using the Telit HE920, since there’s no antenna connector on the module, the antenna
must be connected to the HE920 through the PCB with the antenna pad.
In the case that the antenna is not directly connected at the antenna pad of the HE920, then a
PCB line is required.
This line of transmission shall fulfill the following requirements:
Antenna Line on PCB Requirements
Characteristic Impedance
50Ohm
Max Attenuation
0.3dB
Coupling with other signals shall be avoided
Cold End (Ground Plane) of antenna shall be equipotential to the HE920 ground pads
Furthermore if the device is developed for the US and/or Canada market, it must comply with
the FCC and/or IC requirements.
This device is to be used only for mobile and fixed application.
6.5.4.
GPS/GNSS Antenna - PCB Line Guidelines



Ensure that the antenna line impedance is 50ohm.
Keep line on the PCB as short as possible to reduce the loss.
Antenna line must have uniform characteristics, constant cross section, avoid meanders
and abrupt curves.
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






6.5.5.
Keep one layer of the PCB used only for the Ground plane; if possible.
Surround (on the sides, over and under) the antenna line on PCB with Ground. Avoid
having other signal tracks directly facing the antenna line track.
The Ground around the antenna line on PCB has to be strictly connected to the main
Ground plane by placing vias once per 2mm at least.
Place EM noisy devices as far as possible from HE920 antenna line.
Keep the antenna line far away from the HE920 power supply lines.
If EM noisy devices are around the PCB hosting the HE920, such as fast switching ICs,
take care of shielding of 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 do not have EM noisy devices around the PCB of HE920, use a strip line on the
superficial copper layer for the antenna line. The line attenuation will be lower than a
buried one.
GPS/GNSS Antenna – Installation Guidelines




The HE920, due to its sensitivity characteristics, is capable of performing a fix inside
buildings. (In any case the sensitivity could be affected by the building characteristics
i.e. shielding)
The Antenna 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 manufacture instructions.
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7. Logic Level Specifications
Where not specifically stated, all the interface circuits work at 1.8V CMOS logic levels.
The following table shows the logic level specifications used in the Telit HE920 interface
circuits:
NOTE:
Do not connect HE920’s digital logic signal directly to OEM’s digital logic signal of with
level higher than 2.7V for 1.8V CMOS signals.
For 1,8V CMOS signals:
Absolute Maximum Ratings -Not Functional
HE920
Parameter
Min
Max
Input level on any
-0.3V
+2.7V
digital pin when on
Input voltage on
-0.3V
+2.7 V
analog pins when on
Operating Range - Interface levels (1.8V CMOS)
HE920
Level
Min
Max
Input high level
1.5V
2.1V
Input low level
Output high level
Output low level
-0.3V
1.35V
0V
0.5V
1.8V
0.45V
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7.1.
Reset Signal(Module Restart)
Signal
RESET*
Function
Phone reset
(restart)
I/O
PAD Number
AP1
RESET is used to reset the HE920 module. Whenever this signal is pulled low HE920 is reset
(restart). When the device is reset it stops all operations. After the release of the reset HE920
is unconditionally shut down, without doing any detach operations from the network where it
is registered. This behavior is not a proper shutdown because the device is requested to issue a
detach request on turn off. For this reason, the Reset signal must not be used for 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. There is 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 HE920. Use the ON/OFF signal to perform this function
or the AT#SHDN command.
Reset Signal Operating levels:
Signal
RESET Input high
RESET Input low
Min
1.5V*
0V
Max
2.1V
0.2V
* 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, it must always be connected with an
open collector transistor to permit the internal circuitry the power on reset and under voltage
lockout functions.
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 module when is powered OFF or during an
ON/OFF transition.
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8. USB Port
The HE920 module includes a Universal Serial Bus (USB) transceiver, which operates at
USB low-speed (1.5Mbits/sec), USB full-speed (12Mbits/sec) and USB high-speed
(480Mbits/sec).
It is compliant with the USB 2.0 specification and can be used for diagnostic monitoring,
control and data transfers.
The USB_DPLUS and USB_DMINUS signals have a clock rate of 480MHz. The signal
traces should be routed carefully. Trace lengths, number of vias and capacitive loading should
be minimized. The impedance value should be as close as possible to 90 Ohms differential.
The table below describes the USB interface signals:
Pad No.
Signal
I/O
A18
USB_VBUS
AI
F19
D19
USB_DUSB D+
USB_ID
(for future use)
I/O
I/O
B19
Function
Power sense for the internal USB
transceiver.
USB differential Data (-)
USB differential Data (+)
Type
NOTE
5V
TIP:
HE920 does NOT support host device operation at the moment, that is, it works as a slave
device. Consequently USB_ID must be opened (not connected).
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9. Serial Ports
The serial port on the Telit HE920 is the interface between the module and OEM hardware.
2 serial ports are available on the module:

MODEM SERIAL PORT 1(Main)

MODEM SERIAL PORT 2 (Auxiliary)
Several configurations can be designed for the serial port on the OEM hardware.
The most common are:

RS232 PC com port;

microcontroller UART @ 1.8V (Universal Asynchronous Receive Transmit) ;

microcontroller UART @ 5V or other voltages different from 1.8V.
Depending on 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 does not need a level translation
is the 1.8V UART.
The serial port 1 on HE920 is a +1.8V UART with all the 7 RS232 signals. It differs from the
PC-RS232 in signal polarity (RS232 is reversed) and levels.
The Serial port 2 is a +1.8V Auxiliary UART.
The levels for HE920 UART are the CMOS levels:
Absolute Maximum Ratings -Not Functional
HE920
Parameter
Min
Max
Input level on any
-0.3V
+2.7V
digital pin when on
Input voltage on
-0.3V
+2.7 V
analog pins when on
Operating Range - Interface levels
HE920
Level
Min
Max
Input high level
1.5V
2.1V
Input low level
Output high level
Output low level
-0.3V
1.35V
0V
0.5V
1.8V
0.45V
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9.1.
Modem Serial Port 1
Serial port 1 on the HE920 is a +1.8V UART with all 7 RS232 signals.
It differs from the PC-RS232 in the signal polarity (RS232 is reversed) and levels.
RS232
Pin
Number
HE920
Pad Number
Signal
DCD dcd_uart
RXD Tx_uart
TXD Rx_uart
DTR dtr_uart
GND
DSR dsr_uart
RTS rts_uart
CTS cts_uart
RI ri_uart
Name
Data Carrier
Detect
Transmit line
AF19
*see Note
Receive line
AH19
*see Note
Data Terminal
AC18
Ready
A6, A12, B13, B15…. Ground
AE18
AG18
Data Set Ready
AA18
Request to Send
AK19
Clear to Send
AJ18
Ring Indicator
Usage
Output from the HE920 that indicates the carrier
presence
Output transmit line of the HE920 UART
Input receive of the HE920 UART
Input to the HE920 that controls the DTE READY
condition
ground
Output from the HE920 that indicates the module is
ready
Input to the HE920 that controls the Hardware flow
control
Output from the HE920 that controls the Hardware flow
control
Output from the HE920 that indicates the Incoming call
condition
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 module when is powered OFF or during an
ON/OFF transition.
TIP:
For 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:
According to V.24, RX/TX signal names are referred to the application side, therefore on the
HE920 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 HE920 serial port and vice
versa for RX.
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9.2.
Modem Serial Port 2
Serial port 2 on the HE920 is a +1.8V UART with only the RX and TX signals.
The signals of the HE920 serial port are:
PAD
Signal
I/O
Function
Type
AB19 TXD_AUX O Auxiliary UART (TX Data to DTE) 1.8V
Auxiliary UART (RX Data to DTE) 1.8V
AD19 RXD_AUX I
COMMENT
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 module when is powered OFF or during an
ON/OFF transition.
9.3.
RS232 Level Translation
In order to interface the Telit HE920 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 0/1.8V 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 0-1.8V UART to the RS232 level.
The receiver is the translator from the RS232 level to 0-1.8V 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 1.8V CMOS have an absolute maximum input voltage of
2.7V; therefore the level translator IC shall not be powered by the +3.8V supply of the
module. Instead, it must be powered from a +1.8V (dedicated) power supply.
This is because in this way the level translator IC outputs on the module side (i.e. HE920
inputs) will work at +3.8V interface levels, damaging the module inputs.
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An example of RS232 level adaption circuitry could be accomplished using a MAXIM
transceiver (MAX218).
In this case the chipset is capable of translating directly from 1.8V to the RS232 levels
(Example on 4 signals only).
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: signal names and directions are named and defined from the DTE point of view
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HE920 Hardware User Guide
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10. Audio Section Overview
The HE920 module supports an analog audio interface and digital audio interface.
10.1.
Analog Audio
The HE920 module provides two analog audio paths transmitting and receiving.
Please refer to the xE920_Audio_Settings_Application_Note, 80404NT10095A
10.2.
Digital Audio
HE920 module can be connected to external codec through digital interface.
The product is providing one Digital Audio Interface (DVI) on the following Pins:
PAD
Signal
I/O
Function
D11
DVI_WA0
I/O
Digital Audio Interface (WA0)
C8
DVI_RX
Digital Audio Interface (RX)
D9
DVI_TX
Digital Audio Interface (TX)
C10
DVI_CLK
I/O
Digital Audio Interface (CLK)
Type
B-PD
1.8V
B-PD
1.8V
B-PD
1.8V
B-PD
1.8V
COMMENT
10.2.1. CODEC Example
Please refer to the Telit_UE_HE910V2_DE_CE910_HE920_DVI_Application_Note.
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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 and 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 HE920 firmware and acts depending on
the function implemented.
The following GPIOs are available on the HE920.
PAD
Signal
I/O
Function
F9
GPIO_01
I/O Configurable GPIO
E10
GPIO_02
I/O
F11
GPIO_03
I/O
E12
GPIO_04
I/O
F13
GPIO_05
I/O
E14
GPIO_06
I/O
R18
GPIO_07
I/O
S19
GPIO_08
I/O Configurable GPIO
U19
GPIO_09
I/O Configurable GPIO
W19
GPIO_10
I/O Configurable GPIO
Configurable GPIO
Configurable GPIO
Configurable GPIO
Configurable GPIO
Configurable GPIO
Configurable GPIO
Type
B-PD
1.8V
B-PD
1.8V
B-PD
1.8V
B-PD
1.8V
B-PD
1.8V
B-PD
1.8V
B-PD
1.8V
B-PD
1.8V
B-PD
1.8V
B-PD
1.8V
Drive Strength
2 mA
2 mA
2 mA
2 mA
2 mA
2 mA
2 mA
2 mA
2 mA
2 mA
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 module when is powered OFF or during an
ON/OFF transition.
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11.1.
Logic Level Specifications
Where not specifically stated, all the interface circuits work at 1.8V CMOS logic levels.
The following table shows the logic level specifications used in the HE920 interface circuits:
For 1,8V signals:
Absolute Maximum Ratings -Not Functional
HE920
Parameter
Min
Max
Input level on any
-0.3V
+2.7V
digital pin when on
Input voltage on
-0.3V
+2.7 V
analog pins when on
Operating Range - Interface levels (1.8V CMOS)
HE920
Level
Min
Max
Input high level
1.5V
2.1V
Input low level
Output high level
Output low level
11.2.
-0.3V
1.35V
0V
0.5V
1.8V
0.45V
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 1.8V
CMOS levels of the GPIO.
If the digital output of the device is connected with the GPIO input, the pad has interface
levels different from the 1.8V CMOS. It can be buffered with an open collector transistor with
a 47KΩ pull-up resistor to 1.8V.
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11.3.
Using a GPIO Pad as Output
The GPIO pads, when used as outputs, can drive 1.8V 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.
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11.4.
Using the Temperature Monitor Function
11.4.1. Short Description
The Temperature Monitor is a function of the module that permits to control its internal
temperature and if properly set (see the #TEMPMON command on AT Interface guide) it
raises to High Logic level a GPIO when the maximum temperature is reached.
11.5.
Indication of Network Service Availability
The STAT_LED pin status shows information on the network service availability and Call
status. In the HE920 modules, the STAT_LED usually needs an external transistor to drive an
external LED. Because of the above, the status indicated in the following table is reversed
with respect to the pin status:
LED status
Permanently off
Fast blinking
(Period 1s, Ton 0,5s)
Slow blinking
(Period 3s, Ton 0,3s)
Permanently on
Device Status
Device off
Net search / Not registered /
turning off
Registered full service
a call is active
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11.6.
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 capacitor can be added in order to increase the RTC autonomy
during power off of the battery.
NOTE:
NO devices must be powered from this pin.
11.7.
VAUX Power Output
A regulated power supply output is provided in order to supply small devices from the
module. This output is active when the module is ON and goes OFF when the module is shut
down. The operating range characteristics of the supply are:
Operating Range – VAUX power supply
Min
Typical
Max
1.75V
1.85V
Output voltage
1.80V
Output current
100mA
Output bypass capacitor
(Inside the module)
2.2μF
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12. DAC and ADC section
12.1.
DAC Converter
12.1.1. Description
The HE920 module provides a Digital to Analog Converter. The signal (named DAC_OUT)
is available on pad E14 of the HE920 module.
The on board DAC is in the range from 0 to 1023.
However, an external low-pass filter is necessary.
Voltage range (filtered)
Range
Min
Max
1.8
1023
Units
Volt
Steps
The precision is 1023 steps, so if we consider that the maximum voltage is 1.8V, the
integrated voltage could be calculated with the following formula:
Integrated output voltage = 1.8 * value / 1023
DAC_OUT line must be integrated (for example with a low band pass filter) in order to obtain
an analog voltage.
12.1.2. Enabling DAC
An AT command is available to use the DAC function.
The command is:AT#DAC[=[,]]
 - scale factor of the integrated output voltage (0..1023 - 10 bit precision)
it must be present if =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.
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12.1.3. Low Pass Filter Example
12.2.
ADC Converter
12.2.1. Description
The on board ADCs are 8-bit converters. They are able to read a voltage level in the range of
0-2 volts applied on the ADC pin input and store and convert it into 8 bit word.
Input Voltage range
AD conversion
Resolution
Min
Max
2.0
< 8.6
Units
Volt
bits
mV
The HE920 module provides 2 Analog to Digital Converters.
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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13. Mounting the module on your board
13.1.
General
The HE920 modules have been designed in order to be compliant with a standard lead-free
SMT process.
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13.2.
Module Finishing & Dimensions
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13.3.
Recommended foot print for the application
198 pads
Top View
In order to easily rework the HE920 it is suggested to consider on the application having a 1.5
mm placement inhibit area around the module.
It is also suggested, as a 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 above) must be
clear from signal or ground paths.
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13.4.
Stencil
Stencil’s apertures layout can be the same as the recommended footprint (1:1), we suggest a
thickness of stencil foil ≥ 120 µm.
13.5.
PCB Pad Design
Non solder mask defined (NSMD) type is recommended for the solder pads on the PCB.
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13.6.
Recommendations for PCB Pad Dimensions (mm)
The recommendation for the PCB pads dimensions are described in the following image
(dimensions in mm)
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It is not recommended to place via or micro-via not covered by solder resist in an
area of 0,3 mm around the pads unless it carries the same signal of the pad itself
(see following figure).
Holes in pad are allowed only for blind holes and not for through holes.
Recommendations for PCB Pad Surfaces:
Finish
Electro-less Ni / Immersion Au
Layer thickness (um)
3 –7 / 0.05 – 0.15
Properties
good solder ability protection,
high shear force values
The PCB must be able to resist the higher temperatures which are occurring at the lead-free
process. This issue should be discussed with the PCB-supplier. Generally, the wettability of
tin-lead solder paste on the described surface plating is better compared to lead-free solder
paste.
It is not necessary to panel the application’s PCB, however in that case it is suggested to use
milled contours and predrilled board breakouts; scoring or v-cut solutions are not
recommended.
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13.7.
Solder Paste
Solder Paste
Lead free
Sn/Ag/Cu
We recommend using only “no clean” solder paste in order to avoid the cleaning of the
modules after assembly.
13.7.1. Solder Reflow
Recommended solder reflow profile:
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Profile Feature
Average ramp-up rate(TL to Tp)
Preheat
- Temperature Min(Tsmin)
- Temperature Max(Tsmax)
- Time (min to max) (ts)
Tsmax to TL
- Ramp-up Rate
Time maintained above:
- Temperature (TL)
- Time(tL)
Peak Temperature (Tp)
Time within 5℃ of actual Peak Temperature(tp)
Ramp-down Rate
Time 25℃ to Peak Temperature
Pb-Free Assembly
3℃/second max
150℃
200℃
60 - 180 seconds
3℃/second max
217℃
60 - 150 seconds
245 +0/-5℃
10 - 30 seconds
6℃/sec max
8 minutes max
NOTE:
All temperatures refer to topside of the package, measured on the package body surface.
WARNIG:
The HE920 module withstands one reflow process only.
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14. Application guide
14.1.
Debug of the HE920 in production
To test and debug the mounting of HE920, we strongly recommend foreseeing test pads on
the host PCB, in order to check the connection between the HE920 itself and the application
and to test the performance of the module connecting it with an external computer. Depending
on the customer application, these pads include, but are not limited to the following signals:

TXD

RXD

ON/OFF

RESET

GND

VBATT

TX_TRACE

RX_TRACE

PWRMON

USB_VBUS

USB_D+

USB_D-
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14.2.
Bypass capacitor on Power supplies
When a sudden voltage is asserted to or cut from the power supplies,
The steep transition makes some reactions such as the overshoot and undershoot.
This abrupt voltage transition can affect the device not to work or make it malfunction.
The bypass capacitors are needed to alleviate this behavior and it can be affected
differently according to the various applications. The customers have to pay special
attention to this when they design their application board..
The length and width of the power lines need to be considered carefully and the
capacitance of the capacitors need to be selected accordingly.
The capacitor will also avoid the ripple of the power supplies and the switching noise
caused in TDMA system like GSM.
Specially the suitable bypass capacitor must be mounted on the VBATT and VBATT_PA
lines in the application board.
The recommended values can be presented as;
 100uF for VBATT and VBATT_PA
But the customers still have to consider that the capacitance mainly depends on the
conditions of their application board.
Generally more capacitance is required as the power line is longer.
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14.3.
SIM interface
This section deals with the recommended schematics for the design of SIM interfaces on the
application boards.
14.3.1. SIM schematic example
Figure 1 illustrates in particular how the application side should be designed, and what values
the components should have.
NOTE FOR R1:
The resistor value on SIMIO pulled up to SIMVCC should be defined accordingly in order to
be compliant to 3GPP specification.
For HE920-EU and HE920-NA contain an internal pull-up resistor on SIMIO.
However, the un-mounted option in application design can be recommended in order to tune
R1 if necessary.
The following Table lists the values of C1 to be adopted with the HE920 product:
Product P/N
HE920-EU
HE920-NA
C1 range (nF)
100 nF
Refer to the following document for the detail;
 Telit_SIM_Integration_Design_Guide_Application_Note
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14.4.
EMC recommendations
HE920 signals are provided by some EMC protections. In any case the accepted levels are
different on the pins. The characteristics are described in the following Table:
Pad
Signal
AP17,AP19,
AR18,AS17, VBATT_PA
AS19,AT18, And VBATT
AU17,AU19
I/O
A8
B11
B9
A10
SIMVCC
SIMRST
SIMIO
SIMCLK
I/O
P17
VAUX
AS1
ON/OFF
AP1
F17
RESET
VRTC
AO
AD1,AU9,S1 Antenna Pad
AI
Function
Power Supply
Main power supply
SIM Card Interface
External SIM signal – Power supply for the SIM
External SIM signal – Reset
External SIM signal - Data I/O
External SIM signal – Clock
Miscellaneous Functions
Power output for external accessories
Input command for switching power ON or OFF
(toggle command).
Reset input
Power supply for RTC block
Antenna
Antenna pad
Contact
Air
± 8KV
± 15KV
±
±
±
±
±
±
±
±
8KV
8KV
8KV
8KV
15KV
15KV
15KV
15KV
± 8KV
± 15KV
± 8KV
± 15KV
± 8KV
± 8KV
± 15KV
± 15KV
± 8KV
± 15KV
All other pins have the following characteristics:
HBM JESD22-A114-B ± 2000 V
CDM JESD22-C101-C ± 500 V
Appropriate series resistors have to be considered to protect the input lines from overvoltage.
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14.5.
Download and Debug Port
One of the following options should be chosen in the design of host system in order to
download or upgrade the Telit’s software and debug HE920 when HE920 is already mounted
on a host system.
Users who use both of UART and USB interfaces to communicate HE920
Must implement a download method in a host system for upgrading HE920 when it’s
mounted.
Users who use USB interface only to communicate HE920
Must arrange UART port in a host system for debugging or upgrading HE920 when it’s
mounted.
Users who use UART interface only to communicate HE920
Must arrange USB port in a host system for debugging or upgrading HE920 when it’s
mounted.
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15. Packing system
The Telit HE920 is packaged on trays. Each tray contains 20 pieces with the following
dimensions:
15.1.
Tray Drawing
(1VV0700623_DTS)
WARNIG:
These trays can withstand a maximum temperature of 65℃.
15.2.
Moisture Sensibility
The HE920 is a Moisture Sensitive Device level 3, in accordance with standard IPC/JEDEC
J-STD-020, take care all the relatives requirements for using this kind of components.
Moreover, the customer has to take care of the following conditions:
a) Calculated shelf life in sealed bag: 12 months at <40°C and <90% relative humidity (RH).
b) Environmental condition during the production: 30°C / 60% RH according to IPC/JEDEC
J-STD-033A paragraph 5.
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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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16. Conformity Assessment Issues
16.1.
1999/5/EC Directive
The HE920-EU 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 harmonized standards with the final involvement of a
Notified Body.
In order to satisfy the essential requirements of 1999/5/EC Directive, the HE920-EU is compliant with the
following standards:
RF spectrum use (R&TTE art. 3.2)
EN 300 440-2 V1.4.1
EN 301 511 V9.0.2
EN 301 908-1 V5.2.1
EN 301 908-2 V5.2.1
EMC (R&TTE art. 3.1b)
EN 301 489-1 V1.9.2
EN 301 489-3 V1.4.1
EN 301 489-7 V1.3.1
EN 301 489-24 V1.5.1
Health & Safety (R&TTE art. 3.1a)
EN 60950-1:2006 + A11:2009 + A1:2010 + A12:2011+AC:2011
The conformity assessment procedure referred to in Article 10 and detailed in Annex IV of Directive
1999/5/EC has been followed with the involvement of the following Notified Body:
AT4 wireless, S.A.
Parque Tecnologico de Andalucía
C/ Severo Ochoa 2
29590 Campanillas – Málaga
SPAIN
Notified Body No: 1909
Thus, the following marking is included in the product:
The full declaration of conformity can be found on the following address:
http://www.telit.com
There is no restriction for the commercialization of the HE920-EU module in all the countries of the European
Union.
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Final product integrating this module must be assessed against essential requirements of the 1999/5/EC
(R&TTE) Directive. It should be noted that assessment does not necessarily lead to testing. Telit
Communications S.p.A. recommends carrying out the following assessments:
RF spectrum use (R&TTE art. 3.2)
EMC (R&TTE art. 3.1b)
Health & Safety (R&TTE art. 3.1a)
It will depend on the antenna used on the final product.
Testing
Testing
Alternately, assessment of the final product against EMC (Art. 3.1b) and Electrical safety (Art. 3.1a) essential
requirements can be done against the essential requirements of the EMC and the LVD Directives:


Low Voltage Directive 2006/95/EC and product safety
Directive EMC 2004/108/EC for conformity for EMC
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16.2.
FCC/IC Regulatory notices
Modification statement
Telit has not approved any changes or modifications to this device by the user. Any changes or modifications
could void the user’s authority to operate the equipment.
Telit n’approuve aucune modification apportée à l’appareil par l’utilisateur, quelle qu’en soit la nature. Tout
changement ou modification peuvent annuler le droit d’utilisation de l’appareil par l’utilisateur.
Interference statement
This device complies with Part 15 of the FCC Rules and Industry Canada licence-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.
This Class B digital apparatus complies with Canadian ICES-0003.
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.
Wireless notice
This equipment complies with FCC and IC radiation exposure limits set forth for an uncontrolled environment.
The antenna should be installed and operated with minimum distance of 20 cm between the radiator and your
body. Antenna gain must be below:
Frequency band
GSM850 / FDD V
PCS1900 / FDD II
FDD IV
HE920-NA
6.79 dBi
3.01 dBi
2.7 dBi
This transmitter must not be co-located or operating in conjunction with any other antenna or transmitter.
Cet appareil est conforme aux limites d'exposition aux rayonnements de la IC pour un environnement non
contrôlé. L'antenne doit être installé de façon à garder une distance minimale de 20 centimètres entre la
source de rayonnements et votre corps. Gain de l'antenne doit être ci-dessous:
Bande de fréquence
GSM850 / FDD V
PCS1900 / FDD II
FDD IV
HE920-NA
6.79 dBi
3.01 dBi
2.7 dBi
L'émetteur ne doit pas être colocalisé ni fonctionner conjointement avec à autre antenne ou autre émetteur.
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FCC Class B digital device notice
This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to
part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful
interference in a residential installation. This equipment generates, uses and can radiate radio frequency
energy and, if not installed and used in accordance with the instructions, may cause harmful interference to
radio communications. However, there is no guarantee that interference will not occur in a particular
installation. If this equipment does cause harmful interference to radio or television reception, which can be
determined by turning the equipment off and on, the user is encouraged to try to correct the interference by
one or more of the following measures:
- Reorient or relocate the receiving antenna.
- Increase the separation between the equipment and receiver.
- Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
- Consult the dealer or an experienced radio/TV technician for help.
Information To Be Supplied to the End User by the OEM or Integrator notice
Modular information form OEM Information to Be Supplied to the End User by the OEM or Integrator
The following regulatory and safety notices must be published in documentation supplied to the end user of
the product or system incorporating an adapter in compliance with local regulations. Host system must be
labeled with "Contains IC: 5131A-HE920NA " or "Contains FCCID:RI7HE920NA ", FCC ID/IC displayed
on label.
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17. Safety Recommendations
READ CAREFULLY
Be sure about that the use of this product is allowed in your 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 be installed with the guarantee of a minimum 20 cm distance from the
body. 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 are available on the European Community
website:
http://europa.eu.int/comm/enterprise/rtte/dir99-5.htm
The text of the Directive 99/05 regarding telecommunication equipments is available, while
the applicable Directives (Low Voltage and EMC) are available at:
http://europa.eu.int/comm/enterprise/rtte/dir99-5.htm
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18. Document History
Revision
Date
2012-02-02
2012-06-04
2012-10-24
2012-11-14
2013-01-02
2013-03-21
2013-05-14
2013-11-08
2013-11-13
2014-01-23
Changes
First issue
Renumbered chapters
Updated 2.3 Weight
Updated 3 HE920 Module Connections
Updated 5.1 Power Supply Requirements
Updated 6.5 GPS/GNSS Antenna Requirements
Updated 9.2 Modem Serial Port 2
Updated 13.2 ADC Converter
Updated 14.2 Module Finishing & Dimensions
Updated 4 Hardware Commands
Added 4.5 Hardware Unconditional Shutdown (Power Off)
Updated 5.1 Power Supply Requirements
Updated 5.2.2 Thermal Design Guidelines
Updated 6.1 GSM/WCDMA Antenna Requirements
Updated 7.1 Reset Signal
Updated 8 USB Port
Updated 13.2 Module Finishing & Dimensions
Updated 14.2 Bypass capacitor on Power supplies
Updated 14.4 EMC recommendations
Updated 15.2 Moisture Sensibility
Updated 5.1 Power Supply Requirements
Updated 6.1 GSM/WCDMA Antenna Requirements
Updated 5.1 Power Supply Requirements
Updated 6 Antenna(s)
Updated 6.1 GSM/WCDMA Antenna Requirements
Added 16.1 1999/5/EC Directive
Added 16.2 FCC/IC Regulatory notices
Updated 1.6 Related Documents
Updated 10.1 Analog Audio
Updated 13.4 Stencil
Updated 13.5 PCB Pad Design
Updated 13.6 Recommendations for PCB Pad Dimensions (mm)
Updated 13.7.1 Solder Reflow
Updated 15.1 Tray Drawing
Updated 6.5.3 LNA and Front End Design Considerations
Updated 13.2 Module Finishing & Dimensions
Updated 14.3 SIM Interface
Updated 13.3 Recommended foot print for the application
Updated 2.4.2 RoHS compliance
Updated 6.1 GSM/WCDMA Antenna Requirements
Updated 8 USB Port
Updated 12.1 DAC Converter
Updated 16.2 FCC/IC Regulatory notices
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Language                        : ko-KR
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Title                           : HW User Guide Template
Author                          : federicovi
Subject                         : HW User Guide Template
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Create Date                     : 2014:02:03 14:04:24+09:00
Modify Date                     : 2014:02:03 14:04:24+09:00
Producer                        : Microsoft® Word 2010
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