Telit Wireless Solutions LM960 Guide

LM960
Thermal Design Guide
1VV0301620 Rev. 2 –2021-09-09
Telit Technical Documentation

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APPLICABILITY TABLE
PRODUCTS
LM960
LM960A18

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CONTENTS
APPLICABILITY TABLE 2
CONTENTS 3
1. INTRODUCTION 5
Scope 5
Audience 5
Contact Information, Support 5
Symbol Conventions 6
Related Documents 6
2. THERMAL MODEL 7
Temperature Sensor and Hotspot 7
2.1.1. Temperature Reading and Monitoring 7
Thermal Mitigation Algorithm 9
2.2.1. Thermal Mitigation Level Reading 10
2.2.2. How to Change Thermal Mitigation Level Range 11
Thermal Model -TBD 13
Temperature Range 14
Current Consumption in Each Mode 14
3. THERMAL DESIGN 16
Thermal Design Guidelines 16
Thermal Design Solution 16
4. PRODUCT AND SAFETY INFORMATION 20
Copyrights and Other Notices 20
4.1.1. Copyrights 20
4.1.2. Computer Software Copyrights 20
Usage and Disclosure Restrictions 21
4.2.1. License Agreements 21
4.2.2. Copyrighted Materials 21

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4.2.3. High Risk Materials 21
4.2.4. Trademarks 22
4.2.5. Third Party Rights 22
4.2.6. Waiver of Liability 22
Safety Recommendations 23
5. GLOSSARY 24
6. DOCUMENT HISTORY 25

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1. INTRODUCTION
Scope
This document provides thermal model and design guidelines useful for developing a
product with the Telit LM960.
Note: Proper thermal protection design protects against human or
component damage under the worst-case conditions.
And it reduces the probability of failure and does not adversely affect
the use of the module, and greatly extends the operation time with
maximum performance.
Audience
This document is intended system integrators that are using the Telit LM960 module in
their products.
Contact Information, Support
For technical support and general questions please e-mail:
• TS[email protected]
• TS[email protected]
• TS[email protected]
• TS[email protected]
• TS[email protected]
Alternatively, use:
https://www.telit.com/contact-us/
Product information and technical documents are accessible 24/7 on our web site:
https://www.telit.com

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Symbol Conventions
Danger: This information MUST be followed or catastrophic
equipment failure or personal injury may occur.
Warning: Alerts the user on important steps about the module
integration.
Note/Tip: Provides advice and suggestions that may be useful when
integrating the module.
Electro-static Discharge: Notifies the user to take proper grounding
precautions before handling the product.
Table 1: Symbol Conventions
All dates are in ISO 8601 format, that is YYYY-MM-DD.
Related Documents
•LM960 HW User Guide, 1VV0301485
•LM960 SW User Guide, 1VV0301477

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2. THERMAL MODEL
Temperature Sensor and Hotspot
LM960 has three thermistors inside the module. The internal temperature can be
monitored by the AT command.
Figure 1: LM960 Temp Sensor & Hotspot
As you can see in the figure above, inside the LM960 there are three temperature sensors
(TSENS2, PA_THERM0, PA_THERM1). And it can be read from internal temperatures
using the AT#TEMPSENS command.
2.1.1. Temperature Reading and Monitoring
AT#TEMPSENS command provides several methods to read the internal temperature as
instant or periodic reports and to monitor the internal temperature using URC and GPIO.

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#TEMPSENS –Temperature monitor
AT#TEMPSENS=
<mod>[,<interval>
[,<action>
,<low_temp>
,<high_temp>
[,<gpio>]]]
Set command sets the operation of the internal temperature monitor.
Parameters:
<mod>
0 –disables the periodic reporting (factory default)
1 –enables the periodic reporting
2 –instantaneous reporting of the Temperature
Note: the module cannot enter sleep when <mod>=1.
<interval> - duration in seconds of the interval between next measurement. It has
meaning only if <mod> is 1.
The unsolicited message is in the format:
#TEMPSENS: <sensor>,<value>
where:
<sensor> - temperature sensor name
<value> - actual temperature expressed in Celsius degrees
<action>
1 - (01) - it enables the presentation of the temperature monitor
URC periodically. If <action> is not specified, this is
default.
2 - (10) - it enables the presentation of the temperature notification
URC, whenever the module internal temperature
reaches either <low_temp> or <high_temp> levels.
4 - (100) - output pin <gpio> is tied HIGH when set temperature
bounds are reached; when the temperature is back to
normal the output pin <gpio> is tied LOW. It is
mandatory to set the <gpio> parameter too to set this
<action>.
The notification message is in the format:
#TEMPNOTI: <level>,<value>
where:
<level> - threshold level
-1 - <low_temp> set temperature lower bound
0 - normal temperature
1 - <high_temp> set temperature upper bound
Note: Possible values for the parameter <action> are form 1 to 7 (001, 010, 011, 100, 101,
110 and 111)
<low_temp> - Temperature Lower Bound
(-40 –0, Celsius Degrees)
<high_temp> - Temperature Upper Bound
(0 –100, Celsius Degrees)

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#TEMPSENS –Temperature monitor
<gpio> - GPIO number. Valid range is any GPIO pin as described in
#GPIO command. This parameter is needed and required
only if <action>=4, 5, 6 or 7 are enabled.
AT#TEMPSENS?
Read command reports the current parameter settings in the format:
#TEMPSENS: <mod>,<interval>[,<action>,<low_temp>,<high_temp>,[<gpio>]]
AT#TEMPSENS=?
Test command reports supported range of values for parameters
<mod>,<interval>,<action>,<low_temp>,<high_temp> and <gpio>.
Example
AT#TEMPSENS=2
#TEMPSENS: TSENS2,29
#TEMPSENS: PA_THERM0,30
#TEMPSENS: PA_THERM1,30
OK
Table 2: AT Command for Temperature Monitoring
Thermal Mitigation Algorithm
LM960 has a built-in thermal mitigation algorithm to reduce the probability of failure and
extend the operation time with maximum performance. The thermal mitigation algorithm
operates according to the internal temperature value read through the three
temperature sensors. The Thermal mitigation algorithm limits the performance(DL/UL
throttling, Tx power back off, call drop.. etc) when the temperature is above a defined
certain level.
Thermal Mitigation Level
Temperature sensors have several levels of thermal mitigation. Each level has
predefined actions as in the table below and works individually in the sensor. Performs
the following actions based on the mitigation level to reduce/control the temperature.
Sensor
Level
Action
Comment
PA_THERM
0
-
Normal
1
Enable UL data throttling
Start throttling the uplink data rate by reporting
a smaller buffer status report.
2
Enable MTPL back-off
Limit maximum Tx power (23dBm)
3
Lmitied service mode
Call released.
TSENS
0
-
Normal
1
Start DL data throttling
#3DL CA drops to 1DL (PCC only)
3
Limited service mode
Call released.
Table 3: Thermal Mitigation Level and Action

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After entering mitigation level 3, the limited service mode is released after the
PA_THERM and TSENS sensor reaches mitigation level 0. In other words, the sensor
reading falls below the level 1 clearing thresholds.
2.2.1. Thermal Mitigation Level Reading
AT#TMLVL command used for read current thermal mitigation level of each temperature
sensors.
#TMLVL –Thermal Mitigation Level
AT#TMLVL=<device_id>
Set command reports a current thermal mitigation level of specific <device_id>.
Parameters:
<device_id> - which device to get mitigation level
1 –TSENS2
2 –PA_THERM
The report message is in the format:
#TMLVL: <level>
Where:
<level> - thermal mitigation level
0 –normal
1 –level1
2 –level2
3 –level3
Note : level2 is shown only with PA_THERM device.
AT#TMLVL?
Read command reports a current thermal mitigation level of all devices in the format:
#TMLVL: TSENS2,<level>
#TMLVL: PA_THERM,<level>
AT#TMLVL=?
Test command returns the supported range of values for parameter <device_id>.
Example
AT#TMLVL?
#TMLVL: TSENS2,1
#TMLVL: PA_THERM,1
OK
AT#TMLVL=2
#TMLVL: 1
OK
Table 4: AT Command for Thermal Mitigation Level Reading

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2.2.2. How to Change Thermal Mitigation Level Range
The range of the Thermal mitigation level could be modified through thermal engine
configuration file.
For using ADB on Windows OS
Download the ADB tool through google (Can be skipped if you already have it).
https://adbshell.com/downloads
Check ADB device detection.
•Connect USB to Windows Laptop.
•Run Command Prompt or PowerShell of Windows in downloaded ADB tool
directory.
adb devices
•If ADB detection success, you can see the specific device id. In case of detection
failed, please do next step.
Register Telit USB VID to ADB tool (This step needs only once at one Laptop.
•If ADB detection filed, please do following commands.
echo 0x1BC7 >> %HOMEPATH%\.android\adb_usb.ini
adb kill-server
adb devices

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•After do commands, you can see ADB device that attached on Laptop.
Change thermal engine configuration file
Current thermal engine configuration file can be got from LM960 through ADB command.
•adb pull /etc/thermal-engine.conf
•Open and edit the thermal-engine.conf file.
•Put the modified thermal-engine.conf file to LM960.
adb push thermal-engine /etc
•Please do reboot LM960 to apply your changes.

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Thermal Model -TBD
Thermal Model is evaluated by thermal simulation and RF test with thermal chamber.
Figure 2: Equivalent thermal resistance model
The two-resistor compact model is calculated according to JEDEC standard.
ƟJT is the thermal resistance from junction to the top side: 9 °C/W
ƟJA is the thermal resistance from the top side to the air side: 22 °C/W
ƟJB is the thermal resistance from junction to the bottom side: 7 °C/W
ƟBA is the thermal resistance from the bottom to the air side: 19 °C/W
**Measure condition:
- Thermal resistances were measured in 100mm * 90mm * 1mm FR4 Evaluation
board
- Network condition
Downlink 4*4MIMO 1.2Gbps throughput (B2, B66C)
Uplink QPSK and maximum power status

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Note: And we also provide the FloTHERM detail modeling file for help
customers to design and simulate their design easily.
Thermal simulation was performed with Flotherm V12.1
If you want to get the thermal simulation file, please contact Telit
Technical Support at
• TS[email protected]
• TS[email protected]
• TS[email protected]
• TS[email protected]
Temperature Range
The maximum operating temperature allowed is +105°C which can be read by
AT#TEMPSENS. It is not recommended to operature the LM960 above the allowable
maximum operating temperature.
Operating Condition
Condition
Min
Typ
Max
The Temperature read by AT#TEMPSENS
-
-
+105°C
Table 5: Operating Condition
Current Consumption in Each Mode
LM960 Current Consumption
Mode
Average [Typ.]
Mode Description
IDLE Mode
CFUN=1
20mA
No call connection
USB3.0 is connected to a host
Power Saving Mode (PSMWDISACFG=1, W_DISABLE_N:Low)
CFUN=4
2.5mA
Tx and Rx are disabled; module is not registered on the
network (Flight mode)
WCDMA
3mA
DRx7 (1.28 sec DRx cycle)
LTE
3.3mA
Paging cycle #128 frames (1.28 sec DRx cycle)
Operative Mode (LTE)
Non-CA mode (1DL / 1UL)
600mA
Non-CA, Band 2, Single carrier, BW 5MHz, 23dBm, 1RB

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Mode
Average [Typ.]
Mode Description
2DL CA with 2x2 MIMO / 2UL CA
900mA
CA_2A-5A, 2x2 MIMO, Full RB, 256QAM DL / 64QAM UL
(FDD 300Mbps DL / 150Mbps UL)
5DL CA with 2x2 MIMO / 1UL
1000mA
CA_2A-5B-66A-66A, 2x2 MIMO, Full RB, 256QAM DL /
64QAM UL (FDD 1Gbps DL / 75Mbps UL)
3DL CA with 4x4 MIMO / 1UL
1200mA
CA_2A-66C, 4x4 MIMO, Full RB, 256QAM DL / 64QAM UL
(FDD 1.2Gbps DL / 75Mbps UL)
Operative Mode (WCDMA)
WCDMA Voice
750 mA
WCDMA voice call (Tx = 23 dBm)
WCDMA HSPA (22 dBm)
650 mA
WCDMA data call (DC-HSDPA up to 42 Mbps, Max
Throughput)
Table 6: Current Consumption
* Worst/best case current values depend on network configuration
** Loop-back mode in call equipment
*** 3.3 voltage / room temperature
Note: The electrical design for the power supply must ensure a peak
current output of at least 2A.

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3. THERMAL DESIGN
This chapter provides thermal design guidance to assist the customer in thermal design.
Thermal Design Guidelines
To enhance heat dissipation:
•Make sure there is sufficient air flow around the LM960 . (Spread the heat)
- Balance the heat flow between front and back of the PCB
- Insulate hot spots on the device skin from hot areas below
•Separate the hottest components (Spread the heat)
•Optimize the ground plane and connections. (Spread the heat)
- Use a larger copper weight for a solid ground plane layer
- Connect each ground pad of LM960 directly.
•Use Thermal Interface Material. (Spread the heat)
- Eliminate the air gaps between the top/bottom of LM960 and the heat
spreaders; use TIM under compression and thermal grease for better
thermal conduction
- Use large surface areas with high thermal conductivity
•Use phase change material or heat pipes. (Absorb the heat)
•Keep the TCXO or any XO away from heat sources/gradients near the LM960.
•If the thermal conductive material is attached between LM960 and the customer
board, the heat dissipation is better for multilayer PCB.
•Attach the conductive material and heat sink at top and bottom side of module for
the heat dissipation.
Thermal Design Solution
There are the 1.2 W/m-k thermal conductive materials between the main chipset and the
shield cover of the LM960 for the better heat dissipation.

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Figure 3: LM960 Side View
Warning: RF and Baseband areas must be dissipated from heat
Figure 4: LM960 Shield Cover with TIM (Bottom View)
Figure 5: Copper Pad Location on Bottom of LM960

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On the back of LM960 there is the large resist opening area for soldering for better heat
dissipation to the heat sinks found on the customer’s application board.
This chapter defines the heat sink or TIM for application as the basic element of the heat
sink design. LM960 is capable of getting et very hot when operating at the upper limit of
its range.
A heat sink or TIM is a component that is attached to a module to transfer heat from the
device to its surrounding environment. This environment is most commonly air, but it can
also be other fluids. Heat sinks are typically made of aluminum or copper. It expedites
the heat transfer to the surrounding fluid.
Figure 6: Thermal Solution on Both sides
The best method is to connect a heat sink on the top and a TIM on the bottom side.
Inevitable environment where heat sink or TIM cannot be attached on both sides, a heat
sink or TIM can only be connected on one side, but this is not the best option.
It is recommended to connect a TIM pad to the bottom side of customer PCB.
Please refer to the figure as below.
Figure 7: Heat Sink on Top Side

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Figure 8: TIM on Bottom Side
Note: If you ignore the above contents, the network connection may
be terminated due to overheating. When the temperature drops, the
network connection will be restarted

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4. PRODUCT AND SAFETY INFORMATION
Copyrights and Other Notices
SPECIFICATIONS ARE SUBJECT TO CHANGE WITHOUT NOTICE
Although reasonable efforts have been made to ensure the accuracy of this document,
Telit assumes no liability resulting from any inaccuracies or omissions in this document,
or from the use of the information contained herein. The information contained in this
document has been carefully checked and is believed to be reliable. Telit reserves the
right to make changes to any of the products described herein, to revise it and to make
changes from time to time without any obligation to notify anyone of such revisions or
changes. Telit does not assume any liability arising from 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.
This document may contain references or information about Telit’s products (machines
and programs), or services that are not announced in your country. Such references or
information do not necessarily mean that Telit intends to announce such Telit products,
programming, or services in your country.
4.1.1. Copyrights
This instruction manual and the Telit products described herein may include or describe
Telit copyrighted material, such as computer programs stored in semiconductor
memories or other media. The laws in Italy and in other countries reserve to Telit and its
licensors certain exclusive rights for copyrighted material, including the exclusive righ to
copy, reproduce in any form, distribute and make derivative works of the copyrighted
material. Accordingly, any of Telit’s or its licensors’ copyrighted material contained
herein or described in this instruction manual, shall not be copied, reproduced,
distributed, merged or modified in any way without the express written permission of the
owner. Furthermore, the purchase of Telit products shall not be deemed to grant in any
way, neither directly nor by implication, or estoppel, any license.
4.1.2. Computer Software Copyrights
Telit and the Third Party supplied Software (SW) products, described in this instruction
manual may include Telit’s and other Third Party’s copyrighted computer programs
stored in semiconductor memories or other media. The laws in Italy and in other
countries reserve to Telit and other Third Party, SW exclusive rights for copyrighted