Telit Wireless Solutions LM960 Guide

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

LM960 Thermal Design Guide
1VV0301620 Rev. 2 Page 2of 26 2021-09-09
Not Subject to NDA
APPLICABILITY TABLE
PRODUCTS
LM960
LM960A18

LM960 Thermal Design Guide
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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