Telit Wireless Solutions LE910C series Guide

LE910Cx mPCIe
Thermal Design Guide
1VV0301626 Rev. 2 –2021-07-09
Telit Technical Documentation

LE910Cx mPCIe Thermal Design Guide
1VV0301626 Rev. 2 Page 2of 26 2021-07-09
Not Subject to NDA
APPLICABILITY TABLE
PRODUCTS
LE910C4-NF MPCIE
LE910C1-NF MPCIE
LE910C1-NA MPCIE
LE910C1-NS MPCIE
LE910C1-AP MPCIE
LE910C4-AP MPCIE
LE910C1-EU MPCIE
LE910C4-EU MPCIE
LE910C1-SA MPCIE
LE910C1-ST MPCIE
LE910C1-SV MPCIE
LE910C1-LA MPCIE
LE910C4-LA MPCIE
LE910C4-CN MPCIE
LE910C1-EUX MPCIE
LE910C1-SVX MPCIE
LE910C1-SAX MPCIE

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CONTENTS
APPLICABILITY TABLE 2
CONTENTS 3
1. INTRODUCTION 5
2. THERMAL MODEL 6
Temperature Sensor and Hotspot 6
2.1.1. Temperature Reading and Monitoring 7
Thermal Mitigation Algorithm 8
2.2.1. How to Change Thermal Mitigation Level Range 9
Thermal Model 13
Temperature Range 14
Current Consumption in Each Mode 14
3. THERMAL DESIGN 16
Thermal Design Guidelines 16
Thermal Design Solution 17
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
4.2.3. High Risk Materials 21
4.2.4. Trademarks 22
4.2.5. Third Party Rights 22
4.2.6. Waiwer of Liability 22
Safety Recommendations 23

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5. GLOSSARY 24
6. DOCUMENT HISTORY 25

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1. INTRODUCTION
This document provides a thermal model and design guidelines useful for developing a
product with the Telit LE910Cx mPCIe.
Note: Proper thermal protection design protects against damage to
people or component under 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.

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2. THERMAL MODEL
Temperature Sensor and Hotspot
LE910Cx mPCIe has two thermistors inside the module. The internal temperature can be
monitored by the AT command.
Figure 1: LE910Cx mPCIe Temp Sensor & Hotspot
As you can see in the figure above, there is a temperature sensor (PA_THERM0) inside
the LE910Cx mPCIe. And it can be read by the internal temperatures using the
AT#TEMPMON command.

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2.1.1. Temperature Reading and Monitoring
AT#TEMPMON command provides several methods to read the internal temperature as
instant reports and to monitor the internal temperature using URC and GPIO.
#TEMPMON –Temperature monitor
AT#TEMPMON=
<mod>
[,<urcmode>
[,<action>
[,<GPIO>]]]
Set command sets the behavior of the module internal temperature monitor.
Parameters:
<mod>
0 - sets the command parameters.
1 - triggers the measurement of the module internal temperature, reporting the result
in the format:
#TEMPMEAS: <level>,<value>
where:
<level> - threshold level
-2 - Extreme temperature lower bound.
-1 - Operating temperature lower bound.
0 - normal temperature.
1 - Operating temperature upper bound.
2 - Extreme temperature upper bound.
(see note 1)
<value> - actual temperature expressed in Celsius degrees.
Setting of the following optional parameters has meaning only if <mod>=0:
<urcmode> - URC presentation mode. (Default 1)
0 - It disables the presentation of the temperature monitor URC.
1 - It enables the presentation of the temperature monitor URC, whenever the module
internal temperature reaches either operating or extreme levels. The unsolicited
message is in the format:
#TEMPMEAS: <level>,<value>
where:
<level> and <value> are as before.
<action> - sum of integers, each representing the action to be done whenever the
module internal temperature reaches either operating or extreme levels (default is 1).
0 - (00) - No action.
1 - (01) - Activating of thermal mitigation according to thermal configuration file.
2 - (10) - Output pin <GPIO> is tied HIGH when operating temperature bounds are
reached; when the temperature is back to normal the output pin <GPIO> is tied LOW. If
this <action> is required, it is mandatory to set the <GPIO> parameter too.
3- (11) - This value contains <action=1> and <action=2> i.e. activate thermal mitigation
and a GPIO indication. If this <action> is required, it is mandatory to set the <GPIO>
parameter too.
<GPIO> - GPIO number. Valid range is any TGPIO pin as described in #GPIO command.
This parameter is needed and required only if <action>=2 or 3 are enabled.
AT#TEMPMON?
Read command reports the current parameter settings for #TEMPMON command in
the format:
#TEMPMON: <urcmode>,<action> [,<GPIO>]

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#TEMPMON –Temperature monitor
AT#TEMPMON=?
Test command reports the supported range of values for parameters <mod>,
<urcmode>, <action>, and <GPIO>
Notes
1. Thresholds levels are defined in #TEMPCFG command. See there for detailed
description on thermal mitigation configuration.
2. Last <action> setting is saved in the 'config.ini' file ('mitigate'/'none mitigate'), and
in the NVM ('gpio indication'/'none gpio indication').
3. Last <GPIO> is saved in the NVM.
4. Thermal mitigation is disabled automatically when using laboratory test SIM.
Table 1: #TEMPMON –Temperature Monitor
Thermal Mitigation Algorithm
LE910Cx mPCIe has 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 temperature sensor.
The thermal mitigation algorithm limits the performance (UL throttling, Tx power back
off, call drop.. and so on) when the temperature is above a defined certain level.
Thermal Mitigation Level
The temperature sensor has several levels of thermal mitigation. Each level has
predefined actions as below table and works in sensor individually.
Performs the following actions according to mitigation level to reduce/control the
temperature.
Sensor
Level
Action
Comment
PA_THERM
0
-
Normal
1
Enable MTPL back-off
Limit maximum Tx power (23dBm)
2
Emergency Calls Only
Table 2: Thermal Mitigation Level
After entering mitigation level 2, the device will register on the network after PA_THERM
sensor reaches mitigation level 0. In other words, the sensor reading falls below the level
1 clear thresholds.

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2.2.1. How to Change Thermal Mitigation Level Range
Thermal mitigation level range and action could be modified through AT#TEMPCFG
command.
AT#TEMPCFG=
<etlz_clr>,<etlz>
,<etlz_act_in>,
<otlz_clr>,<otlz>
,<otlz_act_in>,
<otnz_clr>,<otnz>,<otnz_
act_in>,
<otuz_clr>,<otuz>,<otuz_
act_in>,
<etuz_clr>,<etuz>,<etuz_
act_in>
Set command sets the Temperature zones used in the #TEMPMON command.
Parameters:
<etlz_clr>: Extreme low zone temperature threshold clear. Has only one valid value: -
273°C. see notes
<etlz>: Extreme low zone temperature threshold. Default value -33°C.
<etlz_act_in>: Extreme low zone action info. Default value 0.
<otlz_clr>: Operate low zone temperature threshold clear. Default value -35°C.
<otlz>: Operate low zone temperature threshold. Default value -28°C.
<otlz_act_in >: Operate low zone action info. Default value 0.
<otnz_clr>: Operate normal zone temperature threshold clear. Default value -30°C.
<otnz>: Operate normal zone temperature threshold. Default value 97°C.
<otnz_act_in>: Operate normal zone action info. Default value 0.
<otuz_clr>: Operate up zone temperature threshold clear. Default value 95°C.
<otuz>: Operate up zone temperature threshold. Default value 102°C.
<otuz_act_in>: Operate up zone action info. Default value 2.
<etuz_clr>: Extreme up zone temperature threshold clear. Default value 100°C.
<etuz>: Extreme up zone temperature threshold. Has only one valid value: 528°C.
see notes
<etuz_act_in>: Extreme up zone action info. Default value 3.
See notes for detailed description of thermal mitigation configuration.
AT#TEMPCFG?
Read command reports the current parameter setting for #TEMPCFG command in the
format:
#TEMPCFG:
<etlz_clr>,<etlz>,<etlz_act_in>,<otlz_clr>,<otlz>,<otlz_act_in>,<otnz_clr>,<otnz>,<otnz
_act_in>,<otuz_clr>,<otuz>,<otuz_act_in>,<etuz_clr>,<etuz>,<etuz_act_in>
AT#TEMPCFG =?
Test command reports the supported range values for parameters
<x_clr>,<x>,<x_action_info>.
Where "x" is substitute for "etlz", "otlz", "otnz", "otuz", "etuz".
Values are:
#TEMPCFG: (-40-102),(-40-102),(0-5)
Table 3: #TEMPCFG –Temperature Monitor Configuration
Note: After setting new values, it is necessary to execute the power
cycle or #REBOOT command in order the mitigation algorithm will
operate from them.
#TEMPCFG –Temperature Monitor Configuration

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Thermal mitigation mechanism works like this:
The whole temperature scale is divided into 5 states (zones).
Each temperature measured should belong to a particular state called "current state".
State is defined by the following fields:
"thresholds" –upper temperature boundary of the state. Values are in °C.
"thresholds_clr" –lower temperature boundary of the state. Values are in °C.
"actions" –indicator that indicates if an action should be taken or not in the "current
state". Values are: "none"/"mitigate".
"action_info" –thermal mitigation action type that should be taken care if "actions" field
is "mitigate".
Values are:
0 - No mitigation action is required.
1 - Mitigation action - data throttling (reducing uplink baud rate).
2 - Mitigation action - TX backoff (reducing MTPL - Max Tx Power Limit).
3 - Emergency Calls Only.
4 - RF OFF. RX and TX circuits automatically disabled (using +CFUN=4).
5 - Automatic shutdown. Module is powered off.
There are five limitations on setting temperature and actions, in-order to keep module
safety.
•The User is prohibited from setting an "automatic shutdown" action to ‘operate the
normal zone’.
•The User is prohibited from setting a “no mitigation” or "data throttling" action to
“operate up the zone”.
•The User is prohibited from setting a "no mitigation" or "data throttling" or "tx
backoff" action to “extreme up zone”.
•The User is prohibited from setting the “normal zone” above 97deg.
•If the module enters into a state of "emergency only" calls, it registers to a regular
call, only when the module returns to "no mitigation" state.
•An error message “+CME ERROR: operation not supported” will be received in
response.