User's Guide

LE910Cx HW User Guide
Doc#: 1VV0301298
Rev. 13.0 Page 58 of 124 2019-07-15
6.3.2. Thermal Design Guidelines
The thermal design for the power supply heat sink must be done with the following
specifications:
• Average current consumption during RF transmission @PWR level max in
LE910Cx as shown in Table 18: LE910Cx Current Consumption
• Average current consumption during Class10 GPRS transmission @PWR level
max as shown in Table 18: LE910Cx Current Consumption
• Average GPS current consumption during GPS tracking (LTE @ idle): mA (40mA)
NOTE:
The average consumption during transmission depends on the power level
at which the device is requested to transmit via the network. Therefore, the
average current consumption 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 (LTE/HSPA)/GPRS
plus average consumption in GPS Tracking mode.
Considering the very low current during Idle, especially if the Power Saving function is
enabled, it is possible to consider from the thermal point of view that the device absorbs
significant current only during an Active Call or Data session.
For the heat generated by the LE910Cx module, consider it to be 2W max during
transmission at Class10 GPRS upload.
In LTE/WCDMA/HSPA mode, the LE910Cx emits RF signals continuously during
transmission. Therefore, you must pay special attention how to dissipate the heat
generated.
The LE910Cx is designed to conduct the heat flow from the module IC’s towards the
bottom of the PCB across GND metal layers
The generated heat is mostly conducted to the ground plane under the LE910Cx module.
The application board should be properly designed to dissipate this heat.
Application board design needs to make sure the area under the LE910Cx module is as
large as possible. Make sure that the LE910Cx is mounted on the large ground area of
application board and provide many ground vias to dissipate the heat.
Even though peak current consumption in GSM mode is higher than in
LTE/WCDMA/HSPA, considerations for the heat sink are more important in the case of
WCDMA due to the continuous transmission conditions.