User's Manual

UE910 V2 Hardware User Guide

1VV0301065 Rev.1 – 2013-12-12

An example of switching regulator with 12V input is in the schematic below:

5.3.4. Battery Source Power Supply Design Guidelines

The desired nominal output for the power supply is 3.8V and the maximum voltage allowed is 4.2V.

A single 3.7V lithium-ion cell battery type is ideal to supply power to the Telit UE910 V2 module.

WARNING:

The three battery cells (Ni/Cd or Ni/MH 3.6V nom. battery types or 4V PB types) MUST NOT be

used directly because their maximum voltage can rise over the absolute maximum voltage for the

UE910 V2 and cause damage. USE only Li-Ion battery types.

 A bypass low (usually a 100uF tantalum) ESR capacitor with adequate capacity must be

provided in order to cut the current absorption peaks.

 Make sure the low ESR capacitor (usually a tantalum) is rated at least 10V.

 A protection diode must be inserted close to the power input in order to protect the

UE910 V2 module from power 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 battery capacity is from 500mAh to 1000mAh.

5.3.5. Thermal Design Guidelines

The thermal design for the power supply heat sink must be done with the following specifications:

Average current consumption during GSM/WCDMA @PWR level max : 700mA

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.