Network Hardware User Manual

UC864-E Hardware User Guide

1vv0300766a Rev.1 - 31/01/08

5 Power Supply

The power supply circuitry and board layout are a very important part in the full product design and

they strongly reflect on the product overall performances, hence read carefully the requirements and

the guidelines that will follow for a proper design.

5.1 Power Supply Requirements

POWER SUPPLY

Nominal Supply Voltage 3.8V

Max Supply Voltage 4.2

Supply Voltage Range 3.51 – 4.2

The UC864-E power consumptions are:

UC864-E (GSM900)

Mode Average (mA) Mode description

IDLE mode

Stand by mode; no call in progress

AT+CFUN=1 21,7

Normal mode: full functionality of the module (MF=9)

AT+CFUN=4 21,3

Disabled TX and RX; module is not registered on the

network

AT+CFUN=0 or

AT+CFUN=5

3,3

Power saving: CFUN=0 module registered on the network

and can receive voice call or an SMS; but it is not possible

to send AT commands; module wakes up with an

unsolicited code (call or SMS) or rising RTS line. CFUN=5

full functionality with power saving; module registered on

the network can receive incoming calls and SMS – (MF=2)

GSM TX and RX mode

GSM Sending data mode

Min power level 139.1

Max power level 340.8

GPRS (class 10) TX and RX mode

GPRS Sending data mode (3 slot TX)

Max power level 728.2

WCDMA

WCDMA Call in progress

Max power level 619,7

In GSM/GPRS mode, RF transmission is not continuous and it is packed into bursts at a base

frequency of about 216 Hz, and the relative current peaks can be as high as about 2A. Therefore the

power supply has to be designed in order to withstand with these current peaks without big voltage

drops; this means that both the electrical design and the board layout must be designed for this

current flow.