Wavenet Technology Pty Ltd. BM2900D Benutzerhandbuch

Seite von 147
Installation_________________________________________________ Boomer II User Manual & Integrator’s Guide 
 
Copyright Wavenet Technology © November 2003 
44 
BM210012WT37 
Supplying Power 
The Boomer II OEM Modem must be provided with a clean power 
source capable of delivering bursts of high current. 
The modem draws its power in bursts. The power required changes 
rapidly depending on whether the modem is transmitting, receiving or 
on standby. 
Ratings 
The power supply requirements are: 
Voltage: 
3.8V (3.4 to 4.2V range) 
Transmit Current: 
1.6A maximum 
 
(2.2A maximum if antenna mismatched) 
Transmit Duration: 
32ms (minimum) 
  
7s (maximum) 
Duty Cycle 
30% (maximum) data dependant 
Receive Current 
85 mA (maximum) 
Standby Current 
4.6 mA (maximum)  
 
Add ~1.2mA if LED’s enabled 
Off current consumption: 
100 µA (nominal) 
Power Supply Ripple: 
< 15mV peak to peak 
Design Considerations 
The power supply is one of the key issues of design of wireless 
terminals. 
Due to the burst nature of transmit periods the power supply must be 
able to deliver high current peaks for short periods of 32ms to a 
maximum of 7 seconds (RD-LAP 9600 bps) or for 20 seconds (MDC 
4800 bps). During this time the drop in the supply at the module itself 
must not exceed 200mV (total at the module), such that at no time 
module shall module supply drop below 3.4V and ripple must not 
exceed 15mVp-p during transmit. 
The maximum transmit current into a matched antenna is 1.6A, 
however, this can increase if antenna mismatch occurs. 
Wavenet recommends designing a robust power supply that can 
provide adequate power under non-ideal conditions such as an 
improperly matched antenna, where current can be up to 2.2A. 
It is recommended that for ensuring power supply margin the following 
be done: 
 
A short FPC cable (e.g < 100mm) is used to minimise power 
supply voltage drop during transmission.