A3LA-RG Guide Version B
Document Number: 451-93156-009B
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A
PPENDIX
F:
P
OWER
C
ONSUMPTION
This section provides the electrical power profile of the A3LA-RG. It does not describe every
situation; however, it does offer a starting point for users to continue their own development
design. The actual usage profile can vary for a number of reasons including manufacturing
variation from unit-to-unit. Optimize your setup to attain the lowest possible power
consumption. Some of the setup parameters carefully observe include:
1.
Have a clear view of the sky for the antenna—poor visibility of the sky is when a clear
line-of-sight is not available between the A3LA-RG and the satellites.
2.
Keep the antenna’s VSWR low—the higher the antenna VSWR, the higher the current
consumed by the A3LA-RG.
3.
Keep the antenna cables’ loss to less than 3dB—the higher the antenna cable loss, the
higher the current consumed by the A3LA-RG.
4.
Keep the power cable between the A3LA-RG and the power source as short as possible.
5.
Use both power input pins on the multi-interface connector.
Power consumption of the A3LA-RG can be divided into five distinct operating segments: (1)
standby, (2) data-switch/RUDICS call, (3) SBD transmission, (4) SMS transmission, and (5) audio
call. Typical current drawn and power consumption for these cases are shown in the plots
below.
The A3LA-RG is designed to accept input power at two different voltage ranges—either from
4.0 V to 5.4 V or from 5.0 V to 32 V. A different internal DC-DC converter is used for each range.
In each figure below, the electrical profiles for both ranges are displayed in separate curves.
The A3LA-RG can be connected to a DPL handset through an HRC-24-8R data kit to make voice
calls. The DPL handset requires 12 V, which is supplied by the A3LA-RG through pin 2 of the
multi-interface connector. When the DPL handset is on with the backlight turned on, the DPL
handset current drawn is about 350 mA at 12 V or about 500 mA at 5 V. Therefore, when a DPL
handset is connected to an A3LA-RG, account for the added current drawn.
