Power requirements: Plug-in supplies
RIM 801D OEM Radio Modem – Integrator’s Guide
15
Plug-in supplies
A plug-in supply converts normal AC power (usually 110 volts or 220 volts)
into a steady DC source that can be used instead of batteries. The plug-in
supply must be designed to ensure voltage spikes, lightning, and other
power fluctuations cannot damage the radio modem.
RIM recommends a supply capable of providing 8 volts and 1.5 amps peak
current. This can be accomplished by employing a 12 volt 1.5 amp peak (1.0
amp continuous) unregulated power source, and adding an 8 volt regulator
(such as an LM7808).
The schematic drawing for a sample plug-in supply is provided below. This
circuit provides 8 volts DC to operate the RIM 801D, as well as 5 volts for
the embedded system VCC. Please note that it is not necessary to supply the
RIM 801D with a 5 volt VCC — there is only one power source to the radio
modem, and that is the 8 volt supply.
Figure 4: Sample plug-in supply
