User`s manual

User’s Manual 59
APPENDIX C. POWER SUPPLY
Appendix C provides information on the current requirements of
the RCM2300, and some background on the chip select circuit
used in power management.
C.1 Power Supplies
The RCM2300 requires a regulated 5 V ± 0.25 V DC power source. The RabbitCore
design presumes that the voltage regulator is on the user board, and that the power is made
available to the RabbitCore board through headers J4 and J5.
An RCM2300 with no loading at the out puts operating at 22.1 MHz typically draws 108 mA .
The RCM2300 will consume an additional 10 mA when the programming cable is used to
connect J1 to a PC.
C.2 Battery Backup
The RCM2300 does not have a factory-installed battery, but there is provision for a cus-
tomer-supplied battery to back up SRAM and keep the internal Rabbit 2000 real-time
clock running.
Header J5, shown in Figure C-1, allows access to an external battery. This header makes it
possible to connect an external 3 V power supply.
Figure C-1. External Battery Connections
at Header J5
D0
VCC
24
25
23
26
VBAT
GND
External
Battery
J5