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Appendix D provides information on the current requirements
of the RCM3305/RCM3315, and includes some background on
the reset generator.
D.1 Power Supplies
Power is supplied from the motherboard to which the RCM3305/RCM3315 is connected
via header J4. The RCM3305/RCM3315 requires a regulated 3.15 V to 3.45 V DC power
source. An RCM3305/RCM3315 with no loading at the outputs operating at 44.2 MHz
typically draws 350 mA.
D.1.1 Battery Backup
The RCM3305/RCM3315 does not have a battery, but there is provision for a customer-
supplied battery to back up the data SRAM and keep the internal Rabbit 3000 real-time
clock running.
Header J4, shown in Figure D-1, allows access to the external battery. This header makes
it possible to connect an external 3 V power supply. This allows the SRAM and the inter-
nal Rabbit 3000 real-time clock to retain data with the RCM3305/RCM3315 powered
down.
User's Manual
A
PPENDIX
J4
VRAM
30
29
+3.3 VIN
31
32
Figure D-1. External Battery Connections
at Header J4
D. P
OWER
External
Battery
VBAT_EXT
GND
S
UPPLY
135
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