101-1218 Rabbit Semiconductor, 101-1218 Datasheet - Page 122

• Manufacturer Part Number: 101-1218
• Description: KIT APPLCTN RABBITCORE RCM4010
• Manufacturer: Rabbit Semiconductor
• Series: RabbitCore®r

Specifications of 101-1218

• Main Purpose: *
• Embedded: *
• Utilized Ic / Part: RCM4010
• Primary Attributes: *
• Secondary Attributes: *
• Processor To Be Evaluated: Rabbit 4000
• Interface Type: Ethernet
• Operating Supply Voltage: 12 V
• Lead Free Status / RoHS Status: Not applicable / Not applicable
• Other names: 316-1156

The drain on the battery by the RCM4000 is typically 7.5 µA when no other power is sup-
plied. If a 165 mA·h battery is used, the battery can last about 2.5 years:
The actual battery life in your application will depend on the current drawn by components
not on the RCM4000 and on the storage capacity of the battery. The RCM4000 does not
drain the battery while it is powered up normally.
Cycle the main power off/on after you install a backup battery for the first time, and when-
ever you replace the battery. This step will minimize the current drawn by the real-time
clock oscillator circuit from the backup battery should the RCM4000 experience a loss of
main power.
Rabbit’s Technical Note TN235, External 32.768 kHz Oscillator Circuits, provides addi-
tional information about the current draw by the real-time clock oscillator circuit.
C.1.2 Battery-Backup Circuit
Figure C-2 shows the battery-backup circuit.
The battery-backup circuit serves three purposes:
• It reduces the battery voltage to the SRAM and to the real-time clock, thereby limiting
• It ensures that current can flow only out of the battery to prevent charging the battery.
• A voltage, VOSC, is supplied to U8, which keeps the 32.768 kHz oscillator working
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the current consumed by the real-time clock and lengthening the battery life.
when the voltage begins to drop.
NOTE: Remember to cycle the main power off/on any time the RCM4000 is removed
165 mA·h
----------------------- -
7.5 µA
from the Prototyping Board or motherboard since that is where the backup battery
would be located.
=
Figure C-2. RCM4000 Backup Battery Circuit
2.5 years.
W
W
RabbitCore RCM4000