M E M O R Y Backup Power - Xycom XVME-100 Manual

XVME-100 Manual
March, 1987
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2.4.5 M e m o r y Backup Power

During p o w e r loss, t h e CMOS R A M chips m a y h a v e a n alternative p o w e r source
connected t o r e t a i n t h e d a t a stored. T w o alternative power sources a r c available:
the on board battery and the + 5 V standby signal f r o m the VMEbus. T h e f o l l o w i n g
chart shows the jumper configuration f o r each option:
In o r d e r t o achieve m a x i m u m b a t t e r y l i f e , R A M chips m u s t h a v e a s m a l l d a t a
retention current. M o s t static R A M suppliers have chips t h a t guarantee v e r y l o w
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data retention currents. These should be used to prolong battery life.
Alternative
Power
Source J 3 4
None A *
Battery B
+5V Standby A
* Factory shipped configuration
Figure 2-5. L o c a t i o n o f Jumper J34
J 3 5
O u t *
O u t
I n
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