10
Specifications
2.3
Power Requirements
In order to guarantee a stable functionality of the system, it is rec-
ommended to provide more power than the system requires.
An
industrial power supply unit should be able to provide at least
twice as much power as the entire system requires of each
voltage
. An ATX power supply unit should be able to provide at
least three times as much power as the entire system requires of
each voltage.
The tolerance of the voltage lines described in the CompactPCI
specification (PICMG 2.0 R3.0) is +5%/-3% for 5, 3.3 V and ±5%
for ±12V. This specification is for power delivered to each slot and
it includes both the power supply and the backplane tolerance.
Voltage
Nominal
Value
Tolerance
Max. Ripple
(P - P)
5V
+5.0 VDC
+5% / -3%
50 mV
3.3V
+3.3 VDC
+5% / -3%
50 mV
+12V
+12 VDC
+5% / -5%
240 mV
-12V
-12 VDC
+5% / -5%
240 mV
V I/O (PCI I/O
Buffer Voltage)
+3.3 VDC or
+5 VDC
+5% / -3%
50 mV
GND
