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Architecture
a large amount of current and is referred to as “VCC_12V_BULK”. The latter is used solely for the
VCORE power supply rail, while the former is used for miscellaneous purposes such as fan power and PCI
slots.
Note that to support PIXIS standby operation and to support video cards or other high-power-dissipation
cards in the PCIExpress slot, the PSU should support the following minimum specification:
• minimum 450 W overall
• supports one PCIE 12 V connector
• PCIE 12 V support a minimum of 150 W
• minimum 5 V 2 A standby current
All other power sources are derived from the ATX PSU. Figure 20 shows the principal power connections.
+12V_BULK
ATX PSU
EN
GD
PWRON
PWRGD
SC457
EN
SPS
1.8V
GD
SPS
1.2V
EN
GD
SPS
2.5V
GD
+5VSTB
SPS
LDO
+5V
VCORE/
PLAT/SERDES
LDO
+3.3V_HOT
PIXIS
EN
+2.5V_HOT
+1.8V_HOT
ULI
+3.3V
+12V
+12V_BULK
Figure 20. MPC8572DS Power Architecture
MPC8572 Development System User’s Guide, Rev. 1
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Freescale Semiconductor