Compaq AlphaPC 264DP Technical Reference Manual page 65

Figure 4–5 shows that the +12 V dc, −12 V dc, +5 V dc, and −5 V dc are supplied to
ISA connector J47. The +12 V dc and −12 V dc are supplied to the PCI connectors
J35, J40–42, J44, and J46, and to the two daughtercard connectors J18 and J23. The
+12 V dc is also supplied to the fan box connectors J2, J15, J22, and J24.
In addition to the ISA connector, +5.0 V dc is supplied to the PCI connectors and to
most of the board's integrated circuits.
The +3.3 V dc is provided to the PCI slots, the 21272 core logic chipset, the DIMMs,
the daughtercard connectors, and the linear regulator that provides the 2.0-V termi-
nation voltage to the mainboard and the daughtercard connectors.
The power supply also provides 5 VSB to the comm port (J19) and soft power.
Figure 4–5 also shows that the daughtercard receives +5 V dc from the power supply
and distributes it to the dc-to-dc converter and miscellaneous logic on the card. The
daughtercard edge connector (J3) provides the following voltages from the main-
board:
•
+3.3 V for the SSRAMs, miscellaneous logic on the card, and for the linear reg-
ulator for conversion to 1.5 V for SSRAM I/O
•
+12 V for fan power and RS-232 logic
•
–12 V for RS-232 logic
•
+2.0 V for termination logic
12 February 1999 – Subject To Change
DC Power Distribution
Functional Description
4–15