ATX12V Power Supply Connector
With the introduction of the Pentium 4 processor, Intel extended the ATX 2.03 specification to define a new type of power supply called ATX12V, which is a superset of ATX 2.03, and is now incorporated in the ATX Specification 2.1 and the ATX/ATX12V Power Supply Design Guide Version 1.2. ATX12V power supplies include an additional 2X2 4-pin +12V power connector, shown in Table 26-15. The motherboard connector is a Molex 39-29-9042 or equivalent. The power supply connector is a Molex 39-01-2040 or equivalent. All wires are 20 AWG. Wire colors are standard. The purpose of this new connector is to deliver more +12V current to the motherboard than is available from the standard ATX main power connector. The presence of the 4-pin +12V connector indicates that a power supply is ATX12V. The absence of that connector indicates that it is a standard ATX power supply.
Table 26-15. ATX12V Power Supply Connector
|
Pin |
Color |
Signal |
Pin |
Color |
Signal | |
|---|---|---|---|---|---|---|
|
1 |
black |
COM |
3 |
yellow |
+12VDC | |
|
2 |
black |
COM |
4 |
yellow |
+12VDC |
According to Intel’s policy, all Pentium 4 motherboards and all power supplies used with those motherboards must include the 4-pin +12V connector. Because installing such motherboards in existing systems may also require upgrading the power supply, some third-party motherboard makers have produced motherboards that lack the 4-pin +12V connector. This allows those motherboards to be installed in existing systems without a power supply upgrade, but ...