ATX 24 pin power supply connector pinout

24 pin MiniFit Jr 5566-24 male (MOLEX 44206-0007)connectorat the motherboard

24 pin MiniFit Jr 5557-24 female (MOLEX 39-01-2240)connectorat the PSU cable

ATX 2.2 and later (ATX12V 2) is common ATX standard, 24 pin connector.

Changes to ATX standard were made to support 75 watt PCI Express requirements. Most power is now provided on 12 V rails and the power on 3.3 V and 5 V rails was significantly reduced. The standard specifies that two independent 12 V rails (12 V2 for the 4 pin connector and 12 V1 for everything else) with independent overcurrent protection are needed to meet the power requirements.

New ATX v 2.2 uses new connector, but most motherboards nowdays allow to use an old ATX v 1.x power supply with ATX 20 pin connector - it connects to 24 pin motherboard receptacle.

PinNameColorDescription

13.3VOrange+3.3 VDC

23.3VOrange+3.3 VDC

3COMBlackGround

45VRed+5 VDC

5COMBlackGround

65VRed+5 VDC

7COMBlackGround

8PWR_OKGrayPower Ok is a status signal generated by the power supply to notify the computer that the DC operating voltages are within the ranges required for proper computer operation (+5 VDC when power is Ok)

95VSBPurple+5 VDC Standby Voltage (max 10mA, max 2A in ATX 2.2 spec)

1012VYellow+12 VDC

1112VYellow+12 VDC

123.3VOrange+3.3 VDC

133.3VOrange+3.3 VDC.ATX V2.3 / EPS12V V2.92 both define that the PSU has to use remote sensing to compensate cable drops on the 3.3V line. Because of this there is an additional brown cable crimped together with the orange cable either to pin 13 (ATX) or pin 1 (EPS12V).

14-12VBlue-12 VDC

15COMBlackGround

16/PS_ONGreenPower Supply On (active low). Short this pin to GND to switch power supply ON, disconnect from GND to switch OFF.

17COMBlackGround

18COMBlackGround

19COMBlackGround

20-5VWhite-5 VDC (this is optional on newer ATX-2 supplies, it is for use with older AT class expansion cards and can be omitted on newer units)

21+5VRed+5 VDC

22+5VRed+5 VDC

23+5VRed+5 VDC

24COMBlackGround

/PSON activated by pressing and releasing the power button while the power supply is in standby mode. Activating /PSON connects the power supply's /PSON input to ground, thereby switching the power supply to full-on condition.

18 AWG is recommended for all wires except pin 11, which should be 22 AWG. For 300W configurations 16 AWG is recommended.