Intel ATX Version 3 (doc 336521)

ATX 24-Pin Motherboard Connector Pinout

The 24-pin main power connector links an ATX power supply to the motherboard. Select a contact to see its supply rail or control signal and what it does.

Pin assignment

Pin 1: +3.3V1Pin 2: +3.3V2Pin 3: GND3Pin 4: +5V4Pin 5: GND5Pin 6: +5V6Pin 7: GND7Pin 8: PWR_OK8Pin 9: +5VSB9Pin 10: +12V110Pin 11: +12V111Pin 12: +3.3V12Pin 13: +3.3V13Pin 14: -12V14Pin 15: GND15Pin 16: PS_ON#16Pin 17: GND17Pin 18: GND18Pin 19: GND19Pin 20: Reserved20Pin 21: +5V21Pin 22: +5V22Pin 23: +5V23Pin 24: GND24Pin 1: +3.3V1Pin 2: +3.3V2Pin 3: GND3Pin 4: +5V4Pin 5: GND5Pin 6: +5V6Pin 7: GND7Pin 8: PWR_OK8Pin 9: +5VSB9Pin 10: +12V110Pin 11: +12V111Pin 12: +3.3V12Pin 13: +3.3V13Pin 14: -12V14Pin 15: GND15Pin 16: PS_ON#16Pin 17: GND17Pin 18: GND18Pin 19: GND19Pin 20: Reserved20Pin 21: +5V21Pin 22: +5V22Pin 23: +5V23Pin 24: GND24
  • Power
  • Ground
  • Control
  • Not connected

Schematic face view, not to scale · numbering per Intel ATX Version 3 (doc 336521)

Pin assignment of ATX 24-Pin Power Supply Connector
PinSignalFunctionStatus
+3.3V+3.3 VDC Power RailStandard
+3.3V+3.3 VDC Power RailStandard
GNDGround ReturnStandard
+5V+5 VDC Power RailStandard
GNDGround ReturnStandard
+5V+5 VDC Power RailStandard
GNDGround ReturnStandard
PWR_OKPower good: driven high (+5 V TTL compatible, 2.4–5 V) once +12 V, +5 V and +3.3 V are within regulation; low when any of them drops or mains hold-up runs outStandard
+5VSB+5 VDC standby: present whenever mains power is applied, not switched by PS_ON#Standard
+12V1+12 VDC Power RailStandard
+12V1+12 VDC Power RailStandard
+3.3V+3.3 VDC Power RailStandard
+3.3V+3.3 VDC Power Rail, shared with the +3.3 V remote sense wire (brown, 22 AWG)Standard
-12V-12 VDC rail (±10 %; optional in ATX Version 3)Standard
GNDGround ReturnStandard
PS_ON#Power supply on, active low: pull to ground to switch on +12 V, +5 V, +3.3 V and -12 V; an internal pull-up keeps them off when openStandard
GNDGround ReturnStandard
GNDGround ReturnStandard
GNDGround ReturnStandard
ReservedReserved, not connectedStandard
+5V+5 VDC Power RailStandard
+5V+5 VDC Power RailStandard
+5V+5 VDC Power RailStandard
GNDGround ReturnStandard

Pin details

Select a pin on the diagram or table for full details.

Pin details

About this connector

Standard 24-pin ATX motherboard power connector carrying the main supply rails, control signals, and ground returns.

Specifications

Standard
Molex Mini-Fit Jr. 24-pin
Positions
24

Primary sources

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