ATX Power Connector Specification: A Comprehensive Guide

Introduction

The Advanced Technology Extended (ATX) power connector is a fundamental component of modern computer systems, providing a standardized interface for delivering power from the power supply unit (PSU) to the motherboard and other system components. The ATX power connector specification defines the physical dimensions, pin assignments, and electrical characteristics to ensure interoperability between different manufacturers. Understanding the ATX power connector specification is crucial for building and troubleshooting computer systems.

ATX Power Connector Types

The ATX power connector has evolved over the years, with different versions introduced to support new technologies and higher power requirements. The most common ATX power connector types include:

• ATX 20/24-pin connector: This is the standard power connector used in most modern computer systems. It consists of a 20-pin connector with additional 4 pins for enhanced power delivery.
• ATX 12V 4+4-pin connector: This connector provides additional 12V power to the CPU. It typically connects to the motherboard near the CPU socket.
• ATX 12V 8-pin connector: This connector provides even more 12V power to the CPU. It is commonly used in high-performance systems or systems with a powerful CPU.
• ATX 12V 8+8-pin connector: This is a newer connector that provides even more power to the CPU. It is typically used in workstations and high-end gaming systems.

Physical Dimensions and Pin Assignments

The ATX 20/24-pin connector is a rectangular-shaped connector with the following dimensions:

• Length: 22.9 mm
• Width: 11.7 mm
• Height: 10.5 mm

The pin assignment for the ATX 20/24-pin connector is as follows:

The ATX 12V 4+4-pin connector has the following dimensions:

• Length: 13.2 mm
• Width: 11.7 mm
• Height: 10.5 mm

The pin assignment for the ATX 12V 4+4-pin connector is as follows:

The ATX 12V 8-pin connector has the following dimensions:

• Length: 21.0 mm
• Width: 11.7 mm
• Height: 10.5 mm

The pin assignment for the ATX 12V 8-pin connector is as follows:

The ATX 12V 8+8-pin connector has the following dimensions:

• Length: 27.5 mm
• Width: 11.7 mm
• Height: 10.5 mm

The pin assignment for the ATX 12V 8+8-pin connector is as follows:

Electrical Characteristics

The ATX power connector specification defines the following electrical characteristics:

• Voltage:
  • +3.3V
  • +5V
  • +12V
  • -12V (optional)
  • +5V Standby
• Current:
  • +3.3V: 20A
  • +5V: 30A
  • +12V: 60A (per rail)
  • -12V: 0.5A
  • +5V Standby: 2A
• Power:
  • +3.3V: 66W
  • +5V: 150W
  • +12V: 720W (per rail)
  • -12V: 6W
  • +5V Standby: 10W

Why Matters

The ATX power connector specification matters for the following key reasons: