microATX Motherboard Interface Specification

Version 1.2

Page 3

Revision History

Changes from Version 1.1 to Version 1.2

Global

— Replaced ATX 2.01 with ATX 2.1, where appropriate and removed SFX in SFX/SFX12V Power

Supply Design Guide.

Important Information and Disclaimers updated.

Section 2.3.7 and Section3.1 Main Power Connector changed from 20 pin to 24 pin (2 x 12) to support PCI-

Express* requirements.

Changes from Version 1.0 to Version 1.1

Global—Removed references to AT, Baby AT, and Mini-ATX.

Section 1—Revised introductory paragraph, updated the specification Web site URL, and changed ATX 2.01

to ATX 2.1 in Table 1.

Section 1.1—Updated Web site URL and list of related documents.

Section 1.2—Revised Figure 1.

Section 2.3.4—Replaced Figure 4. Updated the text in the paragraph immediately preceding Figure 5:

corrected the dimensions of the hatched area in Figure 5. Replaced Figure 6.

Section 2.4—Moved text in Section 2.4 under a new subheading, 2.4.1. Added subheading, 2.4.2, to specify

secondary side height constraints. Revised Figure 7 to reflect an increase in the maximum component height

restriction. Zones C, D, and E formerly specified three different height restrictions. This revision replaces

those three zones (C, D, and E) with one maximum component height restriction zone (C) for the entire

region.

Section 3—Removed discrepancies between this document and the SFX12V Power Supply Design Guide.

Section 3.2—Added new section titled “2x2 Connector” to describe a new +12V power connector.

Renumbered subsequent sections.

Global—Replaced ATX 2.01 with ATX 2.1, where appropriate. Replaced SFX with SFX12V (SMALL

FORM FACTOR), where appropriate.