ATX Specification - Version 2.2
Page 3
Revision History
Changes from Version 2.1 to Version 2.2
Global change removed ATX in ATX/ATX12V Power Supply Design Guide.
Important Information and Disclaimers updated.
Section 4.1—Main Power Connector changed from 20 pin to 24 pin to support PCI-Express* requirements.
Section 4.1.1—Removed Aux Power Connector Recommendation if using a power supply designed using
ATX12V Power Supply Design Guide Rev 2.0 or greater.
Section 4.1.4—Update 3.3 V tolerance.
Changes from Version 2.03 to Version 2.1
Global change—Removed references to Mini-ATX.
Section 2—Replace existing text with new text that adds requirement for ATX12V connector; substitute
revised Figure 1.
Section 3.3—Add ATX12V power connector information to Table 3.
Section 3.3.2—Replace existing text with new text that includes the 12V requirement for processor voltage
regulators.
Section 3.4—Moved text in Section 3.4 under a new subheading, 3.4.1. Added subheading, 3.4.2, 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. Added two sentences at the end of the note that follows Figure 7.
Section 4—Replace existing text with new text that adds the 12V connector and a reference to the
ATX/ATX12V Power Supply Design Guide.
Section 4.2—Add references to the ATX12V connector; substitute revised Figure 10.
Section 4.4—Add new Table 10 that lists wire color code for ATX12V power supplies.
Section 6—Update Web site URL for ATX information and document downloading.
Changes from Version 2.02 to Version 2.03
Replaced seven occurrences of the erroneous name “microATX” with the correct name “Mini-ATX.” The
error was introduced accidentally in Version 2.02. The Mini-ATX form factor is 11.2" x 8.2" (284mm x
208mm; the Mini-ATX form factor referred to in this ATX Specification is NOT the same as the microATX
form factor, which is described in a separate specification.
Changes from Version 2.01 to Version 2.02
Section 3.3.5—Replaced Figures 4 and 5.
Section 4.2.1—Added new section to define Aux Power Connector; renumbered the subsequent sections,
figures, and tables accordingly.
Section 4.2.2.3—Replaced Figure 11 to better explain the power supply timing.
Section 4.2.3—Corrected two values in Table 7, Voltage Tolerances: -5VDC and -12VDC should comply
to ± 10%, not ±5%. This change was made to match the newly released Intel ATX Power Supply Design
Guide, Version 0.9.
Section 4.4—Corrected Table 9; the 1394R signal is carried on Pin 4, and Pin 6 is Reserved. This matches
the information shown in Figure 12.
Section 6—Added section to provide the Internet location of the ATX home page, for access to documents
with information beyond the requirements of this ATX Specification.
