Intel ATX 3.0, Design Manual

Page: 31 / 89

Electrical
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4.2 DC Output - REQUIRED
4.2.1 DC Voltage Regulation – REQUIRED
The DC output voltages are required to remain within the regulation ranges shown in
Table 4-2 , when measured at the load end of the output connectors under all line,
load, and environmental conditions specified in Chapter 7 .
The lower voltage range for 12V is allowed to be -7% to allow for the power excursion
requirements now described in Section 3.1 . To compensate for these power
excursions the nominal voltage could be changed to 12.1 or 12.2 Volts, depending on
Power Supply design.
Table 4-2: DC Output Voltage Regulation
Output Range Min Nom Max Unit
+12V1DC 2
+
5% / -7% +11.20 +12.00 +12.60 V
+12V2DC 2
+
5% / -7% +11.20 +12.00 +12.60 V
+5VDC
±
5% +4.75 +5.00 +5.25 V
+3.3VDC
±
5% +3.14 +3.30 +3.47 V
-12VDC 3
±
10% -10.80 -12.00 -13.20 V
+5VSB
±
5% +4.75 +5.00 +5.25 V
NOTES:
1. Voltage tolerance is required at all connectors
2. +12V1DC and +12V2DC requirement applies to all +12V power rails
3. -12VDC output is optional
4.2.2 DC Output Current – REQUIRED
The below table summarizes the expected output transient step sizes for each output.
All items in the below table are REQUIRED, unless specifically called out as
RECOMMENDED.
Table 4-3: DC Output Transient Step Sizes
Output
Maximum Step Size
(% of rated output amps)
Maximum Step Size
(A)
+12V1DC 4
40% (Required)
70% (Recommended)
-
+12V2DC 4 85% of CPU supported in Table 2-1 2 -
+12V3/4 4
Steps from 100%

300%
30%

100%
3
+5VDC 30% -
+3.3VDC 30% -