ATX12VO (12V Only) Desktop Power Supply
Design Guide
ID
613768
Date
01/03/2022
Public
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Introduction
Processor Configurations
PCI Express* Add-in Card Considerations
Electrical
Mechanical
Acoustics
Environmental
Electromagnetic Compatibility
Safety
Reliability
CFX12V Specific Guidelines 2.0
LFX12V Specific Guidelines 2.0
ATX12V Specific Guidelines 3.0
SFX12V Specific Guidelines 4.0
TFX12V Specific Guidelines 3.0
Flex ATX Specific Guidelines 2.0
DC Output (Required)
DC Voltage Regulation (Required)
DC Output Current (Required)
Remote Sensing (Optional)
Other Low Power System Requirements (Required)
Output Ripple Noise (Required)
Capacitive Load (Recommended)
Closed Loop Stability (Required)
Multiple 12V Rail Power Sequencing (Required)
Voltage Hold-Up Time (Required)
Over Voltage Protection (OVP) (Required)
Short Circuit Protection (SCP) (Required)
No-Load Situation (Required)
Over Current Protection (OCP) (Required)
Over Temperature Protection (OTP) (Required)
Output Bypass (Required)
Separate Current Limit for 12V2 (Optional)
Overall Power Supply Efficiency Levels
Power Supply Efficiency for Energy Regulations - ENERGY STAR* and CEC PC Computers with High Expandability Score (Recommended)
SFX12V Specific Guidelines 4.0
Lower Profile Package – Physical Dimensions (Required)
Fan Requirements (Required)
Top Fan Mount Package – Physical Dimensions (Required)
Fan Requirements (Required)
Reduced Depth Top Mount Fan – Physical Dimensions (Required)
Fan Requirements (Required)
Standard SFX Profile Package – Physical Dimensions (Required)
Fan Requirements (Required)
PS3 Form Factor – Physical Dimensions (Required)
Fan Requirements (Required)
Venting
In general, more venting in a power supply case yields reduced airflow impedance and improved cooling performance. Intake and exhaust vents should be large, open, and unobstructed as possible so as not to impede airflow or generate excessive acoustic noise. In particular, avoid placing objects within 0.5 inches of the intake or exhaust of the fan itself. A flush-mount wire fan grill can be used instead of a stamped metal vent for improved airflow and reduced acoustic noise.
The limitations to the venting guidelines above are:
- Openings must be sufficiently designed to meet the safety requirements described in Section 9.
- Larger openings yield decreased EMI-shielding performance. Refer to Section 8.
- Venting in inappropriate locations can detrimentally allow airflow to bypass those areas where it is needed.