Intel ATX12V - Manual (Page 38)

ATX12V Power Supply Design Guide
Version 2.0 Final Review Copy
38
5.5. Mechanical Shock
Non-operating 50 g, trapezoidal input; velocity change
≥ 170 in/s
Three drops on each of six faces are applied to each sample.
5.6. Random Vibration
Non-operating 0.01 g²/Hz at 5 Hz, sloping to 0.02 g²/Hz at 20 Hz, and
maintaining 0.02 g²/Hz from 20 Hz to 500 Hz. The area under
the PSD curve is 3.13 gRMS. The duration shall be 10 minutes
per axis for all three axes on all samples.
5.7. Acoustics
For power supplies designed for low noise, the following provides some general guidance.
Guidelines Sound Power: The power supply assembly shall not produce a declared sound
power level greater than 4.0 BA. Sound power determination is to be performed at 43C,
50% of maximum rated load, at sea level. This test point is chosen to represent the
environment seen inside a typical system at the idle acoustic test condition, with the 43C
being derived from the standard ambient assumption of 23C, with 20C added for the
temperature rise within the system (what is typically seen by the inlet fan). The declared
sound power level shall be measured according to ISO 7779 and reported according to ISO
9296.
Pure Tones: The power supply assembly shall not produce any prominent discrete tone
determined according to ISO 7779, Annex D
.