Intel ATX12V Benutzerhandbuch

ATX12V Power Supply Design Guide 
Version 2.0 Final Review Copy 

38  

Non-operating  

50 g, trapezoidal input; velocity change 

≥ 170 in/s 

 

Three drops on each of six faces are applied to each sample. 

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. 

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