Ripple Measurements
You will see the ripple levels we measured on the main rails of the ST75F-GS in the following table. The limits are, according to the ATX specification, 120 mV (+12V) and 50 mV (5V, 3.3V, and 5VSB).
Ripple Measurements - Silverstone ST75F-GS |
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Test | 12 V | 5 V | 3.3 V | 5VSB | Pass/Fail |
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20% Load | 15.9 mV | 7.4 mV | 9.5 mV | 10.0 mV | Pass |
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40% Load | 22.0 mV | 8.4 mV | 11.7 mV | 12.2 mV | Pass |
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50% Load | 26.6 mV | 9.2 mV | 14.4 mV | 14.2 mV | Pass |
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60% Load | 31.0 mV | 10.2 mV | 15.6 mV | 16.5 mV | Pass |
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80% Load | 41.7 mV | 11.7 mV | 21.5 mV | 20.5 mV | Pass |
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100% Load | 55.2 mV | 14.2 mV | 25.7 mV | 26.9 mV | Pass |
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110% Load | 61.6 mV | 15.1 mV | 28.5 mV | 28.2 mV | Pass |
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Crossload 1 | 25.9 mV | 10.2 mV | 13.2 mV | 22.3 mV | Pass |
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Crossload 2 | 51.8 mV | 11.7 mV | 22.5 mV | 20.5 mV | Pass |
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Ripple suppression on the 5VSB rail was superb and quite good on all other rails, though we would like to see ripple below 50 mV on the +12V rail at full load, and while 40 mV would be ideal in this category, 55 mV at +12V can't be called bad. Yet we rarely see Gold-certified PSUs with more than 45-50 mV ripple on the +12V rail at full load, which made us very picky on this matter.
Ripple at Full Load
In the following oscilloscope screenshots, you can see the AC ripple and noise the main rails registered (+12V, 5V, 3.3V, and 5VSB). The bigger the fluctuations on the oscilloscope's screen, the bigger the ripple/noise. We set 0.01 V/Div (each vertical division/box equals 0.01 V) as standard for all measurements.
Ripple at 110% Load
Ripple at Crossload 1
Ripple at Crossload 2