Ripple Measurements
In the following table you will find the ripple levels that we measured on the main rails of the SS-1000XP. According to ATX specification the limits are 120 mV (+12V) and 50 mV (5V, 3.3V and 5VSB).
Ripple Measurements Seasonic SS-1000XP |
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Test | 12 V | 5 V | 3.3 V | 5VSB | Pass/Fail |
20% Load | 23.6 mV | 9.7 mV | 8.5 mV | 17.0 mV | Pass |
40% Load | 15.5 mV | 8.8 mV | 9.4 mV | 7.7 mV | Pass |
50% Load | 15.8 mV | 11.2 mV | 9.6 mV | 8.2 mV | Pass |
60% Load | 16.6 mV | 11.4 mV | 10.6 mV | 10.8 mV | Pass |
80% Load | 20.1 mV | 11.4 mV | 11.4 mV | 11.9 mV | Pass |
100% Load | 24.0 mV | 12.5 mV | 14.9 mV | 13.6 mV | Pass |
Crossload 1 | 37.6 mV | 9.5 mV | 9.7 mV | 12.3 mV | Pass |
Crossload 2 | 23.8 mV | 11.8 mV | 12.2 mV | 22.4 mV | Pass |
As expected from Seasonic's flagship PSU, ripple/noise suppression is excellent. Even at full load ripple at +12V is at one fifth of the limit. With 20% load, ripple is higher compared to other load levels because at low loads the unit works in PWM mode and only at higher loads it uses FM mode.
Ripple at Full Load
In the following oscilloscope screenshots you can see the AC ripple and noise that the main rails registered (+12V, 5V, 3.3V and 5VSB). The bigger the fluctuations on the oscilloscope's screen the bigger the ripple/noise. For all measurements we set 0.01 V/Div (each vertical division/box equals to 0.01V) as standard.
Ripple at Crossload 1
Ripple at Crossload 2