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Ripple Measurements

To learn how we measure ripple, please click here.

The following table includes the ripple levels we measured on the SDA600's rails. The limits, according to the ATX specification, are 120mV (+12V) and 50mV (5V, 3.3V and 5VSB).

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Test	12V	5V	3.3V	5VSB	Pass/Fail
10% Load	17.4mV	21.4mV	26.6mV	10.6mV	Pass
20% Load	19.3mV	20.5mV	29.5mV	11.4mV	Pass
30% Load	25.1mV	22.7mV	34.1mV	11.5mV	Pass
40% Load	21.2mV	23.3mV	38.9mV	11.4mV	Pass
50% Load	22.6mV	25.6mV	43.7mV	11.8mV	Pass
60% Load	22.0mV	27.5mV	49.6mV	16.1mV	Pass
70% Load	23.0mV	29.2mV	54.9mV	19.7mV	Fail
80% Load	23.2mV	30.0mV	62.5mV	17.3mV	Fail
90% Load	27.1mV	33.2mV	63.7mV	18.1mV	Fail
100% Load	27.5mV	35.1mV	68.2mV	20.7mV	Fail
110% Load	27.9mV	36.6mV	72.6mV	21.6mV	Fail
Cross-Load 1	18.6mV	21.0mV	33.0mV	6.1mV	Pass
Cross-Load 2	26.2mV	24.5mV	72.6mV	17.5mV	Fail

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It looks like FSP paid great attention to ripple suppression at +12V (the most important rail), but totally ignored the 3.3V rail. From the 70% load test and beyond, it goes out of control.

We're disappointed to see a high-end SFX unit unable to keep its ripple within the ATX spec's limits, which are already set very high. We had a couple of SDA600s in our possession, so we tested both of them to check for a possible bad sample. Unfortunately, the second unit's performance was identical. That means the 3.3V module has a problem FSP needs to fix.

Ripple Oscilloscope Screenshots

The following oscilloscope screenshots illustrate the AC ripple and noise registered on the main rails (+12V, 5V, 3.3V and 5VSB). The bigger the fluctuations on the screen, the bigger the ripple/noise. We set 0.01 V/Div (each vertical division/box equals 0.01V) as the standard for all measurements.