Ripple Measurements
To learn how we measure ripple, please click here.
The following table includes the ripple levels we measured on the BF450G’s rails. The limits, according to the ATX specification, are 120mV (+12V) and 50mV (5V, 3.3V, and 5VSB).
| Test | 12V | 5V | 3.3V | 5VSB | Pass/Fail |
|---|---|---|---|---|---|
| 10% Load | 13.5mV | 7.0mV | 6.2mV | 9.2mV | Pass |
| 20% Load | 22.4mV | 6.1mV | 5.9mV | 9.1mV | Pass |
| 30% Load | 24.7mV | 6.6mV | 6.3mV | 10.5mV | Pass |
| 40% Load | 22.5mV | 6.7mV | 7.0mV | 10.7mV | Pass |
| 50% Load | 21.9mV | 7.8mV | 7.4mV | 11.0mV | Pass |
| 60% Load | 24.3mV | 8.8mV | 8.3mV | 11.6mV | Pass |
| 70% Load | 26.3mV | 10.5mV | 10.3mV | 12.1mV | Pass |
| 80% Load | 25.7mV | 14.3mV | 15.3mV | 18.5mV | Pass |
| 90% Load | 26.3mV | 16.8mV | 18.8mV | 19.5mV | Pass |
| 100% Load | 29.0mV | 13.9mV | 15.2mV | 21.7mV | Pass |
| 110% Load | 27.7mV | 13.9mV | 14.3mV | 25.1mV | Pass |
| Cross-Load 1 | 28.0mV | 12.6mV | 11.5mV | 6.4mV | Pass |
| Cross-Load 2 | 24.5mV | 10.3mV | 13.5mV | 11.5mV | Pass |
Ripple suppression was very good on every rail. And strangely enough, the ripple at +12V with 110% load decreased slightly; normally we'd expect the opposite. The 3.3V rail also behaves strangely, registering its peak ripple reading with 90% load.
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.
Ripple At Full Load
Ripple At 110-Percent Load
Ripple At Cross-Load 1
Ripple At Cross-Load 2
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