LEPA B650 Power Supply Review
Ripple and Noise Tests
Contents
Voltages at the power supply outputs must be as “clean” as possible, with no noise or oscillation (also known as “ripple”). The maximum ripple and noise levels allowed are 120 mV for +12 V and -12 V outputs, and 50 mV for +5 V, +3.3 V and +5VSB outputs. All values are peak-to-peak figures. We consider a power supply as being top-notch if it can produce half or less of the maximum allowed ripple and noise levels.
The LEPA B650 provided ripple and noise levels inside the specification. See the table below.
| Input | Test 1 | Test 2 | Test 3 | Test 4 | Test 5 |
| +12VA | 13.2 mV | 14.2 mV | 19.6 mV | 43.6 mV | 70.6 mV |
| +12VB | 13.6 mV | 14.0 mV | 20.0 mV | 43.6 mV | 70.2 mV |
| +5 V | 11.2 mV | 12.2 mV | 13.4 mV | 16.0 mV | 20.2 mV |
| +3.3 V | 11.2 mV | 12.6 mV | 15.2 mV | 17.8 mV | 20.6 mV |
| +5VSB | 19.4 mV | 20.6 mV | 23.2 mV | 26.4 mV | 30.6 mV |
| -12 V | 32.2 mV | 34.2 mV | 37.8 mV | 41.2 mV | 47.4 mV |
Below you can see the waveforms of the outputs during test five.
Figure 17: +12VA input from load tester during test five at 644.9 W (70.6 mV)
Figure 18: +12VB input from load tester during test five at 644.9 W (70.2 mV)
Figure 19: +5V rail during test five at 644.9 W (20.2 mV)
Figure 20: +3.3 V rail during test five at 644.9 W (20.6 mV)