Spire JEWEL 420W / SP-ATX-420W-C1-PFC - Manual (Page 8)

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2.2.6 Output Ripple/Noise
The output ripple/noise requirements listed in Table 5 should be met
throughout the load ranges specified and under all input voltage conditions as
specified. Ripple and noise are defined as periodic or random signals over a
frequency band of 10 Hz to 20MHz. Measurements shall be made with an
oscilloscope with 20 MHZ bandwidth. Outputs should be bypassed at the
connector with a 0.1μF ceramic disk capacitor and a 10μF electrolytic capacitor
to simulate system loading. See Figure1.
Figure1. Differential Noise Test Setup
Power Supply
Gene ral Notes:
1.Load the output with its minimum load current.
2.Connect the probes as shown.
3.Repeat the measurement with maximum load on the output.
AC Ground
V out
V return
Load
Scope
10 μ F 0.1 μ F
Loa d must be
isolat ed from the
ground of the
power supply
AC Hot
AC Neutral
Table 5. DC Output Ripple/Noise
Output
Max. Ripple
(mVpp)
Max. Ripple& Noise
(mVpp)
+12 VDC 120 240
+5 VDC 50 100
+3.3 VDC 50 100
-12 VDC 120 240
+5 VSB 50 100