Ripple And Noise - TDK-Lambda PFH500 Series Instruction Manual

6.14 Ripple and Noise

The output ripple and noise is measured in accordance with industry practices.
The output noise measurement connection can be found in the diagram shown in Figure 6-9 below.
A 0.1µF ceramic capacitor, C13, and four (4) 10µF ceramic capacitors, C14, are connected across the PFH module's output
bus at a location 50mm from the module output terminals. A 20MHz bandwidth oscilloscope is recommended to be used to
measure peak-peak and RMS values.
Note that the measured high frequency noise spikes may vary depending on the wiring pattern of the printed circuit board,
and the contact impedance of the scope coaxial cable connection.
In general, the module's output ripple spikes can be reduced by increasing external ceramic capacitor quantity and value.
NOTE: Noise is an RF frequency measurement that requires RF measurement techniques. Do not use flying ground leads
on oscilloscope probes. An RF connector is required for accurate measurements.
Fig 6-10 Output Noise or Ripple (including Spike Noise) Measurement Method.
REV 2.8 (March 30, 2020)
+V
-V
50mm RF Connector
+
Load
-
Oscilloscope
Frequency
Bandwidth
20MHz
TDK-Lambda
PFH500-SERIES
INSTRUCTION MANUAL
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