TOP245P_1 POWERINT [Power Integrations, Inc.], TOP245P_1 Datasheet - Page 21

• Manufacturer Part Number: TOP245P_1
• Description: Title 32W (47W peak) Multiple Output supply
• Manufacturer: POWERINT [Power Integrations, Inc.]

DER-19
TOP245P Multiple Output Set Top Box
March 30, 2004
11.5 Output Ripple Measurements
11.5.1 Ripple Measurement Technique
For DC output ripple measurements, a modified oscilloscope test probe must be utilized in
order to reduce spurious signals due to pickup. Details of the probe modification are
provided in Figure 20 and Figure 21.
The 5125BA probe adapter is affixed with two capacitors tied in parallel across the probe
tip. The capacitors include one (1) 0.1 µF/50 V ceramic type and one (1) 1.0 µF/50 V
aluminum electrolytic.
The aluminum electrolytic type capacitor is polarized, so
proper polarity across DC outputs must be maintained (see below).
Probe Ground
Probe Tip
Figure 20 - Oscilloscope Probe Prepared for Ripple Measurement.
(End Cap and Ground Lead Removed)
Figure 21 - Oscilloscope Probe with Probe Master 5125BA BNC Adapter.
(Modified with wires for probe ground for ripple measurement, and two parallel decoupling capacitors added)
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