RDK-138 Power Integrations, RDK-138 Datasheet - Page 21

• Manufacturer Part Number: RDK-138
• Description: KIT REF DESIGN 1.2W PS TN FAMILY
• Manufacturer: Power Integrations

Specifications of RDK-138

• Mfg Application Notes: LinkSwitch-TN Design Guide, AN-37
• Main Purpose: AC/DC, Non-Isolated
• Outputs And Type: 2, Non-Isolated
• Power - Output: 1.2W
• Voltage - Output: 12V, 5V
• Current - Output: 80mA, 50mA
• Voltage - Input: 85 ~ 265VAC
• Regulator Topology: Buck
• Frequency - Switching: 66kHz
• Board Type: Fully Populated
• Utilized Ic / Part: LNK304
• Product: Accessories & Kits
• Lead Free Status / RoHS Status: Not applicable / Not applicable
• Other names: 596-1197

12-Nov-2007
RDR-138 1.2 W Non Isolated Dual Output Supply
9.5 Output Ripple Measurements
9.5.1 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 21 and Figure 22.
The 4987BA 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 type. The aluminum electrolytic type capacitor is polarized, so
proper polarity across DC outputs must be maintained (see below).
Probe Ground
Probe Tip
Figure 21 – Oscilloscope Probe Prepared for Ripple Measurement. (End Cap and Ground Lead Removed)
Figure 22 – Oscilloscope Probe with Probe Master (www.probemaster.com) 4987A BNC Adapter.
(Modified with Wires for Ripple Measurement, and Two Parallel Decoupling Capacitors Added)
Power Integrations
Tel: [phone] Fax: [phone]
Page 21 of 28
www.powerint.com