AN-311 Test note for DCDC module

Test note for DCDC module
Basic connection on Delta evaluation board
Test note
Test note for DCDC module
General measurement
1. Preparation for test:
1) Press the 4 clips on bottom side to make sure sense+/- terminal good contact with the Vin/Vo Pin;
2) Insert the module as Fig-3;
Fig-2 Bottom view
Fig-3 Top view
2. Output Voltage measurement:
Mesure output voltage between Vo sense+ and Vo sense- as shown on Fig-4.
Fig-4 Vout test point
3. Line/Load Regulation Test:
1) It’s better to have cooling fan beside the module, and measure output voltage at the moment of power
on or loaded, otherwise the temperature of module increases rapidly, and the temperature regulation will
affect the accuracy of the line/load regulation measurements.
2) Mesure output voltage between Vo sense+ and Vo sense- as shown on Fig-4.
Test note
Test note for DCDC module
4. Ripple and noise test:
1) A 20 MHz bandwidth oscilloscope is normally used for the measurement.
2) Use coaxial-cable connect between oscilloscope and BNC connector on evaluation board.
Fig-5 Ripple and noise test point
3) The conventional ground clip on an oscilloscope probe(see Fig-6) should never be used in this kind of
measurement. This clip, when placed in a field of radiated high frequency energy, acts as an antenna or
inductive pickup loop, creating an extraneous voltage that is not part of the output noise of the converter.
Fig-6 Probe
4) Another method is shown in Fig-7 in case of coaxial-cable/BNC is not available. The noise pickup is
eliminated by pressing scope probe ground ring directly against the -Vout terminal while the tip contacts
the +Vout terminal. This makes the shortest possible connection across the output termianls.
 For more detail specification, please refer to product datasheet or contact with Delta’s
technical support team.
Test note