February 2010
Page 4 of 6
©Enpirion 2008 all rights rese rved, E&OE
Enpirion Confidential
Test Recommendations
Recommendations
To guarantee measurement accuracy, the following precautions should be
observed:
1. Make all input and output voltage measurements at the board using the
test points provided. This will eliminate voltage drop across the line and
load cables that can produce false readings.
2. Measure input and output current with series ammeters or accurate
shunt resistors. This is especially important when measuring efficiency.
3. Use a low loop inductance scope probe across COUT to measure VOUT
Ripple to avoid noise coupling into the probe ground lead. The
recommended probe configuration is shown in Figure 3.
Figure 3. Recommended probe configuration.
4. The board has soldermask openings for 0805 ceramic capacitors at the
input and output edges. If you are planning to do any radiated EMI
testing on this board, place a 10uF, 0805, X7R or X5R capacitor at
each board edge. The added capacitor at the input edge is for high-
frequency decoupling of the input cables. The added capacitor at the
output edge is meant to represent a typical load decoupling capacitor.
Please contact Enpirion Applications Support for further details
regarding radiated EMI testing.
Input and Output Capacitors
The input capacitance on the board is a 4.7uF 0603 MLCC. There is a pre-tinned
pad that allows for an additional 0603 case size MLCC to experiment with input
filter performance.
The output capacitance on the board is a 10uF 0603 in parallel with a 1uF 0402.
NOTE: Capacitors must be X5R or X7R dielectric formulations.