Enpirion
®
Power Evaluation Board User Guide
EP5358xUI PowerSoC
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 inaccurate measurements – especially
efficiency.
2. Measure input and output current with series ammeters or accurate
shunt resistors. This is especially important when measuring efficiency.
3. Use a balanced impedance probe tip as shown in Figure 2, and
through-hole test point pair TP2 to measure the output voltage ripple to
avoid noise coupling into the probe ground lead and for load transient
response measurements.
Using The External Voltage Divider
The EP5358xUI evaluation board is designed to provide a great deal of flexibility
in evaluating the performance of Altera’s Enpirion DC/DC module.
Pre-tinned pads are provided to place 0805 sized 1% resistors on the board to
implement an external resistor divider for the EP5358LUI to choose an output
voltage other than one of the seven pre-set voltages available on the VID. See
Figure 3 for the basic circuit.
Figure 2: Balanced-impedance oscilloscope probe. Wrap bare wire
around the ground shaft and bring the wire close to the probe tip.
This minimizes probe loop inductance and stray noise pickup by
the probe.
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