UG-824 ADP5310READJ-EVALZ User Guide
Rev. A | Page 4 of 8
MEASURING EVALUATION BOARD PERFORMANCE
MEASURING THE SWITCHING WAVEFORM
To observe the switching waveform with an oscilloscope, place
the oscilloscope probe tip at the TP2 and TP5 test points with the
probe ground connected to ground. Set the oscilloscope to a dc
coupling, 5 V/division, 1 µs/division time base. The switching
waveform alternates between 0 V and the approximate input
voltage.
MEASURING LOAD REGULATION
Test load regulation by increasing the load at the output and
measuring the output voltage between the TP3 and TP6 test
points, the TP4 and TP8 test points, and the TP9 and TP13 test
points.
MEASURING LINE REGULATION
Vary the input voltage and measure the output voltage at a fixed
output current. Measure the input voltage between the TP1 and
TP7 test points. Measure the output voltage between the TP3
and TP6 test points, the TP4 and TP8 test points, and the TP9
and TP13 test points.
MEASURING EFFICIENCY
Measure the efficiency, η, by comparing the input power with
the output power.
ININ
OUT
OUT
IV
IV
η
×
×
=
To accurately measure the input current of Channel 2, particularly
with a lower light load current, set a higher number of power
line cycles (NPLC) for the digital multimeters. The longer a
signal is integrated, the more accurate the reading result.
MEASURING INDUCTOR CURRENT
Measure the inductor current by removing one end of the inductor
from the pad on the evaluation board and using a wire connected
between the pad and the inductor. Then use a current probe to
measure the inductor current.
MEASURING OUTPUT VOLTAGE RIPPLE
To observe the output voltage ripple, place an oscilloscope probe
across the C1, C8, and C10 output capacitors with the probe
ground lead placed at the negative (−) capacitor terminal and
the probe tip placed at the positive (+) capacitor terminal. Set
the oscilloscope to an ac coupling, 10 mV/division, 2 µs/division
time base and a 20 MHz bandwidth.
A standard oscilloscope probe has a long wire ground clip. For
high frequency measurements, this ground clip picks up high
frequency noise and injects it into the measured output ripple.
A simple way to properly measure the output ripple requires
removing the oscilloscope probe sheath and wrapping a non-
shielded wire around the oscilloscope probe. Keep the ground
lengths of the oscilloscope probe as short as possible when
measuring the true ripple.
OUTPUT VOLTAGE CHANGE
The output voltage of the ADP5310 evaluation board is preset to
1.8 V and 3.3 V. However, the output voltage can be adjusted
using the following equations:
+
×=
4
43
V8.0
1
R
RR
V
OUT
+
×=
2
21
V8.0
2
R
RR
V
OUT
