ADP165Z-REDYKIT/ADP166Z-REDYKIT User Guide UG-717
LINE REGULATION MEASUREMENTS
For line regulation measurements, the output of the regulator
is monitored while its input is varied. For good line regulation,
the output must change as little as possible with varying input
levels. To ensure that the device is not in dropout mode during line
regulation measurement, V
IN
must be varied between V
OUTNOM
+
0.4 V (or 2.2 V, whichever is greater) and V
INMAX
. For example,
for an ADP165 with a fixed 3.3 V output, VIN must be varied
between 2.7 V and 5.5 V. This measurement can be repeated under
different load conditions. Figure 9 shows the typical line regulation
performance of an ADP165 with a fixed 3.3 V output.
Figure 9. Output Voltage (V
OUT
) vs. Input Voltage (V
IN
) at
V
OUT
= 3.3 V, T
A
= 25°C
LOAD REGULATION MEASUREMENTS
For load regulation measurements, the output of the regulator is
monitored while the load is varied. For good load regulation, the
output must change as little as possible with varying load. The input
voltage must be held constant during load regulation measurement.
The load current can be varied from 0 mA to 150 mA. Figure 10
shows the typical load regulation performance of an ADP165
with a fixed 3.3 V output for an input voltage of 3.8 V.
Figure 10. Output Voltage (V
OUT
) vs. Load Current (I
OUT
) at
V
IN
= 3.8 V, V
OUT
= 3.3 V, T
A
= 25°C
DROPOUT VOLTAGE MEASUREMENTS
The dropout voltage can be measured using the configurations
shown in Figure 7 and Figure 8. Dropout voltage is defined as
the input to output voltage differential when the input voltage is
set to the nominal output voltage. The ADP165/ADP166 only
enter dropout mode for output voltages higher than 2.2 V; for
lower voltage outputs, the ADP165/ADP166 shut down. The
dropout voltage increases with larger loads.
For accurate measurements, use a second voltmeter to monitor
the input voltage across the input capacitor. The input supply
voltage may need adjusting to account for IR drops, especially
when using large load currents. Figure 11 shows the typical curve
of dropout voltage measurements with different load currents.
Figure 11. Dropout Voltage vs. Load Currents (I
LOAD
),
V
OUT
= 2.0 V and 3.3 V, T
A
= 25°C
3.33
3.23
3.24
3.25
3.26
3.27
3.28
3.29
3.30
3.31
3.32
3.7 3.9 4.1 4.3 4.5 4.7 4.9 5.1 5.55.3
V
OUT
(V)
V
IN
(V)
1µA
100µA
1mA
10mA
100mA
150mA
12433-009
3.35
3.25
3.26
3.27
3.28
3.29
3.30
3.31
3.32
3.33
3.34
0.001 0.01 10001001010.1
V
OUT
(V)
I
LOAD
(mA)
12433-010
0.27
0.24
0.
21
0.18
0.15
0.12
0.09
0.06
0.03
0
0.
001 10.10.0
1
DRO
POU
T VOLTA
GE (V)
I
L
OAD
(A
)
V
OUT
= 2.0V
V
OUT
= 3
.3V
12433-011
Rev. A | Page 5 of 9
