Datasheet

Evaluation Board User Guide UG-186
Rev. 0 | Page 5 of 12
1.800
1.805
1.810
1.815
1.820
2.12.52.93.33.74.14.54.95.3
V
IN
(V)
V
OUT
(V)
LOAD = 1mA
LOAD = 5mA
LOAD = 10mA
LOAD = 50mA
LOAD = 100mA
LOAD = 200mA
0
9299-008
Figure 4. Output Voltage vs. Input Voltage
LOAD REGULATION MEASUREMENTS
For load regulation measurements, the regulator’s outputs are
monitored while the loads are varied. For good load regulation,
the outputs must change as little as possible with varying load.
The input voltage must be held constant during this measure-
ment. The load currents can be varied from 0 mA to 200 mA
per output. Figure 5 shows the typical load regulation perfor-
mance of a single 1.8 V output of the ADP322/ADP323 for an
input voltage of 2.3 V to 5.5 V.
1.800
1.805
1.810
1.815
1.820
1 10 100 1000
I
LOAD
(mA)
V
OUT
(V)
0
9299-007
Figure 5. Output Voltage vs. Load Current
DROPOUT VOLTAGE MEASUREMENTS
Dropout voltage can be measured using the configuration
shown in Figure 3. Dropout voltage is defined as the input-to-
output voltage differential when the input voltage is set to the
nominal output voltage. This applies only to output voltages
above 1.8 V. Dropout voltage increases with larger loads.
For more accurate measurements, an additional voltmeter can
be used to monitor the input voltage across the input capacitor.
The input supply voltage may need to be adjusted to account
for IR drops, especially if large load currents are used. Figure 6
shows the typical curve of the dropout voltage measurement
with different load currents.
0
10
20
30
40
50
60
70
80
90
100
1 10 100 1000
I
LOAD
(mA)
DROPOUT VOLTAGE (mV)
09299-022
Figure 6. Dropout Voltage vs. Load Current, V
OUT
= 3.3 V