Datasheet

EVAL-ADP1715/ADP1716
Rev. 0 | Page 6 of 8
LOAD REGULATION DROPOUT VOLTAGE
For load regulation measurements, the regulator output is
monitored while the load is varied. For good load regulation,
the output needs to change as little as possible with varying
loads. The input voltage must be held constant during this
meas-urement. The load current can be varied from 0 mA
to 500 mA.
Dropout voltage measurements can also be performed using
the configuration shown in
Figure 6. 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
for output voltages above 2.5 V. Dropout voltage increases with
larger loads. For more accurate measurements, a second voltage
meter 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 8 shows the typical load regulation
performance of an ADP1715 with 3.3 V fixed output for
an input voltage of 3.8 V.
3.325
3.265
0.1 1000
06309-008
I
LOAD
(mA)
V
OUT
(V)
1 10 100
3.315
3.305
3.295
3.285
3.275
Figure 9 shows a typical curve of dropout voltage measurements
with different load currents.
350
0
0.1 1000
06309-009
I
LOAD
(mA)
V
DROPOUT
(mV)
300
250
200
150
100
50
1 10 100
Figure 8. ADP1715 Load Regulation
Figure 9. Dropout Voltage vs. Load Current