Evaluation Board User Guide

UG-054

Rev. 0 | Page 5 of 8

3.288

3.5

3.7

3.9

4.1

4.3

4.5

4.7

4.9

5.1

5.3

5.5

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

must be varied between 3.7 V and 5.5 V. This measurement

can be repeated under different load conditions. Figure 7

shows the typical line regulation performance of an ADP150

with a fixed 3.3 V output.

3.300

3.290

3.292

3.294

3.296

3.298

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 this measure-

ment. The load current can be varied from 0 mA to 150 mA.

Figure 8 shows the typical load regulation performance of an

ADP150 with a fixed 3.3 V output for an input voltage of 3.7 V.

3.298

3.291

3.292

3.293

3.294

3.295

3.296

3.297

3.290

0.01

1000

100

10

1

0.1

DROPOUT VOLTAGE MEASUREMENTS

Dropout voltage can be measured using the configurations

shown in Figure 5 and 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 to output

voltages above 2.2 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 9

shows the typical curve of dropout voltage measurements with

different load currents.

80

70

60

50

40

30

20

10

0

1

10

100

1000