UG-054 Datasheet, PDF (5/8 Pages) Analog Devices – Setting Up the Evaluation Board for the ADP150

Evaluation Board User Guide
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
this measurement, VIN must be varied between VOUTNOM + 0.4 V
(or 2.2 V, whichever is greater) and VINMAX.
For example, for an ADP150 with a fixed 3.3 V output, VIN
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
3.298
3.296
I_OUT = 0.1mA
I_OUT = 1mA
I_OUT = 10mA
3.294
3.292
I_OUT = 50mA
3.290
I_OUT = 100mA
3.288
I_OUT = 150mA
3.5 3.7 3.9 4.1 4.3 4.5 4.7 4.9 5.1 5.3 5.5
V_IN (V)
Figure 7. Output Voltage (VOUT) vs. Input Voltage (VIN) at TA = 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 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
3.297
3.296
3.295
3.294
3.293
3.292
3.291
3.290
0.01
0.1
1
10
I_OUT (mA)
100
1000
Figure 8. Output Voltage (VOUT) vs. Load Current (IOUT) at VIN = 3.7 V,
VOUT = 3.3 V, TA = 25°C
UG-054
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
I_OUT (mA)
Figure 9. Dropout Voltage vs. Load Current (IOUT) at VOUT = 3.3 V, TA = 25°C
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