Datasheet

EVAL-ADP1720
Rev. 0 | Page 7 of 8
GROUND CURRENT MEASUREMENTS
GND GND
GND GND
VIN VOUT
J1
C1 C2
R2
EN
U1
J2
R1
GND/ADJ
EVAL-ADP1720
+
_
VOLTAGE SOURCE
LOAD
CURRENT
METER
_
+
μA
06768-009
Figure 9.
Figure 9 shows how the evaluation board can be connected
to a voltage source and a current meter for ground current
measurements. A resistor can be used as the load for the
regulator. Ensure the resistor has a power rating adequate to
handle the power expected to be dissipated across it. An electronic
load can be used as an alternative. Ensure the voltage source
used can supply adequate current for the expected load levels.
Follow these steps to connect to a voltage source and current meter:
1. Connect the positive terminal (+) of the voltage source to
the VIN pad on the evaluation board.
2. Connect the positive terminal (+) of the current meter to
one of the GND pads of the evaluation board.
3. Connect the negative terminal (−) of the current meter to
the negative (−) terminal of the voltage source.
4. Connect a load between the VOUT pad of the evaluation
board and the negative (−) terminal of the voltage source.
5. The voltage source can now be turned on. If J1 is inserted
(this connects EN to VIN for automatic startup), then the
regulator powers up.
GROUND CURRENT CONSUMPTION
Ground current measurements are a way of determining how
much current the regulator’s internal circuits are consuming,
while performing the regulation function. To be efficient, the
regulator must consume as little current as possible. Typically,
the regulator consumes maximum current when supplying its
largest load level (50 mA).
Figure 10 shows the typical ground
current consumption for various load levels.
1200
0
0.01 100
I
LOAD
(mA)
I
GND
(µA)
0.1 1 10
1000
800
600
400
200
06768-010
Figure 10. Ground Current vs. Load Current
When the device is disabled (EN = 0 V), ground current is
reduced to less than 1 μA.
Note that larger ground current levels are observed when using
an evaluation board with R1 and R2 present.