Datasheet

UG-230 Evaluation Board User Guide
Rev. 0 | Page 6 of 10
GROUND CURRENT MEASUREMENT
Figure 9 and Figure 10 show how the evaluation board can be
connected to a voltage source and an ammeter for ground current
measurements. A resistor can be used as the load for the
regulator. Ensure that 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 that the
voltage source used can supply enough current for the expected
load levels. If voltmeters are connected at the input or output
terminals, subtract the current resulting from the shunt
resistance of the voltmeter for accurate ground current
measurement.
Follow these steps to connect to a voltage source and ammeter:
1. Connect the positive terminal (+) of the voltage source to
the VIN pad on the evaluation board.
2. Connect the positive terminal (+) of the ammeter to one of
the GND pads of the evaluation board.
3. Connect the negative terminal (−) of the ammeter 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.
The voltage source can now be turned on. If J1 is inserted
(connecting EN to VIN for automatic startup), the regulator
powers up.
GROUND CURRENT CONSUMPTION
Ground current measurement is a way of determining how
much current the internal circuits of the regulator are consum-
ing, while performing the power switch function. To be efficient,
the power switch needs to consume as little current as possible.
Figure 8 shows the typical ground current consumption for
various load levels.
20
0
4
8
12
16
2
6
10
14
18
1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5
GROUND CURRENT (µA)
V
IN
(V)
10mA
100mA
200mA
400mA
800mA
1000mA
09562-008
Figure 8. Ground Current vs. Input Voltage
+
–
AMMETER
+
–
VOLTAGE
SOURCE
LOAD
0.00112
09562-009
Figure 9. LFCSP Ground Current Measurement