Datasheet

EVAL-ADP190
Rev. 0 | Page 4 of 8
VIN TO VOUT RESISTANCE (RDS
ON
)
RDS
ON
can be measured using the configuration shown in
Figure 4. RDS
ON
is defined as the input-to-output voltage
differential divided by load current.
The voltmeter reading divided by the load current value gives
the equivalent RDS
ON
value. 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 3 shows a typical curve of RDS
ON
measurements
with different load currents.
07862-003
200
180
160
140
120
100
80
1.2 2.01.6 2.4 2.8 3.2 3.6
V
IN
(V)
RDS
ON
(mΩ)
I
LOAD
= 10mA
I
LOAD
= 100mA
I
LOAD
= 250mA
I
LOAD
= 350mA
I
LOAD
= 500mA
Figure 3. RDS
ON
vs. Input Voltage, V
IN
(Includes ~15 mΩ Trace Resistance)
VOLTAGE SOURCE
VIN
VOLTMETER
RDS
ON
0.035
LOAD
07862-004
Figure 4. RDS
ON
Measurement