SI9181DB Datasheet, PDF (2/9 Pages) Vishay Siliconix – Si9181DB/Si9182DB Demonstration Board

Si9181DB/Si9182DB
Vishay Siliconix
POWER UP CHECK LIST AND OPERATION
Visually inspect the PCB to be sure that all the components are
intact and no foreign substance is lying on the board.
1 Insert jumper JP2 and remove jumper JP3.
2 Insert JP1 to EN position.
3 Load the output to the rated load current.
4 Increase the input from 0 V slowly, while monitoring the
output. Note the regulated output voltage.
5 Increase the input to 6 V and check the line regulation. Vary
the load from 0 to 350 mA (Si9181DB) and 0 to 250 mA
(Si9182DB) and check the load regulation.
6 Follow the “Typical Waveforms and Performance” to verify
the dropout, transient response ground current and output
noise.
DROPOUT VOLTAGE
LOAD TRANSIENT RESPONSE
The Si9181DB and Si9182DB are provided with additional
circuit to measure the load step response from 1 to 150 mA
with 2-mSec load rise/fall times. The load step and slew-rate
can be easily changed by selecting R4, R5, R7 and R8.
Remove the external load from the output, insert the jumper
JP3 and apply 5-V_pk-pk/5-kHz square wave signal at P5
(TRAN). Remove the oscilloscope probe-cap and insert the
probe into the probe-clip. Set the oscilloscope to 10 mV/div
and 5-mSec/div. Refer to Figures 3 through 5 for typical load
transient waveform.
GROUND CURRENT
Remove the jumper JP2 and insert micro-ampere meter. Use
thick and short wires to connect the meter. Vary the load to
measure the ground current at all loads. (See Figure 2.)
The dropout voltage is defined as the input to output voltage
differential measured, when the output drops by 100 mV from
its normal value. The output voltage is nominal at V_IN equal to
V_OUT + 1. The dropout voltage is different at different output.
Plots in Figure 1 and Figure 3 show the typical dropouts
measured on bench at 25_C ambient temperature.
Dropout vs. V_OUT
250
200
150
Si9181DB, I_OUT = 350 mA
100
50
Si9182DB, I_OUT = 250 mA
0
1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
V_OUT (V)
FIGURE 1. Dropout Voltage Si9181DB/Si9182DB
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2
Ground Current Measurement
mA–meter
V_IN
JP2
V_OUT
GND
GND
Si9181DB/Si9182DB
LOAD
FIGURE 2. Ground Current Measurement
Document Number: 71306
26-Sep-00