SBOA103C
Jan 2006
PGA309 Quick Start
System Reference Guide
83
For the ratiometric calibration
method it is useful to adjust the
power supply to see how PSR
affects the PGA309 calibrated
accuracy. A 10% power supply
deviation is used in this example
because it is a typical worst case
deviation for ratiometric systems.
Connecting a 53k
Ω
resistor
between the 3V pin and the
center pin on JA will cause the
power supply to shift from 5V to
4.5V. You can adjust the value of
the shunt resistance to get more
or less power supply deviation.
A short will cause the power
supply to deviate from 5V to 3V.
Vout
ADJ
GND
Vin
Vin
NC
EN
Vout
53k
3V
JA
5V
JA
JB
JF
JC
JD
JE
VOUT
5V
PROG
3V
PC
1PU
INPU
ON
SDN
RTS
DTR
DIS
PGA309 PC Interface Board
To PC
Serial
Port
6V dc Power
from wall
adaptor
53k
Schematic
Mechanical Diagram