Datasheet

REF19x Series
Rev. J | Page 25 of 28
LOW POWER, STRAIN GAGE CIRCUIT
As shown in Figure 31, the REF19x family of references can be
used in conjunction with low supply voltage operational ampli-
fiers, such as the OP492 or the OP747, in a self-contained strain
gage circuit in which the REF195 is used as the core. Other
references can be easily accommodated by changing circuit
element values. The references play a dual role, first as the
voltage regulator to provide the supply voltage requirements of
the strain gage and the operational amplifiers, and second as a
precision voltage reference for the current source used to
stimulate the bridge. A distinct feature of the circuit is that it
can be remotely controlled on or off by digital means via
the
SLEEP
pin.
500Ω
0.1%
57kΩ
1%
0.1μF
10kΩ
1%
0.1μF
1/4
OP492
10μF
REF195
2.21kΩ
20kΩ
1%
10kΩ
1%
20kΩ
1%
20kΩ
1%
20kΩ
1%
0.01μF
10μF
100Ω
OUTPUT
2N2222
+
1μF
+
62
4
+
–
1
4
11
2
3
1/4
OP492
+
–
7
5
6
1/4
OP492
+
–
14
12
13
1/4
OP492
+
–
8
10
9
10kΩ
1%
00371-031
Figure 31. Low Power, Strain Gage Circuit