Datasheet

TL03x, TL03xA
ENHANCED-JFET LOW-POWER LOW-OFFSET
OPERATIONAL AMPLIFIERS
SLOS180C − FEBRUARY 1997 − REVISED DECEMBER 2001
49
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
APPLICATION INFORMATION
instrumentation amplifier with linear gain adjust
The low offset voltage and low power consumption of the TL03x provide an accurate but inexpensive
instrumentation amplifier (see Figure 70). This particular configuration offers the advantage that the gain can
be linearly set by one resistor:
V
O
=
R6
R5
× (V
B
− V
A
)
Adjusting R6 varies the gain. The value of R6 always should be greater than, or equal to, the value of R5 to
ensure stability. The disadvantage of this instrumentation amplifier topology is the high degree of CMRR
degradation resulting from mismatches between R1, R2, R3, and R4. For this reason, these four resistors
should be 0.1%-tolerance resistors.
+
−
U1C
+
−
U1A
R6
1 MΩ
V
A
V
CC+
V
O
+
−
+
−
V
B
U1B
R2
10 kΩ
0.1%
R4
10 kΩ
0.1%
R7
100 kΩ
R5
100 kΩ
R1
10 kΩ
0.1%
R3
10 kΩ
0.1%
U1D
V
CC−
NOTE A: U1A through U1D = TL03x; V
CC
±
= ±15 V
Figure 70. Instrumentation Amplifier With Linear Gain-Adjust Circuit