LMC6081 Datasheet, PDF (13/21 Pages) National Semiconductor (TI) – Precision CMOS Single Operational Amplifier

LMC6081
www.ti.com
SNOS649C – AUGUST 2000 – REVISED MARCH 2013
The extremely high input impedance, and low power consumption, of the LMC6081 make it ideal for applications
that require battery-powered instrumentation amplifiers. Examples of these types of applications are hand-held
pH probes, analytic medical instruments, magnetic field detectors, gas detectors, and silicon based pressure
transducers.
Figure 30 shows an instrumentation amplifier that features high differential and common mode input resistance
(>10¹⁴Ω), 0.01% gain accuracy at A_V = 1000, excellent CMRR with 1 kΩ imbalance in bridge source resistance.
Input current is less than 100 fA and offset drift is less than 2.5 μV/°C. R₂ provides a simple means of adjusting
gain over a wide range without degrading CMRR. R₇ is an initial trim used to maximize CMRR without using
super precision matched resistors. For good CMRR over temperature, low drift resistors should be used.
If R₁ = R₅, R₃ = R₆, and R₄ = R₇; then
A_V ≈ 100 for circuit shown (R₂ = 9.822k).
Figure 30. Instrumentation Amplifier
Figure 31. Low-Leakage Sample and Hold
Figure 32. 1 Hz Square Wave Oscillator
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