The extremely high input impedance, and low power consumption, make the LMC608x an excellent choice for applications that require battery-powered operation. 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 6-4 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 1kΩ imbalance in bridge source resistance. Input current is less than 100fA and offset drift is less than 2.5μV/°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, use low drift resistors like the RES11A. An example of an instrumentation amplifier with the LMC608x is provided in the next section.

If R₁ = R₅, R₃ = R₆, and R₄ = R₇; then

Equation 3. $\frac{V_{OUT}}{V_{IN}} =\frac{R_2+{2R}_1}{R_2}\times \frac{R_4}{R_3}$

A_V ≈ 100 for circuit shown (R₂ = 9.822kΩ).

Figure 6-4 Instrumentation Amplifier

Figure 6-5 Low Leakage Sample and Hold

Figure 6-6 1Hz Square-Wave Oscillator