SNOS674G November 1997 – April 2020 LMC6482
The LMC6482 has the high input impedance, large common-mode range and high CMRR needed for designing instrumentation circuits. Instrumentation circuits designed with the LMC6482 can reject a larger range of common-mode signals than most in-amps. This makes instrumentation circuits designed with the LMC6482 an excellent choice of noisy or industrial environments. Other applications that benefit from these features include analytic medical instruments, magnetic field detectors, gas detectors, and silicon-based transducers.
A small valued potentiometer is used in series with Rg to set the differential gain of the 3-op-amp instrumentation circuit in Figure 57. This combination is used instead of one large valued potentiometer to increase gain trim accuracy and reduce error due to vibration.
A two-op-amp instrumentation amplifier designed for a gain of 100 is shown in Figure 58. Low sensitivity trimming is made for offset voltage, CMRR, and gain. Low cost and low power consumption are the main advantages of this two-op-amp circuit.
Higher frequency and larger common-mode range applications are best facilitated by a three-op-amp instrumentation amplifier.