A High-Temperature, Low-Drift Instrumentation Amplifier

In industrial control, detection devices need to operate at temperatures several times higher than room temperature. High-temperature environments can lead to offset voltage, increased noise, and reduced closed-loop gain accuracy in integrated circuits. This paper presents the design of an instrumentation amplifier circuit with offset self-calibration. The circuit employs an improved constant $\mathbf{G m}$ biasing circuit for secondary compensation, enabling the instrumentation amplifier to exhibit low offset and low noise characteristics over a wide temperature range. Simulation results indicate that within the temperature range of $-55^{\circ} \mathrm{C}$ to $175^{\circ} \mathrm{C}$, the equivalent input offset voltage is less than 777.711 nV, the input bias current is less than 26.398 nA, the total supply current is 2.747 mA, the commonmode rejection ratio is greater than 129.492 dB, and the 1 kHz noise is $75.55 \mathbf{n V} / \sqrt{ } \mathbf{H z}$.