Design and Simulation of Two Low-Voltage, Low-Power Transresistance Instrumentation Amplifiers with Electronic Adjustment Capability

This article introduces two designs for transresistance amplifiers. The first and second precision instrument amplifiers utilize ten and eight MOS transistors. Both proposed precision amplifiers were simulated with 0.18 µm CMOS technology and a supply voltage of ±0.7 V using Hspice software. According to the results, the Common Mode Rejection Ratio (CMRR) of the first precision amplifier can vary from 72.6 dB to 75.7 dB with a change in control voltage. In contrast, the second amplifier can range from 71.7 dB to 74 dB. The -3dB cutoff frequency for the CMRR of the first precision amplifier is accessible between 0.969 MHz and 16.4 MHz, and for the second precision amplifier, it ranges from 4.34 MHz to 40.8 MHz. The power consumption of the first proposed design varies from 203.33 µW to 372.77 µW within the adjustment range, and for the second proposed design, it changes from 234.57 µW to 338.73 µW. Time-domain analysis indicates that for a 20 µA(p-p) input signal, the maximum Total Harmonic Distortion (THD) at various frequencies for the first design is 3.37%. For the second design, it is 2.13%. The output impedance of the first proposed precision amplifier can vary from 779 to 1190 Ω with a change in control voltage, and for the second proposed amplifier, it can change from 860 Ω to 1640 Ω. Therefore, these two circuits are suitable for precision amplifier applications with electronic adjustability in medical instruments, biosensor reading circuits, electrocardiography, and signal processing.