A novel topology voltage-mode instrumentation amplifier based on CFOAs

Abstract

This paper presents a new voltage-mode instrumentation amplifier circuit that employs two current-feedback operational amplifiers (CFOAs) and three grounded resistors. The ideal and non-ideal analyses of the proposed circuit are presented. SPICE simulations with 0.18 mu m TSMC CMOS process parameters are conducted to validate the theoretical analyses. The proposed circuit provides a high differential-mode gain (40 dB) and high bandwidth (23.13 MHz). Moreover, the common-mode rejection ratio (CMRR) is also high (60.23 dB), with a CMRR bandwidth of 1.07 MHz. The supply voltage is +/- 1.25 V, and the total power consumption is found to be low at 0.954 mW. The robustness of the circuit is confirmed through simulations, and its performance against Process-Voltage-Temperature (PVT) variations is also examined. A key advantage of the proposed circuit is its ability to be easily implemented using commercially available integrated circuits, such as the AD844, which underscores its practical superiority over current-mode designs in terms of simplicity and accessibility. Additionally, the proposed circuit has been experimentally tested using these commercially available ICs.