Novel tunable current feedback instrumentation amplifier based on BBFC OP-AMP for biomedical applications with low power and high CMRR

Abstract

The paper presents a novel low power, low noise and high CMRR current feedback instrumentation amplifier (CFIA) design for biomedical signal acquisition i.e. EEG/ECG applications is presented. The proposed instrumentation amplifier performance is evaluated using 0.18μm, CMOS technology with 1.8 V supply and results are obtained in Cadence EDA tool. The proposed CFIA is implemented using a dual output bandwidth boosted folded cascode operational amplifier (BBFC OP-AMP) active block. In this paper the proposed CFIA performance parameters has been considered for optimization to get better results by using the idea of signal to noise ratio (SNR) with Taguchi design of experiments (Taguchi DoE) and analysis of variance (ANOVA) to estimate the most important independent variable which control the performance of the design. The bias voltage, channel length and width of input MOS transistors have been selected to optimize the proposed circuit performance. The proposed CFIA structure have 50.33 to 69.67 dB tunable differential gain, common mode rejection ratio (CMRR) of 143.19 dB, tunable bandwidth of 148.24 kHz to 1.31 MHz, dynamic range (DR) of 74.31 dB and 297.73 dB of figure of merit (FoM). The CFIA shows an equivalent input referred noise (IRN) of 0.586 μV at 0.1 Hz to 148.24 kHz frequency range, with total power dissipation of 102.73 μW and occupies 8194μm2 of core area. The simulation results of the proposed CFIA are close to the predicted solution obtained from ANOVA. The PVT analysis and post layout simulation has been performed to check the robustness of the proposed design. The proposed design has been compared with the other existing literature which shows the competence of the design.