High PSRR Folded Cascode OTA for Neural Signal Applications

Bioelectrical signal acquisition systems are used to record, amplify, store and process data, the amplification stage being one of the most important. In this paper presents an operational transconductance amplifier based on the Complementary Metal-Oxide-Semiconductor commercial technology of 0.18 μm TSMC using a folded cascode topology. Interdigitated technique was used to improve chip area and reduce parasitic capacitances. The proposed OTA is polarized at ± 1.8 V, obtaining a 53.40 dB gain with a 10 mHz – 2.21kHz bandwidth, Power Supply Rejection Ratio (PSRR) of 105.65 dB, and a Common Mode Rejection Ratio (CMRR) of 82.17 dB.