An ultra-low power high gain CMOS OTA for biomedical applications

An ultra-low power bulk-driven operational transconductance amplifier circuit for biomedical applications is presented. Higher DC gain and improved slew rate is achieved using double recycling technique, cross-coupled positive feedback configuration and driver transistors to enhance the transconductance of the conventional bulk-driven folded cascode amplifier. The post layout simulation of the proposed bulk-driven double recycling OTA in 180nm CMOS technology, shows a 30dB DC gain improvement and a 250% enhancement in GBW. The above results are validated using the Monte Carlo process variation and corner case simulations. The amplifier consumes 145nW @ 0.6V supply voltage.