A 0.006 mm2 Low Input Capacitance Low Power Fully Differential Neural Amplifier

Neural amplifiers are desired to have ultra low power, low noise, low area, high input impedance, band pass response and high CMRR. Capacitively coupled instrumentation amplifier (CCIA) is a widely used topology as it features high power efficiency and moderate area, CMRR and input impedance. The main idea of area minimization relies on the minimum value implementation of the feedback capacitor of the CCIA and optimum mid band gain. We have proposed a feedback network which gives better mismatch for a given equivalent feedback capacitor which allows us to minimize the feedback capacitance without degrading the CMRR and gain mismatch. The amplifier implemented in 180 nm CMOS technology has among the lowest reported area of 0.006
$mm^{2}$
and has an input capacitance of 1 pF. The amplifier consumes 1.08
$\mu W$
of power and has an NEF of 5.2 with input referred noise of 12.4
$\mu V$
in 1 – 5 KHz bandwidth. The post layout simulation results of the amplifier are presented.