91dB Dynamic Range 9.5nW Low Pass Filter for Bio-Medical Applications

Abstract

This paper presents a second order, fully differential, low pass filter. The filter has a tunable bandwidth in the range 4 Hz to 100 Hz and offers a dynamic range of 91 dB. The filter is based on the source-follower biquad operating in the sub-threshold region. The main idea is to exploit the strengths of sub-threshold source follower circuit, like low noise, low output impedance, high linearity and low power. The filter design has been validated in UMC 0.18 um CMOS process. The filter consumes only 9.5 nW of power at 1.8 V supply, making it suitable for bio-medical applications. In terms of noise and dynamic range the reported filter is better than previous works found from the literature.