A low-area digitalized low-pass-filter with programmable active-RC load

This paper proposes a digitalized low-pass filter (LPF) with wide tuning range and low-area. The parallel connection of active inductor and Miller capacitor are utilized to achieve a low transition band and a low circuit area. Band selectivity is raised by cascading stages of LPF cell. In 0.18um CMOS technology, a 4bits 8-stage LPF template occupies an active area of 0.075mm2 and consumes a power of 17.4mW under 1.8V of supplies. The -3dB frequency is ranged form 0.8MHz to 12.7MHz with an average frequency resolution of 0.74 MHz.