Infoscience

Conference paper

A Widely-Tunable and Ultra-Low-Power MOSFET-C Filter Operating in Subthreshold

A very wide tuning range ultra-low-power MOSFET-C filter is presented. The wide tuning range in this filter has been achieved without using any switchable components or programmable building blocks, and the cutoff frequency of the filter can be adjusted simply through a controlling bias current. The filter has low-pass characteristics with $f_{c}$ = 20Hz to 184kHz while exhibiting a constant power consumption per cutoff frequency over its entire tuning range that is almost four decades wide. The proposed MOSFET-C filter uses PMOS transistors in subthreshold regime for implementing floating and widely adjustable resistors. The ultra high resistivity of the PMOS devices makes them very suitable for implementing very low frequency and compact filters. Realized in 0.18$\mu$m CMOS technology, the filter exhibits a relatively constant noise and linearity performance over its entire tuning range. The active area of the proposed MOSFET-C filter is 0.09mm$^2$.

Keywords: CMOS ; CMOS integrated circuits ; Analog CMOS circuits ; Continuous-time filters ; MOSFET-C filter ; Ultra low power ; High valued resistance ; Very low frequency ; Biquadratic filter

Reference

Record created on 2009-07-27, modified on 2012-03-20