An Eighth-Order CMOS Lowpass Filter with 30-120 Mhz Tuning Range and Programmable Boost

摘要

A CMOS lowpass filter with programmable cutoff frequency is presented. The architecture is gm/C type with the gm controlled through a resistor servo approach. The wide tuning range is achieved by exploiting a dual loop control over a degenerated differential pair. This filter, implemented in a 0.25um 2.5V CMOS technology, dissipates 120mW with fc=120MHz and has a die area of 0.23mm~2.