CMOS linear programmable transconductor suitable for adjustable Gm-C filters

摘要

A novel CMOS linear programmable transconductor is presented. It is based on a telescopic cascode operational transconductance amplifier with source degeneration implemented by means of highly linear tunable active resistors. The transconductor has been designed in a 0.5 μm CMOS technology featuring a third-order intermodulation (IM3) of - 54.8 dB at 10 MHz for a 1 V_(pp) output voltage. Its feasibility for Gm-C filter design has been experimentally validated with a 1 MHz tunable third-order Chebyshev lowpass filter suitable for Bluetooth applications.