A new CMOS tunable transconductor dedicated to VHF continuous-time filters

A new CMOS transconductance (Gm) circuit with voltage-tunability and very wide bandwidth is proposed and analysed. The transconductance circuit is then used to realize a tunable VHF 2nd-order bandpass filter cell. The center frequency (f0) of the designed filter can be tuned by varying the transconductance value (gm) of the tunable GM circuit. Simulation results indicate the excellent performances of both the transconductance circuit and the filter over a wideband range. The transconductance value can be tuned from 40 mu S to 950 mu S (490 mu S) and the filter center frequency (f0) in the range 30 MHz (4 MHz)-110 MHz (49 MHz)for +/-2.5 V (+/-1.5 V) supply voltages.