Floating-gate-based tunable CMOS low-voltage linear transconductor and its application to HF g/sub m/-C filter design

This paper presents a new CMOS low-voltage linear transconductor for very high frequency. It uses multiple-input floating-gate transistors in each inverter of the differential structure transconductor presented by Nauta [1992]. The proposed transconductor operates under a constant low-voltage supply as low as 1.2 V, and its transconductance and output resistance are independently tunable, as shown by experimental measurements. This architecture is suitable for use in high-frequency continuous-time filters with programmable center frequency and quality factor. Simulation results of a 10.7-MHz and Q=40 g/sub m/-C filter operating with a voltage supply of 1.4 V and with rail-to rail input swing are presented.