New folded cascode transconductor for bandpass ladder filters

The problems of designing CMOS transconductors for high frequency bandpass ladder filters are discussed, and an original circuit for overcoming these problems is presented. This circuit features a new grounded-quad input stage, a very high output impedance and the facility of low impedance inputs to avoid the requirement for transconductance ratios in scaled filters. The application of the new transconductor is illustrated by the design of a high frequency sixth-order Chebyshev bandpass filter. The performance of the transconductor and the filter are demonstrated by analysis and simulation results