Transconductor and integrator circuits for integrated bipolar video frequency filters

A description is presented of novel transconductor and integrator circuits which can be used in integrated video frequency filters in bipolar technology. The transconductor consists of a parallel connection of a passive nominal transconductance and an active variable transconductance, resulting in good high-frequency performance up to 70 MHz and less than 1% linearity error for input signals up to 2V/sub pp/. The integrator incorporates an operation transconductance amplifier circuit which provides a tunable integrator phase. Simulation results for all circuits and for a fifth-order elliptic low-pass filter with a nominal cutoff frequency of 5 MHz are presented.<>