Design techniques for low-voltage VHF BiCMOS transconductance-filters with automatic tuning

A third-order Chebyshev low-pass filter with automatic tuning based on new BiCMOS low-voltage triode transconductors for applications in the very-high-frequency (VHF) range is presented. Simulation results of the filter and the automatic tuning circuitry are described. The complete system operates with supply voltages of /spl plusmn/1.5 V. The filter achieves a 42.8 MHz cutoff frequency. The filter total harmonic distortion (THD) stays lower than 1% for an input signal up to 1.061 V/sub pp/ at 8 MHz frequency. The dynamic range of the filter is 60 dB.