A 3V 12-55MHz BiCMOS Continuous-Time Filter with Pseudo-Differential Structure

In this paper a 3V 2nd order lowpass continuous-time filter is presented. The filter is based on a highly linear pseudo-differential transconductor. The input common-mode signal is cancelled at the transconductor level using a feed-forward path. The output common-mode voltage is controlled at the filter level using lossy-integrators. A prototype cell has been realized in 1.2μBiCMOS technology. The pole frequency can be tuned in the range 12-55MHz. A THD of -40dB is achieved for signals up to lVpp at 10MHz. The dynamic range is approximately 60dB.