A 3 V 12-55 MHz BiCMOS pseudo-differential continuous-time filter

The reduction of the supply voltage forces one to develop system and circuit solutions able to achieve the same performance previously obtained with higher supply voltage. In this paper, a second-order low-pass continuous-time filter operating at a 3 V power supply is presented. The prototype filter is implemented using a highly linear pseudo-differential transconductor. The input common-mode signal is canceled 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 1.2 μm BiCMOS technology. The pole frequency can be tuned in the range 12-55 MHz. A THD of -40 dB is achieved for signals up to 1 Vpp at 10 MHz. The dynamic range is approximately 60 dB