1.5-V high-performance SC filters in BiCMOS technology

The authors describe two low-voltage switched-capacitor (SC) filters: one can operate from a minimum supply of 1.5 V and the other from a minimum supply of 2 V (for typical parameter values). Both filters use a fully differential architecture and are fabricated in a standard BiCMOS technology. The lowest supply filter, operated from a 2-V supply, has an SNR (signal-to-noise ratio) of 92 dB and a THD (total harmonic distortion) of -70 dB for a 2.4-Vpp differential signal. Power consumption and area per pole are 60 μW and 0.18 mm2, respectively, with a clock frequency of 447 kHz. The realized filters can be used as building blocks to implement more complex functions, like the active synthesis of a given impedance in line-fed telecom systems