Low-power complex channel filtering using cascoded class AB switched-currents

The development of switched-current (SI) complex bandpass filters targeted for radio receiver applications is described in this paper. A filter architecture well suited for SI realisation is introduced followed by the development of the cascoded class AB SI technique to allow high precision in the implemented filter. A verification is given via the design and simulation of a 5th-order 1 MHz centre frequency and bandwidth complex SI bandpass filter with 13 MHz sampling frequency. Operating at 1.8 V supply, the resulting circuit offers precise passband response, less than -54.7 dB and -77 dB in-band and out-band intermodulation, respectively, with 4.9 mW power consumption.