CMOS analog baseband channel filter for direct a conversion WCDMA receiver

The direct conversion receiver architecture is a good candidate to achieve wireless transceiver systems-on-chip, because, among other reasons, the channel selection filter is lowpass and can be implemented on-chip. This paper reports the design of an analog baseband filter chain for a direct conversion WCDMA receiver. The filter chain consists of a 5th order Chebyshev lowpass active RC filter with automatic frequency tuning, a programmable gain amplifier (PGA), and a DC servo feedback circuit to suppress the DC offset.