A low-power programmable low-pass switched capacitor filter using double sampling technique

A fifth order low-pass Chebyshev II filter with cascaded biquad realization has been designed which is digitally programmable with variable-rate (three lower cut-off frequency fc=8, 12, 20 MHz). Using very useful high frequency techniques such as double sampling scheme (DSS) and differencing-input SC integrators, the sampling frequency of designed filter is up to fs=103.68 MHz (fs=2fclk=103.68 MHz) with a SFDR=68 dB and THD=62 dB. The attenuation of filter is more than 30 dB at 1.5 f/sub c/ and more than 40 dB at 1.75 f/sub c/, respectively. Input and output swing of the filter is 1.6 Vpp with 3 V supply in a 0.35 /spl mu/m CMOS technology consuming approximately 45 mW power in the worst power case.