A 5th order bilinear elliptic switched-current filter

A fifth-order lowpass bilinear elliptic filter, employing second-generation regulated-cascode switched-current cells, has been integrated on a standard 1.2-μm digital CMOS process. The filter is based on the bilinear s → z transformation, which results in a simple circuit realization using switched currents. The filter occupies an area of 1.5 mm², has been tested up to a clock frequency of 5.75 MHz, and consumes 27 mW quiescent power. Detailed measurements were taken at a clock frequency of 2 MHz, giving a measured passband edge of 350 kHz, a stopband edge of 420 kHz, a passband ripple of 0.6 dB, and a minimum stopband attenuation of 26 dB. This integrated filter has demonstrated the level of complexity and performance achievable using switched-current techniques