A Fourth Order Elliptic Low-Pass Filter with Wide Range of Programmable Bandwidth, Using Four Identical Integrators
Behzad Saeidi · 2007
A new method to implement elliptic filter with identical integrators and no derivatives is presented. Using identical capacitor arrays as opposed to highly spread capacitor arrays of conventional implementation makes elliptic filter design with wide range of programmable/tunable bandwidths extremely simple, time-efficient and accurate. The proposed method also reduces the die size while realizing elliptic filter more faithfully. To demonstrate the method, a fourth order elliptic filter with nine programmable bandwidths ranging from 1.1MHz to 17.6MHz is designed. The 1.75mm2filter draws 10mA from 3.3V supply at output swing of 4.0V ppd in 0.35μm CMOS process to meet less than50nV/√Hzin-band output-referred noise and SFDR of better than 80dBc.