A 5.8-mW, 20-MHz, 4th-order programmable elliptic filter achieving over −80-dB IM3

Frequency compensation of active-RC elliptic filter is enabled for the first time by employing a derivative-free architecture. In conjunction with a built-in automatic unity-gain band-width (ω u ) tracking scheme, the prototype 4th-order active-RC elliptic low-pass filter (LPF) measures a digitally programmable bandwidth of 14-23 MHz, a two-tone IM3 at 6 MHz consistently better than -80 dB with a full-scale input of over 800 mVpp, a 1-dB in-band ripple and 45-dB stop-band rejection, all across wide temperature and voltage ranges. The LPF dissipates 5.8 mW from a 1.2-V supply and occupies 0.1 mm 2 in 0.13-μm CMOS.