An anti-blocker structure MOSFET-C filter for a direct conversion receiver

A linearized MOSFET-C lowpass filter suitable for a baseband channel selection filter for a direct conversion receiver is presented. Using polysilicon resistors instead of MOSFET resistors in the input and output part, the filter achieves very high out-of-band linearity but keeps the original transfer function of the filter under a continuous on-chip cutoff tuning scheme. The filter achieves -1.8 dBV in-band IIP3, +27.8 dBV out-of-band IIP3, +93.8 dBV out-of-band IIP2 and 46.7 /spl mu/Vrms input-referred noise.