Noise-shaped post-mixer blocker filter for integrated receivers

In this paper, analysis and design of a frequency dependent negative resistance (FDNR) based noise-shaping elliptic blocker filtering technique is presented. Due to its noise shaping characteristics, the circuit can provide a third-order low-pass elliptic response with an input referred noise density of 7.2nV/sqrtHz. The proposed circuit relaxes the noise-linearity trade-off a receiver chain by providing blocker rejection with a minimal area and noise cost. The design occupies a die area of 350 ¿m by 700 ¿m in a 65-nm CMOS process covering a frequency band of 700-KHz to 5.2 MHz as a universal direct-conversion base-band filtering solution.