Digitally-Assisted Linearization of Wideband Direct Conversion Receivers

A SAW-less direct-conversion receiver is presented which utilizes a mixed-signal feedforward path to regenerate and equalize IM3 products, thus accomplishing system-level linearization. The receiver system performance is dominated by a custom integrated front end realized in 130 nm CMOS and achieves an uncorrected out-of-band IIP3 of -7.1 dBm under the worst-case UMTS FDD region 1 blocking specifications. IM3 equalization results in an effective IIP3 of +5.3 dBm and reduces total input-referred error by over 23 dB.