Circuits for field-programmable receiver front ends are provided. These front ends can include a field programmable common source low noise transconductance amplifier (LNTA), a field programmable common gate LNTA, first and second four-phase I/Q mixers, first, second, third, and fourth transimpedance amplifiers, an I-path complex combiner, and a Q-path complex combiner. Transconductance cells in each of the field programmable common source LNTA and field programmable common gate LNTA can be programmed to operate in one of a class-AB mode, a class-C mode, and an OFF mode.