Bias point selection circuitry for improved linearity

Abstract

Wireless circuitry is provided that includes a radio-frequency circuit having an input transistor and bias point selection circuitry configured to determine an optimal bias voltage for the input transistor. The bias point selection circuitry may include a replica transistor, a voltage generator configured to output one or more voltage levels to a gate terminal of the replica transistor, a current-to-voltage converter coupled to a source-drain terminal of the replica transistor, an analog-to-digital converter configured to receive analog voltages from the current-to-voltage converter and to output corresponding digital codes based on the received analog voltages, and associated control circuitry configured to receive the digital codes from the analog-to-digital converter and to adjust the voltage generator to output the optimal bias voltage based on the digital codes. The optimal bias voltage produces a third order transconductance of zero for the input transistor, which results in improved linearity for the radio-frequency circuit.