A RF/DC current-mode detector for BiST and digital calibration of current-driven mixers

This paper presents a CMOS RF/DC current-mode detector as an essential requirement to realize Built-in Self Test (BiST) and calibration functionalities for current-mode based RFICs and demonstrates its application on the calibration of a current-driven passive mixer. A method is presented to extract test friendly DC features from the RF signal, without deteriorating the performance of test blocks in the transceiver. Simulation performance with IBM 90-nm process using 1.2 V power supply shows that the proposed detector is able to provide an RF to DC conversion gain of 35 mV/dB in a dynamic range of 25 dB from 900 MHz to 10 GHz. The current-mode detector is then applied in the IP2 digital calibration technique on the down-conversion mixer under several corner conditions. Simulation results confirm the feasibility of the calibration as IIP2 improves more than 20 dBm.