A CMOS PGA with DCOC and I/Q mismatch calibration

A programmable gain amplifier (PGA) with DC-offset cancellation (DCOC) and I/Q gain and phase mismatch calibration is proposed in this paper. It achieves a gain tuning range of 9dB to 27dB with 6dB per step and a 30MHz bandwidth. DC negative feedback technique is adopted in the design of DCOC, while the gain mismatch calibration can be implemented in the first stage of PGA using variable resistor calibration and the phase mismatch calibration can be implemented in the second stage of PGA using feed through resistor calibration. Designed and simulated in a 0.18um CMOS process, the proposed PGA has a DC gain of -1dB, and after mismatch calibration, it has a gain error less than 0.1dB and a phase error less than 0.25 deg between I and Q.