A 2-GHz CMOS image-reject receiver with LMS calibration

This paper describes a sign-sign least-mean squares (LMS) technique to calibrate gain and phase errors in the signal path of a Weaver image-reject receiver. The calibration occurs at startup and the results are stored digitally, allowing continuous signal reception thereafter. Fabricated in a standard digital 0.25-/spl mu/m CMOS technology, the receiver achieves an image-rejection ratio of 57 dB after calibration, a noise figure of 5.2 dB, and a third-order input intercept point of -17 dBm. The circuit consumes 55 mW in calibration mode and 50 mW in normal receiver mode from a 2.5-V power supply.