A multi-GHz phase detector with auto-zeroing scheme for self-calibrated quadrature generation

Closed loop based quadrature generation systems depend highly on the accuracy of the phase detector. However the phase detector accuracy is susceptible to device mismatch. We present an implementation of a phase detector in SiGe BiCMOS technology and also a simple scheme for auto-zeroing of phase detector for reducing the effects of the device mismatch in phase detector and error amplifier (EA). This scheme does not require any reference signal and hence can be easily implemented at minimal overhead. Significant improvement in performance is observed for device mismatch.