On-die self-healing of mixer image-rejection ratio for mixed-signal electronic systems

An integrated wideband (6-20 GHz) image-reject mixer and test signal source for "self-healing" of image-rejection ratio (IRR) is demonstrated for the first time. The mixer can be adapted to deliver consistent performance over process variations, environmental changes, and/or aging effects. An IRR of over 36 dB is obtained in measurement for a wide range of IF frequencies. The healing is achieved by means of an automated procedure controlled by MATLAB algorithms. The test signal source consists of an on-die wideband differential ring oscillator with an amplitude-control mechanism to provide a 20 dB range of adjustable power at the input of the mixer. The circuits were fabricated in a commercially-available 180 nm SiGe BiCMOS platform.