Techniques for calibrating differential signals in measurement instruments

Differential amplifiers are often used in several measurement instruments for fast processing of sensor data, images etc. Such circuits are sensitive to component mismatches, temperature and process variations that modify the amplitude and the level of the differential signals. A number of calibration techniques that can restore such differential signals are presented in this paper. These techniques include level shifting, frequency detection and signal delay adaptation and are applied to a novel integer divider circuit that is incorporated in an ultra low area and power 8bit subrange Analog/Digital Converter that has been developed in CMOS TSMC90nm process.