Temperature compensation in combination selection based mismatch calibration

The temperature behaviour of a combination selection based mismatch calibration is discussed. The functionality of the calibration structure has already been presented. Clear benefits in implementation area and accuracy can be reached when using mismatch calibration based on combination selection of minimum-sized transistors. However, with the used high accuracy requirements, the effects of temperature must be taken into the account. Temperature compensation circuitry for combination selection based mismatch calibration is developed, designed and simulated. The new temperature compensated and mismatch calibrated current source achieves 99% accuracy in 4σ confidence over the temperature range of 30 degrees in centigrade. This range can still be extended by recalibrating the current source in intervals of 15 degrees in centigrade.