A Capacitor Mismatch Calibration for Multi-bit Sub-DAC in 16 bit Pipelined ADC

Capacitor mismatches in multi-bit sub-DAC will introduce non-linear errors in pipelined ADC output. Therefore,conversion resolution will be greatly deteriorated.But normal calibration technique cannot correct nonlinear error.Based on this calibration requirement,a capacitor mismatch calibration for multi-bit sub-DAC in 16 bit pipelined ADC is presented in this paper.In this calibration,a post-production capacitor mismatch extraction method is designed.After mismatch errors are obtained,MDAC output errors of different inputs are calculated. According to these errors,calibration code are calculated and then be stored on chip to correct mismatch errors through compensation circuit.Simulation results show that after calibration.SINAD is 93.34 dB,SFDR is 117.86 dB and ENOB increased from 12.63 bit to 15.26 bit.