A Newton iteration-based calibration algorithm for pipelined ADC

This paper presents a Newton iteration-based calibration algorithm for pipelined analog-to-digital converter (ADC). The proposed calibration algorithm equalizes the errors induced by incomplete settling of operational amplifier (op-amp) to the inter-stage gain errors. To compensate the inter-stage gain errors, a significant calibration parameter p
₃
is introduced, whose optimal solution is searched through Newton iteration method. With this parameter which is estimated through Newton iteration method, inter-stage gain errors will be compensated, and the digital output calibrated of ADC can be obtained. The presented calibration algorithm not only improves the ADC performance, but also is helpful to reduce the design difficulty of analog circuit by tolerating the incomplete settling errors caused by op-amp with low performance. A 14-bit 100MS/s pipelined ADC model with this calibration algorithm is built and simulated on MATLAB. Simulation results show this calibration algorithm improves SFDR from 55.08dB to 105.43dB, SNDR from 45.69dB to 82.85dB and ENOB from 7.29 to 13.47 at Nyquist input frequencies.