Design of a capacitive DAC mismatch calibrator for split SAR ADC in 65 nm CMOS

Abstract

This paper presents the design and implementation of a capacitive digital to analog converter (CDAC) mismatch calibrator used in split successive approximation resistor (SAR) analog to digital converter (ADC) in a 65 nm complementary metal oxide semiconductor (CMOS) process. The calibrator adopts a compensation capacitor connected to the least significant bit (LSB) capacitor array to calibrate the mismatch between the lowest-bit capacitor of the most significant bit (MSB) array and the LSB array. An 11-bit 50-MS/s split SAR ADC using this calibrator was developed. The measurement results show that the calibration process improves the differential nonlinearity (DNL) value from -1.2/+1.9 LSBs ..