A calibration technique for SAR analog-to-digital converter based on INL testing with quantization bits and redundant bit

A calibration technique for SAR analog-to-digital converters is proposed in this paper which is ready to be integrated on chip. This technique is based on the integral nonlinearity (INL) test and utilizes one redundant bit and extra two quantization bits to improve the calibration accuracy. In the calibration mode, mismatch errors are saved as higher-bit level INL information and then translated to calibration codes. During the conversion, higher-bit level outputs are adjusted and truncated to generate the required bits. Finally, 0.375LSB improvement of INL is observed by theoretical analysis and the effectiveness of this method is verified by simulations in which the maximum INL is reduced from 0.9LSB to 0.23LSB.