Patent ID: 9621177
Date: 2017-04-11
CPC Classifications: H03M

Claim:
1. A method to calibrate a digital-to-analog converter (DAC), the method comprising: determining a first calibration codeword based on a first nonlinearity error value measured at an output of the DAC when a most-significant-bit (MSB) portion of an input codeword is applied to an input of the DAC; determining a second calibration codeword based on a second measured nonlinearity error value measured at the output of the DAC when a least-significant-bit (LSB) portion of the input codeword is applied to the input of the DAC; and combining the first calibration codeword and the second calibration codeword to determine a third calibration codeword to be accessed by the DAC to calibrate the output of the DAC when the input codeword is applied to the DAC; wherein the DAC is an interpolating string DAC including a main coarse string DAC circuit and a main interpolator circuit, the MSB portion of the input codeword corresponds to a number of bits of resolution of the main coarse string DAC circuit, and the LSB portion of the input codeword corresponds to a number of bits of resolution of the main interpolator circuit.