Doubly-segmented current-steering DAC calibration

This paper addresses the calibration of segmented current-steering Digital-to-Analog Converters (DACs). In many design cases, current-steering DACs are divided into a thermometer-coded unary section and a binary section. This is done mostly for dynamic reasons. However, the decisions on the segmentation also impact an eventual static calibration. In this paper, we show that the introduction of an intermediate thermometer-coded unary section allows to perform static calibration to a high resolution levels without compromising the dynamic behavior. The individual current sources of the two unary sections are calibrated against two current references and the gain mismatch between sections is calibrated through the biasing circuit.