Parallel current-steering D/A Converters for Flexibility and Smartness

This paper presents a DAC architecture built on parallel current-steering sub-DAC entities. Two main novelties are explored: flexibility and smartness. Firstly, a number of available operating modes (op-modes) can set the overall DAC performance and functionality. These op-modes transfer some of the important design trade-offs to the end-user and constitute the DAC flexibility. The main examples include: resolution-power-number of DACs, static-dynamic performance, etc. Secondly, specific signal processing techniques become possible. The main examples of such techniques include: full self-calibration, cancellation of harmonic distortion (HD) components, and linearity improvement through redundancy. This paper concentrates on a method to suppress undesired HD components through DA processing of phase shifted replicas of the main input signal. The presented theoretical concepts are realized in a 14-bit DAC built from 4 parallel 12-bit sub-DACs. Transistor simulations and a layout design are also presented. The demonstrated flexibility characteristics of the new DAC architecture make the discussed concepts particularly suitable for FPGA integration.