Patent ID: 7511650
Filing Date: 2009-03-31
Classification: H03M

Abstract:
1. A digital-to-analog converter (DAC), for converting an input word into an output voltage, wherein the input word has a least significant bit (LSB) and remaining bits, the DAC comprising: an R-string section providing a first group of voltage levels and a second group of voltage levels; a first DAC section, providing a first voltage level according to the input word when the input word corresponds to a voltage level within a range of the first group of voltage levels; a second DAC section, providing a second voltage level and a third voltage level according to the remaining bits when the input word corresponds to a voltage level within a range of the second group of voltage levels; a multiplexer, coupled to the second DAC section to provide an intermediate voltage from the second and the third voltage levels according to the LSB bit; and an operational amplifier generating the output voltage by using the first voltage level when the input word corresponds to the voltage level within the range of the first group of voltage levels, or by averaging the intermediate voltage and the second voltage level when the input word corresponds to the voltage level within the range of the second group of voltage levels.