Design of a 12-Bit Segmented Current Steering DAC Based on DWA

DAC (Digital to Analog Converter, namely DAC) is a digital-analog hybrid system is an important part of the wide range of applications . This paper focuses on the data based on weighted average algorithm (DWA) of the 12 type segmented current steering DAC design. Currently, they use a current-steering DAC structure, and one of the sub-structure and is more suitable for designing high-speed high-precision DAC. However, due to process error exists , it is difficult to ensure DAC current source module in the degree of matching , this paper uses data weighted averaging algorithm to solve this problem . Firstly, from a systems perspective on the design uses three -stage DAC structure, which considering the chip area and circuit performance, and analyze the performance limits of current-steering DAC type main factors in order to this is the basis for the design of each module consisting DAC . This paper designs a temperature coefficient of 5.44ppm bandgap reference circuit provides bias to each module , the design of a high output impedance current source to improve the performance of the DAC , and is designed based on the DWA circuit transmission gate array technology to solve the error result of the current source mismatch . For differential output DAC is designed to produce high cross point control signal of the current source switching control circuitry to reduce the output of the burr to improve the overall dynamic performance. Finally, we did a DAC spectrum analysis , and, for DWA algorithm, using the first imitation of the current source plus mismatch method proved DWA circuit DAC dynamic performance is greatly improved . This design of DAC is a \Maximum four and intermediate four respectively thermometer code structure , the lowest four binary -weighted structure . Dual power are digital and analog modules supply and ship using 0.18-micron process technology .