A14-bit Dynamic Element Matching1GSPS D/A Converter

In this paper, a14-Bit DEM (Dynamic Element Matching) segmentedcurrent-steering D/A Converter is designed with SMIC0.18μm mixed-signal CMOStechnology library, and the sampling clock frequency is1GHz.In the segmentedarchitecture with5+5+4sub-way, the5most significant bits and the middle5significant bits are dynamic thermometer decoded, the4least significant bits usesbinary-weighted current source structure. This paper focuses on the impedance and themismatch of current source； Based on MATLAB mode, current source layout isverified to be effective in reducing the mismatch；In order to enhance the DAC linear, anew type of high speed low cross point switch drive circuit, Temperature coefficient of13ppm/℃bandgap reference and bias circuit are designed. Using duplicate supply,while digital supply is1.8V and analog supply is3.3V. This thesis uses a differentialoutput structure, full-scale output current is10mA, and we can transfer it to outputvoltage with a50Ω resister.Using Spectre and Matlab tools, circuits-designing and simulations are done, thedesigned D/A Converter has the differential output voltage swing of±0.5V,SFDR=72.6dB@Fclk=1GHz and Fin=10MHz,SFDR=63.9dB@Fclk=1GHz andFin=50MHz，SFDR=61.5dB@Fclk=1GHz and Fin=100MHz.Using virtuso, Layout isdraw and verified. The core dynamic power consumption is280mW; the chip area isabout0.85mm*1.17mm.