An embedded 14-bit 800MS/s DAC for direct digital frequency synthesizer in 0.18-μm CMOS

摘要

An embedded 14-bit 1-GS/s digital-to-analog converter for Direct Digital Frequency Synthesizer (DDFS) application is presented. The DAC is implemented using a segmented current-steering architecture, with the top 6bits and the remaining 8 bits. The output stage of dual return-to-zero scheme is used to enhance the dynamic performance of spurious-free dynamic range (SFDR). The DAC core is fabricated in a 1P6M 0.18 μm standard CMOS technology occupies a die area of only 1.6 × 1.5 mm². The measured differential nonlinearity lies between −0.8 LSB and 0.3LSB, integral nonlinearity lies between −1.5LSB and 1LSB. And the SFDR is 76.47 dB for 80 MHz output at 0.8GHz sampling clock rate.