A 65-nm CMOS 6-Bit 20 GS/s Time-Interleaved DAC with Full-Binary Sub-DACs

A 6-bit 20 GS/s two-channel time-interleaved current-steering digital-to-analog converter (DAC) with compact full-binary sub-DACs is presented. Optimally adjusted transition timings between the input data and the interleaving clock minimize glitches by the time-interleaving switches and enhance the high-frequency linearity. In order to prevent static linearity degradation by the leakage current through the time-interleaving switches, the relationship between the output current and the leakage current is analyzed. The proposed DAC architecture and the pseudo-differential logic gates for the high-speed data interface reduce the circuit complexity as well as the power consumption. The prototype 6-bit 20 GS/s DAC, fabricated in a 65-nm CMOS process, achieves a spurious-free dynamic range of 35.1 dB up to the Nyquist input, and consumes 136 mW given a 1.2-V power supply.