Low-power 14-bit current steering DAC, for ADSL2+/CO applications in 0.13/spl mu/m CMOS

Abstract

This work presents a 6-bit fully-differential current steering digital-to-analog converter (DAC), oversampled and 2/sup nd/ order noiseshaped. It is implemented in a 0.13 /spl mu/m standard CMOS process, using only regular threshold voltage devices. The circuit is targeted at ADSL2+ central-office (CO) applications. Clocked at 105 MHz from a low-jitter PLL, it yields a multi-tone power ratio (MTPR) higher than 75 dBc for DMT signals, with an output swing of 1.4 V peak-to-peak. It has an effective resolution of more than 14.5 ENOBs (effective number of bits), consuming only 9 mW from a single 1.5 V supply.