A 12-bit CMOS Current Steering D/A Converter for Embedded Systems

This paper describes the design of a 12-bit digital-to-analog converter for a wireline modem chip implemented in a 0.13mum digital CMOS technology. Transistor-level simulations from extracted layout at the nominal modem data rate of 80MS/s show an spurious-free dynamic-range (SFDR) better than 62dB at Nyquist rate under industrial operation conditions (-40 to 85deg temperature range and plusmn10% supply variations) and for all technology process corners. Additionally, the converter achieves a multi-tone power ratio (MTPR) higher than 59dB for different discrete multitone (DMT) test patterns consisting of 1536 carriers that fall in the Nyquist band. Simulation results at a higher data rate of 200MS/s are also shown in the paper. The converter dissipates less than 150mW from a mixed 3.3/1.2V supply and occupies less than 1.7mm²