A 9-bit, 45 mW, 0.05 mm2 Source-Series-Terminated DAC Driver With Echo Canceller in 22-nm CMOS for In-Vehicle Communication

This letter presents an SST 9-bit TX-DAC driver, that is fully compliant to the new Automotive Ethernet (AE) Standard IEEE P802.3ch. The TX driver design incorporates a highly correlated timing-matched 9-bit echo DAC canceller (EC-DAC) to eliminate up-to 24.4 dB of the transmit power from RX path, due to full-duplex transmission scheme. The TX–EC-DAC driver combination inherently provides $100\Omega $ differential termination and possesses a PVT calibration scheme covering up to 3 sigma process variation with a resolution of $2.5\Omega $ . Designed and fabricated in a 22-nm FD-SOI technology, the TX-DAC enables a 1-Vppd PAM4 signal swing with raw data rates up to 11.2 Gb/s and Nyquist tone sine wave linearity SFDR of better than 54.4 dBFS thanks to the supply degeneration approach. The driver pair is backward compatible to all relevant AE Standards 10/5/2.5/1GBase-T1 and occupies the smallest area of only 0.05 mm2. The 9-bit TX–EC-DAC combination dissipates 3/42 mW from dual 0.8/1.2-V power supply with a power efficiency of 2 mW/Gb/s per DAC.