A 10-Gb/s, 107-mW Double-Edge Pulsewidth Modulation Transceiver

A 10-Gb/s serial link transceiver is demonstrated using double-edged pulsewidth modulation to overcome frequency-dependent losses in electrical interconnects. Time domain modulation is discussed as a means to enhance the spectral efficiency in channels with sharp frequency roll-off similar to multilevel voltage-domain modulation such as 4-PAM. The transmitter and receiver are high-speed programmable digital-to-time and time-to-digital converters that adapt to channel bandwidth characteristics with a timing resolution of 40 ps. This paper presents a low-jitter, phase rotation architecture for cycle-to-cycle transmit pulsewidth control. The transceiver includes an elastic buffer to move data between synchronous and plesiochronous clock domains and is implemented in 45-nm CMOS SOI. Transmitter and receiver functionality is demonstrated to 10 Gb/s at a BER of under 10^-12 and is compared against NRZ schemes at the same rate. The inductor-less transmitter and receiver active circuitry respectively occupy an area of 93 × 94 and 218 × 160 μm², and consume a total 107 mW from a 1.2 V supply.