A 6-to-32 Gb/s voltage-mode transmitter with scalable supply, voltage swing, and pre-emphasis in 65-nm CMOS

Abstract

A voltage-mode (VM) transmitter which offers a wide operation range of 6-to-32 Gb/s, controllable pre-emphasis equalization and output voltage swing without altering output impedance, and a power supply scalability is presented. A quarter-rate clocking architecture is employed in order to maximize the scalability and energy efficiency across the various operating conditions. A P-over-N VM driver is used for CMOS compatibility and wide voltage-swing range required for various I/O standards. Two supply regulators calibrate the output impedance of the VM driver across the wide swing and pre-emphasis range. A single phase-locked loop is used to provide a wide frequency range. The prototype chip is fabricated in 65-nm CMOS technology and occupies active area of 0.48×0.36 mm2. The proposed transmitter achieves 250-to-600-mV single-ended swing and exhibits the energy efficiency of 2.10-to-2.93 pJ/bit across the data rate of 6-to-32 Gb/s.