A 6.4/3.2/1.6 Gb/S Low Power Interface With All Digital Clock Multiplier For On-The-Fly Rate Switching

A dynamic rate adjustable interface is designed a 40-nm LP CMOS process. On-the-fly dynamic rate change is enabled by an all-digital frequency multiplier that detects a reference frequency change, and accordingly provides 4x multiplied clock without any idle time. The clock multiplier, along with matched source synchronous clocking and clock equalization, allows blind reference clock shifting to scale the data rate from 1.6 to 6.4 Gb/s within 6.125ns without idle time or bit errors during transitions. The interface efficiency is 2.6 mW/Gb/s @6.4 Gb/s & 3.4 mW/Gb/s @3.2 Gb/s when using reduced clock swing and external transmitter swing at the reduced data rates.