A 12.8-Gb/s/link tri-modal single-ended memory interface for graphics applications

A single-ended (SE) memory interface utilizing a compact voltage-mode (VM) driver and equalizer, and a reference-voltage (VREF) noise tracking system achieves 12.8-Gbps per pin data rate. Same interface can also communicate with 6.4-Gbps GDDR5 and 1.6-Gbps DDR3 DRAM with no package change. Implemented in a 40-nm CMOS process, the x16 tri-modal interface achieves an energy efficiency of better than 5.0-mW/Gbps per data link at 12.8-Gbps.