A 16-Gb, 18-Gb/s/pin GDDR6 DRAM With Per-Bit Trainable Single-Ended DFE and PLL-Less Clocking

Abstract

The graphic DRAM standard GDDR6 is developed to overcome the limitation of previous standards GDDR5/5X for achieving high-speed operation. This paper introduces 16-Gb GDDR6 DRAM with a per-bit trainable single-ended decision feedback equalizer (DFE), a reference impedance (ZQ)-coded transmitter, and a phase-locked loop (PLL)-less clocking to overcome I/O speed limitation by the DRAM process. Furthermore, this paper optimizes clock- and power-domain crossings and adopts split-die architecture to improve signal integrity (SI). This GDDR6 operates 16 Gb/s/pin with 1.15 V and achieves 18 Gb/s/pin with 1.35 V in the DRAM process.