This article introduces a 16-Gb T-coil-based graphics double-data-rate 6 (GDDR6) dynamic random access memory (DRAM) with merged-multiplexer (MUX) transmitter (TX), optimized data clock (WCK) ...operation to enhance I/O bandwidth. T-coil is implemented for the first time in a DRAM process. Moreover, an alternative-data-bus (ADB) is employed to solve the frequency limit of the data bus. The proposed T-coil-based GDDR6 DRAM achieves 27 Gb/s/pin with 1.35 V in a DRAM process.
Graphic DRAMs have been developed to increase maximum I/O interface speeds to satisfy the demand of high-performance graphic applications 1-5. Recently, PAM4 signaling was utilized to increase the ...I/O bandwidth up to 22Gb/s/pin 5. However, the reduced voltage margin of PAM4, compared to NRZ, complicates circuit design; margins also become worse with a reduced power supply. This paper achieves 27Gb/s in NRZ, a 1.5× speed enhancement, by improving on previous GDDR6 3. A T-coil is designed, for the first time in a DRAM process, so that the maximum operation frequency is increased. The proposed merged-MUX TX increases the maximum speed and reduces power and area consumption. A quad-skew training technique enables a wider clock sampling margin for WCK: up to 3ps, which is 8.1% of 1UI at 27Gbp/s/pin. Furthermore, a dual-mode frequency divider allows a wide-range operation from sub-1Gb/s/pin to 27Gb/s/pin. An alternative-data-bus (ADB) is proposed to solve the frequency limit of the data bus.
