A 1.5-V 3.2Gb/s/pin Graphic DDR4 SDRAM with Dual-Clock System, 4 Phase Input Strobing and Low Jitter Fully Analog DLL

A 1.5V, 512 Mbit GDDR4 SDRAM using a 90-nm DRAM process has been developed. The data rate is 3.2 Gbps/pin, which corresponds to 12.8 GBps in x32 GDDR4 based I/O. A multi-divided architecture consisting of 4 independent 128 Mb core arrays is designed to reduce power and output noise. Also, a dual-clock system, 4 phase data input strobe scheme and 4 phase fully analog DLL are used to increase internal timing margins.