A 1.6 GB/s data-rate 1 Gb synchronous DRAM with hierarchical square-shaped memory block and distributed bank architecture

This paper describes key technologies for a 1.6 GB/s high bandwidth 1 Gb synchronous DRAM (SDRAM). Its high data transfer rate and large memory capacity are intended for a unified memory system in which a single DRAM (array) is time-shared as both main memory and 3D graphics frame memory. 200 MHz operation is achieved by the hierarchical square-shaped memory block (SSMB) layout and the distributed bank (D-BANK) architecture. A built-in self-test (BIST) circuit with margin-test capability is included.