Digital ICs/DSP: Multichip Package Saves Space While Delivering 256 Mbytes

The W3E32M64S-XSBX, a 32-Mword by 64-bit double-data-rate (DDR) SDRAM module, packs 256 Mbytes of storage in a single 208-contact plastic ball-grid-array (BGA) package that measures 13 by 22 by 2.11 mm. Built by stacking four 512-Mbit DRAMs, the W3E32M64S-XSBX provides both high density and performance in one package. Each of its four memory chips is internally configured as a quad-bank DRAM. Data-rate speed grades of 200, 250, and 266 MHz are available. The package saves 73% more space than individual memory chips housed in TSOPs and 43% more than fine-pitch BGA packages. In lots of 500 units, the 256-Mbyte memory is priced at $250 apiece. Delivery takes four to six weeks after receipt of order.