General Description

The 256Mb Mobile DDR SDRAM is a high-speed CMOS, dynamic random-access memory containing 268,435,456 bits. It is internally configured as a quad-bank DRAM. On the x16 device, each of the 67,108,864-bit banks is organized as 8,192 rows by 512 columns by 16 bits. On the x32 device, eachof the 67,108,864-bit banks is organized as 4,096 rows by 512 columns by 32 bits.

特性 Features

?VDD/VDDQ = 1.70–1.95V

? Bidirectional data strobe per byte of data (DQS)

? Internal, pipelined double data rate (DDR) architecture; two data accesses per clock cycle

? Differential clock inputs (CK and CK#)

? Commands entered on each positive CK edge

? DQS edge-aligned with data for READs; center aligned with data for WRITEs

? Four internal banks for concurrent operation

? Data masks (DM) for masking write data—one mask per byte

? Programmable burst lengths: 2, 4, or 8

? Concurrent auto precharge option supported

? Auto refresh and self refresh modes

? 1.8V LVCMOS compatible inputs

? On-chip temperature sensor to control self refresh rate

? Partial-array self refresh (PASR)

? Deep power-down (DPD)

? Selectable output drive (DS)

? Clock stop capability

? 64ms refresh period