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GENERAL DESCRIPTION The 64Mb (x32) DDR SDRAM is a high-speed CMOS, dynamic random-access memory containing 67,108,864 bits. It is internally configured as a quad-bank DRAM. FEATURES • Bidirectional data strobe (DQS) transmitted/ received with data, i.e., source-synchronous data capture • Internal, pipelined double-data-rate (DDR) architecture; two data accesses per clock cycle • Reduced output drive option • Differential clock inputs (CK and CK#) • Commands entered on each positive CK edge • DQS edge-aligned with data for READs; centeraligned with data for WRITEs • DLL to align DQ and DQS transitions with CK • Four internal banks for concurrent operation • Data mask (DM) for masking write data • Programmable burst lengths: 2, 4, 8, or full page • 32ms, 4,096-cycle auto refresh (7.8µs/cycle) • Auto precharge option • Auto Refresh and Self Refresh Modes • Programmable I/O (SSTL_2 compatible) – reduced and impedance matched
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