●GENERAL DESCRIPTION
●The 128Mb DDR SDRAM is a high-speed CMOS, dynamic random-access memory containing 134,217,728 bits. It is internally configured as a quad bank DRAM.
●The 128Mb DDR SDRAM uses a double data rate architecture to achieve high-speed operation. The double data rate architecture is essentially a 2n-prefetch architecture with an interface designed to transfer two data words per clock cycle at the I/O pins. A single read or write access for the 128Mb DDR SDRAM effectively consists of a single 2n-bit wide, one-clock-cycle data transfer at the internal DRAM core and two corresponding n-bit wide, one-half-clock-cycle data transfers at the I/O pins.
●FEATURES
●• VDD = +2.5V ±0.2V, VDDQ = +2.5V ±0.2V
●• Bidirectional data strobe (DQS) transmitted/received with data, i.e., source-synchronous data capture (x16 has two – one per byte)
●• 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
●• DLL to align DQ and DQS transitions with CK
●• Four internal banks for concurrent operation
●• Data mask (DM) for masking write data (x16 has two – one per byte)
●• x16 has programmable IOL/IOH option
●• Programmable burst lengths: 2, 4, or 8
●• Auto precharge option
●• Auto Refresh and Self Refresh Modes
●• Longer lead TSOP for improved reliability (OCPL)
●• 2.5V I/O (SSTL_2 compatible)
