GENERAL DESCRIPTION

The 64Mb SDRAM is a high-speed CMOS, dynamic random-access memory containing 67,108,864-bits. It is internally configured as a quad-bank DRAM with a synchronous interface (all signals are registered on the positive edge of the clock signal, CLK). Each of the 16,777,216-bit banks is organized as 2,048 rows by 256 columns by 32 bits.

Read and write accesses to the SDRAM are burst oriented; accesses start at a selected location and continue for a programmed number of locations in a programmed sequence. Accesses begin with the registration of an ACTIVE command, which is then followed by a READ or WRITE command. The address bits registered coincident with the ACTIVE command are used to select the bank and row to be accessed (BA0, BA1 select the bank, A0-A10 select the row). The address bits registered coincident with the READ or WRITE command are used to select the starting column location for the burst access.

FEATURES

? PC100 functionality

? Fully synchronous; all signals registered on positive edge of system clock

? Internal pipelined operation; column address can be changed every clock cycle

? Internal banks for hiding row access/precharge

? Programmable burst lengths: 1, 2, 4, 8, or full page

? Auto Precharge, includes CONCURRENT AUTO PRECHARGE, and Auto Refresh Modes

? Self Refresh Mode

? 64ms, 4,096-cycle refresh (15.6μs/row)

? LVTTL-compatible inputs and outputs

? Single +3.3V ±0.3V power supply

? Supports CAS latency of 1, 2, and 3