AS7C34098A,3.3伏的CMOS SRAM的256K×16

　　The AS7C34098A is a high-performance CMOS 4，194，304-bit Static Random Access Memory （SRAM） device organized as 262，144 words × 16 bits. It is designed for memory applications where fast data access， low power， and simple interfacing are desired. Equal address access and cycle times （tAA， tRC， tWC） of 10/12/15/20 ns with output enable access times （tOE ） of 4/5/6/7 ns are ideal for high-performance applications. The chip enable input CE permits easy memory expansion with multiple-bank memory systems. When CE is high the device enters standby mode. The device is guaranteed not to exceed 28.8mW power consumption in CMOS standby mode. A write cycle is accomplished by asserting write enable （WE） and chip enable （CE）。 Data on the input pins I/O1–I/O16 is written on the rising edge of WE （write cycle 1） or CE （write cycle 2）。 To avoid bus contention， external devices should drive I/O pins only after outputs have been disabled with output enable （OE） or write enable （WE）。 A read cycle is accomplished by asserting output enable （OE） and chip enable （CE）， with write enable （WE） high. The chip drives I/O pins with the data word referenced by the input address. When either chip enable or output enable is inactive， or write enable is active， output drivers stay in high-impedance mode. The device provides multiple center power and ground pins， and separate byte enable controls， allowing individual bytes to be written and read. LB controls the lower bits， I/O1–I/O8， and UB controls the higher bits， I/O9–I/O16. All chip inputs and outputs are TTL- and CMOS-compatible， and operation is for 3.3V （AS7C34098A） supply. The device is available in the JEDEC standard 400-mil， 44-pin SOJ， TSOP 2.