Alliance Memory | AS7C4098A-20JIN

Equal address access and cycle times (tAA, tRC, tWC) of 10/12/15/20 ns with output enable access times (tOE) of 5/6 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 55mW 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 devicesshould 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 5.0V (AS7C4098A) supply. The device is available in the JEDEC standard 400-mL, 44-pin SOJ, TSOP 2 packages.