Functional Description

The CY7C455, CY7C456, and CY7C457 are high-speed, low-power, first-in first-out (FIFO) memories with clocked read and write interfaces. All are 18 bits wide. The CY7C455 has a 512-word memory array, the CY7C456 has a 1,024-word memory array, and the CY7C457 has a 2,048-word memory array. The CY7C455, CY7C456, and CY7C457 can be cascaded to increase FIFO depth. Programmable features include Almost Full/Empty flags and generation/checking of parity. These FIFOs provide solutions for a wide variety of data buffering needs, including high-speed data acquisition, multiprocessor interfaces, and communications buffering.

Features

• High-speed, low-power, first-in first-out (FIFO) memories

• 512 x 18 (CY7C455)

• 1,024 x 18 (CY7C456)

• 2,048 x 18 (CY7C457)

• 0.65 micron CMOS for optimum speed/power

• High-speed 83-MHz operation (12 ns read/write cycle time)

• Low power — ICC=90 mA

• Fully asynchronous and simultaneous read and write operation

• Empty, Full, Half Full, and programmable Almost Empty and Almost Full status flags

• TTL compatible

• Retransmit function

• Parity generation/checking

• Output Enable (OE) pins

• Independent read and write enable pins

• Center power and ground pins for reduced noise

• Supports free-running 50 duty cycle clock inputs

• Width Expansion Capability

• Depth Expansion Capability

• 52-pin PLCC and 52-pin PQFP