Functional Description
The CY7C4281/91 are high-speed, low-power FIFO memories with clocked read and write interfaces. All are nine bits wide. The CY7C4281/91 are pin-compatible to the CY7C42X1 Synchronous FIFO family. Programmable features include Almost Full/Almost Empty flags. 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
• 64K × 9 (CY7C4281)
• 128K × 9 (CY7C4291)
• 0.5-micron CMOS for optimum speed/power
• High-speed 100-MHz operation (10-ns read/write cycle times)
• Low power
   — ICC = 40 mA
   — ISB = 2 mA
• Fully asynchronous and simultaneous read and write operation
• Empty, Full, and programmable Almost Empty and Almost Full status flags
• TTL compatible
• Output Enable (OE) pin
• 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
• Pin-compatible density upgrade to CY7C42X1 family
• Pin-compatible density upgrade to IDT72201/11/21/31/41/51