20 ns dual-port SRAM for shared-memory arbitration
The Cypress CY7C008-20AC is a 512Kbit dual-port asynchronous SRAM organized as 64K x 8, with a 20 ns access time that sets the bus-turnaround window for two independent bus masters sharing a memory block. The dual-port architecture gives each port its own address, data, and control lines, so two processors or controllers can read or write to different locations simultaneously without arbitration logic — useful in multiprocessor systems, video frame buffers, or telecom line cards where shared memory must not stall either side.
For a processor running at 25 MHz (40 ns cycle), a 20 ns SRAM leaves a 20 ns margin for address decoding, buffer delays, and board trace propagation — enough for most glue-logic setups without inserting wait states. If the system clock is faster than 25 MHz, the 20 ns window tightens and the 15 ns speed grade (CY7C008-15AC) may be needed to avoid wait-state insertion. The 20 ns variant is the middle speed tier in the family, balancing cost against timing margin for typical 16- to 25-MHz bus architectures.
The CY7C008-20AC is listed as obsolete. Cypress has not published a direct pin-compatible successor for this exact order code, so the part is no longer available through the factory channel. Buyers should qualify any sourced parts for date code, moisture sensitivity (MSL), and functional test.