The Sharp LH5402X5 family: mainstream, designer-friendly, 18-bit-wide synchronous FIFOs

The new Sharp LH5402X5-family 18-bit-wide First-in, First-Out memories (FIFOs) are high-speed, synchronous digital specialty-memory devices, useful for local temporary storage and for data-rate-matching applications in high-performance digital systems. These FIFOs are implemented in recent-vintage 0.8 μ/0.7 μ CMOS static-RAM technology, and feature many conveniences and useful options for digital-system designers. One of them can replace two industry-standard 9-bit-wide asynchronous FIFOs of the same depth, and at the same time provide higher-speed operation and more convenient timing characteristics. They also can replace other existing 18-bit-wide FIFOs, in many cases without design changes to the system. The LH5402X5 family indudes four pin-compatible FIFOs, differing in depth: LH540215 (512×18 meaning 512 18-bit words); LH540225 (1024×18); LH540235 (2048×18); and LH540245 (4096×18). As of this article, the first two of these FIFOs are in production; the other two are in the design stage. These FIFOs are available in speed grades up to 50 MHz (20 nsec-cycle-time)