Infineon Technologies CY7C4255-10AC

Overview

CY7C4255-10AC from Cypress Semiconductor is an 8K × 18-bit high-speed asynchronous FIFO memory with TTL-compatible I/O, 100 MHz operation (10 ns read/write cycle), 45 mA active supply current, and programmable Almost Empty/Almost Full flags. It serves as a data buffering interface between mismatched-speed subsystems in high-speed data acquisition and multiprocessor communication systems.

For engineers reviewing the CY7C4255-10AC datasheet, CY7C4255-10AC pinout, CY7C4255-10AC application, or CY7C4255-10AC equivalent, key selection criteria include synchronous/asynchronous flag timing control (via VCC/SMODE), depth/width expansion capability using WXO/RXO pins, retransmit functionality, and 64-pin TQFP package compatibility with IDT72205-series devices.

Technical Context

The CY7C4255-10AC implements a dual-clock FIFO architecture with independent WCLK and RCLK domains, supporting fully asynchronous read/write operations at up to 100 MHz. Its status flags-EF, FF, PAE, PAF, and WXO/HF-are decoded from internal read/write pointer logic with configurable synchronization via VCC/SMODE pin.

It features programmable flag offsets loaded via LD-controlled register access, retransmit capability triggered by FL/RT strobe, and cascade support through WXI/WXO and RXI/RXO for depth expansion. The device uses 0.5 µm CMOS technology, delivers 2.4 V VOH and 0.4 V VOL under load, and maintains <10 ns flag propagation delay in synchronous mode.

Key Specifications

Pinout & Package

64-pin Thin Quad Flat Package (TQFP) with center power/ground pins for noise reduction and thermal dissipation. Pin layout supports both standalone and cascaded configurations.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar FIFO buffering applications.

Compared with IDT72205L10JGI and CY7C425-10AC, the CY7C4255-10AC uniquely combines programmable flag offsets, retransmit capability, and dual-mode WXO/HF in a pin-compatible 64-pin TQFP, making it optimal for adaptive buffering in evolving embedded protocols.

Availability

CY7C4255-10AC is available at Aetrix Electronics and suitable for high-speed data acquisition, multiprocessor interfacing, and communications buffering requiring stable component supply across industrial temperature ranges and long-lifecycle programs.

Supply support for CY7C4255-10AC includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Cypress Semiconductor (now part of Infineon Technologies) designs high-performance mixed-signal ICs for embedded control, connectivity, and memory applications.

The CY7C4255 belongs to Cypress's Deep Sync FIFO product line, engineered specifically for deterministic, low-latency data buffering across asynchronous clock domains in test equipment, telecom infrastructure, and industrial automation.

FAQ

What is the function of the VCC/SMODE pin on CY7C4255-10AC?

The VCC/SMODE pin configures synchronization behavior of the Programmable Almost Empty (PAE) and Programmable Almost Full (PAF) flags. When tied to VCC, PAE/PAF operate asynchronously; when tied to VSS, they synchronize to RCLK and WCLK respectively-enabling precise timing alignment in synchronous systems.

Can CY7C4255-10AC be used in single-clock mode?

Yes. The WCLK and RCLK inputs can be connected to the same clock source, and WEN/REN controlled independently to achieve single-clock operation. This configuration simplifies timing analysis while retaining full FIFO functionality including all status flags and retransmit capability.

How does the retransmit (RT) function work in standalone mode?

In standalone mode, pulsing the FL/RT pin low initiates retransmission: the FIFO outputs the most recently read data word on Q0–Q17 during the next valid RCLK edge, regardless of current read pointer position-enabling protocol-level retry without host CPU intervention.

What is the purpose of the center power and ground pins in the 64-pin TQFP package?

The center-placed VCC and GND pins reduce simultaneous switching noise (SSN) by shortening current return paths and improving power distribution uniformity across the die-critical for maintaining signal integrity at 100 MHz operation and minimizing jitter on status flag edges.