Infineon Technologies CY7C4251-15AXCT

Overview

CY7C4251-15AXCT from Cypress Semiconductor is an 8K × 9-bit synchronous FIFO memory with TTL-compatible interfaces, 10 ns read/write cycle time, programmable Almost Empty/Almost Full flags, and dual-clock asynchronous operation. It serves as a high-speed data buffer in communication gateways, multiprocessor interconnects, and real-time data acquisition systems where deterministic latency and depth expansion are required.

For engineers reviewing the CY7C4251-15AXCT datasheet, CY7C4251-15AXCT pinout, CY7C4251-15AXCT application, or CY7C4251-15AXCT equivalent, key selection criteria include its 8K-depth buffering capability, 100 MHz clock support, programmable flag offsets, independent RCLK/WCLK domains, and TQFP-32 package compatibility with industrial temperature range operation.

Technical Context

The CY7C4251-15AXCT implements a dual-port SRAM-based FIFO architecture with separate read and write pointer logic, synchronized status flags (EF/FF updated on RCLK/WCLK respectively), and programmable PAE/PAF registers accessible via WEN2/LD-controlled load mode. Its 9-bit data path supports width expansion while maintaining pin compatibility across the CY7C42X1 family.

Flag behavior is strictly clock-domain isolated: EF and PAE respond only to RCLK edges; FF and PAF respond only to WCLK edges. The device requires RS assertion at power-up to initialize pointers and flags, and supports both single-clock (RCLK = WCLK) and fully asynchronous configurations with tENS setup timing for REN/WEN signals.

Key Specifications

Pinout & Package

The CY7C4251-15AXCT is housed in a 32-pin Thin Quad Flat Package (TQFP) with center power (VCC) and ground (GND) pins to minimize switching noise. Pin layout follows standard FIFO I/O grouping: data inputs D0–D8 (pins 1–9), data outputs Q0–Q8 (pins 25–32), and dedicated clock/enable/control pins distributed across remaining positions.

Key Features

Applications

Equivalent & Alternatives

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

Compared with IDT72251L15PG and NB3N502M, the CY7C4251-15AXCT uniquely combines 8K depth, synchronous flag timing, and full width/depth expansion capability - making it optimal for deterministic, scalable buffering in industrial and communications infrastructure.

Availability

CY7C4251-15AXCT is available at Aetrix Electronics and suitable for industrial data acquisition, communications protocol bridging, multiprocessor interconnects, and real-time video buffering requiring stable component supply across extended product lifecycles.

Supply support for CY7C4251-15AXCT 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) is a fabless semiconductor company specializing in programmable system-on-chip solutions, memory, and interface ICs for industrial, automotive, and consumer applications.

The CY7C42X1 FIFO family was designed specifically for high-reliability, low-latency data buffering in mixed-clock-domain systems - emphasizing deterministic flag timing, expandability, and industrial temperature operation.

FAQ

What is the default Almost Empty offset value for CY7C4251-15AXCT?

The default Almost Empty offset is 7 words, stored across the empty offset LSB and MSB registers. This value is factory-programmed and applies immediately after reset unless overwritten via WEN2/LD load mode. The offset determines the FIFO word count threshold at which the PAE flag asserts LOW, enabling early flow-control signaling before actual emptiness.

Can CY7C4251-15AXCT operate with RCLK and WCLK tied together?

Yes - tying RCLK and WCLK enables single-clock synchronous operation, simplifying timing analysis and reducing board routing complexity. In this mode, all read/write operations and flag updates occur on the same clock edge, preserving data integrity while eliminating clock-domain crossing considerations for basic buffering use cases.

How does the WEN2/LD pin determine FIFO configuration at power-up?

At reset (RS assertion), the logic state of WEN2/LD sets the operational mode: HIGH configures dual write enables for depth expansion; LOW configures programmable flag mode where WEN2/LD becomes the load control for flag-offset registers. This configuration is latched and remains fixed until next reset - no runtime reconfiguration is supported.

Is CY7C4251-15AXCT RoHS compliant and Pb-free?

Yes - the "XCT" suffix denotes a lead-free, RoHS-compliant 32-pin TQFP package. Cypress confirmed Pb-free construction in Document #38-06016 Rev. *D, with JEDEC-standard reflow profiles and moisture sensitivity level (MSL) 3 rating - suitable for standard surface-mount assembly processes without special handling requirements.