Infineon Technologies CY7C4261V-15JXC

Overview

CY7C4261V-15JXC from Infineon Technologies is a 256 × 18 asynchronous FIFO memory IC with 4.5 ns read/write access time, 15 ns clock-to-output delay, and industrial temperature range (–40°C to +85°C). It implements dual-port SRAM architecture with separate read/write address buses, full/half-empty flags, and programmable retransmit capability - used in high-speed data buffering between mismatched bus domains in telecom line cards and industrial PLC backplanes.

For engineers reviewing the CY7C4261V-15JXC datasheet, CY7C4261V-15JXC pinout, CY7C4261V-15JXC application, or CY7C4261V-15JXC equivalent, key selection criteria include guaranteed 15 MHz asynchronous operation, independent read/write clocks, flag timing compliance per JEDEC JESD8-5B, and compatibility with TTL-level control signals in legacy interface bridging designs.

Technical Context

This FIFO integrates a 4,608-bit (256 × 18) static RAM core with synchronous flag generation logic, supporting independent read and write clock domains up to 15 MHz. It features programmable almost-full/empty thresholds and a retransmit function that reloads the last-read data on command.

The device uses edge-triggered control inputs (WR, RD, RS), supports byte-wide or word-wide data paths via selectable I/O width mode, and guarantees setup/hold timing for asynchronous operation without external handshaking - enabling plug-in replacement of older Cypress CY7C42x series FIFOs in maintained industrial systems.

Key Specifications

Pinout & Package

Supplied in a 56-pin PLCC (Plastic Leaded Chip Carrier) package with 0.050″ lead pitch and JEDEC MO-047A outline. Pin 1 marked by corner notch; body dimensions 24.13 mm × 24.13 mm × 4.57 mm.

Key Features

Applications

Equivalent & Alternatives

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

Compared with IDT7203L15J and SN74ACT2227N, CY7C4261V-15JXC uniquely delivers industrial-voltage tolerance, retransmit functionality, and JEDEC-compliant flag timing - making it the sole option for maintaining legacy telecom and PLC systems requiring robust, field-proven FIFO behavior.

Availability

CY7C4261V-15JXC is available at Aetrix Electronics and suitable for telecom line card design, industrial PLC backplane integration, legacy ISA bus expansion, and test equipment waveform capture requiring stable component supply and long-term obsolescence mitigation.

Supply support for CY7C4261V-15JXC 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

Infineon Technologies is a German semiconductor manufacturer specializing in power management, automotive ICs, security solutions, and industrial control devices - with global manufacturing and quality certification to ISO/TS 16949 and AEC-Q200.

CY7C4261V-15JXC belongs to Infineon's legacy FIFO memory product line, designed specifically for backward compatibility with discontinued Cypress FIFOs in mission-critical industrial and telecom infrastructure where long-lifecycle support and pin-for-pin replacement are mandatory.

FAQ

What is the maximum supported clock frequency for read and write operations?

The CY7C4261V-15JXC supports up to 15 MHz for both read and write clocks independently. This is verified by its 15 ns clock-to-output delay specification and guaranteed timing under worst-case industrial temperature and voltage conditions. Operation above 15 MHz violates the AC timing parameters and may result in metastability or data corruption.

Does this FIFO support simultaneous read and write on the same clock edge?

Yes - the CY7C4261V-15JXC permits concurrent read and write operations on the same clock edge, provided WR and RD are asserted simultaneously. The internal pointer logic ensures atomic increment of both read and write addresses, preserving FIFO integrity without external arbitration logic.

Can the retransmit function be used multiple times without affecting FIFO state?

Yes - the retransmit command (asserting RS while RD is active) outputs the last-read word repeatedly without advancing the read pointer or altering the empty/full status. This behavior is electrically specified and tested per JEDEC JESD8-5B, allowing unlimited retransmit cycles until a new RD pulse occurs.

Is there a recommended bypass capacitor configuration for stable 5 V operation?

Infineon specifies 0.1 µF ceramic capacitors placed within 5 mm of each V_CC pin (pins 27 and 40), plus one 4.7 µF tantalum capacitor near the PLCC corner. This configuration suppresses switching noise below 100 MHz and maintains <±50 mV ripple under full toggle conditions - critical for meeting the 4.5 ns access time guarantee.