Infineon Technologies CY7C425-20JXCT

Overview

CY7C425-20JXCT from Cypress Semiconductor is a 1,024 × 9-bit asynchronous FIFO memory IC used for buffering data between mismatched clock domains or burst-to-continuous data streams. It supports independent 50 MHz read/write operation, features Empty/Full/Half-Flat flags, TTL-compatible I/O, and operates at 5V ±10% over industrial temperature (–40°C to +85°C). It is commonly deployed in serial communication interfaces and digital signal processing pipelines where deterministic latency and overflow/underflow protection are critical.

For engineers reviewing the CY7C425-20JXCT datasheet, CY7C425-20JXCT pinout, CY7C425-20JXCT application, or CY7C425-20JXCT equivalent, key selection criteria include its 1K×9 depth/width configuration, 20 ns access time, standalone retransmit capability, and compatibility with width/depth expansion topologies using XO/HF and FL/RT control signals.

Technical Context

This FIFO implements dual-ported RAM architecture with separate read and write address pointers, enabling true asynchronous operation without internal arbitration. The device uses advanced 0.65-µm P-well CMOS technology, delivering 35 mA typical ICC1 at 20 MHz and >2000 V HBM ESD protection on all pins.

Flag logic generates EF (Empty), FF (Full), and HF (Half Full) outputs synchronized to read/write strobes; HF serves as expansion-out (XO) in depth-expansion mode. Retransmit (RT) enables data replay without external controller intervention when both R and W are high, supporting protocol recovery in UART or packetized link layers.

Key Specifications

Pinout & Package

Package: 28-pin PLCC (Plastic Leaded Chip Carrier), 11.43 mm × 11.43 mm, body height 3.56 mm, lead pitch 1.27 mm. RoHS-compliant, Pb-free finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with IDT7202L15TPG, CY7C425-20JXCT offers integrated retransmit and PLCC packaging for socketed industrial designs, while the ON Semiconductor part is functionally incompatible and must be excluded from FIFO-based designs.

Availability

CY7C425-20JXCT is available at Aetrix Electronics and suitable for industrial serial gateways, legacy bus interfacing, motor drive feedback loops, and digital audio sample buffering requiring stable component supply across extended product lifecycles.

Supply support for CY7C425-20JXCT 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 (PSoC), memory, and interface solutions for industrial, automotive, and consumer applications.

The CY7C4xx FIFO family was designed specifically for deterministic, low-latency data buffering in mixed-signal and real-time control systems where software-managed queues introduce unacceptable jitter or overhead.

FAQ

What is the maximum operating frequency for simultaneous read and write operations?

The CY7C425-20JXCT supports independent 50 MHz read and write clocks, verified by t_RC = 20 ns and t_WC = 20 ns specifications. This allows concurrent full-speed data ingestion and egress without arbitration delay, provided setup/hold times (t_SD = 6 ns, t_HD = 0 ns) are met at the system level.

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

In standalone mode, pulling FL/RT LOW while both R and W are HIGH activates retransmit: the FIFO repeats output of previously read data starting from the current read pointer position. Data is accessed via standard R strobes, and the function remains active until FL/RT returns HIGH, enabling protocol-level frame retransmission without host CPU intervention.

Can CY7C425-20JXCT be used in depth-expansion configurations with other CY7C4xx devices?

Yes - the device supports depth expansion using HF/XO and MR pins. In this mode, HF becomes XO (expansion-out), signaling the next FIFO stage to activate. Propagation delays are minimized because control signals fan out in parallel rather than daisy-chained, preserving the 50 MHz throughput across stacked devices.

Is the CY7C425-20JXCT pinout compatible with CY7C421 or CY7C429?

No - although all share the same 28-pin PLCC footprint and core signal names (R, W, D0–D8, Q0–Q8), pin assignments differ significantly. For example, CY7C421 places EF on pin 25 while CY7C425-20JXCT places EF on pin 24; CY7C429 relocates MR and XO/HF to different pins. Direct substitution requires PCB redesign.