Infineon Technologies CY7C425-10AXC

Overview

CY7C425-10AXC from Cypress Semiconductor is a 1,024-word × 9-bit asynchronous FIFO memory IC used for buffering data between mismatched clock domains in communication interfaces and digital subsystems. It supports independent 50 MHz read/write operations, features Empty (EF), Full (FF), and Half Full (HF) flags, and operates at 5V ±10% over the commercial temperature range (0°C to +70°C). Its dual-ported RAM architecture enables seamless data flow in UART bridges, video frame buffers, and protocol translators.

For engineers reviewing the CY7C425-10AXC datasheet, CY7C425-10AXC pinout, CY7C425-10AXC application, or CY7C425-10AXC equivalent, key selection criteria include access time (10 ns), standalone retransmit capability, HF flag behavior in width expansion, and compatibility with IDT7202/AM7202 for legacy system upgrades.

Technical Context

The CY7C425-10AXC implements an asynchronous FIFO using dual-ported static RAM cells with independent read and write address pointers. Control logic generates EF, FF, and HF flags based on pointer comparison, with HF valid only in standalone or width-expansion configurations - in depth expansion, the same pin serves as Expansion Out (XO).

Retransmit functionality is triggered by a LOW on FL/RT while R and W are HIGH, enabling deterministic data replay without external sequencing. The device uses 0.65-µm P-well CMOS technology, with input ESD protection >2000 V and latch-up immunity ensured by guard-ring layout.

Key Specifications

Pinout & Package

Package: 44-pin Plastic Leaded Chip Carrier (PLCC), 7 mm × 7 mm body, JEDEC MS-026AC compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with IDT7202LA-10JGI and AM7202-10JC, the CY7C425-10AXC uniquely combines TTL compatibility, hardware retransmit, Pb-free packaging, and industrial temperature support-making it the sole choice for robust, drop-in replacements in legacy industrial communications hardware.

Availability

CY7C425-10AXC is available at Aetrix Electronics and suitable for UART bridge buffering, video frame synchronization, and protocol translation gateways requiring stable component supply across long-lifecycle industrial programs.

Supply support for CY7C425-10AXC 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-reliability memory and programmable logic solutions for industrial, automotive, and communications infrastructure.

The CY7C4xx FIFO family targets legacy system interoperability-delivering pin- and function-compatible replacements for aging first-generation asynchronous FIFOs with enhanced ESD tolerance and expanded temperature support.

FAQ

What is the function of the FL/RT pin on CY7C425-10AXC?

The FL/RT pin serves a dual role: when HIGH, it functions as the Empty Flag (EF); when pulled LOW while R and W are HIGH, it activates retransmit mode-causing the FIFO to replay the oldest unread data word on Q0–Q8. This enables hardware-level error recovery without CPU intervention, critical in deterministic serial protocols like MIL-STD-1553.

Can CY7C425-10AXC be used in depth-expansion configurations?

Yes-depth expansion is supported via XI (Expansion In), XO/HF (Expansion Out), and FL/RT pins. In this mode, XO/HF becomes an active-high expansion trigger signal that enables the next FIFO in the chain. The CY7C425-10AXC's parallel steering architecture ensures no added propagation delay, preserving the full 50 MHz throughput across stacked devices.

Does CY7C425-10AXC require external pull-up resistors on its flag outputs?

Yes-EF, FF, and HF are open-drain outputs and require external 4.7 kΩ pull-up resistors to V_CC. This design allows wired-OR connection of multiple FIFO flags onto a shared interrupt line, simplifying status monitoring in multi-FIFO systems such as video pipeline buffers or redundant communication channels.

How does the Half Full (HF) flag behave in standalone versus width-expansion modes?

In standalone and width-expansion modes, HF asserts HIGH when exactly 512 words (half of 1,024) are stored. In depth-expansion mode, the same pin becomes Expansion Out (XO), asserting HIGH to signal the next FIFO in the stack to begin accepting data-ensuring seamless depth scaling without flag conflict or external logic.