Infineon Technologies CY7C421-10JXCT

Overview

CY7C421-10JXCT from Cypress Semiconductor is a 512 × 9-bit asynchronous FIFO memory IC with dual-port RAM architecture, 50 MHz max read/write throughput, TTL-compatible I/O, and independent full/empty/half-full flag outputs. It operates at 5 V ±10%, supports standalone and width/depth expansion, and is used in data buffering between mismatched clock domains in industrial communication interfaces.

For engineers reviewing the CY7C421-10JXCT datasheet, CY7C421-10JXCT pinout, CY7C421-10JXCT application, or CY7C421-10JXCT equivalent, key selection criteria include access time (10 ns), power consumption (35 mA at 20 MHz), retransmit capability, and PLCC-32 package compatibility with IDT7201 and AM7201.

Technical Context

This FIFO implements asynchronous read and write operations using separate R and W control signals, with no shared clock dependency. Its dual-ported RAM cell enables concurrent read/write at up to 50 MHz, while flags (EF, FF, HF) are generated directly from internal pointer comparison logic without external timing constraints.

The device supports three operational modes: standalone, width expansion (via D0–D8 and Q0–Q8 steering), and depth expansion (using XO/XI pins). In depth expansion, the HF pin functions as expansion out (XO), propagating activation to cascaded FIFOs without serial delay accumulation.

Key Specifications

Pinout & Package

Package: 32-pin Plastic Leaded Chip Carrier (PLCC), 11.43 mm × 11.43 mm, JEDEC MS-026AC compliant, lead-free (Pb-free) option available.

Key Features

Applications

Equivalent & Alternatives

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

Compared with IDT7201L10TPG and AM7201-10JC, CY7C421-10JXCT uniquely integrates retransmit control and Pb-free compliance while maintaining identical timing and footprint-making it optimal for new designs requiring protocol resilience and environmental compliance.

Availability

CY7C421-10JXCT is available at Aetrix Electronics and suitable for industrial serial bridges, legacy bus interface adapters, avionics data recorders, and military radio modems requiring stable component supply across extended temperature ranges (–40°C to +85°C).

Supply support for CY7C421-10JXCT 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 U.S.-based semiconductor company specializing in programmable systems-on-chip, memory, and interface solutions for industrial, automotive, and aerospace markets.

CY7C4xx FIFO family was designed specifically for high-reliability, asynchronous data buffering in mixed-clock-domain systems where deterministic latency and hardware flow control are mandatory.

FAQ

What is the maximum operating temperature range for CY7C421-10JXCT?

The CY7C421-10JXCT is rated for industrial temperature operation from –40°C to +85°C. This range is validated per the device's operating specifications table and applies under 5 V ±10% supply conditions with all inputs meeting VIH/VIL thresholds. Thermal derating is not required within this ambient range.

Does CY7C421-10JXCT support depth expansion with other CY7C4xx devices?

Yes, CY7C421-10JXCT supports depth expansion using XI (expansion in), XO (expansion out), and XA (expansion acknowledge) pins. When cascaded, the HF pin becomes XO to activate the next FIFO stage, and propagation delays are minimized because control signals fan out in parallel rather than serially.

Can the retransmit (RT) function operate while the FIFO is being written to?

No. During retransmit, both R and W must be held HIGH to freeze pointer movement; RT then causes the FIFO to replay data from the oldest entry. Concurrent write operations are blocked until RT is deasserted and normal R/W sequencing resumes.

Is CY7C421-10JXCT pin-compatible with CY7C425-10JXCT?

No. Although both are in the CY7C4xx FIFO family and share the same PLCC-32 package, CY7C425-10JXCT is a 1K × 9 device with different internal pointer logic and flag timing. Pin assignments for D/Q buses and controls are identical, but depth-dependent timing parameters (e.g., tREF, tWFF) differ and are not interoperable in drop-in replacement.