The XC4085XLA-HQ304 is a high-performance, high-capacity Field Programmable Gate Array (FPGA) from Xilinx’s XC4000XLA family, now under AMD. Housed in a compact 304-pin HQFP package, this device delivers 85,000 usable logic gates and 7,448 configurable logic cells, making it an outstanding choice for complex digital design in industrial, enterprise, and communications applications.

Whether you are sourcing this part for legacy system maintenance or a high-density embedded design, this guide covers everything you need to know: key specifications, pin configuration, electrical characteristics, application use cases, and ordering information.

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What Is the XC4085XLA-HQ304?

The XC4085XLA-HQ304 is a member of the Xilinx FPGA XC4000XLA/XV Series — a family of FPGAs engineered for fully automated implementation of complex, high-density digital logic designs. Manufactured using advanced 0.35 µm CMOS process technology and operating on a 3.3V supply, this device is purpose-built for designs that demand architectural versatility, abundant routing resources, and speed-optimized logic.

The “HQ304” suffix identifies the 304-pin Plastic Quad Flat Pack (HQFP) package. The part is also referenced under the AMD/Xilinx catalog as XC4085XLA-08HQ304I (industrial temperature grade).

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XC4085XLA-HQ304 Key Specifications at a Glance

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XC4085XLA-HQ304 Detailed Electrical Characteristics

Understanding the electrical parameters is critical for correct integration. The table below summarizes the key electrical characteristics for the XC4085XLA series in the HQ304 package.

Note: Always consult the official Xilinx XC4000XLA/XV datasheet for the most current electrical specifications and timing parameters.

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Package & Pin Configuration: 304-Pin HQFP

The HQ304 package refers to the 304-pin High-density Quad Flat Pack (HQFP), a surface-mount package widely used in high pin-count FPGA applications.

The 304-pin HQFP package provides a high I/O count in a manageable footprint, making it suitable for designs that interface with multiple buses, peripherals, or memory devices on a single PCB.

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Part Number Decoder: Understanding XC4085XLA-HQ304

Xilinx part numbers follow a structured naming convention. Here is how to read the XC4085XLA-HQ304 designation:

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XC4085XLA Architecture: Inside the XC4000XLA Family

Configurable Logic Blocks (CLBs)

The XC4085XLA is built around an array of Configurable Logic Blocks (CLBs). Each CLB contains look-up tables (LUTs), flip-flops, and carry-chain logic that enable fast, flexible implementation of both combinational and sequential circuits.

FastCLK Clock Buffers

The XLA/XV devices feature dedicated FastCLK clock buffers located on each side of the die. These buffers deliver a fast clock signal — typically less than 1.5 ns of clock delay — to all I/O Blocks (IOBs) within their respective octant. This architecture enables reliable high-frequency synchronous designs.

Global Clock Distribution

Up to eight global clock signals are supported through a dedicated low-skew global clock network. The BUFGE (Global Early) buffers (#1, #2, #5, #6) can also provide fast clock routing to IOBs, complementing the FastCLK buffers.

I/O Blocks (IOBs) and Signalling

The XC4085XLA supports multiple I/O signalling standards through its configurable IOBs. Because XLA devices use a single 3.3V VCC supply (instead of separate VCCIO and VCCINT), all standard I/O signalling environments supported by the XC4000XLA family remain available.

Routing Resources

Abundant routing resources — including local, long-line, and dedicated carry-chain interconnects — ensure that complex designs achieve predictable and repeatable timing closure.

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Speed Grade Comparison for XC4085XLA – HQ304 Package

The XC4085XLA-HQ304 is available in multiple speed grades. Faster speed grades (-07) offer higher maximum frequencies; slower grades (-09) typically carry lower costs.

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Applications: Where Is the XC4085XLA-HQ304 Used?

The XC4085XLA-HQ304 is deployed across a broad range of industries and system types:

Industrial & Automation

• Electronic Point of Sale (EPOS) systems
• Industrial machine control and automation
• Programmable logic controllers (PLCs)

Enterprise & Data Center

• Enterprise computing infrastructure
• Data center switching and routing hardware
• High-throughput signal processing

Automotive Electronics

• Advanced Driver Assistance Systems (ADAS)
• Automotive body electronics and lighting control
• In-vehicle infotainment and cluster displays

Communications

• Datacom modules and line cards
• Protocol bridging and packet processing
• Base station signal processing

Consumer & Personal Electronics

• Gaming hardware platforms
• Connected peripherals and printers
• Audio/video processing equipment

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XC4085XLA-HQ304 vs. Related Part Numbers

Engineers working with legacy systems frequently encounter multiple suffix variations. The table below clarifies the differences:

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Design Tools & Software Support

The XC4085XLA is supported by legacy Xilinx development environments. Engineers maintaining or migrating designs should be aware of the following toolchain options:

Migration Note: Xilinx’s Vivado Design Suite does not support XC4000XLA devices. Use the legacy ISE toolchain for synthesis, implementation, and bitstream generation.

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Configuration & Programming

The XC4085XLA supports several configuration modes:

• Master Serial – External serial PROM drives the device
• Slave Serial – FPGA is driven by an external controller
• Slave Parallel (SelectMAP) – High-speed parallel configuration
• Pseudo Daisy Chain – Multiple devices configured from a single PROM stream

The PROGRAM pin can initiate reconfiguration by pulling it Low, or by cycling VCC. In daisy-chain configurations, CS1 management is critical: CS1 must remain High throughout configuration data stream loading.

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Ordering Information

Important: This part is classified as obsolete / end-of-life. Engineers are advised to audit existing inventory levels, consider last-time-buy orders, and evaluate migration paths to current Xilinx/AMD FPGA families (e.g., Artix-7, Kintex-7) for new designs.

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Frequently Asked Questions (FAQ)

What is the XC4085XLA-HQ304?

The XC4085XLA-HQ304 is a Xilinx XC4000XLA family FPGA with 85,000 logic gates, 7,448 logic cells, and a 304-pin HQFP package, operating at 3.3V with up to 256 user I/O pins.

What is the difference between the “C” and “I” suffix?

The C suffix denotes a Commercial temperature range (0°C to +85°C junction temperature). The I suffix denotes an Industrial temperature range (−40°C to +100°C), making it suitable for harsher operating environments.

Is the XC4085XLA-HQ304 still in production?

No. This part is classified as obsolete by AMD/Xilinx. It is available through authorized distributors and specialty component brokers as remaining inventory.

What software do I need to program the XC4085XLA?

You will need the legacy Xilinx ISE Design Suite. Vivado does not support XC4000-series devices.

What are common alternatives to the XC4085XLA?

For new designs, Xilinx Artix-7 or Spartan-7 FPGAs offer higher performance, lower power, and active support. Direct pin-compatible replacements do not exist due to the legacy package type.

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Summary

The XC4085XLA-HQ304 remains a capable and well-proven FPGA for engineers supporting legacy systems in industrial, enterprise, automotive, and communications domains. Its 85K-gate density, 256 user I/Os, 3.3V operation, and proven XC4000XLA architecture make it a reliable solution for designs that cannot yet migrate to modern FPGA platforms.

For procurement, technical support, or migration guidance on Xilinx and AMD FPGA solutions, consult your authorized distributor or visit the official AMD/Xilinx product resource portal.