The XC3S4000-4FGG676I is a high-density, industrial-grade Field Programmable Gate Array (FPGA) from AMD Xilinx’s Spartan-3 family. Designed for cost-sensitive, high-volume applications, this device offers 4 million system gates, a robust 676-pin FBGA package, and an extended industrial temperature range — making it one of the most versatile Xilinx FPGA solutions available for embedded, communications, and industrial designs.

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XC3S4000-4FGG676I Key Specifications at a Glance

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What Is the XC3S4000-4FGG676I?

The XC3S4000-4FGG676I belongs to Xilinx’s Spartan-3 generation, a family purpose-built to deliver maximum logic density at the lowest possible cost per gate. With 4 million system gates and 62,208 logic cells, this FPGA is well suited for complex digital designs that demand substantial programmable logic without the premium pricing of higher-end families like Virtex or Kintex.

The “4” in the part number denotes the speed grade — a slower, more power-efficient variant compared to -5. The “FGG676” indicates the Fine-Pitch Ball Grid Array footprint with 676 solder balls, and the trailing “I” confirms the industrial temperature range of -40°C to 100°C, making it suitable for harsh environments such as automotive test equipment, industrial control systems, and outdoor communication infrastructure.

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XC3S4000-4FGG676I Architecture and Logic Resources

Configurable Logic Blocks (CLBs)

The Spartan-3 CLB architecture is organized into slices, each containing two look-up tables (LUTs) and two flip-flops. The XC3S4000 provides:

Each LUT can be configured as a 16×1-bit synchronous RAM or 16-bit shift register, enabling efficient implementation of small FIFOs and delay lines without consuming dedicated block RAM resources.

Block RAM (BRAM)

The device includes 96 dedicated block RAM tiles, each offering 18 Kbits of true dual-port memory, yielding a total of 1,728 Kbits (216 Kbytes) of on-chip BRAM. These resources can be configured as single-port or dual-port memories with independent read/write widths of up to 18 bits.

DSP and Hardware Multipliers

The 96 dedicated multiplier blocks enable efficient digital signal processing (DSP) pipelines for applications including FIR/IIR filters, FFT computation, and fixed-point arithmetic, all without consuming CLB fabric.

Digital Clock Managers (DCMs)

Four integrated DCMs provide:

• Clock frequency synthesis and multiplication/division
• Phase shifting (fine and coarse)
• Clock deskew and duty cycle correction
• Spread-spectrum clock support

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XC3S4000-4FGG676I Pin and Package Details

FGG676 Package Overview

I/O Bank and Voltage Flexibility

The 489 user I/Os are organized across 8 independent I/O banks, each supporting a separate VCCO voltage. This architecture enables simultaneous interfacing to multiple voltage-level logic buses in a single FPGA design.

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Power Supply Requirements

The separate VCCAUX supply powers the DCMs and digitally controlled impedance (DCI) circuitry, isolating sensitive analog resources from noisy digital switching on the core supply.

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Industrial Temperature Grade: Why It Matters

The suffix “I” in XC3S4000-4FGG676I designates the industrial temperature variant, rated from -40°C to +100°C junction temperature. This contrasts with the commercial grade variant (suffix “C”), which is rated only for 0°C to 85°C.

Industrial-grade FPGAs are screened and characterized across the full temperature range, making them the correct choice for:

• Factory automation and programmable logic controllers (PLCs)
• Military and defense test equipment
• Automotive electronics and telematics
• Outdoor telecom infrastructure
• Medical imaging systems

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XC3S4000-4FGG676I Configuration and Programming

The XC3S4000 supports multiple configuration modes, allowing designers flexibility in how the FPGA loads its bitstream at power-up:

Configuration data is stored externally in a compatible SPI or parallel NOR flash device (e.g., Xilinx Platform Flash XCF-series or standard SPI NOR). The JTAG interface supports both in-system configuration and boundary-scan testing.

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Typical Applications for the XC3S4000-4FGG676I

The combination of high logic density, industrial temperature tolerance, rich I/O standards support, and onboard DSP resources makes the XC3S4000-4FGG676I well suited for:

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Comparison: XC3S4000 vs. Nearby Spartan-3 Devices

The XC3S4000 occupies the second-largest density tier in the Spartan-3 family, delivering nearly double the resources of the XC3S2000 while remaining in a manageable 676-ball package.

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Ordering Information

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Design Resources and Support

Designers working with the XC3S4000-4FGG676I have access to the full Xilinx ISE Design Suite (now archived but still supported for legacy Spartan-3 projects), as well as a comprehensive set of reference designs, IP cores, and application notes covering:

• MIG (Memory Interface Generator) for DDR/SDRAM interfaces
• Tri-Mode Ethernet MAC reference designs
• PCI and PCI-X interface IP
• Soft processor cores (MicroBlaze)
• ChipScope Pro in-system logic analysis

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Frequently Asked Questions

Q: Is the XC3S4000-4FGG676I pin-compatible with the XC3S4000-4FGG676C? Yes. The “I” (industrial) and “C” (commercial) variants share the same FGG676 pinout. Swapping between them requires no PCB changes, only a firmware/timing re-validation at the extended temperature extremes.

Q: What software supports this device? The XC3S4000-4FGG676I is supported by Xilinx ISE Design Suite 14.7 (the final ISE release). Vivado does not support Spartan-3 devices.

Q: Can this FPGA run a soft processor? Yes. The MicroBlaze soft processor from Xilinx is well-supported on this device, and the available block RAM and logic resources are sufficient to implement a fully functional embedded processor subsystem including UART, SPI, and GPIO peripherals.

Q: What external flash is compatible for configuration? Common choices include the Xilinx XCF08P/XCF16P Platform Flash devices and standard SPI NOR flash from manufacturers such as Micron, Winbond, or Spansion in the 4Mbit to 32Mbit range.