The XC3S4000-4FG676C is a high-performance, cost-effective Field-Programmable Gate Array (FPGA) from Xilinx’s Spartan®-3 family. Manufactured on advanced 90nm process technology, this device delivers 4 million system gates and 62,208 logic cells in a compact 676-pin Fine-pitch Ball Grid Array (FBGA) package. Whether you are designing for broadband access, digital television, home networking, or industrial control systems, the XC3S4000-4FG676C offers the logic density, I/O flexibility, and performance that demanding applications require.

As part of the broader Xilinx FPGA product line, the XC3S4000-4FG676C combines proven programmable logic technology with exceptional value — making it a preferred choice for engineers worldwide.

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XC3S4000-4FG676C Key Specifications at a Glance

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What Is the XC3S4000-4FG676C? Overview of the Spartan-3 FPGA

The XC3S4000-4FG676C belongs to Xilinx’s eight-member Spartan-3 FPGA family, which spans logic densities from 50,000 to 5,000,000 system gates. This family was purpose-built to serve high-volume, cost-sensitive consumer and industrial electronics applications, bridging the gap between low-cost programmable logic and high-performance ASIC-class designs.

The Spartan-3 platform builds directly on the Virtex®-II architecture, inheriting several advanced features while optimizing for price-per-logic-unit. The result is a device that delivers substantially more functionality and I/O bandwidth per dollar compared to its predecessors.

Part Number Decoding: Understanding XC3S4000-4FG676C

Understanding the part number helps engineers confirm they have the right device:

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XC3S4000-4FG676C Logic Resources and Architecture

The internal architecture of the XC3S4000-4FG676C is designed around five fundamental programmable functional elements that work together to deliver flexible, high-density logic.

Configurable Logic Blocks (CLBs)

The device contains 6,912 CLBs, each composed of four slices. Each slice provides two 4-input Look-Up Tables (LUTs), two storage elements (flip-flops or latches), and carry/arithmetic logic — giving designers fine-grained control over both combinational and sequential logic implementation.

Block RAM (BRAM)

The on-chip Block RAM enables efficient storage of lookup tables, FIFO buffers, packet buffers, and embedded data arrays — reducing external memory requirements and improving system performance.

Dedicated Multipliers

The XC3S4000-4FG676C includes 96 dedicated 18×18-bit hardware multipliers. These multipliers accelerate DSP functions such as digital filtering, FFT computation, and signal processing without consuming CLB resources.

Digital Clock Managers (DCMs)

The four integrated DCMs provide clean, phase-aligned clocking across the device. Engineers can multiply, divide, and phase-shift clock signals — essential for multi-clock-domain designs and high-speed serial interfaces.

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I/O Capabilities and Supported Standards

With 489 user I/O pins in the 676-pin FBGA package, the XC3S4000-4FG676C supports a broad range of single-ended and differential I/O standards.

Supported I/O Standards

The maximum I/O output drive strength is 12 mA, with configurable slew rates for both fast and slow edge-rate control — important for managing signal integrity and EMI in high-density PCB designs.

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Power Supply Requirements

Proper power delivery is critical for reliable FPGA operation. The XC3S4000-4FG676C requires two primary supply rails:

The multi-voltage I/O architecture allows each I/O bank to be powered independently, making it straightforward to interface with 1.8V, 2.5V, or 3.3V peripherals within the same design.

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Package and Physical Characteristics

676-Pin FBGA Package Details

The FBGA package is well-suited for automated SMT assembly and reflow soldering processes. The 1.0mm ball pitch is compatible with standard PCB design rules for via-in-pad and escape routing techniques.

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Programming and Configuration

Configuration Modes

The XC3S4000-4FG676C supports multiple configuration modes to suit different system architectures:

Configuration data is stored externally and loaded into the FPGA at power-up or on demand. The JTAG interface supports both configuration and in-system debugging through Xilinx’s ChipScope Pro logic analyzer tool.

Development Tools

The XC3S4000-4FG676C is supported by the following Xilinx design tools:

• ISE Design Suite — The primary design environment for Spartan-3-era FPGAs, supporting VHDL, Verilog, and schematic entry
• XST (Xilinx Synthesis Technology) — Integrated synthesis engine
• ChipScope Pro — In-system logic analysis and debugging
• iMPACT — Device programming and configuration utility

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Applications: Where the XC3S4000-4FG676C Excels

The XC3S4000-4FG676C is optimized for applications that demand high logic density, broad I/O compatibility, and cost efficiency. Typical use cases include:

Consumer Electronics

• Digital Television (DTV) signal processing
• DVD and Blu-ray player controllers
• Set-top box logic and interface management
• Home networking equipment (routers, switches)

Communications and Networking

• Broadband access infrastructure (DSL, cable)
• Line card and framer logic
• Protocol bridging and conversion (PCI, USB, Ethernet)
• Wireless baseband processing

Industrial and Embedded Systems

• Motor control and motion control systems
• Industrial Ethernet interfaces
• Data acquisition front-ends
• Test and measurement instrumentation

Imaging and Display

• Display controller and scaler logic
• Projection system signal management
• Machine vision pre-processing pipelines

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XC3S4000-4FG676C vs. Other Spartan-3 Variants

The Spartan-3 family offers multiple density options. Here is how the XC3S4000-4FG676C compares to closely related parts:

The -4 speed grade in the XC3S4000-4FG676C denotes a standard commercial speed bin with a maximum operating frequency of 630 MHz, which suits the majority of design requirements. For timing-critical paths requiring higher clock speeds, the -5 grade variant offers up to 725 MHz.

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Advantages Over Traditional ASICs

One of the defining strengths of the XC3S4000-4FG676C — and all Spartan-3 FPGAs — is their programmability advantage over mask-programmed ASICs:

• No NRE (Non-Recurring Engineering) costs — Eliminates expensive mask tooling charges
• Faster time-to-market — Design iterations in hours, not months
• In-field reconfigurability — Update firmware and logic without PCB rework or hardware replacement
• Lower risk — Bugs and design changes are correctable post-deployment
• Scalable production — No minimum order quantities tied to ASIC economics

These advantages make the XC3S4000-4FG676C an excellent choice for products with evolving firmware requirements, short product cycles, or low-to-mid production volumes.

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Ordering Information

For volume pricing, lead time inquiries, or RoHS-compliant alternatives, contact your authorized Xilinx distributor or AMD’s official sales channel.

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Frequently Asked Questions (FAQ)

Q: What is the XC3S4000-4FG676C? The XC3S4000-4FG676C is a Xilinx Spartan-3 FPGA with 4 million system gates, 62,208 logic cells, and a 676-pin FBGA package. It operates at up to 630 MHz on a 1.2V core supply.

Q: What design tools support the XC3S4000-4FG676C? The XC3S4000-4FG676C is fully supported by Xilinx ISE Design Suite, including XST synthesis, ISim simulation, and ChipScope Pro for in-system debug. Xilinx Vivado does not support Spartan-3; ISE 14.7 is the recommended tool.

Q: What is the difference between XC3S4000-4FG676C and XC3S4000-5FG676C? The only difference is the speed grade. The -4 variant runs at up to 630 MHz while the -5 variant achieves up to 725 MHz. Both share identical logic resources, package, and pinout.

Q: Is the XC3S4000-4FG676C RoHS compliant? The standard XC3S4000-4FG676C is not RoHS compliant. Engineers requiring lead-free, RoHS-compliant parts should inquire with distributors about the appropriate Pb-free variant.

Q: What package does the XC3S4000-4FG676C use? It uses a 676-pin Fine-pitch Ball Grid Array (FBGA) measuring 27mm × 27mm with 1.0mm ball pitch, suitable for standard SMT assembly and reflow soldering.