The XC3S400-FG456EGQ is a high-performance, cost-efficient Field-Programmable Gate Array (FPGA) from Xilinx’s Spartan-3 family. Manufactured using advanced 90nm process technology, this device delivers 400,000 system gates and 8,064 logic cells in a compact 456-pin Fine-Pitch Ball Grid Array (FBGA) package. Designed for high-volume, cost-sensitive consumer and industrial applications, the XC3S400-FG456EGQ is an ideal choice for engineers seeking reprogrammable logic with the flexibility to upgrade designs in the field.

As part of the broader Xilinx FPGA portfolio, the XC3S400-FG456EGQ builds on the proven Spartan-IIE architecture while incorporating key enhancements from the Virtex-II platform — delivering more functionality and bandwidth per dollar than ever before.

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XC3S400-FG456EGQ Key Specifications at a Glance

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What Is the XC3S400-FG456EGQ? Product Overview

The XC3S400-FG456EGQ is a member of the Xilinx Spartan-3 FPGA family — one of the most widely deployed programmable logic platforms in the electronics industry. The Spartan-3 generation was specifically engineered to address high-volume, cost-sensitive markets while still delivering robust performance and deep logic integration.

The “XC3S400” portion of the part number indicates a 400K-gate Spartan-3 device. The “FG456” indicates the 456-ball FBGA package. The “E” denotes extended temperature range, and the “GQ” suffix indicates a Pb-free (green) package in tape-and-reel or tray form factor — making the XC3S400-FG456EGQ suitable for environmentally conscious manufacturing processes.

Why Choose the XC3S400-FG456EGQ Over Mask-Programmed ASICs?

The XC3S400-FG456EGQ offers a compelling alternative to traditional mask-programmed ASICs. Key advantages include:

• No high NRE (Non-Recurring Engineering) costs — eliminate expensive mask sets required by ASICs
• Faster time-to-market — prototype and production design in one device
• In-field reprogrammability — update firmware or logic without hardware replacement
• Lower design risk — fix design bugs without spinning a new chip

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XC3S400-FG456EGQ Logic Architecture and Resources

The XC3S400-FG456EGQ is built around five fundamental programmable functional elements that work together to implement complex digital designs.

Configurable Logic Blocks (CLBs)

The device contains 8,064 logic cells organized as Configurable Logic Blocks. Each CLB consists of four slices, with each slice containing two 4-input Look-Up Tables (LUTs) and two flip-flops. This architecture enables efficient implementation of combinational logic, sequential state machines, arithmetic functions, and shift registers.

Block RAM

The XC3S400-FG456EGQ integrates embedded block RAM organized in dual-port 18-Kbit blocks. The two-column RAM architecture provides dedicated memory resources for buffering, FIFOs, lookup tables, and local data storage — all without consuming CLB resources.

Dedicated Multipliers

Each block RAM is paired with a dedicated 18×18-bit hardware multiplier, enabling high-performance DSP functions such as FIR filters, FFTs, and correlation without consuming additional logic fabric.

Digital Clock Managers (DCMs)

The device includes multiple Digital Clock Managers derived from Virtex-II technology. DCMs provide precise clock synthesis, phase shifting, frequency multiplication and division, and spread-spectrum clock generation — critical features for high-speed system designs.

I/O Blocks (IOBs)

The IOBs surround the CLB array and support a wide range of single-ended and differential I/O standards. This flexibility allows the XC3S400-FG456EGQ to interface with virtually any digital logic family or memory device.

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XC3S400-FG456EGQ I/O and Package Information

Supported I/O Standards

The XC3S400-FG456EGQ supports a comprehensive range of I/O voltage standards, making it highly compatible with modern digital systems:

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Electrical Characteristics of the XC3S400-FG456EGQ

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Configuration Modes

The XC3S400-FG456EGQ supports five configuration modes, providing flexible integration options for different system architectures:

Configuration data is stored in robust reprogrammable static CMOS configuration latches (CCLs), which retain their state without refresh — unlike DRAM-based fabrics.

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XC3S400-FG456EGQ Part Number Decoder

Understanding the Xilinx part numbering system helps you select the exact device variant for your application:

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XC3S400-FG456EGQ vs. Related Variants

If you are evaluating the XC3S400-FG456EGQ against similar Spartan-3 devices in the same package, the table below provides a quick comparison:

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Typical Applications for the XC3S400-FG456EGQ

Thanks to its combination of low cost, high logic density, and flexible I/O, the XC3S400-FG456EGQ is used across a wide range of embedded and consumer electronics applications:

• Broadband access equipment — DSL modems, cable modems, FTTH systems
• Home networking — routers, switches, powerline networking
• Display and projection systems — image scaling, timing control, display drivers
• Digital television equipment — MPEG processing, video overlay, transport stream handling
• Industrial control — motor control, sensor fusion, PLC co-processing
• Automotive electronics — ADAS subsystems, in-vehicle networking (with proper environmental qualification)
• Communications infrastructure — protocol bridges, line cards, network interface controllers
• Medical devices — signal acquisition front-ends, digital filtering

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Development Tools for the XC3S400-FG456EGQ

Xilinx (now AMD) provides a full design toolchain for the Spartan-3 family:

Note: For new designs, Xilinx recommends migrating to newer device families (Artix-7, Spartan-7) which are supported by the Vivado Design Suite. However, for existing Spartan-3 production designs, ISE 14.7 remains available and fully supported.

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Ordering Information

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Frequently Asked Questions (FAQ)

What is the XC3S400-FG456EGQ used for?

The XC3S400-FG456EGQ is a general-purpose FPGA used in consumer electronics, industrial automation, communications, and display systems. It is especially well suited to applications requiring programmable digital logic at high volume and low cost.

What is the difference between XC3S400-FG456EGQ and XC3S400-4FG456C?

The primary differences are temperature grade (Extended vs. Commercial), package finish (Pb-free vs. standard), and packaging format (tape-and-reel vs. tray). The core silicon and logic resources are identical.

Is the XC3S400-FG456EGQ RoHS compliant?

The “G” in the part suffix indicates a Pb-free package material. However, customers should verify RoHS compliance documentation directly with their distributor or Xilinx/AMD for production purposes.

What programming software supports the XC3S400-FG456EGQ?

Xilinx ISE Design Suite (version 14.7) is the recommended toolchain for Spartan-3 devices. It supports HDL-based design entry, synthesis, implementation, and JTAG-based configuration of the XC3S400-FG456EGQ.

Can the XC3S400-FG456EGQ replace an ASIC?

Yes. The Spartan-3 family was explicitly designed as a cost-competitive alternative to mask-programmed ASICs, eliminating NRE costs and enabling in-field design updates.