The XC3S400-5FT256C is a high-performance Field-Programmable Gate Array (FPGA) from the Xilinx Spartan-3 family, manufactured on advanced 90nm process technology. Designed for cost-sensitive, high-volume applications, this device delivers 400K logic gates, 8,064 logic cells, and a 725MHz internal clock speed — all packed into a compact 256-pin Fine-Pitch Thin Ball Grid Array (FTBGA) package. Whether you’re building embedded systems, digital signal processing (DSP) hardware, or communication interfaces, the XC3S400-5FT256C offers exceptional programmable logic capability at a competitive price point.

For engineers and designers evaluating the full range of programmable logic solutions, explore the complete selection of Xilinx FPGA devices to find the right fit for your project.

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Key Features of the XC3S400-5FT256C

The XC3S400-5FT256C builds on the success of earlier Spartan-IIE family devices, incorporating enhanced logic resources, expanded internal RAM, increased I/O density, and improved clock management — all derived from the Virtex-II platform architecture.

• 400,000 logic gates for complex digital design
• 8,064 logic cells (CLBs) for flexible, scalable functionality
• 725 MHz system clock performance (Speed Grade -5)
• 90nm CMOS process technology
• 1.2V core supply voltage
• 256-pin FTBGA (Fine-Pitch Thin Ball Grid Array) package
• Up to 195 user I/O pins
• 368,640 total RAM bits for on-chip data storage
• Commercial temperature range: 0°C to +85°C
• Compatible with Verilog and VHDL hardware description languages
• Supported by Xilinx ISE Design Suite and Vivado Design Suite

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XC3S400-5FT256C Technical Specifications

Core Electrical & Logic Specifications

Package & Physical Specifications

I/O & Interface Specifications

Environmental & Operating Conditions

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XC3S400-5FT256C Part Number Decoder

Understanding the part number helps you select the exact variant for your design:

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XC3S400-5FT256C Architecture Overview

Configurable Logic Blocks (CLBs)

The XC3S400-5FT256C is organized around 896 Configurable Logic Blocks. Each CLB contains four slices, and each slice houses two 4-input Look-Up Tables (LUTs) along with flip-flops, carry logic, and multiplexers. This architecture allows dense implementation of combinational and sequential logic functions.

Block RAM

On-chip block RAM totaling 368,640 bits provides high-speed, distributed data storage without relying on external memory for smaller datasets. This is particularly valuable in DSP pipelines, FIFOs, and lookup table implementations.

Digital Clock Managers (DCM)

The device includes dedicated DCMs that enable precise clock synthesis, phase shifting, deskewing, and frequency multiplication or division. This ensures reliable timing closure across complex multi-clock domain designs.

Multiplier Blocks

Dedicated 18×18-bit hardware multipliers accelerate arithmetic-intensive applications such as digital filters, fast Fourier transforms (FFTs), and motor control algorithms — without consuming CLB resources.

I/O Blocks (IOBs)

The 195 available user I/O pins support a wide range of single-ended and differential I/O standards, enabling seamless interfacing with memories, processors, ADCs, DACs, and communication controllers.

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XC3S400-5FT256C vs. Other Spartan-3 Variants

The -5FT256C variant is ideal when maximum speed is required within a compact 256-pin BGA footprint for commercial-temperature environments.

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Applications of the XC3S400-5FT256C

The XC3S400-5FT256C is a versatile FPGA suited for a wide range of industries and application types:

Digital Signal Processing (DSP)

Real-time filtering, FFT computation, audio processing, and image processing pipelines benefit from the device’s dedicated multiplier blocks and high-speed clock rates.

Embedded Systems & SoC Design

Custom embedded processors, co-processors, and peripheral controllers can be implemented within the programmable fabric, offering a fully tailored hardware architecture.

Communications & Networking

The XC3S400-5FT256C supports high-speed serial interfaces and can implement Ethernet controllers, PCIe bridges, UART/SPI/I2C bridges, and custom protocol engines.

Industrial Automation & Control

Motor control algorithms, PLC logic, and sensor fusion applications leverage the device’s deterministic timing behavior and robust I/O capabilities.

Consumer Electronics Prototyping

As a cost-effective alternative to mask-programmed ASICs, this FPGA is widely used for rapid prototyping and field-upgradable product designs in consumer electronics.

Test & Measurement Equipment

The flexible logic fabric and fast clock speeds make it suitable for implementing custom test logic, pattern generators, and protocol analyzers.

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Development Tools & Programming Support

The XC3S400-5FT256C is supported by mature and well-documented design environments:

Hardware description languages supported include Verilog, VHDL, and SystemVerilog for design entry.

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Why Choose the XC3S400-5FT256C?

Superior Alternative to ASICs

Unlike mask-programmed ASICs, the XC3S400-5FT256C eliminates high non-recurring engineering (NRE) costs, long fabrication lead times, and design inflexibility. Field reprogramming means design updates never require a hardware revision.

Proven Spartan-3 Platform

The Spartan-3 family is one of Xilinx’s most widely deployed FPGA platforms, backed by an extensive ecosystem of IP cores, reference designs, application notes, and community support.

Best-in-Class Speed Grade

The -5 speed grade represents the fastest commercial timing specification available for the XC3S400 in the FT256 package, making this variant the preferred choice for timing-critical designs.

Compact 256-Pin BGA Footprint

The FTBGA-256 package offers a space-efficient PCB footprint while providing 195 usable I/O pins — a strong density ratio suitable for compact board designs.

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Ordering Information

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Frequently Asked Questions (FAQ)

Q: What programming languages does the XC3S400-5FT256C support?
A: The device supports Verilog, VHDL, and SystemVerilog through Xilinx ISE and compatible third-party synthesis tools.

Q: Can the XC3S400-5FT256C interface with external memory?
A: Yes. Using dedicated memory controller IP cores, it can interface with SDRAM, DDR SDRAM, Flash, and other external memory devices.

Q: What is the difference between the -4 and -5 speed grade?
A: The -5 speed grade offers higher maximum operating frequency (725 MHz vs. 630 MHz for -4), translating to tighter setup and hold times and lower propagation delays throughout the device.

Q: Is the XC3S400-5FT256C RoHS compliant?
A: No, this specific variant is not RoHS compliant. Engineers requiring RoHS-compliant options should consult alternative part numbers within the Spartan-3 family.

Q: What configuration methods are available?
A: The device supports multiple configuration modes including Master Serial, Slave Serial, Master Parallel (SelectMAP), JTAG, and SPI Flash-based boot configuration.