Meta Description: The XC3S4000-5FG900C is a Xilinx Spartan-3 FPGA with 4 million system gates, 900-pin FBGA package, 1.2V core voltage, and 90nm technology. Read full specs, features, and applications.

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The XC3S4000-5FG900C is a high-performance, cost-effective Field-Programmable Gate Array (FPGA) from Xilinx’s Spartan-3 family. Designed for high-volume, cost-sensitive applications, this device offers 4 million system gates in a compact 900-pin Fine-pitch Ball Grid Array (FBGA) package. Whether you are working on broadband access, home networking, display/projection systems, or digital television equipment, the XC3S4000-5FG900C delivers the logic density, I/O flexibility, and performance your design demands.

If you are looking for a reliable and field-upgradable alternative to mask-programmed ASICs, exploring Xilinx FPGA solutions like the XC3S4000-5FG900C is the right starting point.

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What Is the XC3S4000-5FG900C?

The XC3S4000-5FG900C is part of Xilinx’s eight-member Spartan-3 FPGA family, which covers densities ranging from 50,000 to 5,000,000 system gates. This specific model sits at the upper end of the family with 4,000,000 system gates, making it one of the most capable devices in the Spartan-3 lineup. Built on 90nm process technology and powered by a 1.2V core voltage, it builds upon the success of the earlier Spartan-IIE family with increased logic resources, larger internal RAM capacity, more I/Os, and improved clock management.

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XC3S4000-5FG900C Key Specifications

General Specifications

Logic & Memory Specifications

Performance & Electrical Specifications

Package & Pin Specifications

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XC3S4000-5FG900C Part Number Decoder

Understanding the part number helps engineers quickly identify the device variant:

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XC3S4000-5FG900C Architecture Overview

Configurable Logic Blocks (CLBs)

The XC3S4000-5FG900C contains 6,912 CLBs, each consisting of four slices. Every slice includes two 4-input Look-Up Tables (LUTs), flip-flops, carry logic, and arithmetic resources. This architecture gives designers maximum flexibility for implementing combinational and sequential logic.

Block RAM

With 1,769,472 bits (216 kB) of embedded block RAM, the XC3S4000-5FG900C supports on-chip data buffering, FIFO queues, and local memory requirements for complex designs. Block RAMs are dual-port and configurable in width and depth.

Digital Clock Managers (DCMs)

Eight on-chip DCMs provide clock synthesis, phase shifting, and deskew capabilities. This eliminates the need for external clock conditioning circuits and simplifies board design significantly.

Multipliers

Ninety-six dedicated 18×18-bit hardware multipliers are embedded to accelerate DSP-intensive tasks such as filtering, FFTs, and image processing — without consuming CLB resources.

I/O Flexibility

With 633 user I/O pins, the device supports a wide range of single-ended and differential I/O standards. Each I/O bank can be independently powered, enabling multi-voltage board designs.

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XC3S4000-5FG900C vs. Similar Spartan-3 Devices

The -5 speed grade distinguishes the XC3S4000-5FG900C from the -4 variant, offering higher clock frequency headroom at 725 MHz — making it the preferred choice for timing-critical designs.

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Applications of the XC3S4000-5FG900C

The XC3S4000-5FG900C is engineered for a broad range of industrial and consumer applications:

Broadband & Networking

• DSL/cable modem line cards
• Ethernet switches and routers
• Protocol bridging and conversion

Display & Projection Systems

• LCD/DLP display controllers
• Video scalar and frame buffers
• Digital projector timing controllers

Digital Television & Video

• MPEG encode/decode acceleration
• Video overlay and mixing
• Set-top box processing pipelines

Industrial & Embedded Systems

• Motor control and industrial automation
• Custom processor implementations
• ASIC prototyping and emulation

Communications & Defense

• Software-defined radio (SDR) front-ends
• Radar/sonar signal processing
• Encryption and data security modules

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Why Choose the XC3S4000-5FG900C Over an ASIC?

One of the most compelling advantages of the XC3S4000-5FG900C is its in-field programmability. Unlike mask-programmed ASICs:

• No Non-Recurring Engineering (NRE) cost — skip expensive mask tooling fees
• Fast time-to-market — go from design to working silicon in days, not months
• Field upgradeable — update logic via configuration bitstream without hardware replacement
• Risk reduction — iterate designs freely without costly re-spins

This makes the XC3S4000-5FG900C the ideal solution for low-to-medium volume products where ASIC economics do not apply, or for prototyping systems destined for eventual ASIC migration.

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Development Tools for XC3S4000-5FG900C

Xilinx ISE Design Suite

The XC3S4000-5FG900C is supported by Xilinx ISE (Integrated Software Environment), the primary design tool for the Spartan-3 family. ISE provides:

• HDL synthesis (VHDL, Verilog)
• Place-and-route
• Timing analysis and simulation
• iMPACT programming tool for JTAG/SVF configuration

Programming & Configuration

The device is typically configured via JTAG or through an external SPI/parallel Flash memory. Supported configuration modes include Master Serial, Slave Serial, Master SelectMAP, and Slave SelectMAP.

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XC3S4000-5FG900C Ordering Information

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Frequently Asked Questions (FAQ)

What does the “C” at the end of XC3S4000-5FG900C mean?

The “C” designates the Commercial temperature range, meaning the device is rated for operation between 0°C and 85°C junction temperature. The industrial variant would end in “I” and is rated for –40°C to 100°C.

What is the difference between XC3S4000-5FG900C and XC3S4000-4FG900C?

The only difference is the speed grade: the -5 variant supports a higher maximum clock frequency (725 MHz) compared to the -4 variant (~630 MHz). Both share the same logic resources, pin count, and package.

Is the XC3S4000-5FG900C RoHS compliant?

No, the XC3S4000-5FG900C is not RoHS compliant. If RoHS compliance is required, consider the XC3S4000-5FGG900C variant (note the double “G”), which carries the RoHS-compliant designation.

What configuration memory does the XC3S4000-5FG900C use?

The Spartan-3 family uses external configuration memory, typically an SPI or parallel NOR Flash. Xilinx Platform Flash (XCFxxS/XCFxxP) devices are commonly paired with Spartan-3 FPGAs for reliable boot-up configuration.

Can the XC3S4000-5FG900C replace an ASIC?

Yes. The XC3S4000-5FG900C is explicitly positioned as a superior alternative to mask-programmed ASICs for designs that require flexibility, fast time-to-market, or in-field upgradability.

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Conclusion

The XC3S4000-5FG900C is a proven, high-density FPGA from Xilinx’s Spartan-3 family that delivers 4 million system gates, 633 user I/Os, 216 kB of block RAM, and a fast -5 speed grade — all in a compact 900-pin FBGA package. Its combination of logic density, on-chip memory, dedicated multipliers, and field programmability makes it an excellent choice for a wide range of applications from consumer electronics to industrial control and communications systems.

Whether you are designing from scratch or upgrading an existing system, the XC3S4000-5FG900C offers the performance, flexibility, and cost-efficiency that engineers demand.