The XC3S50-4TQG144I is a high-performance, cost-optimized Field Programmable Gate Array (FPGA) from Xilinx (now AMD), part of the industry-proven Spartan-3 family. Designed for high-volume, cost-sensitive industrial and embedded applications, this 50K-gate FPGA delivers robust logic density, reliable I/O performance, and industrial-grade temperature tolerance — all in a compact 144-pin TQFP package.

Whether you are designing embedded control systems, signal processing boards, or communications hardware, the XC3S50-4TQG144I provides the programmable logic flexibility engineers need without the high cost of ASICs. For the full range of programmable solutions, explore our selection of Xilinx FPGA products.

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What Is the XC3S50-4TQG144I?

The XC3S50-4TQG144I is a member of the Xilinx Spartan-3 FPGA family — an eight-member series spanning 50K to 5,000,000 system gates. The “XC3S50” designation identifies it as the entry-level 50,000-gate variant, while the suffix breakdown tells engineers exactly what they are getting:

The “I” suffix is critical for engineers targeting industrial, automotive-adjacent, or ruggedized environments, as it guarantees operation across the full –40°C to +100°C temperature range — a step beyond the commercial-grade “C” variant.

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XC3S50-4TQG144I Key Specifications

Core Logic Resources

I/O and Interface Specifications

Electrical and Environmental Specifications

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XC3S50-4TQG144I Functional Architecture

## Configurable Logic Blocks (CLBs)

The Spartan-3 CLB architecture organizes logic into slices, each containing two 4-input LUTs (Look-Up Tables), two storage elements (flip-flops or latches), carry logic, and arithmetic gates. This flexible structure allows each CLB to implement combinational logic, registered logic, or small distributed RAM. The XC3S50 contains 768 slices across its CLB array, sufficient for modest but complete embedded system designs.

### Dedicated Block RAM

Four 18-Kbit block RAMs provide 72 Kbits of on-chip memory, configurable as true dual-port RAM with independent read and write widths of 1, 2, 4, 9, or 18 bits per port. Each block RAM is paired with a dedicated 18×18-bit multiplier, enabling efficient DSP pipelines without consuming CLB resources.

### Digital Clock Managers (DCMs)

Two DCMs deliver precise clock control, including frequency synthesis, phase shifting, deskewing, and duty-cycle correction. The DCMs support a wide input frequency range and can generate multiple derived clocks from a single reference, simplifying system clocking in multi-domain designs.

### Multi-Standard I/O Banks

The 144-pin TQG package provides 97 user-configurable I/O pins organized into independent banks, each powered by its own VCCO supply rail. This bank architecture allows a single device to simultaneously interface with 1.8V, 2.5V, and 3.3V logic families, supporting standards including LVDS, SSTL2, SSTL3, HSTL, and PCI.

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XC3S50-4TQG144I Part Number Decoder

Understanding the full ordering code ensures engineers select the correct variant for their application.

Note: The “G” in TQG indicates a Pb-free (RoHS-compliant) package using lead-free solder balls. The non-“G” variant (TQ144) uses standard tin-lead solder.

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XC3S50-4TQG144I vs. Related Variants

Engineers frequently need to choose between the commercial and industrial grades, or between Spartan-3 and Spartan-3A variants. The table below compares key differences.

The XC3S50-4TQG144I is the correct choice when industrial temperature range is required and the 50K gate density meets the design’s logic budget.

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Configuration and Programming

The XC3S50-4TQG144I supports SRAM-based configuration, which means the device is reprogrammed at power-up from an external non-volatile memory source. Supported configuration modes include:

• Master Serial – from Xilinx Platform Flash (XCFxxS/XCFxxP)
• Slave Serial – driven by an external microcontroller or FPGA
• Master SPI – from standard SPI Flash memory
• Master BPI (Parallel) – from parallel NOR Flash
• JTAG – for in-system programming and debug via boundary scan

The bitstream size for the XC3S50 is approximately 440 Kbits, enabling fast configuration times even from low-cost serial Flash devices.

### Recommended Design Tools

The XC3S50-4TQG144I is not supported in Vivado Design Suite, as Vivado targets UltraScale and 7-Series devices and later. ISE 14.7 remains the supported toolchain for all Spartan-3 devices.

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Typical Applications for the XC3S50-4TQG144I

The combination of industrial temperature rating, compact TQFP packaging, and 50K-gate logic capacity makes the XC3S50-4TQG144I well-suited for:

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PCB Design Considerations

#### Power Supply Requirements

The XC3S50-4TQG144I requires three supply voltages:

• VCCINT = 1.2V (core logic) — low-noise, decoupled supply
• VCCAUX = 2.5V (auxiliary, including DCMs and I/O drivers)
• VCCO — per I/O bank, set to the target interface voltage (1.2V, 1.5V, 1.8V, 2.5V, or 3.3V)

A proper decoupling strategy is essential: place 100nF ceramic capacitors at each power pin, supplemented by bulk capacitors (4.7µF–10µF) per supply rail.

#### Thermal Characteristics

At typical power consumption levels (under 200mW for small designs), the XC3S50-4TQG144I operates well within thermal limits at ambient temperatures up to +100°C.

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Ordering Information

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Frequently Asked Questions (FAQ)

Q: What is the difference between XC3S50-4TQG144I and XC3S50-4TQG144C? The only difference is the operating temperature range. The “I” suffix denotes the Industrial grade (–40°C to +100°C), while the “C” suffix denotes Commercial grade (0°C to +85°C). All logic resources, speed grades, and pin assignments are identical.

Q: Is the XC3S50-4TQG144I pin-compatible with XC3S200-4TQG144I? Yes. All Spartan-3 devices in the TQG144 package share the same pin-out, enabling density migration without PCB redesign.

Q: Can I use Vivado to design for the XC3S50-4TQG144I? No. Vivado does not support Spartan-3 devices. Use Xilinx ISE 14.7, the final and recommended version for all Spartan-3 designs.

Q: What external memory is recommended for configuring the XC3S50-4TQG144I? Xilinx Platform Flash devices (XCF01S, XCF02S) or standard SPI NOR Flash (e.g., Winbond W25Q series) are commonly used. The bitstream is approximately 440 Kbits, so a 1Mbit or larger device is sufficient.

Q: Is the XC3S50-4TQG144I recommended for new designs? Xilinx updated its documentation in 2013 to confirm that Spartan-3 devices are recommended for new designs (reversing an earlier notice). However, for designs with a long production horizon, engineers may also evaluate the Spartan-7 family for better performance, lower power, and longer-term supply availability.

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Summary

The XC3S50-4TQG144I delivers a proven combination of 50K gates, 97 user I/Os, 72 Kbits of block RAM, dedicated multipliers, and dual DCMs in a compact 144-pin Pb-free TQFP — with the industrial temperature rating that demanding applications require. Its mature 90nm process, wide I/O standard support, and straightforward ISE-based design flow make it a reliable choice for embedded, industrial, and communications designs.

For broader programmable logic options including 7-Series and UltraScale families, browse our full range of Xilinx FPGA solutions.