The XC3S400-4TQG144I is a high-performance, cost-optimized field-programmable gate array (FPGA) from AMD Xilinx’s Spartan-3 family. Designed for a wide range of embedded and industrial applications, this device delivers 400,000 system gates, 144-pin TQFP packaging, and industrial-grade temperature operation. Whether you are building a DSP system, high-speed communication interface, or custom logic controller, the XC3S400-4TQG144I offers the flexibility, density, and reliability your design demands.
What Is the XC3S400-4TQG144I?
The XC3S400-4TQG144I belongs to AMD Xilinx’s Spartan-3 series — a family of Xilinx FPGA devices engineered to deliver maximum logic density at minimal cost. The “4” in its part number indicates a –4 speed grade, offering faster timing performance compared to slower-grade variants. The “I” suffix designates industrial temperature range operation (–40°C to +85°C), making it suitable for demanding environments.
This FPGA is a popular choice among electronics engineers, FPGA designers, and PCB developers who need a proven, programmable logic device for prototyping and production designs alike.
XC3S400-4TQG144I Key Specifications
General Product Information
| Parameter |
Value |
| Manufacturer |
AMD (Xilinx) |
| Part Number |
XC3S400-4TQG144I |
| Series |
Spartan-3 |
| Product Category |
Embedded – FPGAs (Field Programmable Gate Array) |
| Rohs Status |
RoHS Compliant |
Logic and Configuration Resources
| Feature |
Value |
| System Gates |
400,000 |
| Logic Cells |
8,064 |
| CLB Array (Rows × Cols) |
28 × 24 |
| CLBs (Configurable Logic Blocks) |
672 |
| Flip-Flops |
8,064 |
| Maximum Distributed RAM |
56 Kb |
| Block RAM |
288 Kb (16 × 18 Kb blocks) |
| DSP / Multiplier Blocks |
16 × 18×18 hardware multipliers |
Speed and Timing
| Parameter |
Value |
| Speed Grade |
–4 (Fastest in Spartan-3 family) |
| Maximum Internal Clock |
Up to ~630 MHz (internal DCM-based) |
| DCMs (Digital Clock Managers) |
4 |
I/O and Packaging
| Feature |
Value |
| Package Type |
TQFP (Thin Quad Flat Pack) |
| Package Code |
TQG144 |
| Total Pin Count |
144 |
| Maximum User I/O Pins |
97 |
| I/O Standards Supported |
LVTTL, LVCMOS, LVDS, PCI, HSTL, SSTL |
| Input Voltage (VCCO) |
1.2 V – 3.3 V |
| Core Voltage (VCCINT) |
1.2 V |
Environmental and Thermal
| Parameter |
Value |
| Temperature Grade |
Industrial (I) |
| Operating Temperature Range |
–40°C to +85°C |
| Moisture Sensitivity Level (MSL) |
3 |
| Mounting Type |
Surface Mount |
XC3S400-4TQG144I Pin Configuration Overview
The 144-pin TQFP package offers a compact, surface-mount footprint ideal for space-constrained PCB layouts. The 97 user-configurable I/O pins are organized into four I/O banks, each independently powered and configurable for different voltage standards.
| I/O Bank |
Pin Range |
Supported Standards |
| Bank 0 |
Top side |
LVTTL, LVCMOS, PCI |
| Bank 1 |
Right side |
LVCMOS, LVDS, HSTL |
| Bank 2 |
Bottom side |
LVTTL, LVCMOS, SSTL |
| Bank 3 |
Left side |
LVCMOS, LVDS, PCI |
Each bank’s VCCO supply can be set independently, giving designers maximum flexibility when interfacing with mixed-voltage peripherals.
Spartan-3 Architecture Highlights
Configurable Logic Blocks (CLBs)
Each CLB in the XC3S400-4TQG144I contains four slices, and each slice includes two 4-input LUTs (Look-Up Tables) and two flip-flops. LUTs can be configured as logic, shift registers, or distributed RAM, giving designers multiple implementation strategies for the same design element.
Block RAM (BRAM)
The 288 Kb of on-chip block RAM is organized in sixteen 18 Kb dual-port blocks. These synchronous RAM blocks support independent read and write clocking, making them ideal for FIFO buffers, frame buffers, and lookup tables in high-speed designs.
Hardware Multipliers
Sixteen dedicated 18×18-bit hardware multipliers accelerate DSP-intensive tasks such as FIR filters, FFT cores, and motor control algorithms without consuming CLB resources.
Digital Clock Managers (DCMs)
Four integrated DCMs provide clock frequency synthesis, phase shifting, and duty-cycle correction. This eliminates the need for external PLL chips and simplifies board-level clock distribution for complex multi-clock designs.
XC3S400-4TQG144I vs. Other Spartan-3 Variants
| Part Number |
Gates |
I/O Pins |
Package |
Temp Grade |
| XC3S200-4TQG144I |
200K |
97 |
TQFP-144 |
Industrial |
| XC3S400-4TQG144I |
400K |
97 |
TQFP-144 |
Industrial |
| XC3S400-4PQG208I |
400K |
141 |
PQFP-208 |
Industrial |
| XC3S1000-4TQG144I |
1M |
97 |
TQFP-144 |
Industrial |
| XC3S400-4FTG256I |
400K |
173 |
FBGA-256 |
Industrial |
The XC3S400-4TQG144I sits at a sweet spot — delivering 400K gates with the compact 144-pin TQFP package, balancing logic density and board space efficiency.
Supported I/O Standards
One of the key strengths of the XC3S400-4TQG144I is its broad I/O standard support, enabling seamless integration with a wide variety of external components.
| I/O Standard |
Description |
Typical Use Case |
| LVTTL |
Low-Voltage TTL (3.3 V) |
General-purpose digital logic |
| LVCMOS 3.3 / 2.5 / 1.8 / 1.5 |
Low-Voltage CMOS |
Microcontroller interfaces |
| PCI / PCI-X |
3.3 V PCI signaling |
PCI peripheral design |
| LVDS |
Low-Voltage Differential Signaling |
High-speed serial links |
| HSTL |
High-Speed Transceiver Logic |
Memory bus interfaces |
| SSTL 2 / SSTL 3 |
Stub Series Terminated Logic |
SDRAM/DDR interfaces |
Typical Applications of the XC3S400-4TQG144I
The XC3S400-4TQG144I FPGA is a versatile device used across multiple industries and application domains:
Industrial Automation and Control
Its industrial temperature rating (–40°C to +85°C) and robust I/O standards make it ideal for PLCs, motor drives, sensor data acquisition systems, and industrial communication gateways.
Embedded Processing
When combined with a soft-core processor such as MicroBlaze or PicoBlaze (both synthesizable in Xilinx ISE/Vivado), the FPGA functions as a fully customizable embedded processor with peripheral logic included.
Digital Signal Processing (DSP)
The 16 dedicated multiplier blocks and 288 Kb of on-chip BRAM support efficient implementation of FIR/IIR filters, FFT engines, and real-time signal processing chains.
Communications and Networking
With LVDS and high-speed I/O capability, the device supports UART, SPI, I²C, CAN, and custom protocol bridging for embedded networking applications.
Prototyping and Development
Paired with an evaluation board such as the Spartan-3 Starter Kit, the XC3S400-4TQG144I is a widely used FPGA for university coursework, FPGA training labs, and rapid logic prototyping.
Automotive and Harsh Environments
The industrial-grade “I” suffix ensures reliable operation in temperature-extreme environments common in automotive, avionics support equipment, and outdoor industrial systems.
Configuration and Programming
The XC3S400-4TQG144I supports multiple configuration modes to suit different production and development scenarios:
| Configuration Mode |
Description |
| Master Serial (SPI Flash) |
Single-device or daisy-chain from SPI flash |
| Slave Serial |
Controlled by external microcontroller or processor |
| Master SelectMAP (x8) |
Byte-wide parallel configuration from a processor |
| Slave SelectMAP |
Byte-wide parallel from external host |
| JTAG (IEEE 1149.1) |
Boundary scan and debug configuration |
JTAG is the most commonly used interface for development and field updates, compatible with Xilinx’s Platform Cable USB and iMPACT software tools.
Development Tools and Software Support
AMD Xilinx provides a comprehensive toolchain for designing with the XC3S400-4TQG144I:
| Tool |
Purpose |
| Xilinx ISE Design Suite |
Primary HDL synthesis, implementation, and bitstream generation |
| ISIM / ModelSim |
RTL and gate-level simulation |
| ChipScope Pro |
On-chip logic analysis and debugging |
| iMPACT |
JTAG-based device programming and configuration |
| IP Core Generator (CORE Generator) |
Pre-verified IP blocks (FIFOs, memory controllers, DSP cores) |
Design entry supports both VHDL and Verilog HDL, as well as schematic entry for beginners.
Ordering Information
| Attribute |
Detail |
| Full Part Number |
XC3S400-4TQG144I |
| DigiKey Part Number |
122-1449-ND (reference) |
| Manufacturer |
AMD (Xilinx) |
| Package |
TQFP-144 (TQG144) |
| Lead-Free / RoHS |
Yes |
| Quantity Pricing |
Available for volume orders |
Why Choose the XC3S400-4TQG144I?
The XC3S400-4TQG144I offers an exceptional combination of:
- High logic density — 400K gates in a compact 144-pin TQFP footprint
- Industrial reliability — Rated for –40°C to +85°C, proven in harsh environments
- Flexible I/O — 97 user I/O pins with multi-standard support across four independent banks
- On-chip resources — Dedicated multipliers and block RAM for DSP and data buffering
- Mature ecosystem — Supported by decades of Xilinx ISE tooling, application notes, and community resources
- Cost-effectiveness — The Spartan-3 family is designed for high-volume, cost-sensitive deployments
For engineers working with embedded FPGA designs, custom logic, or hardware prototyping, the XC3S400-4TQG144I remains one of the most trusted and widely deployed Spartan-3 devices on the market.
Frequently Asked Questions (FAQ)
Q: What is the core voltage for the XC3S400-4TQG144I? A: The core voltage (VCCINT) is 1.2 V. I/O bank voltages (VCCO) are configurable from 1.2 V to 3.3 V per bank.
Q: What is the difference between the “C” and “I” temperature suffix? A: The “C” suffix denotes commercial grade (0°C to +85°C), while the “I” suffix denotes industrial grade (–40°C to +85°C).
Q: Can I use Vivado to program the XC3S400-4TQG144I? A: Vivado does not support Spartan-3 devices. Xilinx ISE Design Suite (version 14.7) is the correct toolset for this FPGA.
Q: How many block RAM bits are available? A: The XC3S400-4TQG144I provides 288,000 bits (288 Kb) of block RAM across 16 dual-port 18 Kb blocks.
Q: Is this device RoHS compliant? A: Yes. The XC3S400-4TQG144I is manufactured in a RoHS-compliant, lead-free process.
