The XC3S50-4TQ144I is a member of the Xilinx FPGA Spartan®-3 family, manufactured by AMD (formerly Xilinx). Designed for high-volume, cost-sensitive consumer and industrial electronics, this 50,000 system gate FPGA delivers reliable programmable logic in a compact 144-pin TQFP package. With industrial-grade temperature tolerance, 90nm process technology, and a 1.2V core supply, the XC3S50-4TQ144I is a proven solution for embedded control, signal processing, and digital logic applications.
What Is the XC3S50-4TQ144I?
The XC3S50-4TQ144I is a Field-Programmable Gate Array (FPGA) from Xilinx’s Spartan-3 series. Part number breakdown:
- XC3S50 – Spartan-3 family, 50K system gates
- -4 – Standard performance speed grade
- TQ144 – 144-pin Thin Quad Flat Pack (TQFP) package
- I – Industrial temperature range (–40°C to +100°C)
This device is well-suited for engineers who need a compact, programmable, reprogrammable logic IC with strong I/O flexibility and low cost-per-gate ratio.
XC3S50-4TQ144I Key Specifications
General Electrical Characteristics
| Parameter |
Value |
| Manufacturer |
AMD (Xilinx) |
| Part Number |
XC3S50-4TQ144I |
| Series |
Spartan®-3 |
| Technology |
90nm CMOS |
| Core Supply Voltage (VCC) |
1.2V |
| System Gates |
50,000 |
| Logic Cells |
1,728 |
| Speed Grade |
-4 (Standard Performance) |
| Maximum System Clock |
630 MHz |
| Package Type |
144-Pin TQFP (Thin Quad Flat Pack) |
| Temperature Range |
Industrial: –40°C to +100°C |
| RoHS Compliance |
Not Compliant (Standard Pb package) |
| Product Status |
Obsolete / End of Life |
Logic & Memory Resources
| Resource |
XC3S50 Specification |
| System Gates |
50,000 |
| Logic Cells (CLBs) |
1,728 |
| Block RAM |
72 Kbits (4 × 18Kbit blocks) |
| Block RAM Columns |
1 |
| Dedicated Multipliers |
4 (18×18-bit) |
| Digital Clock Managers (DCMs) |
2 |
| Maximum Distributed RAM |
12 Kbits |
I/O and Packaging Details
| Parameter |
Value |
| Total Package Pins |
144 |
| User I/O Pins |
97 |
| Differential I/O Pairs |
46 |
| I/O Standards Supported |
LVTTL, LVCMOS, SSTL, HSTL, LVDS, RSDS, and more |
| Package |
TQFP-144 (Thin Quad Flat Pack) |
| Package Dimensions |
20mm × 20mm |
| Pin Pitch |
0.5mm |
XC3S50-4TQ144I Architecture Overview
Configurable Logic Blocks (CLBs)
The XC3S50-4TQ144I contains 1,728 logic cells organized in Configurable Logic Blocks. Each CLB consists of four slices, and each slice includes two 4-input look-up tables (LUTs), two storage elements (registers or latches), carry logic, and arithmetic functions. This architecture enables dense implementation of state machines, arithmetic circuits, and custom digital logic.
Block RAM
The device integrates a single column of block RAM, totaling 72 Kbits across four 18-Kbit dual-port RAM blocks. Each block RAM features:
- True dual-port access (independent Port A and Port B)
- Programmable data width configurations
- Synchronous read/write operation
- Optional output register for improved timing performance
Block RAM is ideal for FIFOs, lookup tables, data buffers, and on-chip storage in embedded applications.
Dedicated Multipliers
Four 18×18-bit dedicated hardware multipliers (MULT18X18S primitives) are embedded in the FPGA fabric. These multipliers operate independently from CLB logic, providing efficient DSP operations without consuming logic resources. The synchronous MULT18X18S primitive includes a registered output stage for pipelined computation.
Digital Clock Managers (DCMs)
The XC3S50-4TQ144I includes 2 Digital Clock Managers, which provide:
- Clock frequency synthesis and multiplication
- Clock phase shifting (fine and coarse)
- Clock deskewing (eliminates clock distribution delay)
- Dynamic clock reconfiguration support
DCMs are positioned at the ends of the block RAM column, and are configured using the DCM primitive in Xilinx ISE design tools.
I/O Blocks (IOBs)
A ring of 97 user-configurable I/O Blocks surrounds the FPGA core. Each IOB supports:
- Programmable drive strength and slew rate control
- Input delay (optional)
- Single-ended and differential signaling
- On-chip pull-up, pull-down, and keeper circuits
- Integrated DCI (Digitally Controlled Impedance) on supported banks
Note: DCI signal standards are not supported in Bank 5 of devices packaged in TQ144.
Supported I/O Standards
| Standard Type |
Supported Standards |
| Single-Ended |
LVTTL, LVCMOS3.3, LVCMOS2.5, LVCMOS1.8, LVCMOS1.5 |
| Differential |
LVDS, RSDS, BLVDS, LVPECL |
| Memory Interface |
SSTL2_I, SSTL2_II, SSTL18_I, SSTL18_II |
| High-Speed Logic |
HSTL_I, HSTL_III, GTL, GTL+ |
Configuration and Programming
The XC3S50-4TQ144I uses reprogrammable static CMOS Configuration Latches (CCLs) that store the device’s functionality. Configuration is loaded on power-up or at any time via the following supported modes:
| Configuration Mode |
Description |
| Master Serial |
Loads bitstream from serial SPI flash memory |
| Slave Serial |
Receives configuration from an external controller |
| Master Parallel (SelectMAP) |
High-speed parallel configuration using 8-bit bus |
| Slave Parallel (SelectMAP) |
Parallel configuration from external processor |
| JTAG (Boundary Scan) |
IEEE 1149.1 JTAG for in-system programming and debug |
Configuration data is stored externally (e.g., in SPI flash or EPROM). The Spartan-3 FPGA retains its configuration as long as power is applied; on power removal, the configuration is lost and must be reloaded.
Ordering Information and Part Number Guide
| Field |
Code |
Meaning |
| Family |
XC3S |
Spartan-3 |
| Density |
50 |
50,000 System Gates |
| Speed Grade |
-4 |
Standard Performance |
| Package |
TQ144 |
144-pin TQFP |
| Temperature |
I |
Industrial (–40°C to +100°C) |
Available Package Options for XC3S50
| Package Code |
Package Type |
User I/O |
| VQ100 |
100-pin Very Thin QFP (VQFP) |
63 |
| TQ144 |
144-pin Thin QFP (TQFP) |
97 |
XC3S50-4TQ144I vs. Other Spartan-3 Variants
| Part Number |
Gates |
I/O Pins |
Package |
Temp Range |
| XC3S50-4TQ144C |
50K |
97 |
TQFP-144 |
Commercial (0°C to 85°C) |
| XC3S50-4TQ144I |
50K |
97 |
TQFP-144 |
Industrial (–40°C to 100°C) |
| XC3S200-4TQ144I |
200K |
141 |
TQFP-144 |
Industrial |
| XC3S400-4TQ144I |
400K |
141 |
TQFP-144 |
Industrial |
The “I” suffix is critical — it designates the industrial temperature grade, making the XC3S50-4TQ144I suitable for environments with wide temperature swings, such as outdoor equipment, factory automation, and transportation systems.
Applications of the XC3S50-4TQ144I
The XC3S50-4TQ144I targets high-volume, cost-conscious design applications where a compact, reliable programmable logic device is required:
- Industrial automation and control – programmable machine control, sensor interfacing, relay control
- Consumer electronics – display controllers, set-top box logic, remote control receivers
- Communications – protocol bridging, UART/SPI/I2C controllers, data framing
- Embedded systems – co-processing, glue logic, peripheral expansion for microcontrollers
- Automotive electronics (non-safety-critical) – body control, infotainment support logic
- Test and measurement – signal generation, digital pattern matching, data capture
- Education and prototyping – FPGA learning platforms, university lab boards
Development Tools and Design Flow
Xilinx (now AMD) supports the Spartan-3 family with:
| Tool |
Description |
| Xilinx ISE Design Suite |
Legacy design tool for Spartan-3 (synthesis, implementation, bitstream generation) |
| ModelSim / ISIM |
HDL simulation for functional and timing verification |
| ChipScope Pro |
In-circuit logic analysis via JTAG |
| iMPACT |
Device programming and configuration management |
| CORE Generator |
IP core generation for standard interfaces and DSP functions |
While Vivado Design Suite is the current flagship tool, Spartan-3 devices require the older Xilinx ISE 14.7 environment for design implementation and bitstream generation.
Product Status: Obsolete / End of Life
The XC3S50-4TQ144I is listed as Obsolete on DigiKey (formerly sold under both Xilinx and AMD branding following AMD’s acquisition of Xilinx in 2022). Engineers sourcing this part for legacy system maintenance should verify inventory availability through authorized distributors.
For new designs, AMD recommends migrating to more modern FPGA families such as:
| Replacement Family |
Key Advantages |
| Spartan-7 (XC7S) |
Lower power, higher performance, Vivado support |
| Artix-7 (XC7A) |
Enhanced DSP, PCIe support, modern tool chain |
| Efinix Trion / Titanium |
Pin-compatible alternatives for Spartan-3 migration |
Frequently Asked Questions (FAQ)
Q: What does the “-4” speed grade mean for the XC3S50-4TQ144I? A: The -4 designates standard performance. The Spartan-3 family offers -4 (standard) and -5 (high performance) speed grades. A higher number indicates faster propagation delays and maximum clock speeds.
Q: What is the difference between XC3S50-4TQ144I and XC3S50-4TQ144C? A: The only difference is the operating temperature range. The “I” suffix supports industrial temperatures (–40°C to +100°C), while the “C” suffix is commercial grade (0°C to +85°C).
Q: Can I program the XC3S50-4TQ144I using Vivado? A: No. Spartan-3 devices are not supported by Vivado. You must use Xilinx ISE Design Suite version 14.7 for synthesis, implementation, and bitstream generation.
Q: How many user I/Os does the XC3S50-4TQ144I have? A: The 144-pin TQFP package provides 97 user-configurable I/O pins, supporting 46 differential I/O pairs.
Q: Is the XC3S50-4TQ144I RoHS compliant? A: The standard (non-“G”) version is not RoHS compliant as it uses a tin-lead (Pb) solder finish. For RoHS-compliant versions, look for the “G” suffix in the package code (e.g., TQG144).
Q: What configuration memory is compatible with this FPGA? A: Common choices include Xilinx XCF platform flash devices and standard SPI flash memories connected via the Master Serial configuration mode.
