The XC3S400-5TQ144I is a high-performance, cost-optimized Field-Programmable Gate Array (FPGA) from Xilinx’s Spartan-3 family. Designed for high-volume, cost-sensitive embedded and consumer electronics applications, this device delivers 400,000 system gates, 8,064 logic cells, and a maximum operating frequency of 725 MHz — all in a compact 144-pin TQFP package. Whether you are building industrial control systems, communications equipment, or custom digital logic, the XC3S400-5TQ144I offers the programmability, performance, and value that engineering teams demand.
What Is the XC3S400-5TQ144I?
The XC3S400-5TQ144I belongs to AMD (formerly Xilinx) Spartan-3 FPGA family — one of the most widely deployed programmable logic platforms in the world. The device is built on a proven 90nm process technology and operates at a core voltage of 1.2V. It is the industrial-temperature-grade variant (suffix “I”), rated for operation from –40°C to +100°C, making it well suited to harsh or demanding environments.
The part number decodes as follows:
| Field |
Value |
Meaning |
| XC3S |
Spartan-3 |
Device Family |
| 400 |
400K |
System Gate Count |
| -5 |
Speed Grade 5 |
Highest speed grade in family |
| TQ |
TQFP |
Package type (Thin Quad Flat Pack) |
| 144 |
144 pins |
Total pin count |
| I |
Industrial |
Temperature range: –40°C to +100°C |
XC3S400-5TQ144I Key Specifications at a Glance
| Parameter |
Value |
| Manufacturer |
AMD (Xilinx) |
| Part Number |
XC3S400-5TQ144I |
| FPGA Family |
Spartan-3 |
| System Gates |
400,000 |
| Logic Cells |
8,064 |
| CLB Array |
32 × 28 |
| Flip-Flops |
7,168 |
| Distributed RAM |
56 Kb |
| Block RAM |
288 Kb (16 blocks × 18 Kb) |
| Dedicated Multipliers |
16 |
| DCMs (Digital Clock Managers) |
4 |
| Maximum User I/Os |
97 (in TQ144 package) |
| Max System Clock |
725 MHz |
| Core Voltage (VCCINT) |
1.2V |
| Process Technology |
90nm |
| Package |
144-pin TQFP (TQ144) |
| Package Dimensions |
20 × 20 mm body |
| Temperature Range |
–40°C to +100°C (Industrial) |
| Configuration Modes |
Master Parallel, Slave Parallel, Master Serial, JTAG, and more |
XC3S400-5TQ144I Detailed Features
Logic Resources
The XC3S400-5TQ144I provides 8,064 logic cells arranged in a 32×28 array of Configurable Logic Blocks (CLBs). Each CLB contains four slices, and each slice includes two 4-input Look-Up Tables (LUTs) and two flip-flops. This architecture supports a wide variety of logic functions, from simple combinational gates to complex state machines, arithmetic units, and custom digital signal processing pipelines.
Block RAM and Distributed RAM
Memory-intensive designs benefit from two distinct RAM architectures:
- Block RAM: 16 dedicated 18-Kbit RAM blocks totaling 288 Kbits of true dual-port SRAM. Each block can be configured as 16K×1, 8K×2, 4K×4, 2K×9, 1K×18, or 512×36 configurations, giving designers significant flexibility.
- Distributed RAM: 56 Kbits of distributed RAM derived from the LUT resources, suitable for small, fast lookup tables and FIFOs embedded within the logic fabric.
Dedicated Multipliers
The XC3S400-5TQ144I includes 16 dedicated 18×18-bit multipliers physically co-located with each block RAM. These hardware multipliers deliver high-throughput DSP operations — such as FIR filters, FFTs, and motor control algorithms — without consuming LUT resources.
Digital Clock Managers (DCMs)
Four Digital Clock Managers provide sophisticated clock synthesis, multiplication, division, deskewing, and phase shifting. DCMs ensure precise, low-jitter clock delivery across the entire device, which is critical for high-speed serial interfaces and synchronous logic designs.
I/O Standards and User I/Os
The TQ144 package version of the XC3S400 provides up to 97 user-configurable I/O pins. Each I/O bank supports a wide range of single-ended and differential I/O standards, including:
| I/O Standard |
Type |
| LVTTL |
Single-ended |
| LVCMOS 3.3V / 2.5V / 1.8V / 1.5V / 1.2V |
Single-ended |
| PCI (3.3V, 33/66 MHz) |
Single-ended |
| SSTL2 Class I/II |
Single-ended/Differential |
| HSTL Class I/II/III/IV |
Single-ended/Differential |
| LVDS |
Differential |
| RSDS |
Differential |
| BLVDS |
Differential |
| GTL / GTL+ |
Open-drain |
Each I/O pin also supports programmable drive strength, slew rate control, and optional on-chip pull-up/pull-down resistors, providing full flexibility for board-level signal integrity optimization.
XC3S400-5TQ144I Package Information
144-Pin TQFP (TQ144) Package
The XC3S400-5TQ144I uses a Thin Quad Flat Pack (TQFP) with 144 leads, a 0.5 mm lead pitch, and a 20×20 mm body size. The thin profile makes it ideal for space-constrained PCB designs. Surface-mount assembly is straightforward using standard SMT reflow processes.
| Package Attribute |
Value |
| Package Type |
TQFP |
| Pin Count |
144 |
| Lead Pitch |
0.5 mm |
| Body Size |
20 × 20 mm |
| Height (max) |
1.6 mm |
| Lead Finish |
Tin/Lead (SnPb) |
| Mounting |
Surface Mount (SMT) |
Note: The “I” suffix denotes the industrial temperature grade (–40°C to +100°C). The equivalent commercial-grade version is the XC3S400-5TQ144C (0°C to +85°C). The “G” suffix variants (e.g., XC3S400-5TQG144I) indicate Pb-free/RoHS-compliant packaging.
Ordering Information & Part Number Variants
The XC3S400 in the TQ144 package is available in several speed grade and temperature combinations:
| Part Number |
Speed Grade |
Temperature Range |
Lead Finish |
| XC3S400-4TQ144C |
-4 (630 MHz) |
Commercial (0°C to +85°C) |
SnPb |
| XC3S400-4TQG144C |
-4 (630 MHz) |
Commercial (0°C to +85°C) |
Pb-Free |
| XC3S400-5TQ144C |
-5 (725 MHz) |
Commercial (0°C to +85°C) |
SnPb |
| XC3S400-5TQ144I |
-5 (725 MHz) |
Industrial (–40°C to +100°C) |
SnPb |
| XC3S400-5TQG144I |
-5 (725 MHz) |
Industrial (–40°C to +100°C) |
Pb-Free |
XC3S400-5TQ144I vs. XC3S400-4TQG144C: Speed Grade Comparison
A common design decision involves choosing between the -4 and -5 speed grades. Here is a direct comparison of the two most popular TQ144 variants:
| Specification |
XC3S400-5TQ144I |
XC3S400-4TQG144C |
| Speed Grade |
-5 (Fastest) |
-4 |
| Max System Frequency |
725 MHz |
630 MHz |
| Temperature Grade |
Industrial |
Commercial |
| Lead Finish |
SnPb |
Pb-Free (RoHS) |
| Logic Cells |
8,064 |
8,064 |
| Block RAM |
288 Kb |
288 Kb |
| User I/Os (TQ144) |
97 |
97 |
| Core Voltage |
1.2V |
1.2V |
The -5 speed grade is the highest-performance option in the Spartan-3 400K family, offering approximately 15% greater maximum frequency compared to the -4 grade. Choose the XC3S400-5TQ144I when your design’s timing closure demands the lowest propagation delays.
Applications of the XC3S400-5TQ144I
The XC3S400-5TQ144I is a proven, versatile device used across a broad range of industries and application domains:
| Application Area |
Typical Use Cases |
| Industrial Automation |
Motor control, PLC logic replacement, sensor interfaces |
| Communications |
UART, SPI, I²C, Ethernet MAC bridging, protocol conversion |
| Medical Electronics |
Signal acquisition front-ends, patient monitoring |
| Automotive Electronics |
Body control modules, ADAS sensor interfaces |
| Test & Measurement |
Signal generation, logic analyzers, pattern generators |
| Consumer Electronics |
Display controllers, custom peripherals |
| Defense & Aerospace |
Rugged embedded computing, signal processing |
| Education & Prototyping |
FPGA learning platforms, student projects |
As a Xilinx FPGA from the cost-optimized Spartan-3 family, the XC3S400-5TQ144I is particularly well suited for designs that require more logic than a microcontroller can provide, but where the cost of an ASIC is prohibitive.
Configuration and Programming
Supported Configuration Modes
The XC3S400-5TQ144I supports five configuration modes, providing maximum flexibility for production programming:
| Mode |
Description |
| Master Serial |
FPGA reads configuration data from a serial PROM (e.g., XCF02S) |
| Slave Serial |
Configuration data is clocked in externally |
| Master Parallel (SelectMAP) |
FPGA reads configuration data from a parallel source |
| Slave Parallel (SelectMAP) |
8-bit or 16-bit parallel configuration from an external host |
| JTAG (IEEE 1149.1) |
Boundary scan, in-circuit debugging, and configuration |
Recommended Configuration PROMs
| PROM |
Capacity |
Suitable For |
| XCF02S |
2 Mbit |
XC3S400 (exact fit) |
| XCF04S |
4 Mbit |
XC3S1000 |
| Platform Flash (XCF) |
Various |
Daisy-chain multi-device configurations |
Design Tools
The XC3S400-5TQ144I is fully supported by the following Xilinx/AMD EDA tools:
- Xilinx ISE Design Suite (legacy, recommended for Spartan-3)
- Vivado Design Suite (limited Spartan-3 support; ISE preferred)
- ChipScope Pro for in-system logic analysis
- Third-party synthesis tools: Synplify Pro, Precision RTL
Electrical Characteristics
| Parameter |
Min |
Typical |
Max |
Unit |
| Core Supply Voltage (VCCINT) |
1.14 |
1.2 |
1.26 |
V |
| I/O Supply Voltage (VCCO) |
1.14 |
— |
3.465 |
V |
| Auxiliary Supply (VCCAUX) |
2.375 |
2.5 |
2.625 |
V |
| Operating Temperature |
–40 |
— |
+100 |
°C |
| Input Voltage (VIN) |
–0.5 |
— |
VCCO + 0.5 |
V |
| Max Toggle Rate |
— |
725 |
— |
MHz |
Why Choose the XC3S400-5TQ144I?
Superior Alternative to ASICs
The XC3S400-5TQ144I eliminates the high NRE costs, multi-month development cycles, and rigid inflexibility of mask-programmed ASICs. Field-programmable reprogrammability means design updates can be deployed without hardware replacement — an advantage ASICs simply cannot match.
Virtex-II Platform Technology
Numerous architectural enhancements in the Spartan-3 family are derived from the Virtex-II platform. These improvements — including advanced CLB architecture, dedicated multipliers, and enhanced DCMs — deliver substantially more functionality and bandwidth per dollar than prior FPGA generations.
Industrial-Grade Reliability
The “I” grade temperature rating (–40°C to +100°C) ensures reliable operation in environments subject to wide temperature swings — from outdoor infrastructure to factory floors and automotive electronics.
Proven, Long-Lifecycle Platform
The Spartan-3 family has been in production for over 20 years and remains widely available through authorized distributors. The XC3S400-5TQ144I is a trusted, stable platform for designs requiring long-term parts availability.
Frequently Asked Questions (FAQ)
Q: What is the difference between XC3S400-5TQ144I and XC3S400-5TQ144C? The only difference is the operating temperature range. The “I” suffix denotes Industrial grade (–40°C to +100°C), while the “C” suffix denotes Commercial grade (0°C to +85°C). All other electrical and functional specifications are identical.
Q: Is the XC3S400-5TQ144I RoHS compliant? The standard TQ144 package uses SnPb (tin/lead) solder and is not RoHS compliant. For a Pb-free, RoHS-compliant equivalent, specify the XC3S400-5TQG144I (with the “G” in the package suffix).
Q: What configuration PROM should I use with the XC3S400-5TQ144I? Xilinx recommends the XCF02S (2 Mbit Platform Flash PROM), which is sized exactly for the XC3S400 configuration bitstream.
Q: Can I use Vivado to design for the XC3S400-5TQ144I? AMD’s current Vivado Design Suite has limited support for Spartan-3 devices. Xilinx ISE Design Suite 14.7 is the recommended and fully supported design environment for this device.
Q: How many I/Os are available in the TQ144 package? The TQ144 package provides a maximum of 97 user I/O pins for the XC3S400 device.
Summary
The XC3S400-5TQ144I is a high-value, high-performance FPGA that brings 400,000 system gates, 725 MHz operation, 288 Kb of block RAM, and 16 dedicated multipliers into a compact, industry-standard 144-pin TQFP package. Its industrial temperature rating makes it suitable for demanding real-world deployments, while its Spartan-3 architecture and long production history ensure design longevity and component availability. For engineers seeking a proven, cost-effective programmable logic solution with flexible I/O and robust clock management, the XC3S400-5TQ144I remains an outstanding choice.
