Overview of XC2S400E-7FTG256C FPGA
The XC2S400E-7FTG256C is a powerful field-programmable gate array from the renowned Spartan-IIE family, manufactured by Xilinx (now AMD). This versatile FPGA delivers exceptional performance for embedded systems, digital signal processing, and custom logic applications. Featuring 400,000 system gates and 10,800 logic cells, the XC2S400E-7FTG256C offers engineers and designers a robust platform for implementing complex digital circuits with superior flexibility and cost-effectiveness.
As part of the second-generation ASIC replacement technology, this FPGA provides an excellent alternative to traditional application-specific integrated circuits, offering unlimited reprogrammability and rapid development cycles without the substantial upfront costs associated with mask-programmed solutions.
Key Technical Specifications
Core Performance Parameters
| Specification |
Value |
| Logic Cells |
10,800 cells |
| System Gates |
400,000 gates |
| Maximum Frequency |
400 MHz |
| Speed Grade |
-7 (high performance) |
| Process Technology |
0.15 µm CMOS |
| Core Voltage |
1.8V |
| Operating Temperature |
-40°C to +85°C (Industrial grade) |
Package and Physical Characteristics
| Feature |
Specification |
| Package Type |
FTBGA (Fine-Pitch Ball Grid Array) |
| Pin Count |
256 pins |
| Package Dimensions |
17mm x 17mm |
| Package Code |
FTG256 |
| Mounting Type |
Surface Mount Technology (SMT) |
| JESD-30 Code |
S-PBGA-B256 |
| Moisture Sensitivity Level |
MSL 3 |
Memory Architecture
| Memory Type |
Capacity |
| Block RAM |
Up to 288 Kbits |
| Distributed RAM |
Up to 221,184 bits |
| Configurable Logic Blocks (CLBs) |
2,400 CLBs |
| Total I/O Pins |
410 inputs/outputs |
Advanced Features and Capabilities
SelectRAM Hierarchical Memory System
The XC2S400E-7FTG256C incorporates Xilinx’s advanced SelectRAM technology, providing flexible memory options through both block RAM and distributed RAM configurations. This hierarchical approach enables designers to optimize memory allocation based on specific application requirements, whether implementing FIFOs, lookup tables, or data buffers.
Enhanced I/O Standards Support
This FPGA supports up to 19 different I/O standards, making it compatible with a wide variety of interface requirements including LVTTL, LVCMOS, SSTL, HSTL, and differential signaling standards. This versatility ensures seamless integration with diverse system architectures and external components.
Delay-Locked Loop (DLL) Technology
Equipped with four DLLs, the XC2S400E-7FTG256C provides precise clock management capabilities essential for synchronous system design. These DLLs enable clock multiplication, division, phase shifting, and skew elimination, ensuring reliable timing across complex digital implementations.
In-System Programmability
The device supports multiple configuration modes including master serial, slave serial, slave parallel, and boundary scan (JTAG), offering maximum flexibility for system integration and in-field updates. This feature is particularly valuable for prototyping, testing, and post-deployment firmware updates.
Technical Architecture Details
Logic Cell Structure
Each logic cell in the XC2S400E-7FTG256C can be configured as either D-type flip-flops or level-sensitive latches, providing exceptional flexibility in sequential logic implementation. The CLB architecture features four logic cells organized in two slices, enabling efficient resource utilization and optimized routing.
Combinatorial Logic Performance
With a maximum combinatorial delay of just 470 picoseconds per CLB, this FPGA delivers outstanding speed for time-critical applications. The fast, predictable interconnect architecture ensures that design iterations consistently meet stringent timing requirements.
Application Areas
The XC2S400E-7FTG256C excels in various demanding applications:
- Digital Signal Processing: Audio and video processing, filtering, and transformation algorithms
- Communication Systems: Protocol converters, data encoders/decoders, and interface bridging
- Industrial Control: Motor control, sensor interfacing, and automated machinery
- Image Processing: Real-time video manipulation, pattern recognition, and computer vision
- Data Encryption: Security algorithms and cryptographic implementations
- Embedded Systems: Custom peripherals and system-on-chip prototyping
Advantages Over Traditional ASIC Solutions
Cost-Effective Development
Unlike mask-programmed ASICs that require substantial non-recurring engineering costs, the XC2S400E-7FTG256C enables immediate development without initial tooling expenses. This makes it ideal for low to medium volume production runs and rapid prototyping.
Field Upgradability
The unlimited reprogrammability of this Xilinx FPGA allows for design modifications and feature enhancements after deployment, something impossible with traditional ASICs. This capability significantly reduces long-term maintenance costs and extends product lifecycles.
Reduced Time-to-Market
With no fabrication wait times and powerful development tools like ISE Design Suite, engineers can move from concept to working prototype in days rather than months, providing crucial competitive advantages in fast-moving markets.
Risk Mitigation
The ability to test and modify designs before final implementation eliminates the risk of costly silicon errors inherent in ASIC development, making the XC2S400E-7FTG256C a safer choice for complex digital designs.
Development Tools and Resources
Design Software Compatibility
The XC2S400E-7FTG256C is supported by Xilinx’s ISE Design Suite, which provides comprehensive tools for:
- HDL synthesis (VHDL and Verilog)
- Place and route optimization
- Timing analysis and verification
- Power estimation
- Hardware co-simulation
Reference Designs and Evaluation Kits
Developers can access various reference designs and evaluation boards specifically tailored for the Spartan-IIE family, accelerating development time and reducing learning curves for new projects.
Reliability and Quality Standards
Environmental Compliance
The XC2S400E-7FTG256C meets RoHS compliance standards, making it suitable for global markets with stringent environmental regulations. The device is manufactured using lead-free processes and materials.
Industrial Temperature Range
With an operating temperature range from -40°C to +85°C, this FPGA is qualified for industrial applications that demand reliable operation in challenging environmental conditions.
Electrostatic Discharge Protection
Proper ESD handling procedures ensure long-term reliability. The device incorporates protection circuits to withstand typical handling and operating conditions when appropriate precautions are observed.
Comparison: Speed Grades Explained
| Speed Grade |
Maximum Frequency |
Application Focus |
| -7 (This Model) |
400 MHz |
High-performance, time-critical designs |
| -6 |
357 MHz |
General-purpose, balanced performance |
| -5 |
~300 MHz |
Cost-optimized, lower-speed applications |
The -7 speed grade designation indicates this is a high-performance variant within the Spartan-IIE family, offering the fastest switching times and highest operating frequencies for demanding applications.
Package Configuration Benefits
FTBGA Advantages
The Fine-Pitch Ball Grid Array package provides several key benefits:
- Excellent Thermal Performance: Efficient heat dissipation through bottom-side thermal pad
- High I/O Density: Maximum pin count in minimal footprint
- Superior Signal Integrity: Reduced inductance and crosstalk compared to leaded packages
- Mechanical Stability: Robust connection suitable for harsh operating environments
Power Consumption Characteristics
The 1.8V core voltage of the XC2S400E-7FTG256C contributes to lower power consumption compared to earlier FPGA generations, making it suitable for power-sensitive applications. The device supports various power management modes, allowing designers to optimize power consumption based on operational requirements.
Ordering Information and Availability
Part Number Breakdown
XC2S400E-7FTG256C
- XC2S: Spartan-IIE family identifier
- 400E: 400,000 system gates, enhanced version
- -7: Speed grade (highest performance)
- FTG256: Fine-pitch BGA, 256 pins
- C: Commercial temperature range
Procurement Considerations
When sourcing the XC2S400E-7FTG256C, ensure components are obtained from authorized distributors to guarantee authenticity and proper handling. Verify moisture sensitivity level requirements and storage conditions to maintain device reliability.
Legacy Considerations
Important Note: The Spartan-IIE family, including the XC2S400E-7FTG256C, has been designated as not recommended for new designs by AMD/Xilinx. While existing applications continue to be well-supported, engineers developing new products should consider newer FPGA families such as Spartan-7, Artix-7, or other current-generation devices that offer enhanced features, improved performance, and long-term availability.
However, for replacement, maintenance, repair operations, and existing product support, the XC2S400E-7FTG256C remains an excellent choice with proven reliability and extensive documentation.
Summary of Key Benefits
The XC2S400E-7FTG256C represents a mature, reliable FPGA solution offering:
- Substantial logic capacity with 10,800 cells and 400,000 system gates
- High-speed performance up to 400 MHz
- Flexible memory architecture with block and distributed RAM
- Comprehensive I/O standard support
- Advanced clock management with four DLLs
- Cost-effective alternative to ASIC development
- Unlimited reprogrammability for design flexibility
- Industrial temperature range qualification
- Proven track record in deployed applications
For engineers maintaining legacy systems or requiring a well-documented, stable FPGA platform, the XC2S400E-7FTG256C delivers exceptional value and performance in a compact, reliable package.
