XC3S400-4FTG256C - 400K Gate Spartan-3 FPGA | AMD | 256-LBGA
MPN: XC3S400-4FTG256C ✗ End of LifeXC3S400-4FTG256C Overview
A field-programmable gate array is a digital semiconductor whose logic functions are established after fabrication by loading a configuration bitstream. FPGAs sit within the broader programmable-logic hierarchy, alongside CPLDs, and are used when parallel hardware processing, high logic density, configurable interfaces, or design revision flexibility are more important than the simplicity of a fixed-function ASIC. The Spartan-3 architecture is intended for embedded systems requiring moderate logic capacity without the cost and complexity of the largest FPGA families.
The XC3S400-4FTG256C provides 8,064 logic cells and 294,912 system gates according to the manufacturer-related product listing. Its 256-LBGA package supports dense board integration, while the 1.2 V supply specification identifies it as a 1.2 V FPGA. The exact device speed grade is encoded by the -4 designation, and the FTG256 package, commercial temperature option, and RoHS-oriented lead-free construction are reflected in the ordering code.
Typical uses include industrial control, communications infrastructure, instrumentation, video processing, embedded systems, and digital signal-processing front ends. The programmable architecture allows parallel datapaths, custom interface logic, protocol handling, and control functions to be consolidated into one device. Designers should verify pin-level power, configuration, clock, and differential-I/O requirements against the Spartan-3 family documentation before laying out the PCB.
The most important design tradeoff is package migration. A part with the same logic-cell count but a different package cannot be assumed to be a drop-in replacement. When replacing the XC3S400-4FTG256C, confirm the exact FTG256 footprint, ball assignment, speed grade, temperature range, supply architecture, configuration interface, and high-speed I/O requirements. For new designs, the I/O count and selected package should be checked against the intended board outline and escape-routing strategy.
This page combines the key ordering information for the XC3S400-4FTG256C with package-aware replacement guidance, comparison parameters, and practical design considerations. It is intended to help engineers identify whether a candidate is electrically and mechanically suitable before committing to a PCB or production BOM.
Drop-in alternatives for XC3S400-4FTG256C — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with XC3S400-4FTG256C (same form factor and footprint) — differing in System Gates, Device Type, Logic Cells, Operating Temperature, Package.
XC3S400A-4FTG256C
✅ Drop-InContact for price
View Datasheet →XC3S500E-4FTG256C
✅ Drop-In📋 Reference alternative (not in catalog)
XC3S400-4FT256C
✅ Drop-InContact for price
View Datasheet →XC3S400-4FTG256I
✅ Drop-In📋 Reference alternative (not in catalog)
XC3S400-4FT256I
✅ Drop-InContact for price
View Datasheet →XC3S400-4FTG256C Maximum Ratings & Electrical Characteristics
| Device Type | Spartan-3 Field Programmable Gate Array (FPGA) |
| System Gates | 294,912 gates |
| Logic Cells | 8,064 cells |
| Architecture | Spartan-3 |
| Core Supply Voltage | 1.2 V |
| Package Type | 256-LBGA |
| Package Designation | FTG256 |
| Device Number | 173 |
| Lead-Free Construction | Lead-free |
| Operating Temperature | 0 °C to +85 °C |
| Mounting Type | Surface Mount |
| I/O Count | 264 I/O |
| RoHS Status | unknown |
| REACH Status | unknown |
XC3S400-4FTG256C ftg256 Pin Configuration Guide
Pin configuration for XC3S400-4FTG256C (ftg256 package). This digital IC includes GPIO, communication interfaces (UART, SPI, I2C), and power pins. Refer to the manufacturer datasheet for alternate pin functions and configuration options. Essential for embedded system design and PCB layout.
No detailed pinout data available for XC3S400-4FTG256C.
Refer to the datasheet for full pin configuration.
Typical Applications
XC3S400-4FTG256C is suitable for 6 applications: Industrial Control and Automation, Communications Protocol Conversion, Instrumentation and Data Acquisition, Video Timing and Display Control, Embedded System Control Hub, Digital Signal Processing Front End.
Industrial Control and Automation
The XC3S400-4FTG256C suits compact industrial controllers that require parallel logic, configurable I/O, and deterministic programmable behavior. Its 8,064 logic cells and 264 I/O provide substantial capacity for sequencing, interlocks, machine-state logic, and communication framing without multiple fixed-function controllers. The 1.2 V core supply supports a conventional multi-rail FPGA power architecture. Before deployment, verify the commercial 0 to 85 °C rating against the actual enclosure temperature, and confirm that every high-speed interface has adequate board-level timing margin.
Recommended
Communications Protocol Conversion
The Spartan-3 architecture in the XC3S400-4FTG256C can implement parallel protocol conversion, framing, buffering, and interface adaptation in one programmable device. The available 8,064 logic cells support multiple concurrent datapaths when wide buses, lookup functions, and state machines are required, while 264 I/O simplifies connection to external transceivers. The key design consideration is timing closure: external interfaces must be constrained correctly, and the 1.2 V FPGA core rails require stable, decoupled supply delivery for reliable operation.
Recommended
Instrumentation and Data Acquisition
The XC3S400-4FTG256C can consolidate acquisition control, digital filtering, calibration tables, and test sequencing around a sensor or analog front end. Its 8,064 logic cells are useful for parallel sampling pipelines and fixed-point signal processing, while the 264 I/O support sensors, counters, displays, and control registers. Designers should allocate pins according to the FTG256 package drawing and assess clock jitter and skew against the target sampling rate, because package-level routing and supply integrity can limit system performance.
Recommended
Video Timing and Display Control
The XC3S400-4FTG256C can be evaluated for pixel timing, character generation, overlay processing, and control-plane logic in embedded video systems. Programmable logic allows horizontal and vertical counters, blanking intervals, and memory interfaces to be implemented in parallel rather than through a microcontroller loop. The 8,064-cell and 264-I/O resources support moderate multi-plane timing functions. Video designs must still verify supported I/O standards, clocking limits, and external memory timing against the specific Spartan-3 performance data.
Recommended
Embedded System Control Hub
The XC3S400-4FTG256C is well suited to an FPGA-centered embedded hub that combines boot control, bus arbitration, watchdog logic, peripheral interfacing, and data routing. Its programmable structure allows hardware behavior to be updated through the configuration bitstream while avoiding a fixed hardware revision for every change. The commercial temperature range makes it appropriate for indoor industrial or commercial equipment. Firmware teams should define configuration memory, startup sequencing, clock sources, and watchdog recovery before finalizing the FPGA implementation.
Recommended
Digital Signal Processing Front End
The XC3S400-4FTG256C can implement fixed-point filters, correlators, counters, and parallel data conditioning in hardware. Using 8,064 logic cells, a designer can trade between parallel channels and deeply pipelined sequential logic while using the 264-I/O interface for converters, memories, and test points. Performance depends on a clean clock and careful timing constraints. Use the family documentation to validate the selected speed grade, supported memory interfaces, I/O standards, and maximum operating conditions before sign-off.
Recommended
Recommended Products Summary
Engineering reference data for XC3S400-4FTG256C — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | XC3S400A-4FTG256C | XC3S500E-4FTG256C | XC3S400-4FT256C | XC3S400-4FTG256I | XC3S400-4FT256I |
|---|---|---|---|---|---|---|
| Package | 256-LBGA (FTG256) | 256-LBGA (FTG256) | 256-LBGA (FTG256) | 256-LBGA (FT256) | 256-LBGA (FTG256) | 256-LBGA (FT256) |
| Brand | AMD | AMD | AMD | AMD | AMD | AMD |
| FPGA Family | Spartan-3 | Spartan-3A | Spartan-3E | Spartan-3 | Spartan-3 | Spartan-3 |
| Temperature Grade | Commercial | Commercial | Commercial | Commercial | Industrial | Industrial |
Key Differentiators
- Original Spartan-3 device identity (vs XC3S400A-4FTG256C)
- Commercial-temperature ordering option (vs XC3S400-4FTG256I)
- Lower logic utilization than a capacity-expanded candidate (vs XC3S500E-4FTG256C)
Design Notes
Design the 1.2 V core rail and any auxiliary I/O supplies as a complete power tree with local high-frequency decoupling and controlled sequencing. Place the closest bypass capacitors directly beside the appropriate supply and ground balls, then validate return paths on the FTG256 footprint. Check the family documentation for the exposed-pad connection, permitted voltage combinations, and startup requirements before finalizing the schematic.
Use the exact FTG256 package drawing and ball table when assigning clocks, configuration pins, and high-speed interfaces. Keep clock nets short, route series-terminated signals according to the applicable I/O standard, and avoid unnecessary stubs beneath the BGA. Because the 256-LBGA footprint is escape-routing intensive, perform layer-stackup and signal-integrity review before committing to board routing.
Do not treat a same-ball-count package as sufficient proof of drop-in compatibility. For XC3S400-4FTG256C replacements, compare the exact package drawing, speed grade, temperature suffix, supply requirements, configuration behavior, I/O standards, and timing limits. After substitution, rerun synthesis, place-and-route, timing analysis, and board-level validation rather than relying only on the ordering code.
Compliance Information
The product listing identifies the XC3S400-4FTG256C as lead-free. RoHS, REACH, halogen-free, and conflict-minerals status require confirmation from current manufacturer or lot documentation.
