XC3S400-4PQG208C - 400K Gate Spartan-3 FPGA | AMD
MPN: XC3S400-4PQG208C ✗ End of LifeXC3S400-4PQG208C Overview
A field-programmable gate array is a semiconductor whose logic, interconnections, and signal-processing blocks are configured after manufacture. The FPGA category sits above programmable-logic devices and enables parallel hardware implementation for control, communications, data acquisition, and signal-processing tasks. Compared with a microcontroller executing instructions sequentially, an FPGA performs configured operations in parallel, making it useful when deterministic response, high I/O density, or hardware-level protocol handling is important.
The Spartan-3 architecture combines configurable logic with dedicated resources for block RAM, digital signal processing, and clock management. In the XC3S400-4PQG208C, 8,064 logic cells provide the programmable fabric, while 141 device inputs and 141 device outputs support external interfaces. The 400,000 system-gate figure describes the family's logic capacity in conventional gate-equivalent terms, whereas 8,064 logic cells and 192 configurable logic blocks better characterize the physically available fabric. A maximum clock frequency of 630 MHz gives a useful upper reference for registered designs.
The 1.2 V internal core supply separates FPGA core power from the I/O supply requirements, which depend on the selected bank voltage and interface mix. External memory interfaces, differential signaling, high-speed clock distribution, and control inputs require careful board-level planning. The large leaded PQFP-208 footprint offers direct PCB access to many I/O pins and is compatible with conventional manufacturing and inspection processes, but its 0.5 mm pitch requires fine-pitch assembly and careful fanout routing.
Typical applications include industrial automation controllers, data-acquisition systems, sensor and motion-control interfaces, communications equipment, and compact embedded processing platforms. The ample I/O count is particularly useful when the design combines parallel control signals with memory, serial transceivers, or multiple peripheral buses. Designers should reserve pins for configuration and error handling and should verify all voltage-domain constraints against the pin-description table in the manufacturer datasheet.
A critical implementation consideration is power planning. Dynamic current depends on logic utilization, switching activity, clock frequency, and I/O standards, so the final supply design should accommodate both the 1.2 V core rail and the required I/O rails. Decoupling, via stitching, ground-plane continuity, and clock routing can materially affect performance and reliability. This page combines device specifications, same-family drop-in options, application guidance, and design notes to support faster component selection and implementation.
Drop-in alternatives for XC3S400-4PQG208C — 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 XC3S400-4PQG208C (same form factor and footprint) — differing in Device Type, System Gates, Logic Cells, Package, Process Technology.
XC3S400-5PQG208C
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
XC3S400-4PQG208I
✅ Drop-In ⚠️ Specs UnverifiedContact for price
View Datasheet →XC3S400-5PQG208I
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
XC3S400-3PQG208C
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
XC3S400-2PQG208C
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
XC3S400-4PQG208C Maximum Ratings & Electrical Characteristics
| Device Type | Spartan-3 field-programmable gate array |
| System Gates | 400,000 gates |
| Logic Cells | 8,064 cells |
| Configurable Logic Blocks | 192 blocks |
| Core Supply Voltage | 1.2 V nominal |
| Maximum Clock Frequency | 630 MHz |
| Device Inputs | 141 inputs |
| Device Outputs | 141 outputs |
| Total I/O Count | 141 I/O |
| Package | 208-pin PQFP |
| Package Body Size | 30.60 mm × 30.60 mm |
| Operating Temperature | 0°C to 85°C |
| Performance Grade | -4 |
| Temperature Grade | Commercial |
| Process Technology | CMOS |
| Mounting Type | Surface mount |
| Lead-Free Status | Lead-free |
XC3S400-4PQG208C 30.60 mm × 30.60 mm Pin Configuration Guide
Pin configuration for XC3S400-4PQG208C (30.60 mm × 30.60 mm 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 XC3S400-4PQG208C.
Refer to the datasheet for full pin configuration.
Typical Applications
XC3S400-4PQG208C is suitable for 6 applications: Industrial Automation Controller, Data Acquisition System, Sensor and Motion Interface, Industrial Communication Gateway, Video Signal Conditioning, Embedded Control Platform.
Industrial Automation Controller
The XC3S400-4PQG208C fits industrial automation because its 8,064 logic cells can host parallel control logic while 141 I/O support encoders, limit switches, actuators, and digital plant equipment. The 630 MHz maximum clock provides ample timing headroom for deterministic state machines and communication engines. Using the commercial 0°C to 85°C part is appropriate for controlled enclosures; wider temperature environments call for the industrial suffix. Configuration data should be stored in a reliable boot interface and validated for power-loss recovery.
Recommended
Data Acquisition System
The XC3S400-4PQG208C can implement parallel acquisition, digital filtering, and packet formatting in configurable logic. Its 141 I/O provide substantial connectivity for multi-channel data capture, while the 1.2 V core and 630 MHz maximum clock support demanding sampling pipelines. Pair the FPGA with suitable analog-to-digital converters and memory, and use registered interfaces to constrain timing. Ensure the selected I/O standard, voltage, and timing of every acquisition channel satisfy the device's bank and pin rules.
Recommended
Sensor and Motion Interface
The Spartan-3 fabric is well suited to collecting digital sensor outputs, decoding position feedback, and coordinating motion-control signals in parallel. The XC3S400-4PQG208C offers 400,000 system gates, 8,064 logic cells, and 141 I/O for integrating multiple buses and timing channels. Place input conditioning close to the FPGA, observe all I/O voltage-domain constraints, and account for clock jitter on encoder or resolver interfaces. The -4 performance grade supports robust control pipelines when timing is closed against the manufacturer timing constraints.
Recommended
Industrial Communication Gateway
The XC3S400-4PQG208C can bridge multiple physical-layer interfaces by combining configurable logic, block RAM, and dedicated serial connectivity in one device. Its 141 I/O support parallel buses and status signals, while programmable state machines can frame packets, translate protocols, and buffer traffic without a separate processor. Pair it with transceivers whose voltage, direction, and timing characteristics match the selected I/O standard. Validate bit rates, propagation delay, termination, and isolation requirements in the complete communications subsystem.
Recommended
Video Signal Conditioning
The programmable Spartan-3 architecture can implement pixel alignment, timing generation, data masking, and format conversion in parallel hardware. The XC3S400-4PQG208C provides 8,064 logic cells for logic-heavy pipelines and 141 I/O for connecting source and destination interfaces. Video designs must assign compatible I/O standards and preserve byte-lane mapping across the device boundary. For higher-resolution or higher-refresh implementations, complete timing analysis and power budgeting are necessary because the 630 MHz value is a device reference rather than a guaranteed system throughput.
Recommended
Embedded Control Platform
The XC3S400-4PQG208C can act as the programmable core of an embedded control platform when deterministic hardware logic and numerous peripheral connections are required. Its dedicated fabric supports parallel state machines, timers, protocol engines, and data buffers without relying on instruction-by-instruction execution. The 208-pin PQFP offers 141 user I/O, reducing the need for multiple interface expanders. Designers should plan a reproducible configuration mechanism, manage startup sequencing for the 1.2 V core and I/O rails, and include a recovery path for incomplete configuration.
Recommended
Recommended Products Summary
Engineering reference data for XC3S400-4PQG208C — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | XC3S400-5PQG208C | XC3S400-4PQG208I | XC3S400-5PQG208I | XC3S400-3PQG208C | XC3S400-2PQG208C |
|---|---|---|---|---|---|---|
| Brand | AMD | AMD | AMD | AMD | AMD | AMD |
| Package | PQFP-208 | PQFP-208 - same | PQFP-208 - same | PQFP-208 - same | PQFP-208 - same | PQFP-208 - same |
| Device Type | Spartan-3 FPGA | Spartan-3 FPGA | Spartan-3 FPGA | Spartan-3 FPGA | Spartan-3 FPGA | Spartan-3 FPGA |
| System Gates | 400,000 gates | 400,000 gates | 400,000 gates | 400,000 gates | 400,000 gates | 400,000 gates |
| Logic Cells | 8,064 cells | 8,064 cells | 8,064 cells | 8,064 cells | 8,064 cells | 8,064 cells |
| Configurable Logic Blocks | 192 blocks | 192 blocks | 192 blocks | 192 blocks | 192 blocks | 192 blocks |
| Core Supply Voltage | 1.2 V nominal | 1.2 V nominal | 1.2 V nominal | 1.2 V nominal | 1.2 V nominal | 1.2 V nominal |
| Performance Grade | -4 | -5 | -4 | -5 | -3 | -2 |
| Temperature Grade | Commercial, 0°C to 85°C | Commercial | Industrial | Industrial | Commercial | Commercial |
Key Differentiators
- Commercial-temperature option with a -4 performance grade (vs XC3S400-4PQG208I)
- Timing-margin option without changing the commercial grade (vs XC3S400-5PQG208C)
- Lower-speed drop-in for cost-oriented legacy designs (vs XC3S400-3PQG208C)
Design Notes
Design the 1.2 V core rail and every required I/O rail independently. The core can experience high configuration-current demand during startup, so the regulator and bulk-decoupling network must support both normal operation and configuration transients. Use the manufacturer datasheet for voltage tolerance, decoupling values, and startup sequencing rather than deriving limits from the nominal 1.2 V figure alone.
Place required input and output capacitors close to the associated PQFP-208 power terminals. The 0.5 mm lead pitch limits escape-routing space, so assign package pins according to electrical function before routing. Keep configuration, clock, and high-fanout nets away from noisy inputs and provide continuous ground planes beneath the device and its supporting circuitry.
Use short, impedance-controlled routes for clock inputs and external memory interfaces, with return paths that do not cross split supply or ground planes. Although the maximum clock frequency is 630 MHz, actual edge rate depends on the selected I/O standard, loading, and routing. Complete static and dynamic timing analysis using the manufacturer constraints for the exact speed grade and I/O assignment.
Do not treat all 141 I/O terminals as interchangeable user signals; the 208-pin package also contains power, ground, configuration, clock, and control functions. Follow the pin-description table when assigning banks and voltage standards. When substituting another Spartan-3 grade, verify the complete bitstream and timing behavior rather than relying only on the package code.
Compliance Information
The device is identified as lead-free. RoHS, REACH, halogen-free, and conflict-minerals status are not confirmed by the cited technical information.
