AMD XC3S400-4FG456C

Overview

XC3S400-4FG456C from AMD (formerly Xilinx) is a Spartan-3 FPGA with 400,000 system gates, 241 I/O pins, and configured in a 456-pin Fine-Pitch Ball Grid Array (FBGA) package. It operates at -4 speed grade (tPD = 4.5 ns), supports SelectIO™ standards up to 333 Mbps, and targets cost-sensitive embedded control and interface bridging applications.

For engineers reviewing the XC3S400-4FG456C datasheet, pinout, applications, or equivalent options, key selection criteria include I/O count, speed grade timing closure, FBGA456 thermal-mechanical compatibility, and legacy Spartan-3 design migration support.

Technical Context

The XC3S400-4FG456C implements a hierarchical FPGA architecture with configurable logic blocks (CLBs), distributed RAM, block RAM (176 Kbits), and dedicated multipliers. It uses 90 nm CMOS process technology and supports JTAG boundary-scan IEEE 1149.1 for programming and testing.

Configuration is performed via Master Serial mode using external PROM or through JTAG. The device includes Digital Clock Managers (DCMs) providing clock synthesis, phase shifting, and duty-cycle correction across four independent clock domains.

Key Specifications

Pinout & Package

XC3S400-4FG456C is housed in a 456-ball fine-pitch BGA (FG456) package with 241 user I/Os, 8 global clock inputs, configuration pins (e.g., INIT_B, PROGRAM_B, DONE), and dedicated power/ground balls arranged per Xilinx SPARTAN-3 FPGA Package and Pinout Specification DS099.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar FPGA-based logic implementation applications.

Compared with XC3S400-4FG456C, XC3S500E-4FG456C provides drop-in logic capacity upgrade within identical mechanical and thermal constraints, while XC6SLX45-3FGG484I delivers architectural improvements at the cost of full hardware and software redesign.

Availability

XC3S400-4FG456C is available at Aetrix Electronics and suitable for industrial automation, legacy system refurbishment, and test equipment requiring stable component supply throughout extended production cycles.

Supply support for XC3S400-4FG456C includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

AMD acquired Xilinx in 2022 and maintains legacy Spartan-3 product support, documentation, and cross-reference tools for industrial and aerospace customers.

The Spartan-3 family was designed for cost-optimized, high-volume embedded logic replacement-targeting applications where ASIC NRE cost or lead time is prohibitive and CPLD density is insufficient.

FAQ

What is the maximum operating frequency supported by the XC3S400-4FG456C?

The XC3S400-4FG456C supports internal clock frequencies up to 280 MHz depending on design placement and routing. Its -4 speed grade guarantees a maximum input-to-output delay (tPD) of 4.5 ns for critical paths, enabling reliable timing closure in synchronous logic implementations. Actual achievable frequency depends on resource utilization and clock domain complexity in the implemented design.

Does the XC3S400-4FG456C support JTAG programming?

Yes, the XC3S400-4FG456C fully supports IEEE 1149.1 JTAG boundary-scan for in-system programming, debugging, and board-level interconnect testing. The TCK, TMS, TDI, and TDO pins are dedicated and electrically compatible with standard JTAG adapters. Configuration via JTAG does not require external PROM and is commonly used during development and field updates.

What voltage levels are supported on the I/O banks of the XC3S400-4FG456C?

The XC3S400-4FG456C supports multiple I/O standards per bank: LVCMOS 1.2/1.5/1.8/2.5/3.3 V, LVTTL, PCI, HSTL Class I/II, and SSTL2 Class I/II. Each bank is independently powered (VCCO), allowing mixed-voltage operation across different interface sections. VCCINT remains fixed at 1.2 V for core logic.

Is the XC3S400-4FG456C still in production or subject to obsolescence?

The XC3S400-4FG456C is no longer in active production by AMD/Xilinx but remains available through authorized distributors and Aetrix Electronics' legacy component program. It is classified as a mature product with documented last-time-buy dates; Aetrix provides lifecycle coordination and long-term stocking to support ongoing industrial and defense programs.

Can the XC3S400-4FG456C replace the XC3S200-4FG456C in an existing design?

Yes, the XC3S400-4FG456C is pin-compatible and functionally upward-compatible with the XC3S200-4FG456C in the same FG456 package. It shares identical pinout, configuration interface, and electrical characteristics, allowing direct substitution to increase logic capacity without PCB modification. Timing analysis must be re-verified due to higher resource utilization potential.