Obsolete device
XC3S400A replacement options
The AMD Xilinx XC3S400A has been discontinued by the manufacturer. There are two ways forward, and for most people reading this the first one is the answer: keep the design and source the part. Changing device means a board revision, so it is only worth it if you are redesigning anyway.
What the manufacturer says
AMD Xilinx's discontinuation notice lists no direct replacement for all 18 XC3S400A parts it covers. Where the manufacturer offers nothing equivalent, the remaining supply is the only way to keep the board unchanged.
From the manufacturer's discontinuation notice: Product Discontinuation Notice for XC9500XL, CoolRunner XPLA 3, CoolRunner II, Spartan II,
1. Keep the design — source the XC3S400A
Discontinued parts are still traded. We hold 18 orderable XC3S400A parts — send the exact code and quantity and we'll come back with stock and pricing, including date-code and traceability requirements.
Request a quote| Part number | Package | Pins | Speed | Temperature |
|---|---|---|---|---|
| XC3S400A-4FG320C | FG320 | 4 | Commercial | |
| XC3S400A-4FG320I | FG320 | 320 | 4 | Industrial |
| XC3S400A-5FG320C | FG320 | 5 | Commercial | |
| XC3S400A-4FG400C | FG400 | 400 | 4 | Commercial |
| XC3S400A-4FG400I | FG400 | 400 | 4 | Industrial |
| XC3S400A-5FG400C | FG400 | 5 | Commercial | |
| XC3S400A-4FGG320C | FGG320 | 320 | 4 | Commercial |
| XC3S400A-4FGG320I | FGG320 | 320 | 4 | Industrial |
| XC3S400A-5FGG320C | FGG320 | 320 | 5 | Commercial |
| XC3S400A-4FGG400C | FGG400 | 400 | 4 | Commercial |
| XC3S400A-4FGG400I | FGG400 | 400 | 4 | Industrial |
| XC3S400A-5FGG400C | FGG400 | 400 | 5 | Commercial |
| XC3S400A-4FT256C | FT256 | 256 | 4 | Commercial |
| XC3S400A-4FT256I | FT256 | 256 | 4 | Industrial |
| XC3S400A-5FT256C | FT256 | 5 | Commercial | |
| XC3S400A-4FTG256C | FTG256 | 256 | 4 | Commercial |
A different package or speed grade of the same device is the closest thing to a like-for-like change: the silicon is the same, so only the footprint or timing differs. It still needs checking against your board.
2. Redesigning? Current devices of similar capacity
AMD Xilinx devices still in production with comparable logic capacity, closest first. These are a shortlist to evaluate, not equivalents: none of them is pin-compatible with the XC3S400A, and none is recommended by the manufacturer as its successor. We select them by capacity from the data on this site.
| Device | Family | Logic cells | vs XC3S400A | Block RAM | DSP | Parts |
|---|---|---|---|---|---|---|
| XC3S400A | Spartan-3 | 8,064 | The original | 360 Kb | 18 | |
| XCSU10P | Spartan UltraScale+ | 10,938 | 1.4× the logic cells | 1,728 Kb | 24 | 4 |
| XC7S15 | Spartan-7 | 12,800 | 1.6× the logic cells | 360 Kb | 20 | 15 |
| XC7A12T | Artix-7 | 12,800 | 1.6× the logic cells | 720 Kb | 40 | 9 |
| XA7A12T | Artix-7 | 12,800 | 1.6× the logic cells | 720 Kb | 2 | |
| XA7S15 | Spartan-7 | 12,800 | 1.6× the logic cells | 360 Kb | 20 | 2 |
| XC7A15T | Artix-7 | 16,640 | 2.1× the logic cells | 900 Kb | 45 | 25 |
What to check before changing device
Footprint and pinout
Ball count, pitch and pin assignment all differ between families. A new device means a new layout.
I/O voltages and banks
Supported I/O standards, bank voltages and the number of banks change between generations.
Core and I/O supplies
Newer devices usually run a lower core voltage and need a different power tree.
Configuration
Flash type, configuration mode and boot timing are family-specific.
Tools and IP
The design has to be rebuilt in the current toolchain, and IP cores may need replacing or re-licensing.
Temperature and lifetime
Check the grade you need exists, and how long the new family is expected to stay in production.
Where a design cannot be revised — certified equipment, long-life industrial and defence builds — sourcing the original is normally the cheaper route, even at obsolete pricing.