What is the NGC file format?
An .ngc file is a Xilinx Native Generic Circuit netlist produced by the XST (Xilinx Synthesis Technology) synthesis tool within the Xilinx ISE Design Suite. It stores a gate-level representation of synthesized FPGA logic - primitive cells, interconnecting nets, and optional constraints - compiled from VHDL or Verilog HDL source.
In the ISE workflow, .ngc files feed into the NGDBuild tool, which merges them into an .NGD (Native Generic Database) file for place-and-route. Third-party IP vendors distributed encrypted .ngc files to protect proprietary logic while still enabling integration into customer designs.
The format is proprietary and binary with no publicly documented magic bytes. Some files begin with ASCII text resembling .EDF (EDIF) syntax, though the native Xilinx variant is binary-packed. The ngc2edif utility converts standard .ngc files to text EDIF for use in other tools; encrypted .ngc files cannot be converted and must be re-licensed for newer toolchains.
Xilinx ISE reached end of life in October 2013 (final version 14.7), and AMD's successor Vivado Design Suite does not support .ngc for UltraScale or newer devices. For 7-series designs, Vivado accepts .ngc via ngc2edif conversion. The .ngc format is therefore a legacy artifact tied exclusively to EOL ISE tooling.
Security & safety
RISK: LOWFPGA netlist files contain no executable code for host CPUs; safe to handle on any OS. Encrypted NGC files protect proprietary IP vendor logic.
Format details
in a nutshell- Nintendo GameCube ROM image - Some GameCube disc image files use the .ngc extension; completely unrelated to Xilinx FPGA netlists.
Programs that open NGC files
Windows2 apps
Xilinx ISE Design Suite 14.7
Free (legacy download, requires amd acco Add NGC as source in ISE Project Navigator; it is used automatically in the implementation flow.
AMD Vivado Design Suite (via ngc2edif)
Freemium Convert NGC to EDIF first: run ngc2edif design.ngc design.edf, then import EDIF into Vivado. 
Linux2 apps
Xilinx ISE Design Suite 14.7
Free (legacy) Preferred legacy platform; run ngdbuild design.ngc to proceed with implementation.
AMD Vivado Design Suite
Freemium Use ngc2edif to convert, then import EDIF. Works for 7-series devices only. Technical details
deep spec| Encoding | Binary proprietary (EDIF-derived, binary-packed) |
| Byte order | Little-endian |
| Netlist level | Gate-level (FPGA primitives and mapped library cells) |
| Encryption | Optional - IP core netlists may be encrypted for 3rd-party distribution |
| Typical file size | 10 KB - 50 MB (scales with design complexity) |
| Produced by | XST (Xilinx Synthesis Technology) within ISE Design Suite |
| Consumed by | NGDBuild, which outputs .ngd for place-and-route |
| Conversion tool | ngc2edif converts standard .ngc to EDIF text format |
| Encrypted files | Cannot be converted with ngc2edif; require re-licensing for Vivado |
| Toolchain status | ISE Design Suite EOL October 2013; final version 14.7 |
| Successor format | DCP (Design Checkpoint) in AMD Vivado Design Suite |
| Device scope | Xilinx 7-series and older (ISE era); not supported for UltraScale/UltraScale+ |
| Associated OS | Windows, Linux |
| Released | Late 1990s with Xilinx ISE / XST synthesis tool |
| Latest version | ISE 14.7 (final ISE release, October 2013); NGC format frozen since then |
| Specification | www.xilinx.com |
NGC conversions
Community Q&A
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