There is only one file type that uses the .NGD extension:
Xilinx Netlist File
File created with Xilinx PLC (programmable logic controller) design software; contains a netlist, which includes the connections and components for the integrated circuit design; converted from a .NGC file and can be generated to a bitstream (.BIT) file for configuring FPGAs (field-programmable gate arrays).
|Xilinx ISE Design Suite||Commercial|
Updated: December 13, 2011