1. A method of creating a design-specific input/output (I/O) model document, the method comprising: reading a plurality of I/O pin models corresponding to available I/O pin profiles on a target device; identifying I/O pins of the target device that are used by a circuit design; determining an I/O pin profile for each I/O pin of the target device that is used by the circuit design; selecting an I/O pin model from the plurality of I/O pin models for each I/O pin of the target device that is used by the circuit design according to the I/O pin profiles; generating, by a processor, the design-specific I/O model document for the circuit design by including each selected I/O pin model within the design-specific I/O model document; reading generic package parasitic information specifying package parasitic information for the target device; and including package parasitic information, selected from the generic package parasitic information, for each selected I/O pin model within a design-specific package parasitic document.