Input Output Buffer Information Specification
IBIS (Input Output Buffer Information Specification) is a method of providing information about the input/output buffers of an integrated circuit to the outside world. It is an EIA (Electronic Industries Alliance) standard. The idea of IBIS is to provide the behavioral aspects of a circuit without providing the actual circuit information to the user. The model is generated in text format and consists of a number of tables that captures Current vs. Voltage (IV) and Voltage vs. Time (Vt) characteristics of the buffer. IBIS models are generally used in lieu of SPICE models, to perform various board level signal integrity (SI) simulations and timing analyses.
Intel initiated IBIS in the early 1990s.<ref> Template:Cite paper </ref> Intel needed to have all of its divisions to present a common standardized model format to its external customers. This prompted Intel to solicit EDA vendors to participate in the development of a common model format. The first IBIS model, version 1.0, was aimed at describing CMOS circuits and TTL I/O buffers.
As IBIS evolved with the participation of more companies and industry members, an IBIS Open Forum was created to promote the application of IBIS as a simulation tool format and to make sure that standards exists. Currently, over 15 semiconductor vendors support IBIS and over 8 EDA vendors develop software for IBIS. In 1995 the IBIS Open Forum teamed with the Electronic Industries Alliance (EIA). Since then the EIA/IBIS Open Forum oversaw all technical developments of IBIS. IBIS version 2.1 was the first version released by the new alliance. IBIS, version 2.1, has developed the ability to simulate ECL and PECL buffers as well as differential lines. The current version, IBIS 3.2, allows for a package model description along with an electrical board description.
The requirements for generating an IBIS model is defined in a specification and is managed by an industry organization called the IBIS Open Forum. The IBIS Open Forum is an official subcommittee of the GEIA (Government Electronics & Information Technology Association).<ref>IBIS FAQ</ref> The current IBIS specification is version 4.2 ratified June 2006.