Input/output Buffer Information Specification (IBIS) is a specification of a method for integrated circuit vendors to provide information about the input/output buffers of their product to their prospective customers without revealing the intellectual property of their implementation and without requiring proprietary encryption keys. From version 5.0, specification contains two separate types of models, "traditional IBIS" and "IBIS-AMI." The traditional 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, as well as the values of certain parasitic components. It is a standard data exchange format for exchanging modeling information among

semiconductor A semiconductor is a material which has an electrical conductivity value falling between that of a conductor, such as copper, and an insulator, such as glass. Its resistivity falls as its temperature rises; metals behave in the opposite way. ...

device suppliers,

simulation A simulation is the imitation of the operation of a real-world process or system over time. Simulations require the use of models; the model represents the key characteristics or behaviors of the selected system or process, whereas the ...

software Software is a set of computer programs and associated software documentation, documentation and data (computing), data. This is in contrast to Computer hardware, hardware, from which the system is built and which actually performs the work. ...

suppliers, and

end user In product development, an end user (sometimes end-user) is a person who ultimately uses or is intended to ultimately use a product. The end user stands in contrast to users who support or maintain the product, such as sysops, system administrat ...

s. Traditional IBIS models are generally used instead of

SPICE A spice is a seed, fruit, root, bark, or other plant substance primarily used for flavoring or coloring food. Spices are distinguished from herbs, which are the leaves, flowers, or stems of plants used for flavoring or as a garnish. Spices a ...

models to perform various

board Board or Boards may refer to: Flat surface * Lumber, or other rigid material, milled or sawn flat ** Plank (wood) ** Cutting board ** Sounding board, of a musical instrument * Cardboard (paper product) * Paperboard * Fiberboard ** Hardboa ...

level

signal integrity Signal integrity or SI is a set of measures of the quality of an electrical signal. In digital electronics, a stream of binary values is represented by a voltage (or current) waveform. However, digital signals are fundamentally analog in nature, ...

(SI) simulations and timing analyses. IBIS models could be used to verify signal integrity requirements, especially for high-speed products. IBIS-AMI models run in a special-purpose SerDes channel simulator, not in a SPICE-like simulator, and consist of two text files (*.ibs and *.ami) plus a platform-specific machine code executable file (*.dll on Windows, *.so on Linux). IBIS-AMI support statistical and so-called time-domain channel simulations, and three types of IC model ("impulse-only," "GetWave-only," and "dual mode")

History

Intel Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California, Santa Clara, California. It is the world's largest semiconductor chip manufacturer by revenue, and is one of the devel ...

initiated IBIS in the early 1990s. 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 a standard exists. Many semiconductor vendors supply IBIS models and many EDA vendors sell IBIS-compliant software tools. In 1995 the IBIS Open Forum teamed with the

American National Standards Institute The American National Standards Institute (ANSI ) is a private non-profit organization that oversees the development of voluntary consensus standards for products, services, processes, systems, and personnel in the United States. The organ ...

Electronic Industries Alliance The Electronic Industries Alliance (EIA; until 1997 Electronic Industries Association) was an American standards and trade organization composed as an alliance of trade associations for electronics manufacturers in the United States. They deve ...

(ANSI/EIA). IBIS version 2.1 was the first version released by the new alliance. It added the ability to simulate ECL and PECL buffers as well as differential lines. IBIS 3.2 allows for a package model description along with an electrical board description. IBIS Version 5.0 was ratified by the IBIS Open Forum on August 29, 2008. Compared to the previous version (IBIS 4.2, ANSI/EIA-656-B), it adds a new flow based not on SPICE transient but on a channel simulator (called ''a''lgorithmic ''m''odel application program ''i''nterface or AMI flow), power integrity, and EMC checking features. For power integrity, it uses Touchstone 2.0 S-parameter files with per-port reference impedance specification. Version 5.1 was ratified on August 24, 2012. Important changes included the so-called "flow BIRD" which resolved many ambiguities in the IBIS AMI flow. The IBIS Open Forum became an official subcommittee of

TechAmerica TechAmerica is a United States technology trade association. It was formed from the merger of AeA (formerly known as the America Electronics Association), the Cyber Security Industry Alliance (CSIA), the Government Electronics & Information Techno ...

in January 2009. Upon its purchase of the standards program of TechAmerica in July 2013,

SAE International SAE International, formerly named the Society of Automotive Engineers, is a United States-based, globally active professional association and standards developing organization for engineering professionals in various industries. SAE Internatio ...

became the parent of IBIS Open Forum. IBIS is an "industry program" within the SAE Industry Technologies Consortia (SAE ITC) trade association.

Evolution

IBIS is an evolving standard with many proposed changes submitted to IBIS Open Forum for consideration. Proposed changes are called BIRDs (Buffer Issue Resolution Documents), a play on the word ''

ibis The ibises () (collective plural ibis; classical plurals ibides and ibes) are a group of long-legged wading birds in the family Threskiornithidae, that inhabit wetlands, forests and plains. "Ibis" derives from the Latin and Ancient Greek word f ...

'', a type of bird. Version 6.0 was ratified on September 20, 2013. Changes included an IBIS‐AMI extension for mid-channel repeaters, new parameters for

jitter In electronics and telecommunications, jitter is the deviation from true periodicity of a presumably periodic signal, often in relation to a reference clock signal. In clock recovery applications it is called timing jitter. Jitter is a significa ...

and noise in IBIS-AMI, and analog buffer modeling improvements. Version 6.1 was ratified on September 11, 2015. Changes included support of PAM-4 in IBIS-AMI, the addition of a new Initial Delay keyword, and additional options for overclocking. Version 7.0 was ratified on March 15, 2019. Changes included support for Touchstone and IBI-ISS (SPICE) modeling of interconnections, and modeling of back-channel link training protocols using IBIS-AMI models. Work on enhancing the specification can be tracked in the work-in-progress section of the IBIS Open Forum website.

Notes

External links

IBIS Home
{{DEFAULTSORT:Input output Buffer Information Specification Electronic design automation