IBIS Version 6.0
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2 STATEMENT OF INTENT
In order to enable an industry standard method to electronically transport IBIS modeling data
between semiconductor vendors, EDA tool vendors, and end customers, this template is proposed.
The intention of this template is to specify a consistent format that can be parsed by software,
allowing EDA tool vendors to derive models compatible with their own products.
One goal of this template is to represent the current state of IBIS data, while allowing a growth
path to more complex models/methods (when deemed appropriate). This would be accomplished
by a revision of the base template, and possibly the addition of new keywords or categories.
Another goal of this template is to ensure that it is simple enough for semiconductor vendors and
customers to use and modify, while ensuring that it is rigid enough for EDA tool vendors to write
reliable parsers.
Finally, this template is meant to contain a complete description of the I/O elements on an entire
component. Consequently, several models will need to be defined in each file, as well as a table
that equates the appropriate buffer to the correct pin and signal name.
Version 6.0 of this electronic template was finalized by an industry-wide group of experts
representing various companies and interests. Regular “IBIS Open Forum” meetings were held to
accomplish this task.
Changes to the specification are proposed and approved through Buffer Issue Resolution
Documents (BIRDs) . All submitted BIRDs may be viewed through the IBIS Open Forum website,
http://www.eda.org/ibis/.
Commitment to Backward Compatibility. Version 1.0 was the first valid IBIS ASCII file format.
It represents the minimum amount of I/O buffer information required to create an accurate IBIS
model of common CMOS and bipolar I/O structures. Future revisions of the ASCII file added
items considered to be “enhancements” to Version 1.0 to allow accurate modeling of new, or other
I/O buffer structures. Consequently, all future revisions are considered supersets of Version 1.0,
allowing backward compatibility. In addition, as modeling platforms develop support for revisions
of the IBIS ASCII template, all previous revisions of the template must also be supported.
Version 1.1. Version 1.1, (published as “ver1_1.ibs”) is conceptually the same as the 1.0 version
of the IBIS ASCII format (published as "ver1_0.ibs"). However, various comments have been
added for further clarification.
Version 2.0. Version 2.0 maintains backward compatibility with Versions 1.0 and 1.1. All new
keywords and elements added in Version 2.0 are optional. A complete list of changes to the
specification is in the IBIS Version 2.0 Release Notes document (“ver2_0.rn.txt”). Some changes
are also documented in 14 BIRDs:
BIRD2.2 Requiring VIH VIL thresholds for input devices
BIRD3 Multiple power supplies and references
BIRD4 ECL Extensions
BIRD5.4 Pin Mapping for Ground Bounce Simulation
BIRD6.2 Differential Pin Specification
BIRD7.2 Open Specification Completion
BIRD8.2 Specification of V/I data monotonicity
BIRD9.3 Terminator Specification
BIRD10.2 Describing coupling effects in package models
