Happy Thirteenth Birthday IBIS – Guest Post from Michael Mirmak

(Syndicated content from http://signal-integrity-tips.com/2008/happy-thirteenth-birthday-ibis-guest-post-from-michael-mirmak/)

Signal Integrity Tips continues our mini-celebration of the anniversary of IBIS 2.1 ANSI/EIA-656 with this guest post from Michael Mirmak, Chair, IBIS Open Forum. Michael writes:

The year 1995 was certainly one of firsts and achievements. NASDAQ crossed the 1000 mark for the first time. Microsoft released Windows 95. eBay and Yahoo! were founded. The first planet outside our solar system was discovered. And, as Colin kindly noted, IBIS 2.1 was formally approved as a US national standard, ANSI/EIA-656 on December 13th, 1995.

IBIS, the I/O Buffer Information Specification, was by then already a “toddler,” as version 1.0 had been released to the public in June, 1993. It was the answer to a strong industry desire for a non-proprietary behavioral format for buffer signal integrity data that could be shared between EDA tools, system designers and IC vendors alike.

Version 2.1 was revolutionary, with the size of the specification almost tripling due to the added features. The simple ramps used to represent buffer transitions were supplemented with tables of voltage-versus-time data. Support for differential pins, as well as ECL buffer types, was included. Matrix-based package models were added, allowing both true pin- and pad-based analysis using a single buffer model. As a national standard and a practical approach, IBIS 2.1 defined a basic structure which has remained useful ever since.

Much has happened over the intervening 13 years. IBIS 3.2 and 4.0 defined new measurement thresholds, added driver scheduling, improved package support and even created a board description format. IBIS 4.1 and 4.2 brought IBIS together with the analog/mixed-signal world, allowing Verilog-AMS and VHDL-AMS code, as well as Berkeley SPICE elements, to be integrated into the IBIS structure. Now, with the approval of IBIS 5.0 in August of this year, combined power delivery and signal integrity modeling using the simple table-driven IBIS approach becomes a reality. And with the addition of the Algorithmic Modeling Interface (AMI), the specification expands to cover advanced serial-differential equalizer behaviors.

Not a bad list of accomplishments for a teenager.

Happy birthday, IBIS and thanks to its many contributors and users over the years.

- Michael Mirmak
Chair, IBIS Open Forum
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Happy Thirteenth Birthday IBIS

(Syndicated content from http://signal-integrity-tips.com/2008/happy-thirteent-birthday-ibis/)

After a gestation of several years, the Input/Output Buffer Information Specification (IBIS) Version 2.1 was formally ratified as ANSI/EIA-656 on December 13, 1995: IBIS turns thirteen tomorrow.

The IBIS behavioral modeling template emerged as a compromise between the need of chip vendors to protect the intellectual property in their SPICE netlists, and the need chip consumers to have an “executable datasheet” of the I/O buffers they design into their systems.

Here’s a snippet from the IBIS home page.

Introduction: IBIS is a standard for electronic behavioral specifications of integrated circuit input/output analog characteristics.

Group Objectives: In order to enable an industry standard method to electronically transport IBIS modeling data between silicon vendors, simulation software 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 simulation vendors to derive models compatible with their own products.

There are mainy excellent IBIS resources on the web including IBIS Modeling Cookbook (Senior editor: Michael Mirmak)

For a look at how our tool, Agilent ADS, uses the IBIS templates, check out this post entitled Workflow with IBIS Models.

And Happy Birthday, IBIS, from Signal Integrity Tips blog!

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