This document provides background on AC coupling and differential signals from a design perspective (why and how they are used). For those of us that are not high speed designers. 

This document provides general background on AC coupling Capacitor characteristics and their effects on AC signaling.

This is the Excel spreadsheet used to generate the Capacitance vs Frequency Graph in the Coupling Capacitors document. Both the termination resistance and degradation values may be changed to estimate the expected board level requirements.

This document provides a graphical view of a board level fault on an AC-coupled differential net. Figure A depicts a differential net with no fault. Figure B adds an open to the positive side of the differntial pair and Figure C shows the circuit resulting from the fault.

This document is the result of over a year of work between Cisco and its MSA partners. This solution is one of two that will be presented at the Working Group Meeting on May 21, 2001.

This document will be presented at the Working group meeting on May 21st by Agilent. This solution was developed as a follow on to the pioneering work done by the MSA partners. 

This document discusses the practical issues in BScan detection and diagnosis of defects. (There is a lot of misunderstanding about this topic. You can see that "Murphy's Law" is alive and well.) Ideally, when AC Extest is formulated the diagnostic processes we use today will require little modification yet produce good results. 

This document describes AC coupled interconnection test using a simple peak detector circuit. The method was succesfully implemented in a test chip of Philips with only little overhead. 

This document analyzes three AC Extest technologies and three DFT approaches for differential signaling. This forms a taxonomy of 9 possible ways to solve the AC Extest problem. Three proposals (Cisco MSA, Agilent Frequency-based, Agilent Edge based) are examined. The Philips edge-based proposal could be considered a subset of the Agilent proposal. (There is an Acrobat error issued on slide 4, please ignore.) 

This document proposes an aggressive schedule for the development of an AC EXTEST standard. 

This drawing shows the treatment options in 1149.1 and 1149.4 for various cases of differential signaling. (The actual clauses in the standards are given in parenthesis.) 

This presentation by a high-speed IC designer (Agilent's Benny Lai) points out some weaknesses of the timing-based approach, and how the frequency-based approach was later developed to overcome these problems.

This document is a first cut evaluation criteria sheet for proposed AC EXTEST solutions

This document is a description of possible faults in AC Coupled circuits.

This document provides simulation results for possible faults in AC Coupled circuits.

This document provides a description of the AMCC input buffer design.

Patent/licensing agreement from Cisco.

Working Document for AC_EXTEST chips tiger team recommendations.

Defect Model And Board/system Requirements.

Tools Tiger Team Evaluation.

Agilent License Statement.

Agilent AC Extest Proposal.

Proposed additions to the Integrating Receiver proposal.

This document provides simulation results for possible faults in AC Coupled LVDS circuit.

Proposal made by Kevin Nary on Sept. 19 , 2000.

A description of the various forms of Board level noise seen in the test environment.

The effect of noise for AC-EXTEST.

This draft includes a massive set of changes and additions in Clause 5 (Instructions) and Clause 6 (Pin Implmentation) per the work done by the Chip Tiger team. First "real" specification of the test receiver. Very few changes elsewhere.

IEEE-SA Standards Board Project Authorization Request (PAR) Form

Please Focus on the Change Bars. A complete description of the Cisco Input buffer is to follow.