Hewlett-packard Company

William A Groves

Matthew L Snook

Rodney Browen

Thomas R Fay

Vance R Harwood

Michael A Teska

Elton C Bingham

T Michael Hendricks

This shorts test method reduces the occurence of phantom shorts and also in those cases where phantom shorts occur, reduces the time required to eliminate the phantom shorts. When an unexpected open or short occurs or when an expected open or short does not occur, the test is repeated either until the phantom result ceases or until a sufficient time has elapsed that the result is real rather than a transient response. Test points are arranged in an order which decreases monotonically with the parallel impedance of all elements connected directly to that test point. This reduces the rate of occurance of phantom shorts caused by parallel inpedances below the shorts threshold even though none of the individual impedances is below the shorts threshold.

Shorts testing technique reducing phantom shorts problems

A circuit tester and test technique are presented that compresses the amount of data stored in local test data RAMs for the implementation of a circuit test, thereby reducing the amount of data that must be downloaded to the local test data RAMs, thereby improving test throughput. Derivative data vectors are utilized in addition to raw data vectors as part of the data compression technique. Further compression results from storing only unique data vectors in the local test data RAMs and utilizing a sequencer to control the order in which the unique data vectors are utilized. The sequencer includes test program logic and logic capable of implementing on test pins indirect counters.

Circuit testing utilizing data compression and derivative mode vectors

Circuit tester having on-the-fly comparison of actual and expected

Circuit tester having indirect counters

A method and apparatus are disclosed for reducing the likelihood of damage to digital logic devices under test or located in close electrical proximity to the device under test while attempting to locate faults in circuit assemblies using digital incircuit test techniques.

High throughput circuit tester and test technique avoiding overdriving

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Loveland, CO, United States of America

William A Groves