Agilent Technologies, Inc.

Stephen Hird

John E Siefers

Kevin G Chandler

Dayton Norrgard

An X-Tree test apparatus for testing combinatorial logic circuits in a multiplexed digital system. The apparatus includes a plurality of contacts for electrical connection with pins on a device under test. A first driver drives a logic one signal, and a second driver drives a logic zero signal, both of which are used for testing the device. Multiplexing circuitry selectively connects the first driver and the second driver with each of the plurality of contacts and device pins. A receiver, connected with the device under test, measures a response from the logic circuit under test to the logic one and zero signals to determine if it functions as intended.

X-tree test method and apparatus in a multiplexed digital system

A method and apparatus for detecting a resistive fault in an electrical conductor is presented. The apparatus of the invention includes an oscillating signal generator that applies an oscillating signal to the electrical conductor under test. The apparatus includes a measuring device for measuring the potential between the electrical conductor under test and a reference node. Such measurements are obtained both when the apparatus is disconnected from the electrical conductor under test and when the apparatus is connected to the electrical conductor under test. A difference in the measurements indicates that the connectivity of the electrical conductor is intact, whereas no difference indicates that a resistive fault exists somewhere in the electrical conductor. For greater accuracy, the longitudinal balance of the disconnected apparatus and connected apparatus measurements are calculated to determine connectivity. In an automated test environment, the measuring apparatus is part of the tester hardware and the connections to the electrical conductor under test are made through tester interface pins and fixture probes.

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Stephen Hird