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Testing Signal Lines Extending Between Semiconductor Chips

IP.com Disclosure Number: IPCOM000051112D
Original Publication Date: 1982-Aug-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Rausch, F: AUTHOR

Abstract

For testing signal lines extending between semiconductor chips, special driver circuits and receivers are used. The driver circuits permit modulating the output level with an AC voltage. By a special line, this AC voltage is also fed to the receiver. If the signal line to be tested is non-defective, compensation of the output level modulation is effected in the receiver.

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Testing Signal Lines Extending Between Semiconductor Chips

For testing signal lines extending between semiconductor chips, special driver circuits and receivers are used. The driver circuits permit modulating the output level with an AC voltage. By a special line, this AC voltage is also fed to the receiver. If the signal line to be tested is non-defective, compensation of the output level modulation is effected in the receiver.

The figure shows two semiconductor chips 1 and 2 interconnected by signal lines 3. All driver circuits 4 are connected by line 7 to an AC generator 6 which permits AC modulation of the output levels of driver circuits 4. The modulation amplitude may be, for example, 10 percent of the voltage difference between the two signal levels which correspond to the binary values 0 and 1. In receiver 5, modulation of the transmitted signal level is eliminated by the AC voltage of generator 6. Thus, if signal lines 3 are non-defective, no modulation frequency signal is available at a special output 8 of the receiver. If they are interrupted or short-circuited, no modulation compensation is effected in the receiver. If the modulation frequency is in the audio range, defects are detectable by the simplest means (audio amplifier and earphone). By linking the outputs of particular receivers in groups, by selectively controlling the drivers and by using different frequencies and/or coded switching of the modulation voltage, defects can be localized, as re...