Texas Instruments Corporation

Neil John Simpson

Alan David Hales

Rubin Ajit Parekhji

Nikila Krishnamoorthy

Anupama Aniruddha Agashe

Gordhan Barevadia

A built-in self-test (BIST) method includes providing expanded test patterns to a logic circuit under test, generating a first signature based on a response of the logic circuit to the expanded test patterns, generating a second signature based on the first signature, wherein the second signature is a compressed version of the first signature, selecting one of the first signature or the second signature in response to a control signal, comparing the selected one of the first signature or the second signature to an expected signature, and, based on the comparison of the selected one of the first signature or the second signature to the expected signature, determining that the logic circuit passes or fails BIST.

Re-programmable self-test

The PRPG provides the test stimulus to the circuit, but it can only generate a finite number of care-bits from any given input seed which limits the maximum coverage that can be achieved. The only way to increase the coverage is to provide additional seed input data to the PRPG. The on-chip one time only programmable eFuse is used to store new PRPG seed data inputs and corresponding MISR output signature data for comparison. An XOR circuit option on the output of the MISR is operable to further compress the output data.

A system and method enhance observability of IC failures during burn-in tests. Scan automatic test pattern generation and memory built-in self-test patterns are monitored during the burn-in tests to provide a mechanism for observing selective scan chain outputs and memory BIST status outputs.

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Neil John Simpson