Elastic compression-optimizing tester bandwidth with compressed test stimuli using overscan and variable serialization

US9470754B1 · kind B1 · utility

Assignee

• Cadence Design Systems, Inc. · US

Inventors

• Vivek Chickermane · Ithaca, US
• Krishna Vijaya Chakravadhanula · Vestal, US
• Brian Foutz · Charlottesville, US
• Steev Wilcox · San Jose, US
• Paul Alexander Cunningham · San Jose, US
• David G. Scott · Duncan, US
• Louis Christopher Milano · Endwell, US
• Dale Edward Meehl · Melbourne, US

Key dates

• Filing date: Jun 11, 2015
• Grant date: Oct 18, 2016
• Expiry date: Jun 11, 2035

Classification

• Technology area (CPC G): Physics
• CPC primary: G01R31/318547
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

Systems and methods disclosed herein provide for utilizing extra variables in the decompression equation set of an ATPG process for test patterns requiring an excess number of care bits than can be supported efficiently by the current hardware. An elastic interface is utilized between a tester and a decompressor network (e.g., sequential and combinational decompressors) in order to expand the test pattern length and/or the number of input variables. The systems and methods also provide care bits in early scan cycles of the ATPG process for sequential decompressors starting from a fixed state.