Method and system for improving efficiency of sequential test compression using overscan

US9817068B1 · 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 29, 2015
• Grant date: Nov 14, 2017
• Expiry date: Jun 29, 2035

Classification

• Technology area (CPC G): Physics
• CPC primary: G01R31/318544
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

Systems and methods efficiently bring additional variables into a Pseudo-Random Pattern Generator (“PRPG”) in the early cycles of an automatic test pattern generation (“ATPG”) process without utilizing any additional hardware or control pins. Overscanning (e.g., scanning longer than the length of the longest channel) for some additional cycles brings in enough variables into the PRPG. Data corresponding to earlier cycles of the ATPG process is removed.