Scan structure for improving transition fault coverage and scan diagnostics

US6490702B1 · kind B1 · utility

Assignee

• International Business Machines Corporation · US

Inventors

• Peilin Song · Lagrangeville, US
• Richard F. Rizzolo · Red Hook, US
• Franco Motika · Hopewell Junction, US
• Ulrich Baur · Holzgerlingen, DE

Key dates

• Filing date: Dec 28, 1999
• Grant date: Dec 3, 2002
• Expiry date: Dec 28, 2019

Classification

• Technology area (CPC G): Physics
• CPC primary: G01R31/318541
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A scan chain latch circuit is provided. The scan chain latch circuit includes a first shift register latch and a second shift register latch. The scan chain latch circuit also includes a multiplexor connected between the first and second shift register latches, the multiplexor has a select line for controlling the function of the multiplexor. The multiplexor is configured for implementing an inverting mode such that a logic value may be passed via the multiplexor from the first shift register latch to the second shift register latch in one of a non-inverted state and an inverted state based upon the state of the select line.