Timing Margin Measurement Using a Laser Technique
Abstract
This report describes a non-contact techniques for obtaining information about the timing margins of internal signal paths in CMOS circuits. A controlled photocurrent is injected by spot illumination of an OFF transistor drain loading a node. The collected photocurrent aids or opposes transistors driving the node. This increases (or decreases) node switching times, and many manifest as a change in the maximum operating frequency of the overall circuit. An approach for extracting timing margin values from plots of maximum operating frequency vs illumination intensity has been developed, which does not require estimation of the drive strength or capacitive load of the node tested. Theory, implementation details, difficulties, and test results on a CMOS microprocessor are discussed.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1990
- Accession Number
- ADA226821
Entities
People
- Glenn C. Fuller
- Harold K. Brown
- Shane S. Clammae
Organizations
- University of Central Florida