Variable-loop-path ring oscillator test circuit and systems and methods utilizing same
US8164966B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 27, 2008 |
| Grant date | Apr 24, 2012 |
| Priority date | — |
| Expiry date | Aug 10, 2030 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11C29/50012
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Circuitry for determining timing characteristics, for example, access time, setup time, hold time, recovery time and removal time, of as-manufactured digital circuit elements, such as latches, flip-flops and memory cells. Each element under test is embodied in variable-loop-path ring oscillator circuitry that includes multiple ring-oscillator loop paths, each of which differs from the other(s) in terms of inclusion and exclusion of ones of a data input and a data output of the element under test. Each loop path is caused to oscillate at each of a plurality of frequencies, and data regarding the oscillation frequencies is used to determine one or more timing characteristics of the element under test. The variable-loop-path ring oscillator circuitry can be incorporated into a variety of test systems, including automated testing equipment, and built-in self test structures and can be used in performing model-to-hardware correlation of library cells that include testable as-manufactured digital circuit elements.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.