Built-in self test method for a digitally controlled crystal oscillator
US7411462B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 19, 2006 |
| Grant date | Aug 12, 2008 |
| Priority date | — |
| Expiry date | Jan 17, 2027 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03J2200/10
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A novel testing mechanism operative to test large capacitor arrays such as those used in a digitally controlled crystal oscillator (DCXO). The invention is adapted for use in DCXO circuits that employ dynamic element matching in their array decoding circuits. The invention combines the use of DEM during regular operation of the DCXO with a testing technique that greatly reduces the number of tests required. The invention tests the capacitors in the array on a row by row, wherein all the capacitors in a row are tested lumped together and treated as a single entity, which results in significantly reduced testing time. This permits the measurement of significantly higher frequency deviations due to the larger capacitances associated with an entire row of capacitors being tested.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.