Source coupled CMOS crystal oscillator
US5914643A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 12, 1997 |
| Grant date | Jun 22, 1999 |
| Priority date | — |
| Expiry date | Dec 12, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K3/3545
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A CMOS oscillator includes two differential input transistors (150) and (152) which have the sources thereof coupled through a resonator element (196). Active loads (166) and (178) provide a squaring up of the output which then drives an output transistor (202). The gates of the differential input transistors (150) and (152) are biased to predetermined voltage levels with bias circuits, with the positive input of the comparator configuration coupled through a feedback capacitor (208) to the output (204). This provides sufficient instability to initiate oscillation with a gain of the device controlled by resonator circuit (196) to be optoimum at the resonant frequency of the resonator circuit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.