XOs - Non-Compensated Crystal Oscillators

Non-compensated crystal oscillators employ no correction or control to reduce
the frequency variation over temperature beyond the intrinsic crystal stability.
However, 'non-compensated' is a bit of a misnomer since AT-cut crystals exhibit
an S-shaped cubic frequency vs temperature curve which can hold the frequency
variation below a few parts per million for modest temperature excursions and
below a few tens of parts per million for extreme temperature variations. The
angle of the crystal cut determine the temperature curve and the manufacturer
selects the most appropriate curve for the design temperature range.

Typical AT-Cut crystal curves for various cut angles.

Simple XOs are a good choice when the stability requirements are not
stringent because they are less expensive, smaller, and more reliable than TCXOs
and OCXOs. Since non-compensated oscillators require few selected components or
critical adjustmenst, the designer may choose to design his own. Here are a few
helpful .pdf files for the designer:

Title

File Name

Tiny CMOS Crystal Oscillator

cmososc.pdf

Low Distortion Crystal Oscillator

xtalosc.pdf

View the Oscillator
Catalog