XTAL011301

SPECIFYING SURFACE MOUNT QUARTZ CRYSTALS A typical surface mount quartz crystal specification reads like this: SURFACE MOUNT QUARTZ CRYSTALS Frequency Stability Frequency stability is normally specified as a frequency tolerance over a defined operating temperature range with respect to the frequency at reference temperature. The temperature ranges are defined for each crystal in the relevant data sheet. However the majority of crystals will continue to operate quite satisfactorily outside the temperature range for which they are specified, but with a possible degradation in the value of frequency stability. Under normal conditions this will not damage the crystal. A crystal designed for operation over a restricted operating temperature range, (such as from 0 to 50°C) has a better frequency stability over that range than one designed for operation over a wide operating temperature range. Therefore it is important not to over specify the temperature range, as doing so will result in inferior performance for the same or greater cost; or greater cost for the same or inferior performance. Operating Temperature Ranges The standard operating temperature ranges for a crystal are: ■ 24.0140MHz Frequency Holder Style 12SMX-B 15 30 20 18 Fund TR T Frequency Tolerance at 25°C Frequency Stability Lower end of Operating Temp Range Circuit Condition Overtone order Packaging Additional Text Code (for non-standard product) The following specification. notes define each element of the ww...