High-specification AT-cut crystals from IQD Frequency Products are available in UM1, HC49, HC43CW (TO8) and HC45CW package options. For the highest possible Q factor, customers can specify the CW (Cold Weld) packages. The Q factor, or loss of energy within the quartz is effected by the quality ofhte blank, surface finish, or lapping, mounting technique and sealing. These crystals offer frequency ranges of 10 to 42MHz at fundamental mode, 10 to 125MHz at third overtone and 70 to 175MHz at fifth overtone. Ageing is low, down to 0.1ppm/year and the frequency tolerance is tight at 25° C down to ±3ppm. According to the company, standard crystals typically have figures of 3ppm/year ageing and ±10ppm frequency tolerance. Temperature stabilities down to 4ppm at 0 to 70°C and 12ppm at -40 to 85°C can be specified.
