Frequency usually refers to the nominal frequency, that is, resonant frequency regulated by contracts and products specification. Frequency scope can be gained by oscillation mode and crystal holder of different size.
Generally speaking, the smaller the crystal holder is, the higher the frequency is.
See table one:
Holder type Oscillation mode Frequency range (MHz)
HC-49U AT Fundamental 1.8432-25
AT 3rd Overtone 20-70
AT 5th Overtone 50-150
HC-49S AT Fundamental 3.579-27
AT 3rd Overtone 20-65
AT 5th Overtone 50-150
SMD7050 AT Fundamental 6-33
AT 3rd Overtone 33-100
SMD5032 AT Fundamental 12-44
AT 3rd Overtone 35-100
The possibility to realize should be taken into consideration when choosing products, if it exceeds the possible scope, the cost will increase dramatically or become impossible to produce. When frequency nears the lowest limit of crystal holder, it is suggested to communicate with the supplier.
FL: Load Resonant Frequency
Under specified conditions, quartz crystal components are in parallel or series with load capacitance. When the combination of impedance presents resistivity, load resonant frequency is one of the two kinds of frequency.