Three aspects to take into consideration when designing an oscillator circuit are mentioned below:

1. Drive Level 

Applying excessive drive level to the crystal units may cause deterioration of characteristics or damage. Circuit design must be such as to maintain a proper drive level.

2. Negative Resistance 

Unless adequate negative resistance is allocated in the oscillation circuit, oscillation start up time may increase or no oscillation may occur. In order to avoid this, provide enough negative resistance in the circuitry design.

3. Load Capacitance 

Differences in the load capacitance in the oscillation circuit may result in deviations in the oscillation frequency from the desired frequency. Attempting to tune by force may merely cause abnormal oscillation. Before use, please specify the load capacitance of the oscillation circuit.