SLLA549 July   2021 TCAN4550 , TCAN4550-Q1 , TCAN4551-Q1

 

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13 Verify and Check for Margin

Re-check the frequency, Drive Level and negative resistance if any components have been modified in the process and repeat until all requirements have been satisfied.

Calculate the temperature derating coefficient’s impact on the circuit, including component tolerances of all resistors and capacitors in the circuit. Recalculate the values with the min/max and derated values.

Test the development board over the desired temperature and voltage range to verify there is no undesired behavior such as an excessive frequency shift, or the crystal fails to start or stops oscillating during operation. The parasitic capacitance is not typically stable across temperature and the total CLoad will tend to vary slightly with temperature.

If issues are detected, adjust the capacitance and series dampening resistance and re-evaluate the frequency, negative resistance, Drive Level, and voltage level parameters as necessary.