Drive level

No.	Item	Title	Contents
1	Outline	Drive level	Drive level indicates power consumption by crystal resonator while oscillation circuit works. It is important for crystal to keep within drive level specification. Excessive drive level might cause unexpected change of frequency and equivalent series resistance.
2	Measure	Calculation	Drive level could be calculated as follows. Drive level = I²･R1 I: Drive current [Effective value] R1: Equivalent series resistance of crystal resonator Drive current is a current through crystal resonator while the oscillation circuit works. Drive current could be measured on actual oscillation circuit. R1 could be measured by network analyzer and so on.
2	Measure	Measurement example	Measurement equipment and device PCB Crystal resonator (with equivalent circuit constants data) Oscilloscope, Current probe Solder a lead wire to crystal and set a current probe as figure shown in below. Supply power voltage to PCB and observe drive current waveform on oscilloscope Caluculate effective value of drive current If waveform is sine wave or similar, effective value is caluculated by Ip-p /2√2 With digital oscilloscope, effective value could be read by function of oscilloscope. Drive level is caluculated by above formula.
3	Judgement		Measured drive level should not exceed drive level specified in crystal specification.

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