A method for reducing a drive level of a quartz crystal in a crystal oscillator circuit, wherein the crystal oscillator circuit comprises: an inverting amplifier having an input and an output ; a feedback resistor having a first terminal connected to the input of the inverting amplifier , and a second terminal connected to the output of the inverting amplifier ; a quartz crystal having a first terminal and a second terminal , the first terminal of the quartz crystal is connected to the input of the inverting amplifier; a first load capacitor (C1) connected between the first terminal of the quartz crystal and a signal ground; a second load capacitor (C2) connected between the second terminal of the quartz crystal and the signal ground; and a third capacitor connected between the second terminal of the feedback resistor and the second terminal of the quartz crystal ; and the method comprising: choosing a target drive level of the quartz crystal ; and calculating a capacitance of the third capacitor , C d , according to an equation C d = C L 2 ⁢ k 1 − k , wherein C L is an equivalent capacitance of the first and second load capacitors calculated according to an equation C L = C 1 − C 2 C 1 + C 2 + C S , where Cs is the total stray capacitance of input and output pad capacitances of the inverting amplifier, and k is a damping factor, such that the supply voltage of the inverting amplifier is damped at the second terminal of the quartz crystal with the damping factor k to match the target drive level of the quartz crystal . an inverting amplifier having an input and an output ; a feedback resistor having a first terminal connected to the input of the inverting amplifier , and a second terminal connected to the output of the inverting amplifier ; a quartz crystal having a first terminal and a second terminal , the first terminal of the quartz crystal is connected to the input of the inverting amplifier; a first load capacitor (C1) connected between the first terminal of the quartz crystal and a signal ground; a second load capacitor (C2) connected between the second terminal of the quartz crystal and the signal ground; and a third capacitor connected between the second terminal of the feedback resistor and the second terminal of the quartz crystal ; and the method comprising: choosing a target drive level of the quartz crystal ; and calculating a capacitance of the third capacitor , C d , according to an equation C d = C L 2 ⁢ k 1 − k , wherein C L is an equivalent capacitance of the first and second load capacitors calculated according to an equation C L = C 1 − C 2 C 1 + C 2 + C S , where Cs is the total stray capacitance of input and output pad capacitances of the inverting amplifier, and k is a damping factor, such that the supply voltage of the inverting amplifier is damped at the second terminal of the quartz crystal with the damping factor k to match the target drive level of the quartz crystal . choosing a target drive level of the quartz crystal ; and calculating a capacitance of the third capacitor , C d , according to an equation C d = C L 2 ⁢ k 1 − k , wherein C L is an equivalent capacitance of the first and second load capacitors calculated according to an equation C L = C 1 − C 2 C 1 + C 2 + C S , where Cs is the total stray capacitance of input and output pad capacitances of the inverting amplifier, and k is a damping factor, such that the supply voltage of the inverting amplifier is damped at the second terminal of the quartz crystal with the damping factor k to match the target drive level of the quartz crystal . <EOS>