Crystal Oscillator Circuit Design

We ll examine the operational theory of crystal oscillators and design a discrete pierce crystal oscillator suitable for use as a local oscillator in an hf receiver.

Crystal oscillator circuit design.

This tutorial explains considerations to be addressed in a design of a simple crystal oscillator using at cut crystals. Topics include load capacitance negative resistance startup time drive level dependency crystal aging and spurious modes. These types of oscillator is practically invariably of the l c variety for functioning frequencies of a few hundred khz and above. It can be used in the normal clock circuit.

A crystal oscillator is an electronic oscillator circuit that is used for the mechanical resonance of a vibrating crystal of piezoelectric material. Ever wonder what goes in to the design of a crystal oscillator. Circuit and design description march 1 2016 by ajay kumar crystal oscillator is an electronic oscillator used to create an electrical signal of precise frequency by using the vibrating crystal mechanical resonance made of piezoelectric material. The design of a crystal oscillator is very similar to the design of the colpitts oscillator we looked at in the previous tutorial except that the lc tank circuit that provides the feedback oscillations has been replaced by a quartz crystal as shown below.

3 cd4060 crystal oscillator circuit this is a 1hz oscillator circuit for a standard digital clock frequency size 1 hz or 2 hz. It consists of ic 4060 and ic 4013 the ic 4060 single acting oscillator and counter. References and additional reading are listed below. It will create an electrical signal with a given frequency.

My discrete pierce oscillator design tool can be found here. Series resonant oscillator circuits are fairly basic and are typically used because of their small component count. Changes in the phase angle will result in a change in the output frequency. A crystal oscillator is obviously designed to offer high firmness at a single frequency and is useless if a tuneable wide range oscillator is needed.

Of the frequency determined by the resistor and external capacitor. Figure 2 4 shows the maximum drive power that can be put into a crystal without excessive heating and frequency shift in the crystal fig ure 2 5 shows the maximum permissible drive voltage across the crystal at exact series resonance. The exact frequency at which an oscillator will operate is dependent on the loop phase angle shifts within the oscillator circuit. In this type of crystal oscillator design the filter consists of the crystal s equivalent model and the external load capacitors.