AN826 Crystal Oscillator Basics and Crystal Selection for rfPICTM and PICmicro® Devices

Oscillators are an important component of radio frequency (RF) and digital devices. Today, product design engineers often do not find themselves designing oscillators because the oscillator circuitry is provided on the device. However, the circuitry is not complete. Selection of the crystal and external capacitors have been left to the product design engineer. If the incorrect crystal and external capacitors are selected, it can lead to a product that does not operate properly, fails prematurely, or will not operate over the intended temperature range. For product success it is important that the designer understand how an oscillator operates in order to select the correct crystal.