Designing a clock oscillator without some knowledge of the fundamental principals of acoustic resonators is possible but fraught with the uncertainty of "cut and try" methods. While the oscillator may be made to run with the chosen resonator, it is quite likely that the unit will be slightly off the intended frequency, be grossly off frequency because it is operating on an unintended mode, or have unacceptable temperature characteris- tics because the wrong resonator was chosen for the application. This application note is primarily for informational purposes. It is intended to help the designer of clock oscillators understand the parameters of crystal resonators and the terminology of the crystal resonator industry, both of which tend to be somewhat mysterious and arcane to the uninitiated. Details of crystal cuts and rotations, for instance, are of no use to the oscillator designer, only the designer of crystals. The oscillator designer still needs to understand and be able to predict the performance and trade-offs associated with these parameters. This is not an in-depth or rigorous treatment of acoustic resonators, but a practical guide, which should allow the designer to gain a basic understanding, and to help in choosing and specifying resonators. AN588 PICmicro Microcontroller Oscillator Design Guide Design Challenges Author: Kim Peck The PICmicro microcontrollers offer unique design Consultant challenges because they are uniquely exible. Flexibility usually demands difcult decisions on the Designing a clock oscillator without some knowledge of part of the designer, but offers otherwise unattainable the fundamental principals of acoustic resonators is ……