In this article, we will discuss the classification of surface mount crystal oscillators (SMXO) and their pin orientation. The term crystal oscillator refers to a quartz crystal resonator, which is a type of quartz crystal component. Quartz crystal resonators, oscillators, and filters are all types of quartz crystal components. Quartz crystal is a type of piezoelectric crystal that generates an electrical charge when subjected to specific directional pressure or tension. Depending on the type of effect, it is classified as either positive or negative piezoelectric effect.

Classification of SMXOs

Surface mount crystal oscillators (SMXOs) are quartz crystals that are mounted on the surface of a printed circuit board. They provide high-precision oscillation and do not have protruding pins. SMXOs are classified into two types: passive and active oscillators. The English name for passive oscillator is "crystal," while active oscillator is called an "oscillator."

Pin Orientation of SMXOs

When using SMXOs, it is often difficult to distinguish the pin orientation of four-pin SMXOs. In the case of passive oscillators with four pins, only two pins are functional, while the other two are left unconnected. We label them as pins 1, 2, 3, and 4. In general, it is difficult to distinguish which pin is pin 1 and which is pin 2. Here's a tip to help you out.

To make it easier for users to distinguish the pin orientation of four-pin passive SMXOs, manufacturers usually put a notch on pin 1. Counting clockwise from pin 1, the pins are labeled 1, 2, 3, and 4. Pins 1 and 3 are grounded, while pins 2 and 4 are not functional.

For active SMXOs, the pin orientation is usually indicated by a dot on the silkscreen. The dot represents pin 1. By flipping the SMXO over and counting clockwise from pin 1, you can easily determine the orientation of the pins.

Conclusion

In summary, we have discussed the classification of surface mount crystal oscillators and their pin orientation. We hope this article has been helpful to you.