Why crystal Frequency Strictly 32.567khz like that in most of the cases

[chandu.kurapati]

Hi,

I Observed that in most of the cases we are selecting that 32.567Khz is the crystal for the oscillator, why what is the reason for that much of precision selection of the crystal.

why it is not a 40 or 50 khz, any one can solve this conflict.

Thanks & Regards,

Chandu.Kurapati.

 

[bigdogguru]

I Observed that in most of the cases we are selecting that 32.567Khz is the crystal for the oscillator, why what is the reason for that much of precision selection of the crystal.

why it is not a 40 or 50 khz, any one can solve this conflict.

There is no conflict.

Perhaps you are referring to the 32.768 kHz crystals used in many Real Time Clock (RTC) applications.

The reason is actually quite simply, the 32.768 kHz provides exactly 2¹⁵ cycles per second and facilitates the design composed of a basic binary counter with a single line to increment the RTC. The use of either a 40 kHz or 50 kHz does not provide the simplicity for such a design.

There is also the economic factor as well, precision 32.768 kHz crystals have been utilized in clock manufacturing for many years, therefore they are abundantly available, relatively inexpensive and compact.


BigDog

 

[HMS1021]

To add to Big Dog's comment you run it into a 15 bit counter and it wraps once per second. They are common in watches.