Oznog
Active Member
I have a crystal in a tiny can case I might want to use for board space reasons.
It says 18 pF load on the bag from the vendor. It occurs to me that I don't know what this means.
Is that the maximum capacitive load? Or a minimum load to remain stable or a maximum load?
The PIC18F252 spec sheet, 22.2 item D100 says OSC2 has a 15pF load. But I also add a 18pF to each leg for stability. At least one of those caps is in parallel with the OSC2 pin. How does the load cap get calculated? Is this too high? Or do I maybe not need the stability caps when a small crystal is loaded this way (wishful thinking)? Getting rid of the caps would certainly help my board space issue too.
It says 18 pF load on the bag from the vendor. It occurs to me that I don't know what this means.
Is that the maximum capacitive load? Or a minimum load to remain stable or a maximum load?
The PIC18F252 spec sheet, 22.2 item D100 says OSC2 has a 15pF load. But I also add a 18pF to each leg for stability. At least one of those caps is in parallel with the OSC2 pin. How does the load cap get calculated? Is this too high? Or do I maybe not need the stability caps when a small crystal is loaded this way (wishful thinking)? Getting rid of the caps would certainly help my board space issue too.