Using a Crystal instead of a Resonator

[fcd72]

Ladies and Gentleman,

sorry for bothering but i didn't find any (at least for me) suitable information on how to substitute a Resonator (16Mhz is hard to come by here in Germany...) with Quartz. Will the Circuit in the attached File work when using the specified Caps from the Crystals Datasheet?

Many thanks for your help,

Frank

 

[bluejets]

ceramic about 15pf each I think......

 

[srnet]

That will do it, as you say the Crystal datasheet should give you the correct load capacitance.

Surprised you say that they are hard to come by in Germany, Farnell Deutschland seem to have plenty, and they can be found on eBay too.

 

[fcd72]

Thanks Guys,

indeed Farnell stocks them but i liked to squeeze this into my REICHELT order as i am not that used to Farnel... maybe i should change my supplier ;-)

 

[westaust55]

If using a crystal as opposed to a resonator, you may also wish to read the Microchip application note: AN826. Title: Crystal Oscillator Basics and Crystal Selection
http://ww1.microchip.com/downloads/en/AppNotes/00826a.pdf
In particular the section on "SPECIFYING A CRYSTAL"

The PIC datasheets (for X2 parts) also suggest that: "A series resistor (Rs) may be required for quartz crystals with low drive level."

 

[Dippy]

Gosh, for a first effort I wouldn't get so carried away.
Just look up (almost) any old cheap HC49 format crystal, check the data sheets for the capacitor values (typically 15pF to 18pF) and stuff it in.
Some crystals require more care but I've never had any probs with a cheap'n'cheerful for rough prototypes.

 

[fcd72]

Indeed the microchip Application Note is a bit more in-depth but interesting nonetheless. Just a Bit more than i asked for ;-) Thanks anyway!

 

[westaust55]

To be aware is half of the "battle".
You can just add a couple of capacitors and there is a good chance it will work.
But if by perchance it does not then through knowledge from datasheets and app notes there is a prospect that you can solve the problem.