Specific Xtal used in LPC1114

[lpcware]

Content originally posted in LPCWare by glenn_mark on Mon Jul 19 01:08:31 MST 2010
[SIZE=2]Hi everyone,

I'm still a newbie here so please be patient with me.[/SIZE] [SIZE=5][COLOR=RoyalBlue][SIZE=2]

[/SIZE]  [SIZE=2][COLOR=Black]What specific crystal that is used in the LPCXpresso with LPC1114 MCU?
Can anyone suggest me a part number that will meets the requirements of the MCU as specified in 11.2 of the datasheet?

Thanks in advance.
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[lpcware]

Content originally posted in LPCWare by rcazalis on Tue Jul 20 01:07:34 MST 2010
For quality there are mainly 2 precisions expressed in ppm.
The first is the "frequency stability" which means different crystals in same conditions can vary within this tolerance.
The second is the "frequency stability over temperature" which shows how much a same crystal can vary if temperature changes within a certain range.
A good crystal would have 10ppm for both and a poor would have 100ppm.

[lpcware]

Content originally posted in LPCWare by glenn_mark on Mon Jul 19 17:25:56 MST 2010
Now it's getting clearer to me. Thanks!

Can you share me any supporting documents for this explanation?
Also, what are the ways to determine the quality of the crystal oscillator?

[lpcware]

Content originally posted in LPCWare by rcazalis on Mon Jul 19 03:04:22 MST 2010
As a general rule, purchase any fondamental crystal and add on both sides the same cap which is double the value of the crystal's load capacitance (CL).
Note you don't need to be perfectly exact; a couple of pF out are fine.

So a 20pF crystal requires two 40pF caps (39pF is a a close enough standard)

A 10pF crystal requires two 20pF : 18pF is fine too..

[lpcware]

Content originally posted in LPCWare by Ex-Zero on Mon Jul 19 02:44:19 MST 2010
With a 'Load Capacitance' of 20 pF I would suggest Cx1/Cx2 of around 39 pF (like described in LPC datasheet).
I'm using 33 pF because I've thousands of 33 pF (603 package) in my SMD box from other projects :D.

[lpcware]

Content originally posted in LPCWare by glenn_mark on Mon Jul 19 02:33:38 MST 2010
Thanks for the reply.

Does this mean that I can immediately connect an 18pF for Cx1/Cx2 instead of 33pF since the part you shown me has a minimum CL of 10pF?
Or does this need some kind of configuration for this setup?

[lpcware]

Content originally posted in LPCWare by Ex-Zero on Mon Jul 19 02:20:41 MST 2010
Seems to be a standard HC49/US SMD package like:

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=XC1298CT-ND

Since I've used several different packages for own boards crystal doesn't seem to be a critical part. My favorite is a HC49/US (cheap & easy to get) with 33pF Cx1/Cx2.