Hardware design questions

Peter Jakacki

I am committing some new propeller pcb designs but I wanted to verify the actual smd packages that the pchip uses. I have a document which has a very basic solder land pattern but I am looking for the standard Jedec package numbers for the QFP and QFN. This is just to make sure that the pcb lands are optimal for this package.

Also, I haven't tried any other crystal except the 5MHz on the demo board. There won't be any problem getting this in production quantities but I am wondering if anyone is using a different frequency and what are the implications of not using the standard 5MHz.

TIA

*Peter*

Peter Jakacki

Anyone know?

OzStamp

Hi Peter.
I have the official docs re those details will dig them out and email them across to ypu pr mail..

Ronald Nollet
Parallax Australia distributor

Peter Jakacki

Many thanks o most southern one!

Here is a link for the QFP package details for anyone who is interested (NXP don't make the Propeller but they have a link for the standard package documents)
www.nxp.com/package/SOT307-2.html

Now Ron, did you happen to have the package number for the QFN?

*Peter*

Graham Stabler

http://forums.parallax.com/forums/default.aspx?f=25&m=137256

taken from my index thread:

http://forums.parallax.com/forums/default.aspx?f=25&m=148376&p=1

Peter Jakacki

Thanks Graham, unfortunately I already have that one but what I wanted was not the incomplete short-form but the full mechanical details similar to the link that I gave for the QFP. Once you know the package type the details are easy enough to obtain.

Now, why is this a problem to find out the package details?? Shouldn't Parallax know?

grrrhhhh

*Peter*

parts-man73

Peter Jakacki said...
Also, I haven't tried any other crystal except the 5MHz on the demo board. There won't be any problem getting this in production quantities but I am wondering if anyone is using a different frequency and what are the implications of not using the standard 5MHz.

I know the DLP-PROP is running at 6 mhz with no problems. They are taking the clock off the FTDI USB chip instead of a dedicated crystal. I've heard reports on this forum that that aren't any issues.

I also used a 4 mhz crystal when I received my first prop because that's all I had in my parts boxes. I bought some 5 mhz crystals on my next Mouser order and have been using them ever since.

Brian

bambino

Peter,

Type "broadcast" into the search engine. You should get a lot of feed back on the crystal issue!

Just tried it again today and didn't get near as much as I did yesterday! I don't know what I did differently. Anyway there's 7 there that may be worth looking at.


Post Edited (bambino) : 11/30/2006 2:51:41 PM GMT

Paul Baker

Peter, check your gmail account. I have sent you the mechanical drawings provided to us by the manufacturer.

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Paul Baker
Propeller Applications Engineer

Parallax, Inc.

Tracy Allen

Peter, I did a lot of digging around to find a Jedec listing or anything of the sort for the QFN package and came to the conclusion that the QFN is at this point in time not well standardized. There are a lot of manufacturers making parts in QFNs, but I never located a single other example using exactly the same package as the P8X32A-M44. Has anyone? There were a few good studies of alternative methods of laying out the pads and stencil layer. I thinkk the diagrams from the manufacturer and the suggestions from Chip are as good as it is going to get.

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Tracy Allen
www.emesystems.com

Paul Baker

Peter, to answer your crystal question: any crystal frequency may be used, however any crystal over 10MHz couldn't use the PLL and crystals above 6MHz require a PLL setting of 8x or less.

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Paul Baker
Propeller Applications Engineer

Parallax, Inc.