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Topic: Got wrong pitch FQFP MCU - possible to make a save? (Read 2 times) previous topic - next topic

harleydk


Are you saying the 5mm, 0.5mm pitch parts I  pointed out do not fit the 5mm, 0.5mm pitch pads on your card?
Atmega328P-MU, -MUR, -MN, -MNR
http://www.mouser.com/Search/Refine.aspx?Keyword=atmega328p-m'


Hello CrossRoads,

they may fit the board well, being rather the novice I remain merely hesitant for two reasons, the first of which is the labelling in my PCB program (which is Fritzing, by the way). If the footprint fits a so-called "QNF32" then why does it say "TQFP32". This a hugely complex, dedicated piece of software written by experienced people, so when I come across something like this I'm prone to declare myself the ignorant party before calling error on the program. Also the footprint has prolonged pads as indicates room for an MCU with spider-legs sticking out, yet the ones you link to have none of those.

I'm coming to the conclusion that I'd about to venture into my first foray into these leg-less MCU- that, and that I should probably start using Eagle as opposed to Fritzing.

Thanks for all your help, I'm very grateful - if I can get this leg-less MCU fixed on that board (although I shudder in horror at the thought I do have a hot-air station, so...), that's the save I was hoping for when I wrote the post.
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My hopefully helpful blog at technicalstuffhopefullyuseful.blogspot.com

harleydk


Hey, I think Crossroads may be right on this.  It's pretty close - the footprint is different but it looks like it is compatible.  This is from DipTrace.  This is the QFP32 7mm/7mm/0.5mm and QFN32 5mm/5mm/0.5mm footprints side by side.   The problem here is that Diptrace doesn't show the exact outline of the package itself so if you imagine a worst case scenario here the QFN's pins might be just inside the radius of the QFP's traces.  But it may be OK too.


Very kind of you to put that image up - thank you for that. By CrossRoad's help it's clear to me now that I'll have to try and get a QFP32 and try and solder it.


A caviat is that QFNs are not as easy to solder as QFPs so keep that in mind.  I hot air solder them myself and inspect them under a microscope.


I shudder at the notion - I've never worked with them before. But there's a first time for everything. Hot air and paste at the ready, then.


I have use Atmel's QFN32 5mm/5mm/0.5mm packages.  Too bad I don't have a PCB with a QFP32 7mm/7mm/0.5mm footprint on it otherwise I would see if it would work out for you.


Again, that's awfully kind of you - thank a lot. I might contact you in the case I need a bit of advice in regards to the soldering - would that be ok with you?
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My hopefully helpful blog at technicalstuffhopefullyuseful.blogspot.com

CrossRoads

Fritzing - you get what you pay for. Not really an optimal design tool.
Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
Arduino for Teens available at Amazon.com.

harleydk


Fritzing - you get what you pay for. Not really an optimal design tool.


I'm inclined to agree with you, now more than ever because of my issue with the foot print obviously, but for those out there who're just starting out I'll hasten to add that it's a great visualizer for getting into electronics, with its combined breadboard/schematic/PCB view. I probably wouldn't have begun to design my own boards if it hadn't been for Fritzing. So good for beginners as an try point into the more serious programs like Eagle and such.
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My hopefully helpful blog at technicalstuffhopefullyuseful.blogspot.com

CrossRoads

I've only seen it from the other side - poor "visualizer" of schematics, simple 'black boxes" for components with no clue as to functionality. To an engineer, a very poor tool.
Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
Arduino for Teens available at Amazon.com.

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