How to build a prototype board to include a QFN package IC cheaply?

Does anyone have any tips on how to build a prototype board to include a QFN package IC without spending £200 on a socket?

I'm currently thinking of teaching a friends 3 year old to solder - it's gotta look pretty big to him...

Steve

prototyping QFN IC?

buy the socket from:
Plastronics Socket Company
tsmith@locknest.com
972-258-2580
972-258-6771 fax

I paid $106 which would be £71. Even with international shipping & duties this beats 200.

Or use a heat gun.

Re: prototyping QFN IC?

Hi,

Have you seen these ..

https://www.curiousinventor.com/guides/Surface_Mount_Soldering/QFN

**broken link removed**

prototyping QFN IC?

Thanks - gonna need a stiff drink before I try this, but I guess that has confirmed - I either shell out £70 or grit my teeth and get it under the microscope...

Re: prototyping QFN IC?

Hi,

Think how easy it will be depends on if you have an underside heatshink to connect ?

If its a low power chip then the outer pins should be ok.

You need one of the proper flux pens to coat both the pcb and the chip before positioning them together, then its more a case of soldering up the track so it runs under the pin.

Once done, do a resistance check to ensure you do not have any pins shorting, if you have, flux the pins again and run some solder braid /wick over the tracks to see if it can remove the short, don't resolder , there will still be enough solder on the actual pin / joint.

Just make sure you get you pcb tracks the right way round, its so easy to get things mirrored the wrong way.

Use a metal probe held by something like one of those ' helping hand' adjsutable clamps to firmly hold the device in posistion.

A JD before and after does help

prototyping QFN IC?



I recently fitted a QFN28 the same way.