Printable Version | Subscribe | Add to Favourites
New Topic New Poll New Reply
Author: Subject: QFN package soldering to board
02GF74

posted on 2/2/19 at 08:25 AM Reply With Quote
QFN package soldering to board

A bit OT but anyone soldered a QFN package to a pcb, and how?

I've seen a couple of videos but would like to hear personal experience s.

Oh, and if you don't know and can't be asked googling, these are tiny surface mount ICs, and I mean tiny.





Visit China. Meet the child that made your trainers.


View User's Profile View All Posts By User U2U Member
rf900rush

posted on 2/2/19 at 11:02 AM Reply With Quote
Yes
Not a easy task

My DIY version is to tin both PCB and IC.
Plenty of flux, then heat with hot air using a hot air pencil.

My hot air source has heat control and a 4mm nozzle.

To check this method get a scrap PCB an practice with any of the components.

And make your life easier and use 60/40 tin lead and not the new unleaded crap.

View User's Profile E-Mail User Visit User's Homepage View All Posts By User U2U Member
DanP

posted on 2/2/19 at 03:25 PM Reply With Quote
its feasible if you have a very fine soldering iron and magnifying gear.

You get sockets for QFN's but they aren't cheap, you can also get QFN to DIP adapters to so that you can have a few goes on the QFN without messing up your PCB if you make a mistake.

Bear in mind some QFN's have a pad underneath that can need soldering although it is often only for thermal/mechanical reasons so can be skipped in less demanding situations

It is very easy to bridge the pads when soldering so get some ‘solder wick’ to help you if you do make a bridge when soldering.

I’m assuming there is no equivalent package with leads like a TQFP available? Most automakers avoid QFN packages and prefer QFP for vibration and thermal reasons. typically QFN are used in cost and space sensitive applications like phones and toys as it is one of the cheapest ways of packaging a chip and the area can be kept reasonably low vs the die area.


[Edited on 2/2/19 by DanP]

View User's Profile View All Posts By User U2U Member
MikeRJ

posted on 2/2/19 at 05:17 PM Reply With Quote
Flux is your friend here, and I mean proper SMD flux rather than something from your plumbing kit. Some very fine solder, or solder paste will also be needed, along with a fine tip on your iron.

With plenty of flux the solder doesn't tend to form bridges easily, so you can drag the end of the iron down the side of the IC to create pretty neat solder joints.

View User's Profile View All Posts By User U2U Member
peter030371

posted on 2/2/19 at 08:02 PM Reply With Quote
Done it loads and in different ways, what tools do you have?
View User's Profile View All Posts By User U2U Member
Oddified

posted on 2/2/19 at 08:47 PM Reply With Quote
Yes, done numerous times. Very fine soldering iron and smt solder paste.

I do need glasses now to do them now though...must be an age thing! lol.

Ian

View User's Profile Visit User's Homepage View All Posts By User U2U Member   Oddified 's Aim
coyoteboy

posted on 2/2/19 at 10:02 PM Reply With Quote
Solder paste and a lot of flux and hot air rework gun.





Report your local potholes, it actually works!

View User's Profile Visit User's Homepage View All Posts By User U2U Member
02GF74

posted on 2/2/19 at 10:14 PM Reply With Quote
Hmm, seems to be easier than I expected, I've got solder paste as well as some pcbs to convert to DIL package on the way, and digital thermometer. . I don't have hot air gun (I do have a small gas soldering iron) so am looking at the oven or griddle method with solder paste, just need to get the special flux.

One things that's been puzzling me is how low can the smd device be kept at the temperatures required for the solder to melt, can't seem to find that in the spec. Sheet.

[Edited on 2/2/19 by 02GF74]





Visit China. Meet the child that made your trainers.


View User's Profile View All Posts By User U2U Member
DanP

posted on 3/2/19 at 11:42 AM Reply With Quote
It’s the reflow profile you need, it’s more for the QFN package than the device itself.

An example: http://infocenter.nordicsemi.com/pdf/nan_400-08.pdf

View User's Profile View All Posts By User U2U Member

New Topic New Poll New Reply


go to top






Website design and SEO by Studio Montage

All content © 2001-16 LocostBuilders. Reproduction prohibited
Opinions expressed in public posts are those of the author and do not necessarily represent
the views of other users or any member of the LocostBuilders team.
Running XMB 1.8 Partagium [© 2002 XMB Group] on Apache under CentOS Linux
Founded, built and operated by ChrisW.