Prototyping with small packages like QFNs and BGAs... how do you do it? - Page 1
Forum section: electronics / general

author: PartialDischarge
author_rank: Super Contributor
timestamp: May 10, 2016, 05:50:38 am
content: Hi,as you probably have noticed, "large" footprints for new ICs are becoming rare, and every new interesting device out therecomes in a tiny thing, like BGA or QFN, which are not specially well suited to be used in a hand made prototype.I've had this problem for a few times now, and since they were personal projects in which I didn't want to spend money on new PCBs, I've resorted to hand soldering (see attached). Besides thats the point of a prototype, testing quick if a device fits your needs or not before building a real thing.Have you ever had this problem before?Have you decided not to use a device cause you couldn't simply use it due to its size?Attached is a hand soldered BGA 0.8mmx1.2mm with a 0.4pitch.The other one is a 1.4x1.8 QFN with 0.4 pitch, nasty but it works

author: bktemp
author_rank: Super Contributor
timestamp: May 10, 2016, 06:06:48 am
content: Quote from: MasterTech on May 10, 2016, 05:50:38 amYes. I made breakout boards for most small packages like QFN, MSOP, TSOP, DFN and TQFP.I've tried hand soldering wires before, but it much more difficult than having a small pcb with the correct footprint ready.Quote from: MasterTechLattice MachXO3:http://www.latticesemi.com/Products/FPGAandCPLD/MachXO3.aspxIt is impossible to get PCBs in small volumes for those 0.4 and 0.5mm BGA packages without paying insane prices.

author: PartialDischarge
author_rank: Super Contributor
timestamp: May 10, 2016, 06:13:41 am
content: Quote from: bktemp on May 10, 2016, 06:06:48 amTrue, Ive bought some breakout boards off ebay, but not all footprints are available, like that 10 pin QFN or 6 pin BGA. The rest footprints you mention (MSOP, TSSOP, TQFP...) are more common

author: JPortici
author_rank: Super Contributor
timestamp: May 10, 2016, 06:40:53 am
content: You make your own, a pcb order from china, with courier shipping of course, will be on your bench at work in a matter of a couple of days an with acceptable quality, at the cost of a single good quality adapter.Or, again, if possible and cost is not a matter you get to order a devkit

author: Fsck
author_rank: Super Contributor
timestamp: May 10, 2016, 06:48:10 am
content: breakout board if you have one or can wait for one.deadbug it if you can't, and the bga doesn't have a ridiculous number of pads. the most I've ever done was a hundred and something and keeping track of all the wiring was pretty tedious. I can only imagine the pain of larger chips. (if someone manages to do those 1k+ pad beasts and get it to work on the first go without going insane, I'll totally worship them.)

author: iampoor
author_rank: Frequent Contributor
timestamp: May 10, 2016, 07:09:55 am
content: Quote from: Fsck on May 10, 2016, 06:48:10 am

author: daqq
author_rank: Super Contributor
timestamp: May 10, 2016, 07:41:54 am
content: Deadbug - I hate it, I hate doing it, but there is generally no quick alternative. See my recent abomination.

author: Fsck
author_rank: Super Contributor
timestamp: May 10, 2016, 07:42:50 am
content: Quote from: iampoor on May 10, 2016, 07:09:55 amI've seen them done before, but I don't recall them saying if they got it on the first try.

author: Psi
author_rank: Super Contributor
timestamp: May 10, 2016, 07:45:03 am
content: Quote from: MasterTech on May 10, 2016, 05:50:38 amCant afford $10 for 5 boards from elecrow?

author: AntiProtonBoy
author_rank: Frequent Contributor
timestamp: May 10, 2016, 07:54:37 am
content: Quote from: iampoor on May 10, 2016, 07:09:55 amWhat's the back story of that pic?

author: PartialDischarge
author_rank: Super Contributor
timestamp: May 10, 2016, 08:18:06 am
content: Quote from: Psi on May 10, 2016, 07:45:03 amI meant a newly designed PCB for the project, find me breakout board for the 10 pin QFN in the first post....

author: tszaboo
author_rank: Super Contributor
timestamp: May 10, 2016, 08:50:27 am
content: If it is an analog stuff or ASIC, then it will surely have an evaluation board. Maybe they dont tell it on the website, but there will be, since the manufacturer will have to evaluate the part. It is possible to get these if you are a company, just ask your supplier to negotiate for the board. If it is a new MCU, then prototype it in a different package. If the core is the same, who cares, until you get the first prototype board? I see very little reason to dead bug a QFN. It is time consuming and prone to error anyway.

author: mathsquid
author_rank: Frequent Contributor
timestamp: May 10, 2016, 02:05:53 pm
content: Quote from: iampoor on May 10, 2016, 07:09:55 amThat looks like a portuguese man o war.

author: KL27x
author_rank: Super Contributor
timestamp: May 10, 2016, 08:34:19 pm
content: Unless it's 10 pins or less, I will prefer to make a board. It's not the soldering. It's keeping track of the pinout upside down. Then having to do it rightside up for the pcb. I don't have that much processing power to spare, lol.

author: VK3DRB
author_rank: Super Contributor
timestamp: May 12, 2016, 10:51:22 am
content: Quote from: iampoor on May 10, 2016, 07:09:55 amI once worked with a bloke who could do that without no worries. In fact he did far more complex wiring harnesses that no-one I know could do. His work was breathtaking and it always worked. But he had serious anger management problems and other personality disorders, possibly partly due to the fact his father was a complete bastard who deserted his kids when he was a young child, or partly due to him smoking cones for years. Despite smashing up some of the workshop with a hammer, slamming doors, and going into a rage every so often, the company kept him on because there was no-one who could do such brilliant work and who had such talent for mechanical problem solving. He built some seriously wonderful test fixtures. His education level was not high, but he was a genius.

author: Kjelt
author_rank: Super Contributor
timestamp: May 12, 2016, 01:40:17 pm
content: I wonder how many of these small devices need a groundplane or have an exposed pad that needs to cool it for normal conditions or other special pcb layout requirements in order to function within specs.So in these days with cheap pcb's i would just make the pcb layout and let it be manufactured. No way you can drive a large power hf smps ic with these kind of wires, no cooling and have a representative behaviour.