PCB Modules - Help in identifying - Page 1
Forum section: electronics / general

author: chimerahitman
author_rank: Contributor
timestamp: June 15, 2012, 09:10:40 pm
content: Hello,I was looking at Altium's page,http://live.altium.com/#index, and looked at the picture to the upper right which had a board with mini modules on it. I was wondering if it had a proper name I could use to google more info on them.If no proper name is available, how could I go about creating my own? I am fluent enough in altium, but still can't get my head around the whole pad out of the board. I would like to make the pcb withwww.batchpcb.comand see if I can roll out a proof of concept sample.Thank you,SRR

author: Rufus
author_rank: Super Contributor
timestamp: June 15, 2012, 11:06:16 pm
content: Quote from: chimerahitman on June 15, 2012, 09:10:40 pmThey are PCB modules with what is called castellated surface mount pads (or possibly holes).As far as Altium is concerned they are called 'our next fail'.

author: Zad
author_rank: Super Contributor
timestamp: June 15, 2012, 11:25:33 pm
content: That has the smell of Marketing Department all over it

author: free_electron
author_rank: Super Contributor
timestamp: June 15, 2012, 11:35:54 pm
content: Indeed boards with castellated contacts.i have design rules to make this. Batchpcb or iteadstudio cannot handle this. it requires additional steps in the pcb process that they don't have.Essentially the castellation contact area is milled first together with the drill holes in the board.Then the board is subjected to a selective plating using electroless copper to create the edge contacts. Then the board is milled again to remove the copper deposits where no copper should be. After that pcb follows classic electroplating so copper grows only on the contact area that was left after milling. At the end of the production run the isolation fingers are milled off. This requires tight tolerances on the countour milling.The sloppy way is to simply specify a large via or pad and mill it in half. The problem is this creates burrs and may rip the metallisation off the hole wall. And the edge of the board will not have vertical plating either.a cleaner way is to simply draw a square pad top and bottom and connect it vertically. You then treat the board as a QFN of MLF style package but you have no true edge plating.Real castellated boards require process technology and steps that are not in amateur domain. i have done castellation board to convert a BGA to TQFP package. The castellated board had fingers that look like TQFP pins. You would solder this little board on a TQFP64 footprint and it would carry the BGA on its back.Board thickness was 8 mils ( not the usual 62 ) 4 layer and used plugged and blind via's ( via in pad. the via is squirted shut after first plating using a conductive epoxy and then another plating step grow copper over the plugged hole as well so you see no holes in this board... )you will need to talk to the boardfab you will use to ask them the milling width and edge pullback numbers. Sierra can mill with a 20 mils router bit and the pullback can be 8 mils.hang on i'm taking a picture( and don't listen to the doomsayers bashing altium. they are just jaleaous they have to muck about with counterintuitive, counterproductive, stone-age tools and can't afford something like Altium)here you go : This is the TQFP to BGA ( actually a bga with a thermal slug in the middle and long outside fingers for high current. the real name is a VQFN-MR package ) board.Made by Sierra Proto Express.

author: chimerahitman
author_rank: Contributor
timestamp: June 16, 2012, 05:09:24 am
content: free_electron:WOW! Thanks for such an informative explanation.It is a bummer that it cannot be achieved with cheap PCB manufacturers. Oh well, I will consider your simple solution with pads used as a QFN style package, if not, I will go with boards with headers near the edges. Last option will give me the possibility of placing components on the bottom layer.Would have been a great way of build up systems with already tested modules to speed up designs.Thank you, free_electron!!!

author: Rufus
author_rank: Super Contributor
timestamp: June 16, 2012, 08:13:36 pm
content: Quote from: free_electron on June 15, 2012, 11:35:54 pmI have an Altium seat and subscription. Maybe some 'doomsayers' base their opinion on past performance, maybe some bought Altium stock - lol.This castellated PCB modules on a carrier board smells like another of Altium's hair-brain schemes. They probably have visions of selling modules (possibly with firmware IP support) in their content store. Situs can probably manage to route the interconnect - lol.They will spend a lot of money providing seamless support for creating systems from these building block modules and you will be able to design your Wifi enabled spirit level or whatever in 15 minutes. Which is great if your business is selling expensive Wifi enabled spirit levels. The real world will look at it, maybe try it and then mostly ignore it because there won't be a set of modules to do what their business is and the product will be expensive unless they have little volume and the module suppliers (and to some extent Altium) would have them by the balls.I and I suspect most Altium customers would rather they spent our subscription money improving the core functions of the package.

author: free_electron
author_rank: Super Contributor
timestamp: June 16, 2012, 08:45:42 pm
content: I too have altium licence and subscription. Both at work and a private one for hobby.I just don't understand how you can deduce from the softwares splash screen that they are going to sell these modules and push this as a new product. Its just a splashscreen...Altium software has served me well in the past 15 years ( yeah i started with autotrax under dos ... , and got any version up till the current one )Haven't run into a single thing a couldn't do with it. Due to my job i frequently use other tools as well Pads, allegro, boardstation and once in a while zuken... I know what prefer... And it's altium.

author: Rufus
author_rank: Super Contributor
timestamp: June 16, 2012, 09:56:53 pm
content: Quote from: free_electron on June 16, 2012, 08:45:42 pmAltium were questioned when the splashscreen first appeared said it was something unannounced they are working on.If you know so much about Altium perhaps you can speculate what about castellated PCB modules mounted on an otherwise blank PCB needs to be worked on and will be worthy of announcing in the future.

author: free_electron
author_rank: Super Contributor
timestamp: June 17, 2012, 01:19:04 am
content: I wont speculate. To me its a splashscreen. And that's it.It is shown when you launs AD12 too. I don't pay attention to it.