Re: SMD Group Build

Dave Bottom <ars.kd6az@...>
 

I’m sure PCB manufacturing houses have improved a great deal, but in the Bay Area where you’d think no problem we found the best terrible. So many defective boards.

Parts were often difficult to obtain with some 52 week lead times - seriously this changes often.

We ended up going to Samsung’s prototype manufacturing facility where they take in small runs of boards to keep their facility humming along. Less than 500 boards max.

In the end they supplied us PCBs loaded with all glue logic (less our chip) and the landed cost was below blank PCBs. Every board worked! Absolutely an amazing facility.  Samsung buys glue logic in the millions so those parts were nearly free, installed.

BTW - They came back with a dozen questions about our Gerber files - all GOOD questions - before they produced anything. 

We used them for all prototype and high end low volume boards.

I really should check with them and see their availability as minimums. 

Dave WI6R


Sent from my iPhone

On Jan 24, 2018, at 8:54 PM, William R Maxwell <wrmaxwell@...> wrote:

0805 is a happy medium.

Bill, VK7MX


On 25/01/2018 3:20 PM, Jack Purdum via Groups.Io wrote:
I can barely see a 0603! I would prefer 1206 if I can find them and am not too worried about the cost differential.
Jack, W8TEE


From: Clark Martin <kk6isp@...>
To: BITX20@groups.io
Sent: Wednesday, January 24, 2018 9:15 PM
Subject: Re: [BITX20] SMD Group Build


Clark Martin
KK6ISP

On Jan 24, 2018, at 5:56 PM, Diver Martin <diver.martin@...> wrote:

Mouser & Digikey are my go-to for SMT parts.  They carry just about everything.  If you have other oddball SMT stuff, and either one are out, head to findchips.com.  There are alternate suppliers, but those two always have what I need, either in the exact specified part number, or an equivalent.  Other places will source 1206's and stuff, but might only sell by the full reel (which I have yet to need, except maybe 0.01uF caps or 0.1uF caps across multiple, multiple projects).

SMD resistors/caps (0603, 5% in my case) are usually cheap enough that I buy them in 1000-piece quantity, because $2 of parts for life or $0.5 for the parts I need for the project, and to always have them on hand, is easy.


I’ve only bought from Digikey a few times but I use Mouser all the time.  Also there are Newark and Allied for such supplies.

I bought a set of 0805 resistors (from 0 ohm through several Mohms) and a set of 0805 caps (10s of pF through 1µF).  They came on cards that fit a day planner binder.  There are between 1 and four strips of 25 each for each value (depending on expected usage levels).  I have little trouble working with 0805 parts and they  fit nicely on .1” grid perfboard (with plated through holes).  

When I use up a strip I buy a new strip of 25 at a local electronics shop (Silicon Valley still has a few).

I haven’t done any PCB fabricating yet but that is in the plans.

SMD diodes and transistors of most any size are easily soldered to perfboard.

I’ve also soldered up to 8 pin SOICss buy putting alternate pins on the perfboard pads and tack soldering leads to the other pins.

It definitely makes for smaller boards.



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