Re: FPGATED prototype

On 1/16/2021 4:15 AM, Istvan Hegedus wrote:
>
>
>
>     I can't argue the smaller footprint FPGA and 4 layer PCB, but I'd
>     keep
>     the surface mount header.  I think they look much more neat in
>     circuit
>     and if you trim the outside of your PCB to just beyond the SMT
>     pins, I
>     don't think the design will be too wide.  Having the pins sticking
>     through reduces top PCB area a lot and then you have to worry about
>     cutting the pins off and making sure they do not touch metal
>     shields and
>     such if folks re-assemble the EMI stuff.
>
>     Jim
>
> You are right, if I use through hole header then I don't have much 
> space left on the two sides for routing and components.
> I will consider it. There are only 2 drawbacks, price of the smd IC 
> header and the lead time (I have ordered it at Mouser in november and 
> they promise it now at the end of feb).
>
> Regards
> Istvan

I plan to buy 1000 of the SMT ones (I have the 28 pins in SMT and 
through hole and the 24 in through hole and plan to buy in SMT as well) 
and am happy to  set aside 100 or so for you if desired.  You can 
directly email me for pricing, but I can't believe 40 pins of smt header 
would be no more than 1.25 USD, and probably $1.00 (from my supplier, 
SMT and though hole differ in price by only a few pennies), which looks 
far cheaper than Mouser options (not sure why Digikey and mouser are so 
expensive on IC headers).  Lead time is about 2-3 weeks. I can mail you 
a few 28 pin ones to check on quality if desired.

You can see what the through hole ones look like here:

http://store.go4retro.com/ic-header/

And the SMT ones look the same on the bottom, but the upper post is bent 
out 90 degrees like in your footprint.

Don't worry if you're not interested.  I plan to buy the 40 pin SMT ones 
either way and use for other projects. Just let me know your thoughts.

If others are looking for non trivial connectors, let me know. I 
regularly source in bulk and if I can put it in the store or think up a 
use in a product, happy to buy 1000 of them (1000 is typically the 
minimum order quantity for manufacturers).


Jim



-- 
Jim Brain
brain_at_jbrain.com
www.jbrain.com