mixed FR4 and microwave dielectrics

[John Larkin]

https://www.dropbox.com/s/mw0gka15okd4qgo/Spinner.AVI?dl=0



--

John Larkin Highland Technology, Inc
picosecond timing precision measurement

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

 

John Larkin <jjlarkin@highland_snip_technology.com> wrote in
news:mgobde1icalgrtmahec61rllfklaohdr9i@4ax.com:

> https://www.dropbox.com/s/mw0gka15okd4qgo/Spinner.AVI?dl=0

So, the other type of MEMS....

Macro Electro-mechanical systems.

Needs a more stable spin.

 

[Bill Sloman]

On Saturday, May 11, 2019 at 6:43:06 AM UTC+10, John Larkin wrote:
> https://www.dropbox.com/s/mw0gka15okd4qgo/Spinner.AVI?dl=0

Back in 1988, we specified isocyanate resin bonded teflon (PTFE) cloth as the outside layers of our six-layer delay board, so we could route the 800MHz clocks and the sub-nanosecnd logic transistions around without losing too much edge speed. The inner layers were all FR4 epoxy resin bonded glass fibre.

It was a triple extended Eurocard (big), but came out flat.

What did you do wrong?

--
Bill Sloman, Sydney

 

[Tim Williams]

"Bill Sloman" <bill.sloman@ieee.org> wrote in message
news:d7aecf2f-1e4d-4daa-95a1-8ca0db2a8b10@googlegroups.com...

What did you do wrong?

IIRC, the fab told them it was a bad idea, customer said go ahead and make
it, and evidently the fab believes the customer is always right.

You ALWAYS make the board stack symmetrical. Whatever you're doing on one
side, you're doing on the other side. Same cores, same prepreg, same copper
thickness, same copper density. Otherwise you get something like this.

Tim

--
Seven Transistor Labs, LLC
Electrical Engineering Consultation and Design
Website: https://www.seventransistorlabs.com/

 

[Robert Baer]

John Larkin wrote:

https://www.dropbox.com/s/mw0gka15okd4qgo/Spinner.AVI?dl=0



Except for cost, what is wrong with using mixed PPO (Panasonic, Isola)