Windfreak Technologies
RF Electronics Symbols, Stencils for Office, Visio by RF Cafe
 

About RF Cafe

Kirt Blattenberger - RF Cafe Webmaster

Copyright: 1996 - 2024
Webmaster:
    Kirt Blattenberger,

    BSEE - KB3UON

RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The World Wide Web (Internet) was largely an unknown entity at the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps while tying up your telephone line, and a nice lady's voice announced "You've Got Mail" when a new message arrived...

All trademarks, copyrights, patents, and other rights of ownership to images and text used on the RF Cafe website are hereby acknowledged.

My Hobby Website:

AirplanesAndRockets.com

Electronics World articles Popular Electronics articles QST articles Radio & TV News articles Radio-Craft articles Radio-Electronics articles Short Wave Craft articles Wireless World articles Google Search of RF Cafe website Sitemap Electronics Equations Mathematics Equations Equations physics Manufacturers & distributors Engineer Jobs LinkedIn Crosswords Engineering Humor Kirt's Cogitations RF Engineering Quizzes Notable Quotes App Notes Calculators Education Engineering magazine articles Engineering software Engineering smorgasbord RF Cafe Archives RF Cascade Workbook 2018 RF Symbols for Visio - Word Advertising RF Cafe Homepage Thank you for visiting RF Cafe!
Anatech Electronics

Mixed Signal PCB layout - RF Cafe Forums

RF Cafe Forums closed its virtual doors in 2012 mainly due to other social media platforms dominating public commenting venues. RF Cafe Forums began sometime around August of 2003 and was quite well-attended for many years. By 2010, Facebook and Twitter were overwhelmingly dominating online personal interaction, and RF Cafe Forums activity dropped off precipitously. If the folks at phpBB would release a version with integrated sign-in from the major social media platforms, I would resurrect the RF Cafe Forums, but until then it is probably not worth the effort. Regardless, there are still lots of great posts in the archive that ware worth looking at.

Below are the old forum threads, including responses to the original posts.

-- Amateur Radio
-- Anecdotes, Gripes & Humor
-- Antennas
-- CAE, CAD, & Software
-- Circuits & Components
-- Employment & Interviews
-- Miscellany
-- Swap Shop
-- Systems
-- Test & Measurement
-- Webmaster

Guest
Post subject: Mixed Signal PCB layout
Unread postPosted: Thu Jun 02, 2005 8:27 am

We make a pCB layout of a mixed signal board (High-speed digital and RF up to 400MHz). The board has 14 layers. The board is divided into 2 sections by a slot across the board. At he RF side we use only in 6 layers for the signals and grounds. My question is can we use the other layers as GND planes and stitch them with vias to the already used GND layers ? Is it recommended?


Top


Guest
Post subject:
Unread postPosted: Fri Jun 03, 2005 7:08 am

It is recommended. At 400MHz there is not alot of concern about stray RF, but the additional ground palnes will serve as a heatsink for the rest of the board. It is there, so you should use it.


Top


Another Guest
Post subject: ground planes
Unread postPosted: Wed Jun 08, 2005 11:23 am

Do remember that the vias which do the stitching together of the ground planes need to be spaced adequately close: well less than 1/10 of a wavelength at c in the medium (and that's not c in free space, but c/epsilon for the board material you're using. So if you're using a board material with a dielectric constant epsilon of 4, at 400 MHz one wavelength of a buried trace is 0.18 meters, so stitching vias should be absolutely no farther than 18 mm apart. I'd actually recommend much closer - say 2 mm - since you may have harmonics, or need a low-impedance connection.)

Good luck!


Top


Guest
Post subject:
Unread postPosted: Wed Jun 08, 2005 1:50 pm

Many thanks for your help!
I will do as you advised.

Thanks again!!! :-D



Posted  11/12/2012
KR Electronics (RF Filters) - RF Cafe
ConductRF Precision RF Test Cables - RF Cafe
 

Please Support RF Cafe by purchasing my  ridiculously low−priced products, all of which I created.

These Are Available for Free