Formulas & Data:
- Electronics
- Mathematics
- Physics
- RF & Microwaves

Parts Vendors:
- all hand-selected

- Amateur Radio
- Vintage Articles:
- Electronics World
- Popular Electronics
- QST
- Radio & TV News
- Radio Craft
- Short Wave Craft
- Wireless World

- Events Calendar
RF Cafe Homepage
Copyright 1999-2015   •−•  ••−•    −•−•  •−  ••−•  •   "RF Cafe" in Morse Code  >> Listen to It <<
- EW & Radar Handbook
- Quizzes       - Software
- App Notes
- Calculators
- Advertise on RF Cafe
- About RF Cafe™
- RF Cafe Shirts & Mugs
- RF Cafe Archives
RF Cafe Book Contest
- RF Cafe on Visit RF Cafe on Facebook Visit RF Cafe on Twitter Visit RF Cafe on LinkedIn
- Tech Humor
- Forums Archive
- Job Board
- Donate to RF Cafe
- Kirt's Cogitations
Custom Search
More than 10,000 searchable pages indexed.
Greetings: There is so much good stuff on RF Cafe that there is no way to list or link to all of it here. Please use the Search box or the Site Map to find what you want - there is a good chance I have it here. Thanks!

Question on biasing circuitry - RF Cafe Forums

Because of the high maintenance needed to monitor and filter spammers from the RF Cafe Forums, I decided that it would be best to just archive the pages to make all the good information posted in the past available for review. It is unfortunate that the scumbags of the world ruin an otherwise useful venue for people wanting to exchanged useful ideas and views. It seems that the more formal social media like Facebook pretty much dominate this kind of venue anymore anyway, so if you would like to post something on RF Cafe's Facebook page, please do.

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


smanoha
Post subject: Question on biasing circuitry Posted: Tue Apr 25, 2006 2:14 am

Captain

Joined: Tue Apr 25, 2006 2:01 am
Posts: 7
I am noticing a difference in the overall gain (of an LNA) depending on where the off-chip decoupling capacitors are placed (close to or away from the chip). Any ideas on why this might be happening?


Top

fred47
Post subject: LNA bypassingPosted: Tue Apr 25, 2006 5:36 pm

General


Joined: Wed Feb 22, 2006 3:51 pm
Posts: 104
Even a short trace on a PCB looks like a non-negligible inductor at a high-enough frequency. So a bypass capacitor away from the chip might even look inductive, depending on the length of pcb trace and the operating frequency. That would give unintended feedback via the power supply pin of the IC, which would affect the gain.

Good Luck!
Fred


Posted  11/12/2012

Your RF Cafe
Progenitor & Webmaster

Click here to read about RF CafeKirt Blattenberger… single-handedly redefining what an engineering website should be.

View the YouTube RF Cafe Intro Video Carpe Diem!
(Seize the Day!)

5th MOB: My USAF radar shop

Airplanes and Rockets: My personal hobby website

Equine Kingdom: My daughter Sally's horse riding website