please dont rip this site

Avoiding Noise

General tips for avoiding noise

General tips for avoiding noise

Given a choice between your chips not agreeing on where ground is and on not agreeing on the supply voltage, its better that they agree on ground. That can help a bit with noise problems. <GRIN>

Avoiding noise in a PCB

one solid unsplit ground plane

There seems to be a bit of controversy between " power isolation " vs others who say "Don't split the ground plane. Don't split the power plane either, unless it actually needs to be different voltages. PCBs@"

Bryan in 1998 made some good recommendations, including "Make sure that you have a good ground plane under anything that uses RF frequencies especially the micro controller and I/O lines. ... Some people use a split ground plane but I have had disastrous results using a split ground plane." -- "RF Noise" thread

"Do not split the ground plane. Use one solid plane under both analog and digital sections of the board." -- Ott, in article "partitioning and layout of a mixed signal pcb" article by Henry W. Ott (EMI consultant) in _printed circuit design_ magazine (june 2001) /* was */

in it he basically makes the case that split planes are generally a bad thing

their best use he says is to correct a badly laid out board after the fact and also in some cases they are needed for safety isolation

but as to localizing noise (preventing polution of low level signals) and minimizing EMI nothing beats a *properly laid out* (i.e. 'routed/placed') board with a single ground plane possessing a single net

-- recc. Dennis Saputelli 2001-06-09

"Nothing is more important to the system design of a circuit than having a solid and complete power system. ... Design the ground system to include as many parallel pathways to ground as possible. ... ground planes are optimal ..." -- Mark Glenewinkel. "Motorola Semiconductor application note AN1259: System design and layout techniques for noise reduction in MCU-base systems". 1995.

US Patent 6023202 "Ground return for high speed digital signals that are capacitively coupled across a DC-isolated interface" by Hill, Gregory A. (02/13/1998) describes the best way to capacitively couple high-speed digital signals (in general) across a galvanic isolation, and (specifically) how it applies to FireWire. "... application of the invention produces improved signal integrity, reduced generation of electromagnetic emissions, and reduced susceptibility to electromagnetic interference."

"Analog-to-Digital Converter Grounding Practices Affect System Performance" describes how "a single ground plane" works best. Attempting to make a "split grounds connected together at the ADC" gave worse DLE.

ground loop

"Ground loops" are a badly misunderstood part of electronics.

Many op-amp data sheets recommend guard rings, such as

other ways of avoiding noise in a PCB

Avoiding noise in wire-wrap circuits

Follow these steps to eliminate noise.


file: /Techref/noises.htm, 15KB, , updated: 2020/9/1 09:06, local time: 2024/7/23 04:25,

 ©2024 These pages are served without commercial sponsorship. (No popup ads, etc...).Bandwidth abuse increases hosting cost forcing sponsorship or shutdown. This server aggressively defends against automated copying for any reason including offline viewing, duplication, etc... Please respect this requirement and DO NOT RIP THIS SITE. Questions?
Please DO link to this page! Digg it! / MAKE!

<A HREF=""> Avoiding Noise</A>

After you find an appropriate page, you are invited to your to this massmind site! (posts will be visible only to you before review) Just type a nice message (short messages are blocked as spam) in the box and press the Post button. (HTML welcomed, but not the <A tag: Instead, use the link box to link to another page. A tutorial is available Members can login to post directly, become page editors, and be credited for their posts.

Link? Put it here: 
if you want a response, please enter your email address: 
Attn spammers: All posts are reviewed before being made visible to anyone other than the poster.
Did you find what you needed?


Welcome to!

Site supported by
sales, advertizing,
& kind contributors
just like you!

Please don't rip/copy
(here's why

Copies of the site on CD
are available at minimal cost.

Welcome to!