element14 Community
element14 Community
    Register Log In
  • Site
  • Search
  • Log In Register
  • Members
    Members
    • Achievement Levels
    • Benefits of Membership
    • Feedback and Support
    • Members Area
    • Personal Blogs
    • What's New on element14
  • Learn
    Learn
    • eBooks
    • Learning Center
    • Learning Groups
    • STEM Academy
    • Webinars, Training and Events
  • Technologies
    Technologies
    • 3D Printing
    • Experts & Guidance
    • FPGA
    • Industrial Automation
    • Internet of Things
    • Power & Energy
    • Sensors
    • Technology Groups
  • Challenges & Projects
    Challenges & Projects
    • Arduino Projects
    • Design Challenges
    • element14 presents
    • Project14
    • Project Groups
    • Raspberry Pi Projects
  • Products
    Products
    • Arduino
    • Avnet Boards Community
    • Dev Tools
    • Manufacturers
    • Product Groups
    • Raspberry Pi
    • RoadTests & Reviews
  • Store
    Store
    • Visit Your Store
    • Or choose another store...
      • Europe
      •  Austria (German)
      •  Belgium (Dutch, French)
      •  Bulgaria (Bulgarian)
      •  Czech Republic (Czech)
      •  Denmark (Danish)
      •  Estonia (Estonian)
      •  Finland (Finnish)
      •  France (French)
      •  Germany (German)
      •  Hungary (Hungarian)
      •  Ireland
      •  Israel
      •  Italy (Italian)
      •  Latvia (Latvian)
      •  
      •  Lithuania (Lithuanian)
      •  Netherlands (Dutch)
      •  Norway (Norwegian)
      •  Poland (Polish)
      •  Portugal (Portuguese)
      •  Romania (Romanian)
      •  Russia (Russian)
      •  Slovakia (Slovak)
      •  Slovenia (Slovenian)
      •  Spain (Spanish)
      •  Sweden (Swedish)
      •  Switzerland(German, French)
      •  Turkey (Turkish)
      •  United Kingdom
      • Asia Pacific
      •  Australia
      •  China
      •  Hong Kong
      •  India
      •  Korea (Korean)
      •  Malaysia
      •  New Zealand
      •  Philippines
      •  Singapore
      •  Taiwan
      •  Thailand (Thai)
      • Americas
      •  Brazil (Portuguese)
      •  Canada
      •  Mexico (Spanish)
      •  United States
      Can't find the country/region you're looking for? Visit our export site or find a local distributor.
  • Translate
  • Profile
Autodesk EAGLE
  • Products
  • More
Autodesk EAGLE
EAGLE User Chat (English) GND on two layers
  • Blog
  • Forum
  • Documents
  • Events
  • Polls
  • Files
  • Members
  • Mentions
  • Sub-Groups
  • Tags
  • More
  • Cancel
  • New
Autodesk EAGLE requires membership for participation - click to join
Actions
  • Share
  • More
  • Cancel
Forum Thread Details
  • Replies 5 replies
  • Subscribers 145 subscribers
  • Views 145 views
  • Users 0 members are here
Related

GND on two layers

autodeskguest
autodeskguest over 13 years ago

LS,

 

Is there a thumbs rule connecting two layers.

 

On the bottom and on the top layer I have a GND polygon.

To reduce stray current I would like to connect these two using via's.

 

Regards

 

Harry

 

  • Sign in to reply
  • Cancel
  • autodeskguest
    autodeskguest over 13 years ago

    In general, if they are to transmit high current, heat or digital

    switching transients between the two ground conductors, you should place

    alot of them. If the conductors are to be AC, or thermally, isolated,

    only one. Not a simple topic, but most hobbyist circuits- doesn't really

    matter.

     

    • Cancel
    • Vote Up 0 Vote Down
    • Sign in to reply
    • Cancel
  • autodeskguest
    autodeskguest over 13 years ago

    Is there a package that one can calculate the voltage drop on a layer that

    uses a polygon with or without via's?

    "Gary Gofstein" <nospam@use.forum.net> schreef in bericht

    news:hkvea1$h1m$1@cheetah.cadsoft.de...

    In general, if they are to transmit high current, heat or digital

    switching transients between the two ground conductors, you should place

    alot of them. If the conductors are to be AC, or thermally, isolated, only

    one. Not a simple topic, but most hobbyist circuits- doesn't really

    matter.

     

     

    • Cancel
    • Vote Up 0 Vote Down
    • Sign in to reply
    • Cancel
  • autodeskguest
    autodeskguest over 13 years ago

    No. You would need to know the distribution of the current for DC. For

    AC currents in the RF range you need to know the shape of the pulse and

    solve the wave equation to know where the current will flow and what

    skin depth it will flow in. Nobody does that.

     

    For "normal circuits", it's seldom an issue. How much current are we

    talking about here anyway? DC, audio or RF current?

     

    To get a comparison for DC currents you can look at trace temp rise vs

    size charts for ordinary traces. You will see that unless you use super

    thin "digital" traces, it's usually okay. I always use the biggest

    traces I can fit anyway. There's a ULP that calculates temperature rise

    on traces for DC currents; you'll see that your plane is likely to be

    much bigger than necessary. You don't need to know how many vias to add,

    because you should just add as many as you can to get the best

    performance. You can estimate the temperature rise of a via by thinking

    of it as  a wire, figure out the equivalent wire guage, consult a

    current vs temp rise site or chart to get the temp rise. You should

    specify your vias to be solder filled for best DC and thermal

    conductance. If you will never solder to them, you don't need thermals

    on vias (EAGLE default anyway). Actually, it's possible to tack solder a

    wire even on a via with no thermal, so it's rare to need a thermal on a

    via. All this applies only to DC currents, RF/pulse currents are a whole

    nother story...

     

    • Cancel
    • Vote Up 0 Vote Down
    • Sign in to reply
    • Cancel
  • autodeskguest
    autodeskguest over 13 years ago

    Oh yeah, if you are thinking that knowing the voltage drop is important,

    it may not be. If you plan on using that ground plane as a voltage

    reference you should just run parallel ground traces that don't carry

    current to anyplace that needs to know ground voltage (like an opamp

    input or voltage regulator). These are separate from the plane returning

    current to ground potential and generating voltage drops.

     

    • Cancel
    • Vote Up 0 Vote Down
    • Sign in to reply
    • Cancel
  • autodeskguest
    autodeskguest over 13 years ago

    The plane should carry a current of approx. 3A at 18V DC

    "Gary Gofstein" <nospam@use.forum.net> schreef in bericht

    news:hl1u5s$8mk$1@cheetah.cadsoft.de...

    No. You would need to know the distribution of the current for DC. For AC

    currents in the RF range you need to know the shape of the pulse and solve

    the wave equation to know where the current will flow and what skin depth

    it will flow in. Nobody does that.

     

    For "normal circuits", it's seldom an issue. How much current are we

    talking about here anyway? DC, audio or RF current?

     

    To get a comparison for DC currents you can look at trace temp rise vs

    size charts for ordinary traces. You will see that unless you use super

    thin "digital" traces, it's usually okay. I always use the biggest traces

    I can fit anyway. There's a ULP that calculates temperature rise on traces

    for DC currents; you'll see that your plane is likely to be much bigger

    than necessary. You don't need to know how many vias to add, because you

    should just add as many as you can to get the best performance. You can

    estimate the temperature rise of a via by thinking of it as  a wire,

    figure out the equivalent wire guage, consult a current vs temp rise site

    or chart to get the temp rise. You should specify your vias to be solder

    filled for best DC and thermal conductance. If you will never solder to

    them, you don't need thermals on vias (EAGLE default anyway). Actually,

    it's possible to tack solder a wire even on a via with no thermal, so it's

    rare to need a thermal on a via. All this applies only to DC currents,

    RF/pulse currents are a whole nother story...

     

     

    • Cancel
    • Vote Up 0 Vote Down
    • Sign in to reply
    • Cancel
element14 Community

element14 is the first online community specifically for engineers. Connect with your peers and get expert answers to your questions.

  • Members
  • Learn
  • Technologies
  • Challenges & Projects
  • Products
  • Store
  • About Us
  • Feedback & Support
  • FAQs
  • Terms of Use
  • Privacy Policy
  • Legal and Copyright Notices
  • Sitemap
  • Cookies

An Avnet Company © 2023 Premier Farnell Limited. All Rights Reserved.

Premier Farnell Ltd, registered in England and Wales (no 00876412), registered office: Farnell House, Forge Lane, Leeds LS12 2NE.

ICP 备案号 10220084.

Follow element14

  • X
  • Facebook
  • linkedin
  • YouTube