Terminology question, no load capacitor and no load resistor

I was reviewing a schematic I found on-line at Cypress Semiconductor for one of their capsense products.· While reading through the schematic I saw references to "no load" as the value on a couple capacitors and a couple resistors.· In the version notes of the schematic there was another note "zero ohm resistors replaced with no load resistors".·

I know what a zero ohm resistor is.· In the places in the Cypress schematic I think a zero ohm resistor would have done.· I don't understand what a "no load" capacitor or a "no load" resistor is.· Can any one educate me?

My best guess, and it is only a guess,·is that a "no load" cap or resistor is an actual device to be stuffed on the board but is really an open (instead of a short. 0 ohm).· Does that make sense?· Even though a device is populated it is still open?· Why populate the device then and instead just leave the footprint empty?· Perhaps to keep someone from accidentally stuffing it and causing a short?· That would make sense for the capacitors but I am not so sure about the resistor, but that probably depends on the application.

Thank you for any insights or defintions you can provide.

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Timothy D. Swieter

www.brilldea.com·- check out the uOLED-IOC, an I/O expansion for the uOLED-96-PROP
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www.brilldea.com :RGB LED Ribbon, LED Painter II-8, PolkaDOT-51 and other gadgets for artistic lighting displays
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Comments

  • 6 Comments sorted by Votes Date Added
  • edited March 2008 Posts: 0Vote Up0Vote Down
    Timothy D. Swieter,

    I've heard the term used before when a board has multiple options, and the "no load" cap or resistor indicates that that component will NOT be populated on that board.

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    Beau Schwabe

    IC Layout Engineer
    Parallax, Inc.
    "Irony hides in the deception of your current view of the situation" - Me ....
    In other words, do not believe what you are told and what you immediately perceive until you find out the absolute truth for yourself from all possible angles.

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  • edited March 2008 Posts: 1,603Vote Up0Vote Down
    Hmmm - so "no load" is similar to Do Not Populate. That makes sense as I reviewed the schematic. The "no load" way of labeling things is perhaps even better than listing a part and a value and then on the BOM making it a Do Not Populate/stuff. I like having the majority of the data in one place so the person viewing the schematic is not confused and doesn't require so many other documents to decode and understand the design. I may have to implement this term in my designs, but make it clear that "no load" means do not populate.

    Thank you Beau for the response.

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    Timothy D. Swieter

    www.brilldea.com·- check out the uOLED-IOC, an I/O expansion for the uOLED-96-PROP
    www.tdswieter.com
    One little spark of imagination is all it takes for an idea to explode
    Timothy D. Swieter, P.E.
    www.brilldea.com :RGB LED Ribbon, LED Painter II-8, PolkaDOT-51 and other gadgets for artistic lighting displays
    http://www.brilldea.com/Prod_Clearance.html :Need to make room for new ideas!
    www.tdswieter.com
  • edited March 2008 Posts: 0Vote Up0Vote Down
    In days gone by, long gone by I'm afraid, components were "loaded" into boards, especially when boards were hand assembled. Could be a connection, or not...

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  • edited March 2008 Posts: 0Vote Up0Vote Down
    hmmm....recently I was going through a schematic for a piece of gear at work.

    I was trying to trace a circuit that I later realized had a resistor that wasn't used....it was silkscreened on the board, but not placed.
    Taking a better look at the schematic I found that the "value" on that particular resistor simply has the letters SAT.

    My boss couldn't quite remember what it stood for....and I had not seen that before. Swapped At Test?? or Supplied At Test...??

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    <FONT>Steve



    What's the best thing to do in a lightning storm? "take a one iron out the bag and hold it straight up above your head, even God cant hit a one iron!"
    Lee Travino after the second time being hit by lightning!
  • edited March 2008 Posts: 0Vote Up0Vote Down
    Steve,
    "Select At Test". We use them all the time at my work.

    Bean.

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