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Altera_Forum's avatar
Altera_Forum
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12 years ago

What's SENSE_PAD SNS RSNS in DC-DC converter's Schematic in reference design

I looked some reference design of ALTERA , and in the Power supply part (DC-DC converter) appear a component SENSE_PAD , but when I checked the BOM file, It doesn't appear in the list of components, besides in the data sheet of the DC-DC converter doesn't show a component called SENSE_PAD. Could someone tell me what component is it? Thanks in advance

4 Replies

  • Altera_Forum's avatar
    Altera_Forum
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    12 years ago

    Without looking at the schematic in question, I would say the sense pad is probably just a special layout structure for the DC-DC converter.

    Typically these have a sense circuit to detect that the output is at the voltage specified, and may have specific layout requirements that they wanted to capture. I would look at the datasheet for the DC-DC.

    Pete
  • Altera_Forum's avatar
    Altera_Forum
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    12 years ago

    I've checked the data sheet, but I couldn't see anything about it,

    I attached picture of schematic
  • Altera_Forum's avatar
    Altera_Forum
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    12 years ago

    The sense pads will simply be easy to probe access points on the PCB. They are not components. They allow you to easily probe and measure the voltage drop across the sense resistor, R87.

  • Altera_Forum's avatar
    Altera_Forum
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    12 years ago

    --- Quote Start ---

    I attached picture of schematic

    --- Quote End ---

    The SENSE_PAD is a 2-pin component. You'll need to look in the PCB layout to see what those correspond to. Most likely they are just a copper shape, eg., the Kelvin sense connections to the current-sense resistor, or test-points.

    Its quite common to see parts in schematics that correspond to PCB structures that do not have physical components. For example, I've seen 0102 sized components that are used to short signals together, eg., an 0102 PCB footprint with a short between the two pads. This allowed the board to be loaded with 0-ohm resistors by default, but allows the end user to cut that trace to remove the (non-existent) 0-ohm resistor, or to add a different value. Its much nicer to "see" this component in the schematic, rather than it be some "magic" hidden in the PCB layout.

    Cheers,

    Dave