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VS pin voltage going higher than supply

Category: Datasheet/Specs
Product Number: AD8210S

In LTSpice I'm modeling a simple circuit using the AD8210.  For space applications we are placing a 4.99Ω resistor in series with the VS pin.  I noticed in the sim, that the VS pin will go up to 6V when supplied with 5V.

With the normally low current draw, the resistor doesn't cause a drop issue.  But in this circuit I'm getting a boost beyond the circuit specs when I add this resistor.  I would have expected ~10mV drop, not a 1V boost!

Is this just a spice model issue?  Can anyone confirm with the real chip?

Thanks!

Aaron

Parents Reply
  • Gilbeys,

    Thanks for trying it out.  I noticed that your example schematic doesn't have a ground connection to the chip.  So I played around with the connections on my circuit.  It looks like as soon as I connect the VIN- pin to ground, then I get the weird behavior.

    I also noticed that I had forgotten to put the shunt resistor in, once I put a 100mΩ resistor across VIN+ and VIN- the weirdness went away.

    So, with VIN- grounded and no shunt = weird.  Add the shunt and all is normal.

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