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LM339A: LM339A

Thomas Heine
Prodigy 10 points

Part Number: LM339A
Other Parts Discussed in Thread: LM339-N, TL331, LM397, LM393

Hello,

I has to use two of four comparators of a LM339AM in a safety function.

How are the internal circuits an components connectet and there are more components as in the pdf shown?

How strong is the insulation between the comparators?

Thank you in advance.

Thomas Heine

0049 30 7622 3732

Germany, 12266 Berlin

  • 0
    Guru 140200 points
    Hi Thomas,

    in any case they sit on the same die and share the same substrate from which they are isolated by parasitic pn-junctions.

    Kai
  • 0
    TI__Guru 64416 points

    Hello Thomas,

    I have verified that the channels are fully independent on the LM339-N family. And as Kai said, they are all on one die and are in their own "tubs".

    However, all channels internally share a single power supply trace that runs sequentially from Ch1 to Ch4.  So it is possible that a severe catastrophic failure on the lower number channels (say, Ch1) could take out the upper channels (CH 2,3,4)  if the power trace is damaged. But you *really* have to try hard to do that!

    Under "normal" operation, the channels should not affect each other.

    So if you are concerned about channel interactions during a failure, you may want to use separate singles (TL331 or LM397) or two duals (LM393) to divide up the risk. Or spread the risk out logically among the quad channels.