[sdiy] Making toast with chips

[Scott Gravenhorst]

<Linc at christeld.freeserve.co.uk> wrote:
>
>Can anyone tell me if Opamps should ever run hot (to the touch) and what
>it implies if they are? I notice on some audio boards I'm looking at
>that the NE5532s (and 5534s) are hot to the touch. Some hotter than
>others. None of them is under much of an output load and the supply is a
>good quality +/- 15V fed in groups through fusible 4.7 ohm resistors
>that periodically blow. Each chip has a pair of 47nF ceramic PS
>decoupling caps right by it though they're 12 years old now. Am I right
>in thinking that the ones that are hottest to touch are the most likely
>to cause excessive current draw or is it a red herring? After all the
>boards don't give trouble 95% of the time- not a very good average I
>know. The odd thing is that usually replacing the resistor cures it at
>least for a while.

Generally, heat is caused by current flow.  I can't think of why one
would want an opamp to supply so much current that it gets hot.

>I notice the hotter ones generally (though not exclusively) have a P
>suffix and are dual types while the cool ones are N suffix.

<smartass mode>

P = poor
N = nice

</smartass mode>


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