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Looking for advice on selecting voltage regulators for a project

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Kremmen:
Well, i didn't proof read your typing (what this board needs is a LaTex renderer), so i assume they are right. But you see, the temperature related fractional power terms are the consequence of carrier density changes. How else would there be a change in current?
The product of carrier concentration, or the law of mass action can be written

nenh = ½(KBT/pi h2)3 (memh)3/2 e?eg/KBT

?eg is the band gap.
You can see that the carrier density is proportional to the 3th power of temperature. So the conductivity goes up with temperature. If you have hot spots or unevenly heated devices the hot silicon hogs the current due to higher carrier concentration, other things being equal.

Edit: Oops, this forum doesn't like greek letters. the ? above should be capital delta.

jahonen:
Well, a quiescent current plot of TI OPA2134:



I don't think that thermal runaway is a problem there. I have never seen an opamp spontaneously doing that, although I have used a lot of them. I think that the chip designers know what they are doing.

±12 volts is perfectly ok voltage for an audio opamp, which are not typically a rail-to-rail ones. That said, I have used MAX743 based switch mode converter to power a headphone amplifier TPA6120A2, works just fine. No problems with noise, although I have another LC-filter in additional of the mandatory ones. There still remains some MHz-range noise, but I don't think that is a severe problem.

Regards,
Janne

SeanB:
Opamps generally have some thermal protection built in, though it is not meant to be used regularly, it generally is there for only extreme cases. It is not tested during production, and is only tested on sampling.

That said I have run 741's as replacements for OP22's, with a supply of +-22V, and they worked well.

Power IC's though need to be kept well within the absolute max voltage and current limits, and heatsinked well enough that the die does not exceed 70C. Running near the max, or at high temp will eventually let the magic smoke out, and may damage both the equipment and the load.

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