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Old November 8th 19, 12:16 PM posted to
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Default overvoltage on audio circuits

On 7 Nov 2019 13:43:57 -0500, (Scott Dorsey) wrote:

>Ralph Barone > wrote:
>>I was under the impression that electromigration was only an issue in
>>modern microprocessors and other ICs built using nanometer scale
>>transistors. I would assume that an op amp is built with huge transistors
>>(and huge traces) in order to achieve low noise, and would therefore be
>>relatively immune to electromigration damage.

>I think it's a matter of scale and voltage. So it's an issue at low voltages
>with tiny transistors, but at higher voltages (and really 15V isn't that
>high) with larger transistors. I think it's also a matter of the shape of
>the metallization traces, with sharp angles promoting migration.
>That said, if it were that big a problem I'd be seeing LM709s and LM301s
>starting to fail by now, right?

Current density and temperature are the important factors. The properties
of the metalization alloy is highly significant and it is this area that has led to
major improvents in time to fail, allowing smaller interconnect widths. AL
dominated ICs until this century when it was figured out how to make a Cu alloy work
Interconnect shape and vias to other metal levels are weak points but these are addressed in layout.