View Single Post
  #21   Report Post  
Posted to rec.audio.pro
[email protected] joe@mich.com is offline
external usenet poster
 
Posts: 22
Default overvoltage on audio circuits

On Wed, 30 Oct 2019 13:58:13 +0000 (UTC), Ralph Barone wrote:

wrote:
On 29 Oct 2019 11:28:57 -0400, (Scott Dorsey) wrote:

geoff wrote:
On 29/10/2019 8:04 am, gareth magennis wrote:



This mechanism exists in all electrical conductors, but is only an issue
in microcircuits because the
conducting lines are so small and the current densities are therefore very high.


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.


Nope, electromigration has always been a concern and is one of the two most important reliability
issues in layouts. The other being electrostatic discharge. Huge traces is a relative term, microcircuits
are tiny.

Besides, large interconnect traces result in large parasitic capacitances which have a major impact on
AC charateristics (phase margin, BW, etc.), not to mention the impact on chip size and therefore
chip cost. Also, bipolar amps don't use large devices to reduce noise.