OPA1637 enable/disable transients

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Joined 2002
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I missed those Marcel, I did look for them but didn't see them ...
In the mean time I rigged up a test on the OPA637 eval module I found back in my 'stuff' box...
There seems to be a transient when coming out of disable, and the disable doesn't fully suppress the signal (probably still leaks through the input/feedback resistors).
So it doesn't really look useful as a mute function.

Jan
 

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  • OPA1637 disable.mp4
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In differential applications at least I've found that series resistors and jfets across the output does a good job of muting in 1632. (The idea is not original.)

1694273201113.png


There are other jfets with lower RDS which might work better than the ones I used (which I could get at the time) J112? IIRC
 
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AX tech editor
Joined 2002
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As you can see in the pics I posted, the 1637 when shutting down doesn't mute the signal.
It can't because there's a connection from input to output through the feedback network.
@bohrok2610 - I wasn't aware of the 1633, I will check it out!

Edit: the OPA1633 seems to be unavailable at the usual suspects ...

Jan
 
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You wonder why they would bother to create a new device...maybe just increased the operating currents of the input pair a bit? Or perhaps the fakes (the OPA1632 from China) are in such mass abundance they can't sell the originals?
 
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There seems to be a transient when coming out of disable, and the disable doesn't fully suppress the signal (probably still leaks through the input/feedback resistors).
So it doesn't really look useful as a mute function.
According to the data sheet it's a power down pin and not a mute pin. So I would expect the purpose to be power savings rather than muting.

Tom
 
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