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Bypassing the LM6171
Bypassing the LM6171
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Old 14th March 2005, 10:14 PM   #1
Fat Dave is offline Fat Dave  Canada
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Default Bypassing the LM6171

Just looking for some user experience on bypassing the power pins on the LM6171

I believe the CarlosFM method is 22-100uF electrolytic with 0.1uF ceramic as close as possible (which I've used happily with other opamps - thanks Carlos!). Datasheet shows a configuration with a 2.2uF tantalum with 0.01uF for the LM6171.

What has worked well for you with this chip?
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Old 14th March 2005, 10:25 PM   #2
Peter Daniel is offline Peter Daniel  Canada
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Bypassing the LM6171 Send a message via AIM to Peter Daniel
4.7 BG N without any other aditional bypasses.
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Old 14th March 2005, 11:27 PM   #3
mikelm is offline mikelm  England
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1uF low inductance film like cap "ERO" MKT 1822 soldered onto the pins also works and sounds good. This arrangement and a battery works well with no further aditions needed.

best avoid using sockets - they could well cause oscillation.

I did it dead bug style.

mike
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Old 15th March 2005, 12:23 AM   #4
carlosfm is offline carlosfm  Portugal
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Default Re: Bypassing the LM6171

Quote:
Originally posted by Fat Dave
Just looking for some user experience on bypassing the power pins on the LM6171

I believe the CarlosFM method is 22-100uF electrolytic with 0.1uF ceramic as close as possible (which I've used happily with other opamps - thanks Carlos!).
That and also a 100~330nf directly across V+ and V- pins works wonders.
No problem with sockets and the LM6171 if you use the small ML ceramics right on the socket's pins to ground.
And btw no need for ultra-fancy caps to have excellent results.
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Old 15th March 2005, 05:09 PM   #5
Fat Dave is offline Fat Dave  Canada
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Thanks all! Good to know it's not hypersensitive - you just need to treat it properly.

I'll probably start with the method I know, and experiment from there.

I was going to go without socket (which I don't like to do, but wanted to avoid the extra capacitance). Maybe I'll give it a try with some good machined sockets first, keep the caps as tight as possible, and see if I can keep it out of oscillation.

And I definitely won't forget the 100-330nF from V+ to V-
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Old 29th February 2016, 06:52 PM   #6
JaredC79 is offline JaredC79  United States
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Quote:
Originally Posted by Peter Daniel View Post
4.7 BG N without any other aditional bypasses.
old thread but can you elaborate? i don't understand BG N. do you mean 4.7 resistor across it? i was told something about a 4.7k resistor bypassing it battery but was across the in and out i think. Are you using this bypass method as a way of doing a line in?
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Old 29th February 2016, 07:00 PM   #7
mlloyd1 is offline mlloyd1  United States
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Bypassing the LM6171
Probably Black Gate (brand/mfr), model N

mlloyd1
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Old 1st March 2016, 03:55 AM   #8
JaredC79 is offline JaredC79  United States
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Gotcha. That is how you use the lm6171 discrete as an input? Does zero offset still need to be completed or is that handled.
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Old 3rd March 2016, 04:02 AM   #9
tomchr is offline tomchr  Canada
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Quote:
Originally Posted by JaredC79 View Post
Does zero offset still need to be completed or is that handled.
You can't get zero offset. Even the LMP2021, which I designed, by the way, has -400 nV of systematic offset.

According to the data sheet (http://www.ti.com/lit/ds/symlink/lm6171.pdf), the LM6171 has 8 mV worst case input offset voltage. If that isn't good enough for your application, you need to do something about it.

Tom
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Old 3rd March 2016, 05:32 PM   #10
JaredC79 is offline JaredC79  United States
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Originally Posted by tomchr View Post
You can't get zero offset. Even the LMP2021, which I designed, by the way, has -400 nV of systematic offset.

According to the data sheet (http://www.ti.com/lit/ds/symlink/lm6171.pdf), the LM6171 has 8 mV worst case input offset voltage. If that isn't good enough for your application, you need to do something about it.

Tom

I am impressed. i was told by a friend it can be used discrete as an in and planning on using it but haven't had the time to pay with it, I have about 100 of em and used them for different things. i remember in the white pages it said something about when discrete using tantanum parts?
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