Spice simulation of LM386?

baggystevo82 · 4th March 2005, 11:10 AM

Hello everyone,
I have a small problem, I'm trying to simulate a little headphone amp circuit for some uni coursework, which uses the LM386 opamp. Unfortunately this opamp is different to usual, in that it has the gain internally set to 20, and I can't find any models of it anywhere. I was wondering if any of you had any suggestions as to how I might approach this?
Here's a link to the datasheet:
http://www.national.com/ds.cgi/LM/LM386.pdf
Cheers,
Steve

baggystevo82 · 4th March 2005, 11:59 AM

no thoughts or ideas at all?
Steve

peranders · 4th March 2005, 12:02 PM

1 LM386 has too much gain for a headphone amp.

2 Why must you use this IC?

3 Why do yoiu have to simulate?

baggystevo82 · 4th March 2005, 12:07 PM

1. Isn't it set at 20 without using extra components on pins 1 and 8? This isn't necessarily a headphone amp in the usual sense, as it has a mic input so probably needs more gain than a CDP source might.

2. It's part of the set coursework, and the ready made circuit boards we were testing... I take no responsibility for my lecturers choices!

3. I missed the lab session as I was the other side of the country at the time, and I would like to learn more about simulating circuits.

Cheers,
Steve

jackinnj · 4th March 2005, 12:31 PM

Quote:

Originally posted by peranders
1 LM386 has too much gain for a headphone amp.

Actually, the LM386 is used in quite a few ham radio audio circuits -- in which case a headphone is used as the transducer. The quiescent current isn't the lowest, but it is versatile.

As far as modeling the device -- just create a "subcircuit" from the National Semiconductor outline.

baggystevo82 · 4th March 2005, 12:37 PM

Hi,
Thanks for the suggestion! Any chance you could elaborate a bit though, bearing in mind I only have half a days experience with Spice so far. I think I know what you mean, but unsure as to how to go about it.
Cheers,
Steve

4th March 2005, 11:10 AM	#1
baggystevo82 diyAudio Member Join Date: Dec 2003 Location: Herefordshire	Spice simulation of LM386? Hello everyone, I have a small problem, I'm trying to simulate a little headphone amp circuit for some uni coursework, which uses the LM386 opamp. Unfortunately this opamp is different to usual, in that it has the gain internally set to 20, and I can't find any models of it anywhere. I was wondering if any of you had any suggestions as to how I might approach this? Here's a link to the datasheet: http://www.national.com/ds.cgi/LM/LM386.pdf Cheers, Steve

4th March 2005, 12:02 PM	#3
peranders Electrons are yellow and more is better! diyAudio Member Join Date: Apr 2002 Location: Göteborg, Sweden Blog Entries: 4	1 LM386 has too much gain for a headphone amp. 2 Why must you use this IC? 3 Why do yoiu have to simulate? __________________ /Per-Anders (my first name) or P-A as my friends call me

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4th March 2005, 11:59 AM	#2
baggystevo82 diyAudio Member Join Date: Dec 2003 Location: Herefordshire	no thoughts or ideas at all? Steve

4th March 2005, 12:07 PM	#4
baggystevo82 diyAudio Member Join Date: Dec 2003 Location: Herefordshire	1. Isn't it set at 20 without using extra components on pins 1 and 8? This isn't necessarily a headphone amp in the usual sense, as it has a mic input so probably needs more gain than a CDP source might. 2. It's part of the set coursework, and the ready made circuit boards we were testing... I take no responsibility for my lecturers choices! 3. I missed the lab session as I was the other side of the country at the time, and I would like to learn more about simulating circuits. Cheers, Steve

4th March 2005, 12:37 PM	#6
baggystevo82 diyAudio Member Join Date: Dec 2003 Location: Herefordshire	Hi, Thanks for the suggestion! Any chance you could elaborate a bit though, bearing in mind I only have half a days experience with Spice so far. I think I know what you mean, but unsure as to how to go about it. Cheers, Steve

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