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Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets.

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Old 12th Oct 2019, 5:58 pm   #1
G6Tanuki
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Default LM380 cooling.

The LM380 is one of my go-to chips when I need an 'indestructible' audio amp with a couple of Watts output - but it's just a straightforward 14DIL package with no facilities for a heatsink so it tends to run rather warm.

In some designs I've seen extended areas of copper PCB material left around the centre 3 pins on each side (these all being earth) in the hope it will conduct the heat away but I doubt it's really that efficient, specially since it's on the underside of the PCB where air circulation is minimal.

I've got some 1.5mm-thick copper sheet here and was planning to make up some 'wings' to solder to the central sets-of-pins in the hope of improving cooling; I was wondering if anyone else has done this sort of thing in the past and how successful it was?
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Old 12th Oct 2019, 6:26 pm   #2
Ambientnoise
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Default Re: LM380 cooling.

Yes it does work. This chip is thermally connected to the 3 pins on each side for this purpose so an area of the pcb or “wings” soldered on can be used. One version of the data sheet outlines such wings.

Ken
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Old 12th Oct 2019, 7:05 pm   #3
G6Tanuki
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Default Re: LM380 cooling.

It's good to know my idea isn't crazy! I feel some research and experimentation coming on.

Current idea: take a square of this copper I've got, slice it diagonally to give 2 pyramids, then slice the 'tops' off the pyramids to produce a straight bit to solder to the central 3 pins on each side. I'm thinking of drilling a hole through the centre of each pyramid too, so I can use a 6BA nut/bolt/spacer-tube to join them and so give added support.
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Old 12th Oct 2019, 8:25 pm   #4
ColinTheAmpMan1
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Default Re: LM380 cooling.

If i understand you correctly, the pieces of copper would be better described as "triangles" wouldn't they? Triangles are essentially two-dimensional, but pyramids are three-dimensional...
Colin.
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Old 12th Oct 2019, 8:33 pm   #5
G6Tanuki
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Default Re: LM380 cooling.

Yes, triangles with the apexes cut-off.
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Old 13th Oct 2019, 12:44 am   #6
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Default Re: LM380 cooling.

From the National datasheet for the LM380
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Old 13th Oct 2019, 3:09 pm   #7
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Default Re: LM380 cooling.

You could also solder on some lengths of solid copper wire from a bit of T+E.
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Old 13th Oct 2019, 3:46 pm   #8
G6Tanuki
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Default Re: LM380 cooling.

Quote:
Originally Posted by paulsherwin View Post
You could also solder on some lengths of solid copper wire from a bit of T+E.
I think my proposed copper 'wings' will be more efficient and elegant. Alas it's on-hold since I just broke my last junior-hacksaw blade!
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Old 13th Oct 2019, 4:03 pm   #9
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Default Re: LM380 cooling.

G6- a few posts to ponder
https://www.diystompboxes.com/smffor...topic=121981.0
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Old 13th Oct 2019, 10:12 pm   #10
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Default Re: LM380 cooling.

Quote:
Originally Posted by Oldcodger View Post
OOh! Thanks for this!!
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Old Yesterday, 7:29 pm   #11
G6Tanuki
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Default Re: LM380 cooling.

I've made up "flags" - see below - and having soldered them to the 'middle' pins each side of my bunch of LM380 amps they're working well-enough that they no longer go into thermal-shutdown when playing 80s high-level bands like Simple Minds/The Chameleons.

I consider this a success!
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