LM3886T mounting question...

[nelsondog]

Hi all interested parties, I have a question regarding the mounting of the chip to the heatsink. Is it necessary to electrically isolate the chip from the heatsink? Will the heatsink compound be enough to separate the two? I’m not able to shop for something like mica washers but I do have some teflon tape. Would this be sufficient to isolate the two if needed at all?
Thanks for taking the time to read my silly question.

 

[A800]

No idea.

 

[JeffS7444]

On the bottom of page 2 of TI's datasheet, they specifically state that the heatsink will be at V- unless you use an insulating washer.
http://www.ti.com/lit/ds/symlink/lm3886.pdf

 

[nelsondog]

Got it! Thank you

 

[JohnYang1997]

Both the back tab and the screw need to be insulated.

 

[quorzar]

It depends. If u have the model with LM3886TF, the temperature coefficient is lower, because of the housing is made of plastic. Then you dont need the insulation. If you have the type without TF at the end, there is metal on the backside and the upper part where the mount hole is, is made out of metal too. So you need insulation. I only use the TF model and never had problems with temperature.

 

[JohnYang1997]

It depends. If u have the model with LM3886TF, the temperature coefficient is lower, because of the housing is made of plastic. Then you dont need the insulation. If u have the type without TF at the end, there is metal on the backside, so u need insulation. I only use the TF model and never had problems with temperature.

T = metal tab
TF = plastic

 

[nelsondog]

What about an alternative material instead of mica? Is there anything else I might be able to use?

 

[Doodski]

Silicon rubberishy insulator works too. Don't combine silicon thermal paste and the silicon rubber washer.

https://www.google.com/search?sxsrf...oAhXLu54KHY6fB6UQsAR6BAgGEAE&biw=1486&bih=807