[Navyblue]

Ok guys, I ordered a bunch of stuffs and realised that I don't have everything I need.

I got some of these heat sinks for TO-220 MOSFET.

Standard Products Found

They have a pin mount at the bottom to attach to the PCB.

I've also gotten myself some Thermasil pad and some insulating shoulder washer. What else do I need to mount these things?

What do I need to secure those pins to the PCB? Or can I pull out those pins and put in some generic screws? Don't tell me I am supposed to solder these pins to the PCB.

If I mounted the heat sink to the PCB, would the Thermasil pads suffice to hold the MOSFET to the heatsink?

If I do need some bolt and nuts, would the generic ones work? I guess the insulating shoulder washer should be on the MOSFET side of the sandwich?

 

[fordgtlover]

You do need to solder those pins to the board.

And, yes you do need to bolt the mosfets to the heatsinks. Once agin you are correct that the shoulder washers go between the bolt and the mosfet.

Here's an example form Tomb's brilliant Millett Max site. (Scroll down to Solder the Heat Sinks and Output Transistors (or MOSFETs) - )

Also check out this link to aavidthermalloy's page on mounting kits.

 

[Daveze]

Only use a small amount of solder for the pins, you're only aiming to tack them down.

I'm pretty sure that I haven't seen a real good method for removing the pins. I recall seeing it done, they then tapped a thread and mounted them using small screws...very tidy. I might buy some cheapy 'sinks and test a few ideas that I have.

 

[Navyblue]

Thanks.

As for the Thermasil, does it matter which side the adhesive is on? Or should it be on the MOSFET side?

 

[tomb]

Quote:

Originally Posted by Navyblue /img/forum/go_quote.gif Thanks. As for the Thermasil, does it matter which side the adhesive is on? Or should it be on the MOSFET side?

Since the Thermasil pad is typically much larger than the MOSFET/transistor, it's more convenient to stick it on the heat sink.

 

[TimmyMac]

If you're using those heat sinks, why use insulators at all? As long as they don't touch it'll be fine, and you'll get better heat transfer with thermal goo instead of a heat pad.

 

[MisterX]

Quote:

Originally Posted by Navyblue /img/forum/go_quote.gif If I do need some bolt and nuts, would the generic ones work? I guess the insulating shoulder washer should be on the MOSFET side of the sandwich?

A mounting kit is a little easier then sourcing the thermal pads, shoulder washers, screws, nuts and washers separately.

Digi-Key - HS417-ND (Aavid Thermalloy - 4880G)
4880G


http://www.onsemi.com/pub_link/Collateral/HB206-D.PDF

 

[Navyblue]

I am someone who can't promise that I won't put my hand inside my amp when it is in operation.

I knew about the mounting kit, and I thought that it is cheaper to order them separately. Now I know that the missing cents goes to the bolts, nuts and washers that I'm missing right now.