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I'm building a design involving Toshiba's TB6600 chip which has an unusal HZIP25-P-1.00F package. I've seen implementations where folks have bent the pins manually and soldered them horizontally such that a heatsink can be bolted directly onto them.

However, I did not want to do this. Instead, I thought of attaching an aluminum right angle bracket to a normally mounted chip (vertical). One side of the right angle bracket would be touching the chip's heatsink area while the other side will be touching an exposed pad on the PCB. This same exposed pad is present on the bottom copper side as well and is connected with the top copper using thermal vias. A large finned heat sink is then fitted onto the back side of the PCB and connected to this bottom copper side.

I haven't gotten around to doing calculations on this yet but any thoughts on if this is a good idea?

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The part you're working with may need to dissipate up to 40W of heat. The package it's in is intended to be mounted vertically and bolted directly to a heat sink, like so:

enter image description here

Passing the heat through the circuit board the way you're describing will not work effectively -- the aluminum bracket and vias will present far too much thermal resistance to keep the chip at an appropriate temperature.

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  • \$\begingroup\$ Got it. What if I can eliminate passing heat through the vias? I can bolt the right angle bracket to the chip and then the bracket onto the heatsink directly. The brackets will actually go through the board to the heatsink at the bottom. There are four of these on the board and it is difficult to mount such a large heatsink for each of them onto the PCB. Each bracket would connect a pair and these would then connect to a common heat sink similar to this one. \$\endgroup\$ – electrophile Oct 5 '17 at 3:31
  • \$\begingroup\$ Unlikely. 40W is a lot of heat. Passing it through anything short of a heat pipe is iffy. \$\endgroup\$ – duskwuff Oct 5 '17 at 4:02
  • \$\begingroup\$ Whats the heatsink used in the picture? Do you have a link for that? \$\endgroup\$ – electrophile Oct 5 '17 at 4:14
  • \$\begingroup\$ Heat pipes are all copper right? So then maybe I can use a copper bracket vs an aluminium one? \$\endgroup\$ – electrophile Oct 5 '17 at 5:03
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    \$\begingroup\$ No. Heat pipes are hollow, and contain a working fluid. \$\endgroup\$ – duskwuff Oct 5 '17 at 6:45

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