I need to use two bridge rectifiers D25XB60 in a project, which are to be attached to a heatsink. The problem is that I do not have enough space to accommodate both of them side by side. I am considering to install one unit over the other as shown in the diagram. Which of these approaches be more better?

Shall highly appreciate valued comments.

 

Can you not add to the top diag by placing aluminum H.S. on the very top also?
Max.

 

the metal on the back of the case muxt contact the heatsink. how can you do that when stacking two packages? the thermal resistance for the top one will be high.

 

Can you not add to the top diag by placing aluminum H.S. on the very top also?
Max.

No, the PCB will be on the top.

 

the metal on the back of the case muxt contact the heatsink. how can you do that when stacking two packages? the thermal resistance for the top one will be high.

There is no metallic back in this device. All is plastic.

 

Since they are thru hole components you should mount them vertically. This has the advantage of adding convection to the cooling mechanism.

 

Since they are thru hole components you should mount them vertically. This has the advantage of adding convection to the cooling mechanism.

After soldering on the PCB, they will be bent and attached to a bulky heatsink.

 

With components like this one and 3 dimensions to work in there is no reason why they have to be bent over to attach to the heatsink. Why can't they be attached to a heatsink that does not even touch the board. Give us a mechanical drawing of the board and heatsink.

 

Neither approaches is a good idea.

You want each device to be in contact with the heat sink.

Then you need to double the size of the heat sink.

 

What about one on one side and the other on the other side having the full flat of each up against the heat sink?

 

Actually, these are to be enclosed in an aluminum housing which will also act as heatsink.



The final position would be something like this:
B/Rectifiers attached at the bottom with pins pulled up and soldered on the PCB.
And the whole set-up would be sealed in that aluminum housing using epoxy glue.

 

So, I think there is no solution. I should make adjustments in the PCB.

Another related question please:
The same project include TO-220 devices which also require heatsink. I shall be using common heatsink with mica insulator and h/s paste. Where the h/s paste should be applied?

a) between the heatsink and the mica insulator
b) between the device and the mica insulator
c) or both