[Moved] Thermal VIA in ORCD

[Rajinder1268]

Hi all,
I am currently using a BTS5090 (power switch) device, it needs to have a thermal via array connected to the cooling pad for heat management.
The thermal pad needs to be 0.3mm, I am not sure how to create this in Padstack editor. I have tried , drill = 0.3mm, design layers begin layer, default internal, end layer = 0.5mm. Do I need to add anything to the anti pad or thermal pad settings?

I have a 2 layer PCB, signals + vcc on top and and on the bottom. If I connect this to the device centre pad which is connected to vsupply, would adding the thermal via not short this to Gnd? Sorry but I am not sure so asking the question.

Thanks in advance

 

[FvM]

Before you design thermal vias, you need to think about the intended function. A thermal pad does only serve a purpose if it either connects to an internal plane or a sufficient large copper pour on the bottom side, otherwise you can simply omit it. Internal layers aren't available on a 2-layer-PCB (neither antipads). You can cut out an area from GND copper pour apparently present on the bottom side. Or place a copper pour on the top that extends the thermal pad and don't use any thermal vias, I'd probably prefer the latter on a 2-layer PCB.

 

[Rajinder1268]

Before you design thermal vias, you need to think about the intended function. A thermal pad does only serve a purpose if it either connects to an internal plane or a sufficient large copper pour on the bottom side, otherwise you can simply omit it. Internal layers aren't available on a 2-layer-PCB (neither antipads). You can cut out an area from GND copper pour apparently present on the bottom side. Or place a copper pour on the top that extends the thermal pad and don't use any thermal vias, I'd probably prefer the latter on a 2-layer PCB.

Hi thanks for your reply. I was thinking of making a larger plane that connects to the centre pad of the device which as you suggest will omit the need for thermal vias. The centre pad is connected to vsupply, so if I increase vsupply plane connected to this centre pad, ( I think this is what you are saying) that should be fine? Is there any way of selecting the size of the plane?
Could I cut the Gnd underneath the device and then stitch the top vsupply plane to this? Thanks innadvance

 

[FvM]

It all depends on the available PCB area and expectable smart switch power dissipation.