Copper Flooding to Thermal Pad/VIAs

[JamesLE32J]

Hi,

I've done this loads of times and I have been over previous devices and I can't see anything obvious.

I've got a package with a thermal pad and a few thermal VIAs all named TH, TH@1, TH@2 etc and and these are appended to the correct pin on the symbol.

For some reason my polygon won't flood into it.  The polygon is named TH.  Thermals are turned off on the polygon.

I've been at it for a couple of hours and I'm stumped - although I'm sure it's something simple.

Anyone got any suggestions, please?

[JamesLE32J]

Hi,

I've done this loads of times and I have been over previous devices and I can't see anything obvious.

I've got a package with a thermal pad and a few thermal VIAs all named TH, TH@1, TH@2 etc and and these are appended to the correct pin on the symbol.

For some reason my polygon won't flood into it.  The polygon is named TH.  Thermals are turned off on the polygon.

I've been at it for a couple of hours and I'm stumped - although I'm sure it's something simple.

Anyone got any suggestions, please?

[one-of-the-robs · Accepted solution]

It's a while since I did this, and I think the device I used wanted the thermal pad grounded, but...

You say the vias are all connected to "the correct" pin on the symbol but don't say anything about your schematic. I assume the symbol pin in question is called "TH" but that, of itself, is not enough to connect it to the net called TH. Either the pin needs to be a power pin or the schematic needs to explictly connect a net called TH to it. In fact, if I remember right (not at a machine with Eagle right now), the power pin trick needs a supply symbol for TH to be on the schematic too.

All from memory, so may be wrong, but hopefully it might not be totally unhelpful.

[one-of-the-robs · Accepted solution]

It's a while since I did this, and I think the device I used wanted the thermal pad grounded, but...

You say the vias are all connected to "the correct" pin on the symbol but don't say anything about your schematic. I assume the symbol pin in question is called "TH" but that, of itself, is not enough to connect it to the net called TH. Either the pin needs to be a power pin or the schematic needs to explictly connect a net called TH to it. In fact, if I remember right (not at a machine with Eagle right now), the power pin trick needs a supply symbol for TH to be on the schematic too.

All from memory, so may be wrong, but hopefully it might not be totally unhelpful.

[JamesLE32J]

Hi @one-of-the-robs,

Yes there is a Thermal symbol in the device which is hidden on the schematic.

You've sussed it though.

The pin on the thermal symbol was done as Passive rather than Power which means that it would have needed a Net connected to it.

Changed it to Power and all is well.

Knew it was going to be something simple.

Thank you very much 🙂

[JamesLE32J]

Hi @one-of-the-robs,

Yes there is a Thermal symbol in the device which is hidden on the schematic.

You've sussed it though.

The pin on the thermal symbol was done as Passive rather than Power which means that it would have needed a Net connected to it.

Changed it to Power and all is well.

Knew it was going to be something simple.

Thank you very much 🙂