PowerFlat 8x8 HV NC pins

[jcarrizo]

Hi ST Community!

I'm working in a HV power design (400VDC) with a STPSC6H065DLF Schottky diode.

I can see from its datasheet that pins 1 and 2 are not connected internally, but I can't find any recommendation about what to do with those pins. Would it be safe to connect them to the Anode?

I'd like to attach a copper plane to them, for improving thermal disipation, but in the other hand I don't want to have a floating copper plane in that area, since it's a switching one.

 

Any recommendation or suggestion will be welcome.

 

Thanks in advance.

 

Julián Carrizo

Electronic Engineer

[Peter BENSCH]

Welcome @jcarrizo, to the community!

Well, you are welcome to measure to be on the safe side, but there are only two ways in which the NC pins on this diode could be connected: either to the anode or to the cathode. If one of these were true, NC would not be Not Connected, but would be labelled with the respective connection. In addition, the NC pins would have to be bonded in order to connect them to the anode, which would only cause additional costs.

So the only conclusion that remains is that the NC pins are what they are labelled as: Not Connected.

Hope that answers your question?

Regards
/Peter

 

[RobK1]

I don't think the question was about the internal connections ...

[Peter BENSCH]

Well, the fact that there are no internal connections due to the lack of bonding means that you can connect the NC pins wherever you want. However, a connection from the NC pins to the cathode would significantly reduce the air and creepage distance and would therefore not be a good idea.

[jcarrizo]

Hi Peter, thank you for your clear answer.

Now I understand that those pins were left unbonded solely to avoid the additional manufacturing cost.

Based on our discussion, I conclude that assigning the same netclass to the NC pins and the Anode does not pose any electrical risk, since the drawing indicates that these pins are internally "close" to the Anode, though not electrically connected.

This approach allows me to avoid enforcing a minimum clearance—such as 2.5 mm—between the NC pins and the Anode nets, which is especially helpful in space-constrained PCB designs.

 

Regards.