DRV8412 Thermal resistance

Yamauchi-san,

The Theta-JCtop (junction-to case (top) thermal resistance) is equal to 16.3 C/W.  It is so large since there is not a good thermal transfer to the top of the case through the mold compound.  That is why we spec junction-to-powerpad since that is where the heat will transfer into the board. 

I don't understand your other question.  Please explain more.

Ryan-san,

I'm sorry for the delay of the reply.

They don't use Theta-JCtop in designing their products. They will check the temperature of the top of IC by thermocouple, because they cannot check junction temerature. So they want to know Theta-JC top.

Best regards,

Atsushi

Atsushi-san,

OK...I understand.  That is what I gave you earlier.  Is this issue now closed?

Dear Ryan-san,

The customer wants to junction temperature with their board (DRV8412 and DRV8842).

In this case, how do they measure the temperature?

They can check the temperature of the top of IC and near the pad.

I think it is difficunt to check it, but I want to give them how to estmate of the junction temperature.

Best regards,

Atsushi

Dear Ryan-san,

I have an addtional question.

Could you please teach theta Jc of the top of package for DRV8842?

If they get the Jc (the top of packge),  they will be able to "estimate"  the junction temperature with measuring the temperature of the top of the package.

Best regards,

Atsushi

Atsushi-san,

This is given in the datasheet on page 5 as 15.9C/W for DRV8842. 

Dear Ryan-san,

I'm sorry.

And thank you for your support.

I will make new sreads.

Best regards,

Atsushi