TPS63700EVM-139: Heat traps to plane

Art Mecina

Part Number: TPS63700EVM-139

Hello,

Our customer plan an 8-layer PCB including two ground planes and two supply planes. While our evaluation board TPS63700-139 is implemented with a two-layer PCB,
they are asking if they can use heat-traps ("cross-hair") for the power vias or does that give too much inductance for the TPS53700 ground pad and input and output capacitors?
Vin = 5 V, Vout = -5 V, and Iout = max.

Thanks in advance.

Art

over 2 years ago

0 Tao Zhang over 2 years ago

TI__Mastermind 31470 points

Hi Art,

could you share a more detailed info about the heat-traps? i am sorry i do not what is it.

May be a picture is better.

Regards

Tao

0 Art Mecina over 2 years ago in reply to Tao Zhang

TI__Genius 16655 points

Hi Tao,

I am not familiar with this either. I'll ask customer for more details.

Cordially,

Art

0 Tao Zhang over 2 years ago in reply to Art Mecina

TI__Mastermind 31470 points

Hi Art,

Got it, i am waiting your update.

Regards

Tao

0 Art Mecina over 2 years ago in reply to Tao Zhang

TI__Genius 16655 points

Hi Tao,

According to them, it is also called a thermal relief according to them. Whereas an ordinary power/ground via contacts to the relevant plane for all 360 degrees, a thermal relief only has (typically) four spoke-like connections to the plane. This reduces heat loss to the plane during soldering but increases electric resistance and inductance a bit - the latter could be a problem at high frequencies.

Cordially,

Art

0 Tao Zhang over 2 years ago in reply to Art Mecina

TI__Mastermind 31470 points

Hi Art,

In customer's application, it will be very sensitive with the parastic inductor at the power-on loop.

so, if this will incease the inductance, i think it is not a good idea.

Regards

Tao

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TPS63700EVM-139: Heat traps to plane