TLV1117: SON (DRJ) heat slug electrical connection

TI_pwr_usr

Part Number: TLV1117

There's conflicted answers to the question in the past. One says the TLV1117CDRJR heat slug is Vout. The other said to connect the heat slug to the ground plane. So would you confirm the following:

DRJ package heat slug is Vout electrically and should tie to Pin 5/6/7.

Thanks..

over 4 years ago

0 Blake Soileau over 4 years ago

TI__Intellectual 1200 points

Hello,

The thermal pad/heat slug is electrically connected to VOUT, however it is at a higher electrical resistance than pins 5, 6 and 7. Maximizing the VOUT copper pour around the power pad and the output pins will help improve thermal performance. Here is a good application note showing how layout affects thermal performance.

0 TI_pwr_usr over 4 years ago in reply to Blake Soileau

Intellectual 280 points

I don't understand "higher electrical resistance" statement. Do you mean wire bonding resistance on the package?

0 Jason Song over 4 years ago in reply to Blake Soileau

TI__Mastermind 23361 points

For some reason, the link Blake posted is not opening, here is the app note:

https://www.ti.com/lit/an/slvae85/slvae85.pdf?ts=1599855741279&ref_url=https%253A%252F%252Fwww.google.com%252F

Regards,
Jason

0 Blake Soileau over 4 years ago in reply to TI_pwr_usr

TI__Intellectual 1200 points

Hello,

Yes, I'm referring to the wire bond resistance in the package.

0 TI_pwr_usr over 4 years ago in reply to Blake Soileau

Intellectual 280 points

Would you quantify the resistance difference between the heat slug and pin_5/6/7?

0 Blake Soileau over 4 years ago in reply to TI_pwr_usr

TI__Intellectual 1200 points

Hello,

Typically we do not quantify the resistance differences, but in general the pins are going to have lower resistance as they use bond wires while the thermal pad is connected via die attach (bond wires offer lower resistance than the die attach). In general it is recommended to have all pins and the thermal pad connected together to ensure the best thermal performance for the device.

Can you clarify if there is a particular reason you requesting this quantification? Are you experiencing an issue while using the device?

0 TI_pwr_usr over 4 years ago in reply to Blake Soileau

Intellectual 280 points

I am weighing the options of either having the heatslug isolated or connected to the power rail in the PCB design. This also decide whether heatslug can be used for decoupling connection. From your answer it feels tying them together is fine.

Thanks..

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TLV1117: SON (DRJ) heat slug electrical connection