WEBENCH-POWER-DESIGNER: RθJA of TPS628512DRLR and TPS628511DRLR

Dice-K

Part Number: WEBENCH-POWER-DESIGNER
Other Parts Discussed in Thread: TPS628512, TPS628511, TPS628511EVM-139, TPS628512EVM-139

Hi support team,

I am asking because the package thermal resistance of WEBENCH's TPS628512 and TPS628511 is different from the JEDEC and EVM values in the data sheet.

In the WEBENCH report, RθJA is "71.1℃/W".
Is this the value of "PCB LAYOUT" on WEBENCH?

Could you please let us know the specifications (size, number of layers, number of vias, etc.) of the 71.1℃/W board?

Regards,
Dice-K

over 2 years ago

0 Farheen over 2 years ago

TI__Genius 12400 points

Hello Dice-K,

I am having a look at it, will get back asap.

Best Regards,

Farheen

0 Farheen over 2 years ago in reply to Farheen

TI__Genius 12400 points

Hello Dice-K,

The ICThetaJA value usually is a function of EVM board design and layout for that device. The EVM for TPS62851x has a user guide which has all the necessary information of EVM design: https://www.ti.com/lit/ug/slvuby6a/slvuby6a.pdf.

You can also use this equation for calculation/estimation of ICthetaJA value.

Ta(25C)+IC Pd*ICThetaJA=IC Tj

If you want to understand more about the thermal metrics, this application note can help you also: https://www.ti.com/lit/an/spra953c/spra953c.pdf

Thanks and Best Regards,

Farheen

0 Dice-K over 2 years ago in reply to Farheen

Mastermind 6560 points

Hi Farheen,
Thank you for your reply.

The RθJA of EVM in the data sheet is 60℃/W, which is different from 71.1℃/W of WEBENCH.

What is the cause of the difference?
Is it related to WEBENCH's PCB LAOUT data?

PCBimages_2341.zip

Best regards,
Dice-K

0 Farheen over 2 years ago in reply to Dice-K

TI__Genius 12400 points

Hello Dice-K,

It should be same as EVM. I am checking with our modeling team to know why this difference exists. I will get back as soon as I will hear from them.

Thanks and Best Regards,

Farheen

0 Dice-K over 2 years ago in reply to Farheen

Mastermind 6560 points

Hi Farheen,
Thank you for your reply.

Did you get an answer from your modeling team?
We look forward to your reply.

Best regards,
Dice-K

0 Farheen over 2 years ago in reply to Dice-K

TI__Genius 12400 points

Hello Dice-K,

Yes I have received the reply from modeling team. The ICθJA value is provided to them by PL according to the copper area on the EVM board While on the datasheet it is the EVM standard value.

I am checking that which one is more accurate according to our EVM board. I will try to answer you by today.

Thanks and Best Regards,

Farheen

+1 Farheen over 2 years ago in reply to Farheen

TI__Genius 12400 points

Hello Dice-K,

The accurate RθJA value for TPS628511DRLR package (EVM) is 60℃/W as mentioned in the datasheet. On the Webench, it will be fixed asap.

Thanks and Best Regards,

Farheen

0 Dice-K over 2 years ago in reply to Farheen

Mastermind 6560 points

Hi Farheen,
Thank you for your support.

I think the 60℃/W EVM are 4-layer boards of TPS628512EVM-139 and TPS628511EVM-139.
What are the sizes of these boards?
(Currently, I don't have them at hand and I can't find the description of the material.)

Best regards,
Dice-K

0 Farheen over 2 years ago in reply to Dice-K

TI__Genius 12400 points

Hello Dice-K,

Yes, you are right about (60℃/W EVM are 4-layer boards of TPS628512EVM-139 and TPS628511EVM-139).The board dimensions are 2200milx1600mil.

Best Regards,

Farheen

0 Farheen over 2 years ago in reply to Farheen

TI__Genius 12400 points

Hello Dice-K,

Do you have any further question? If not, feel free to close this thread.

Thanks and Best Regards,

Farheen

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WEBENCH-POWER-DESIGNER: RθJA of TPS628512DRLR and TPS628511DRLR