LM76005: About LM76005 thermal question..

Peter Tseng

Mastermind 6170 points

Part Number: LM76005
Other Parts Discussed in Thread: LMR51450

Hi Team,

I just use Webench for LM76005 of Vin=22V and the output is 20V/5A.

Please refer to the attached file.

WBDesign869.pdf

customer is worried that the thermal will be an issue.

I found the simulation result, the thetaJA is only 16 degC/W which is smaller than the datasheet's 29.6 degC/W.

What happens to the difference?

Is the customer design critical to the thermal performance?

Thanks.

over 1 year ago

0 Colin Chen over 1 year ago

TI__Mastermind 21101 points

Hi Peter,

The IC thetaJA of WEBENCH is based on EVM.

And the hetaJA of datasheet is based on JEDEC standard, for more information you can refer to :https://www.ti.com/lit/an/spra953c/spra953c.pdf?ts=1708934940333

They are got from two different conditions.

Thanks

Colin

0 Peter Tseng over 1 year ago in reply to Colin Chen

Mastermind 6170 points

Hi Colin,

Thanks for the explanation.

Actually, customer is worried about the thermal of such a design.

May I have your comments to use LM76005 for 22V convert to 20V/5A design? is it workable in real case?

Thanks.

0 Colin Chen over 1 year ago in reply to Peter Tseng

TI__Mastermind 21101 points

Hi Peter,

I won't suggest such a working condition.

The power loss can reach to serval watts and thermal will be high.

We suggest LMR51450 for this application.

Colin

0 Peter Tseng over 1 year ago in reply to Colin Chen

Mastermind 6170 points

Hi Sir,

May I have your help to check if LMR51450 can meet 22V to 20V/5A design?

I cannot simulate it in webench with such conditions.

Thanks.

+1 Colin Chen over 1 year ago in reply to Peter Tseng

TI__Mastermind 21101 points

Hello Peter,

In before test, its thermal is about 80-90 degree

Sorry I connot found teh data now, but it can be used in this application.

Hope these can help you.

Colin

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LM76005: About LM76005 thermal question..