LM60430: Tj estimation for 400KHz fsw on Webench

Hisao Uchikoshi

Genius 13910 points

Part Number: LM60430

Hi Experts,

I ran the Webench with below condition.

Device : LM60430A

Vin : 24V

Vout : 5.15V

Iout : 3A

Tj on Webench shows that Tj becomes 133.61 degC at 30 deg C room temp.

It looks so strange. Could you please check it?

Regards,

Uchikoshi

over 3 years ago

0 Daniel Li14 over 3 years ago

TI__Mastermind 27030 points

HI Uchikoshi:

based on power dissipation and temperature raise, it theta JA is around 41.7deg C/W , a little bit higher than apps note indicated which is 33deg C/W, but the temperature will over 100deg C.

you can refer below:

https://www.ti.com/lit/an/snva935/snva935.pdf?ts=1622546484471&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FLM60430

Thanks

0 Hisao Uchikoshi over 3 years ago in reply to Daniel Li14

TI__Genius 13910 points

Hi Daniel,

This simulation result shows that IC power loss is 2.59W while that for LM60430D shows that IC loss is 1W with the same condition.

Could you please confirm it by running Webench by yourself?

Regards,

Uchikoshi

+1 Daniel Li14 over 3 years ago in reply to Hisao Uchikoshi

TI__Mastermind 27030 points

Hi Uchikoshi:

I will check with wenbench team about it. cause from datasheet, the efficiency should be 92% at this condition. and I will loop you in the email.

is that OK?

customer can use 33deg C/W with datasheet 5V efficiency curve for its junction temperature esimation.

Thanks

Power management

Power management forum

LM60430: Tj estimation for 400KHz fsw on Webench