Simulation issue of LMR14050

takahiko yokota

Mastermind 7135 points

Other Parts Discussed in Thread: LMR14050

I simulated LMR14050 under Vin=8V, Vout=5V, Iout=4.2A, Ta=80℃.

I could simulate it in December 2015, but I couldn't simulate it for high temperature today.

Could you tell this reason?

Best regards,

Yokota

over 9 years ago

0 Nikhil Gupta (Product Folder Models) over 9 years ago

TI__Mastermind 39210 points

Yokota-san,

Can you share the report of the design from December with us? It will help us to debug the issue.

Thanks,

0 takahiko yokota over 9 years ago in reply to Nikhil Gupta (Product Folder Models)

Mastermind 7135 points

Nikhil-san

I only have attached document.

Can you refer to it ?

7077.LMR14050.pdf

Best regards,

Yokota

0 Nikhil Gupta (Product Folder Models) over 9 years ago in reply to takahiko yokota

TI__Mastermind 39210 points

Yakota-san,

I am able to create a design with these specs today from the product folder. Below is the design I got. Can you clarify what steps you followed to try to create your design when it failed Also, when you go back to your old design in WEBENCH, you should see a Print option on top. You can use that to create a PDF report of your entire design,

http://webench.ti.com/appinfo/webench/scripts/SDP.cgi?ID=5E535703A24323E8

0 takahiko yokota over 9 years ago in reply to Nikhil Gupta (Product Folder Models)

Mastermind 7135 points

Nikhil-san

Thank you for the file. But it was configured Ta=30℃.

I couldn't simulate LMR14050 under Vin_min=8V, Vin_max=16V, Vout=5V, Iout=4.2A, Ta=80℃ for too high junction temperature.

Best regards,

Yokota

0 Nikhil Gupta (Product Folder Models) over 9 years ago in reply to takahiko yokota

TI__Mastermind 39210 points

Yokota-san,

Yes, I had missed the Ta change. I am able to replicate your issue now. We will look into this and get back to you.
Can you share your complete design report though using the "Print" Button from the old design. It will help us to debug this more efficiently if we can see what you did in December.

0 Jonathan Arzadon over 9 years ago in reply to takahiko yokota

TI__Intellectual 1825 points

Yokoto-san,

We looked into the design and noticed that for your design at Vin=8 V, the IC Tj is around 130 degC, which is above the maximum operating temperature specified in the datasheet (125 degC).

In December, WEBENCH did not check to see if the IC temperature would go beyond the allowable limit at the minimum input voltage of a design, which is why you were able to create the design initially. Since then, we have added additional design checks to ensure that the design does not violate any design rules over the entire range of input voltages.

With these new design checks in place, you won't be able to create a design in WEBENCH using your initial design inputs. You can try decreasing the ambient temperature (Ta) or increasing the minimum input voltage (VinMin) in order to get a WEBENCH design that is close to your initial design.

If you have any other questions or concerns, please let me know.

Best Regards,
Jonathan Arzadon
Applications Engineer
WEBENCH® Design Center
Texas Instruments

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Simulation issue of LMR14050