LMR14030 Output Capacitor

Hirotsugu Kobayashi

Mastermind 8475 points

Other Parts Discussed in Thread: LMR14030

Hi,

Can LMR14030 use ceramic capacitor?

In Webench, it is error for low pahse margin, but datasheet and EVM use ceramic capacitor.

over 8 years ago

0 Anston Lobo over 8 years ago

TI__Genius 16025 points

We've received your query and will get back to you shortly.

Thanks,
Anston

0 Arief Hernadi over 8 years ago in reply to Anston Lobo

TI__Mastermind 23815 points

I believe it should be able to. Do you have the webench report for it?
If not, what would be your VIN, VOUT, fsw, IOUT and Fsw so that i can try to generate the design for you

Thanks
-Arief

0 Hirotsugu Kobayashi over 8 years ago in reply to Arief Hernadi

Mastermind 8475 points

Hi, Arief.

A report is attaced. Vin=24V, Vout=5V, Iout=3A, Fsw=600kHz

LMR14030 Report.pdf

0 Arief Hernadi over 8 years ago in reply to Hirotsugu Kobayashi

TI__Mastermind 23815 points

Hi Kobayashi-san,

I have run into the same error on your design in webench, but i believe the design should work with 2x47uF ceramic capacitor just like the EVM.

I have also run the electrical simulation/esim on webench using the ceramic capacitor and the load transient seems to be stable.

Here is the attached report for the electrical simulation on the load transient:

webench_esim_LMR14030.pdf

If you want, we can send an EVM for you to test also, just provide your name, company name, address and phone number and send it to the email below:

simpleswitcherapps@ti.com

0 Hirotsugu Kobayashi over 8 years ago in reply to Arief Hernadi

Mastermind 8475 points

Hi Arief,
I think the model of LMR14030 on Webench is wrong.
Don't you think so?

0 Arief Hernadi over 8 years ago in reply to Hirotsugu Kobayashi

TI__Mastermind 23815 points

I will bring this up to the webench team and ask them to comment on the difference between 2 simulation results.

The true measurement i think its going to come from the EVM. Let me know if you need one

Thanks

-Arief

0 Hirotsugu Kobayashi over 8 years ago in reply to Arief Hernadi

Mastermind 8475 points

I will measure loop response in EVM.
So I request EVM to above email address.
Thanks

0 Hirotsugu Kobayashi over 8 years ago in reply to Arief Hernadi

Mastermind 8475 points

Hi Arief,
Do you have any comment from webench team?

0 Jonathan Arzadon over 8 years ago in reply to Hirotsugu Kobayashi

TI__Intellectual 1825 points

Hi,

Thank you for bringing this to our attention and I apologize for any inconvenience this may have caused.

As Arief has mentioned, your design should be stable with a ceramic capacitor at the output.

There was an issue with the Cout ESR calculations in the WEBENCH® model. I have fixed this issue and reduced the minimum ESR limit so that ceramic capacitors can be selected for LMR14030S designs. I will need a little more time to test this, but you should see this fix for the LMR14030S WEBENCH model within the next few days.

While I am doing final tests on this fix, I will try to get you an updated LMR14030S WEBENCH design that uses an output ceramic capacitor and shows the bode plot for the design.

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

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

0 Hirotsugu Kobayashi over 8 years ago in reply to Jonathan Arzadon

Mastermind 8475 points

Hi, Jonathan.

I am very grateful for your efforts.

I will wait for the update of WEBENCH model.

I think there is also this problem is another product, LMR14020S and LMR14050S.

Will these models be updated too?

0 Jonathan Arzadon over 8 years ago in reply to Hirotsugu Kobayashi

TI__Intellectual 1825 points

Hello,

Yes, LMR14020S and LMR14050S will be updated, too.

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

0 Hirotsugu Kobayashi over 8 years ago in reply to Jonathan Arzadon

Mastermind 8475 points

Hi, Jonathan.
Today, I check this issue, but it is not updated yet.
When is it expected to be updated?

0 Jonathan Arzadon over 8 years ago in reply to Hirotsugu Kobayashi

TI__Intellectual 1825 points

Hello!

I apologize for not providing any recent updates. The update is undergoing final testing, just to ensure that there are no other issues. It should go out with our next release, which should be later this week. I will let you know when the update is available.

Also, to answer your previous question, this update will also apply to LMR14020S and LMR14050S.

In the meantime, I have attached a WEBENCH design report using the latest model using the design inputs you previously provided (Vin=24V, Vout=5V, Iout=3A, Fsw=600kHz).

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

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

LMR14030S_24Vin_5Vout_3AIout_600kHzFsw.pdf

0 Jonathan Arzadon over 8 years ago in reply to Hirotsugu Kobayashi

TI__Intellectual 1825 points

Hi Kobayashi-san,

I have completed all necessary testing and have verified that all issues that were found with these three models (LMR14020S, LMR14030S, and LMR14050S) have been fixed. We plan to release this update later today, so you should be able to create an updated design in WEBENCH® later today or tomorrow.

Thank you for your patience, and please let me know if you have any other questions or concerns.

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

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LMR14030 Output Capacitor