LMR64010: EMI problem

Zoey Wu

Part Number: LMR64010

hi team,

my customer is using LMR64010 and they found that there is a whistling noise from the inductance when the power supply hot-swapping.

They tried to remove Cf and the noise disappeared. Do u have any advise on dismissing the noise? Or will it cause any problems if the Cf is removed? Thanks~

over 1 year ago

0 Lei Zhong over 1 year ago

TI__Genius 11410 points

Hi Zoey,

For further check, could you check with customer and provide the schematic(inductor and Cout) and work conditions(Vin, Vout, Iout)?

Thank you.

Regards

Lei

0 Zoey Wu over 1 year ago in reply to Lei Zhong

TI__Expert 4350 points

Hi Lei,

Thanks for your reply!

The SCH is as below.

0 Lei Zhong over 1 year ago in reply to Zoey Wu

TI__Genius 11410 points

Hi Zoey,

Thank you for providing the schematic.

I don't see concerns in this schematic, the capacitance of Cf (C46) is also reasonable. Usually, the Cf is recommended for a better loop stability.

The whistling noise issue was discussed two weeks ago, I just want to check what's the latest status? Does the issue still exist?

If the noise is heard during power supply hot-swapping only, is it acceptable?

We may take the way of removing the Cf as the last choice.

Regards

Lei

0 Zoey Wu over 1 year ago in reply to Lei Zhong

TI__Expert 4350 points

Hi Lei,

the noise doesn't exist when they remove the cf.

they can't accept the noise when hot-swapping.

0 Lei Zhong over 1 year ago in reply to Zoey Wu

TI__Genius 11410 points

Hi Zoey,

Thank you for your quick feedback.

If no unacceptable Vout ring or overshoot were observed during Vin/Iload transition, removing the Cf should be OK.

If further analysis is needed, please help provide the waveforms of SW and Vout in normal work status and in power supply hot-swapping that noise can be heard.

Regards

Lei

Power management

Power management forum

LMR64010: EMI problem