TPS23754EVM-383: PD product EMC test fail

Wendy Hsu

Prodigy 125 points

Part Number: TPS23754EVM-383
Other Parts Discussed in Thread: TPS23734, , TPS23754

Our product is fail in CNS 13438 EMC test.(Over 33dB at 236KHz )

Could you help to review schematic is there any risk? Thanks.

Wendy

over 1 year ago

+1 Michael Pahl over 1 year ago

TI__Mastermind 21320 points

Hello,

It appears the noise is near the switching frequency. Typically this is due to layout. Some corrective actions would be to limit the exposed copper associated with the FETs (U25, Q1, U21 and U26), try a shielded transformer, and minimize gate trace length.

Additionally please know that the next generation part, TPS23734, has spread spectrum frequency dithering, which could be turned on here to help. Thanks

If this post answers your question, please indicate so by marking this thread as resolved. Thank you.

Regards,

Michael P.

Applications Engineer

Texas Instruments

0 Wendy Hsu over 1 year ago in reply to Michael Pahl

Prodigy 125 points

Hi Michael

We replaced the PD module from our PCB to TI EVM (TPS23754EVM-383) as power source and we found that the ISN test result of TI EVM is the same as our PD module.

Please help to review below pictures.

Have TI ever arranged ISN test for TPS23754 EVM?

Do you have any suggestion on the result?

ISN result of our PD board + main board :