TPS5430: Radiation emission data of TPS54340BQDDARQ1 and TPS561201DDCR

Kunal barot

Part Number: TPS5430
Other Parts Discussed in Thread: TPS54340, TPS561201

HI we are using below two dc to dc converter in our product, we have fail in radiation testing. can you check attached failure data and see if this can be from these above two regulator.

we have used UL/CE certified SMPS modue to convert AC to DC(15V) , and this DC feed to these two regulator to make 4.5V and 3.3V.

we also have on board third radio module which is also FCC certified.

SCH and Layout can share on request on email.RE problem.docx

Thanks

over 6 years ago

0 Samuel Jaffe over 6 years ago

TI__Mastermind 25590 points

Kunal,

I don't believe this is caused by the TPS5430. The TPS5430 operates at a fixed 500kHz but you're seeing peaks with an apparent fundamental at 31MHz. Harmonics could be in this band but not in the shape you're seeing (small peaks at 31/62/93MHz, large peak at 123MHz with no other peaks at multiples of 500kHz).

-Sam

0 Kunal barot over 6 years ago in reply to Samuel Jaffe

Intellectual 605 points

Hi Sam
What about the other regulator we used in this design ,TPS561201DDCR.

Thanks

0 Kunal barot over 6 years ago in reply to Samuel Jaffe

Intellectual 605 points

Nothing is running at 31 Mhz in my system. But our micro-controller used 8Mhz Crystal and using internal PLL its multiply its by 4 , that make 8 X 4= 32 Mhz. 123 Mhz can be 4th harmonics of this, but never heard even harmonics cause any issue, any suggestion may help on this.
Thnaks

0 Kunal barot over 6 years ago in reply to Samuel Jaffe

Intellectual 605 points

alos this is TPS54340 not TPS5430.

0 Samuel Jaffe over 6 years ago in reply to Kunal barot

TI__Mastermind 25590 points

Kunal,

I don't think the TPS561201 would cause this either since it's operating at 580kHz. TPS54340 means you can alter the switching frequency and see its effect on the results. Try changing RT and see if it makes a notable difference.

-Sam

0 Kunal barot over 6 years ago in reply to Samuel Jaffe

Intellectual 605 points

Hi Sam

we have disable everything on board except SMPS and TPS54340, and but a dummy load on TPS54340 output of 1 A. and we have the same noise level and peaks, that indicate this noise from SMPS or TPS54340, if you can send me the your email so i can send my sch and layout for your review.

0 Samuel Jaffe over 6 years ago in reply to Kunal barot

TI__Mastermind 25590 points

Kunal,

I have shared my email through private message.

Have you tested with just one on at a time? And have you tried changing the frequency of the TPS54340 and seeing the new results?

-Sam

0 Samuel Jaffe over 6 years ago in reply to Samuel Jaffe

TI__Mastermind 25590 points

Kunal,

Thanks for your patience. We will continue to talk over email and I will circle back when we have a solution.

-Sam

Power management

Power management forum

TPS5430: Radiation emission data of TPS54340BQDDARQ1 and TPS561201DDCR