TPS54335 problem, replace by TPS54335A?

KarlheinzRieber

Other Parts Discussed in Thread: TPS54335A

Dear all,

I designed a 24V to 15V / 2.5A power supply beginning of the year with WEBENCH. Due to some delays my prototypes are now finally ready.

Unfortunately the designed circuit only delivers up to 1A. If higher output currents are drawn then the 15V break down.

I saw now that the TPS54335 has been taken from the market and was replaced by TPS54335A. The new WEBENCH design suggests now different resistor, capacitor and inductor values. May there a chance that only replacing the TPS54435 with the A version will make the circuit work again?

Best regards,

Karlheinz

over 8 years ago

0 Surinder Singh over 8 years ago

TI__Expert 3085 points

Karlheinz,

TPS54335A has replaced the TPS54335. Please design with the new version.

I will loop in application engineers who can assist more with the problem.

0 JohnTucker over 8 years ago in reply to Surinder Singh

TI__Guru**** 191445 points

TPS54335A address some reliability problems. I doubt it is what is affecting your design. If your input supply is falling, you may be current limiting the input supply.

0 KarlheinzRieber over 8 years ago in reply to JohnTucker

Intellectual 550 points

John,

thank you very much for your answer.

Just to be sure: my input supply is not falling, my design with the TPS54435 fails, here the output voltage is falling. It should deliver 2.5 amps but fails even with 0.5 amps.

I designed the whole circuit with WEBENCH and considered the layout recommendation. I will know exchange the TPS54435 by the A version in the next days and see what happens. Until now all my designs of WEBENCH worked, this is the first one which fails.

Best regards,

Karlheinz

0 JohnTucker over 8 years ago in reply to KarlheinzRieber

TI__Guru**** 191445 points

Can you post your schematic?

0 JohnTucker over 8 years ago in reply to JohnTucker

TI__Guru**** 191445 points

Contact me directly at j(dash)tucker(at)ti(dot)com. I can provide some material for your review.

0 KarlheinzRieber over 8 years ago in reply to JohnTucker

Intellectual 550 points

Thanks John,

I will prepare the schematic for you on Monday.

Best regards,

Karlheinz

0 KarlheinzRieber over 8 years ago in reply to KarlheinzRieber

Intellectual 550 points

John,

for your information I solved the problem. It was mainly because of the too small input capacitor in front of the TPS54435A circuit (15V output). Therefore the 24V input voltage dropped and this led to the 15V failure.

Thank you very much for your help.

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TPS54335 problem, replace by TPS54335A?