TPS54335 Failure.

Steve Harrison

Other Parts Discussed in Thread: TPS54335A

Regarding the previous quality notofication. Has the device now been revised ? If so how do we identify the part by code ? We are experiencing consistent failures and need to know if to design the part out on an imminent re-spin.

Thanks

Steve

over 9 years ago

0 JohnTucker over 9 years ago

TI__Guru**** 191445 points

The revised part has a new part number. It is TPS54335A. All TPS54335A will have the revision.

0 Steve Harrison over 9 years ago in reply to JohnTucker

Prodigy 50 points

Thanks. This IS the part we are using and seeing the failures. A fast rise time application of power (hot plug) causes failure. We have removed some pull-ups from the EN pin and added some caps as we suspected glitcthing on the EN was the cause (assuming we had old devices). This seems to have improved things. Can you shed any light on this. I'm happy to send a schematic extract. Regards Steve

0 JohnTucker over 9 years ago in reply to Steve Harrison

TI__Guru**** 191445 points

Typically hot plugging can cause over voltage transients on the input. If it is over the abs max voltage spec the IC can be damaged.

0 Ian Midgley over 9 years ago in reply to JohnTucker

Prodigy 80 points

Hi

We also seem to have some problems with failures using TP54335A devices. We are using the device as 24V Input stepping down to 5V configured as per the application diagram in the datasheet.

Did you find the cause and solution of the failures?

0 JohnTucker over 9 years ago in reply to Ian Midgley

TI__Guru**** 191445 points

Can you describe the type of issues you are seeing?

0 Ian Midgley over 9 years ago in reply to JohnTucker

Prodigy 80 points

Hi,

After powering on the device using a bench PSU the bench supply limits. The TPS54335 device then appears damaged with a short between VIN and GND pins. The Circuity that this device is powering works off of +5V and takes about 100mA, when I bypass the TPS5433 device and power directly with +5V all works fine.

0 JohnTucker over 9 years ago in reply to Ian Midgley

TI__Guru**** 191445 points

How many have failed like this out of how many total systems?

0 Ian Midgley over 9 years ago in reply to JohnTucker

Prodigy 80 points

Currently 4 out of 5 have failed. I have replaced the part 2 or 3 times and had more failures however the parts are not easy to keep swapping out.
Is there a problem with these devices?

0 Ian Midgley over 9 years ago in reply to JohnTucker

Prodigy 80 points

I have had four systems out of five fail. I have also replaced the TPS54335 part two or three times and had similar failures. Its not easy to keep replacing these parts.
Can you tell me if these devices have problems and is there a solution?

0 Steve Harrison over 9 years ago in reply to JohnTucker

Prodigy 50 points

We made 10 prototypes, all the ones that we powered up 'fast' blew. Using a current limit to slow rise time saved a few once we had got wise to it.

We have designed the part out now.

0 Steve Harrison over 9 years ago in reply to Ian Midgley

Prodigy 50 points

We had to slow the rise time. I thinking glitching on EN pin can be an issue. We designed it out. The max of 28v was too close to our nominal 24V anyway.

0 Abull Yang over 9 years ago in reply to Steve Harrison

TI__Intellectual 1100 points

Steve,

The latest version is TPS54335A. TPS54335A version solve the issue.
And do you mind sending me the schematic?

Abull

0 Ian Midgley over 9 years ago in reply to Steve Harrison

Prodigy 80 points

What device did you use instead? Looking to design out this part as well.

0 Abull Yang over 9 years ago in reply to Ian Midgley

TI__Intellectual 1100 points

Did you use TPS54335, right? please use TPS54335A instead..

Abull

0 Ian Midgley over 9 years ago in reply to Abull Yang

Prodigy 80 points

We are using TPS54335A and are having too many issues when power is switched on with the device failing. I need to design out this part so looking for a reliable alternative.

0 Abull Yang over 9 years ago in reply to Ian Midgley

TI__Intellectual 1100 points

Could you please descript the issues in details? And send me the schematic? we need to find out the root cause if it's a real device issue..

Abull

0 Ian Midgley over 9 years ago in reply to Abull Yang

Prodigy 80 points

The schematic is as shown in figure 22 of the datasheet. When I power on the device from a bench power supply most of the time the device fails. If I bypass this circuit and supply direct to the remaining PCB all works correctly. I have 24v Input and 5v output

0 Abull Yang over 9 years ago in reply to Ian Midgley

TI__Intellectual 1100 points

It doesn't make sense. Many of my customers used this device. we never get the feedback as you descript. Did any FAE help you on the debug?
The datasheet circuit is typical application case.
can you send me you layout? I can help to review it..

Abull

0 Ian Midgley over 9 years ago in reply to Abull Yang

Prodigy 80 points

It looks like another user Steve Harrison had the same issues. Im under tight time constraints so I need to replace the part with something more reliable

0 Abull Yang over 9 years ago in reply to Ian Midgley

TI__Intellectual 1100 points

I think you need to find the root cause to check if it is IC issue or the application issue. And I can help with you to dig out the root cause. If you insist to find another solution, we will release another 3A 28V part at the end of this month. If you are interested with this part, please contact the sale to provide the samples and EVM.

Abull

0 Steve Harrison over 9 years ago in reply to Ian Midgley

Prodigy 50 points

I have put in an LM536035QP. It has a higher input voltage as our application is 24V battery and these can exceed 28V. . Only checked it out on eval board. Real pcbs won't arrive for a month.

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TPS54335 Failure.