TPS7A4701EVM-094: EVM APP and EVM board questions

Marco Rojas

Hey team, I had one of my customers have concerns over a couple EVMs blowing up - see below

"I have purchased two of TPS7A47xxEVM-094 now and both have blown up as soon as 30V was applied.
I checked the voltage and it was definitely 30V (Lab power supply)
I had removed all jumpers apart from J9 (Enable) and fitted R2 as 27K to give 33V output. No load was connected.

There is visible damage to the ic near pin 16 (VIN) on both boards. Like I say this happened to both boards.

I like the device but it has to work and I am reluctant to buy any more.

I haven’t had this happen to other EVMs similar to this.

Is there a design issue with this EVM? Is this something you can look at?"

I'm the FAE on this account (Clear-Com / HME), so let me know if there are any further questions

Marco

11 months ago

0 Josh Nachassi 11 months ago

TI__Expert 5231 points

Hi Marco,

Thank you for your question and we apologize for this inconvenience, but this should not happen under normal operating conditions. I will run the test and get back to you on my results.

Thank you,

Josh Nachassi

0 Josh Nachassi 11 months ago in reply to Josh Nachassi

TI__Expert 5231 points

Hi Marco,

I ran the test and my evm is working perfectly and not smoking. I even tested Vin up to 35-V and no problem with that. Can I please see your setup for the input voltage? Can I see a scope shot? Let's get to the bottom of this issue.

Thank you,
Josh Nachassi

0 Marco Rojas 11 months ago in reply to Josh Nachassi

TI__Intellectual 1750 points

Hey Josh,

I've passed along the message to the customer (Nigel) and I'll let you know if I have any update on my side of things. Thanks for handling this quickly!

Marco

0 Josh Nachassi 11 months ago in reply to Marco Rojas

TI__Expert 5231 points

Hi Marco,

No problem, that's what I am here for. Looking forward to the response.

Thank you,

Josh Nachassi

0 Marco Rojas 11 months ago in reply to Josh Nachassi

TI__Intellectual 1750 points

Hey Josh, response from customer below

"Thanks..
What about changing R2 to 27K and removing all jumpers (apart from J9) -still ok?

My EVM is hooked up to a 30V Lab power supply and I used its output switch to apply power. Same as I did for all other TI EVMs such as LT3081 and LT3086 which worked as they should."

Seems like this is for a low-noise 30V supply

0 Josh Nachassi 11 months ago in reply to Marco Rojas

TI__Expert 5231 points

Hi Marco,

Yes, I removed all jumpers except for J9 and changed R2 to 27k. I am using a normal power supply, if I can see waveforms, it will be helpful because it will help me dissect the issue. Even if your power supply is noisy, I doubt it is going past 35-V on the swings which is what I tested at.

There has to be some other reason for this issue because it is not the EVM. What is the output current?

Thank you,

Josh Nachassi

Power management

Power management forum

TPS7A4701EVM-094: EVM APP and EVM board questions