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TPS62088: problems in testing EVM

Vincenzo Pizzolante
Mastermind 25516 points
Part Number: TPS62088

hi all

a customer of mine is testing TPS62088 EVM.

They observed 2 failures of the TPS62088 device, so far:

1.) The first TPS62088 device failed under "no load test" and the input voltage was increasing from 3 to 4 V.
2.) The second TPS62088 device failed under "light load test (Rout = 7 Ohm)" and the input voltage was increasing from 3 to 4 V.

The input voltage was powered from a programmable DC power supply with the current limit set to 400-600 mA, and voltage was swept from 2.5 V - 4.5 V.

The TPS62088 EVM board was used with jumpers at default positions.

any hint?

thanks a lot in advance

KR

Vincenzo

  • 0
    TI__Guru**** 150950 points
    Hi Vincenzo,

    Can you send a waveform of Vin, Vout, and SW when they increase the input voltage?

    What does 'failed' mean?
  • 0 in reply to Chris Glaser
    TI__Mastermind 25516 points

    hi Chris

    thanks for the prompt reply.

    both devices got damaged (Vin and Vout pins are shorted to gnd), so at moment I cannot send any waveform.

    They did not notice any unusual behavior before they got damaged (no oscillations or high voltage ripple).

    They were trying to test the regulators at "battery range" voltage (2.8 V - 4.2 V) with zero (no load) or light load (7Ohm power resistors).

    I know is not much, but is what we have at the moment

    KR

    Vincenzo

  • 0 in reply to Vincenzo Pizzolante
    TI__Guru**** 150950 points
    This is difficult to debug. Of course, the device supports that Vin range.

    You can order new EVMs and retest, with the scope connected and triggering on a too high Vin.

    However, before this we can try 2 things. Can you send a photo of their test setup? There may be some simple connection error.

    As well, can they hook a scope directly to the same input power supply they used for the previous tests and change the voltage in the same way as they did in those tests? Just connect the power supply to the scope. Let's see what their power supply does. I had a dual output power supply, some years ago, which did something very bad and unacceptable: the second output went always to 20V, before returning to the voltage I set it to (5V, for example). This would damage the EVM of course.