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LP2980-ADJ: Output voltage is low

Darren Chang
Expert 4120 points
Part Number: LP2980-ADJ

Expert,

The customer actually measured the ADJ voltage value of 31 boards and found that nearly half of the ADJ voltage values ​​of this LP2980IM5X-ADJ/NOPB are close to or lower than the Vref lower limit.

Please refer to the attachment for data.

TI_LDO LP2980IM5X-ADJ量测数据.xlsx

Is it because the materials are defective, or is there something wrong with our experiment or design?

I checked that LP2980IM5X-ADJ/NOPB is an old chip. The ADJ voltage is as shown in the picture below. Which condition should I refer to?

Assuming Tj=25C, is the ADJ voltage out of range?

Thank you.

Darren

  • 0
    TI__Mastermind 42455 points

    Hi Darren,

    How did they measure the ADJ voltage? Was it with a regular DMM? Do they have a 10Gohm DMM that they can use? Alternatively, if they short ADJ to OUT and measure OUT that would be a better measurement as well.

    Regards,

    Nick

  • 0 in reply to Nick Butts
    TI__Expert 4120 points

    Hi Nick,

    When measured according to short ADJ to OUT, the Vadj value is also low. They use Keysight, 34470A to measure it.

    Do you have any ideas? Customer wants to send back analysis.

    1.2009

    V

    1.2007

    V

    1.1995

    V

    1.1996

    V

    1.2017

    V

    1.2007

    V

    1.2008

    V

    1.2007

    V

    1.2008

    V

    1.2015

    V

    Thank you.

    Darren

  • 0 in reply to Darren Chang
    TI__Mastermind 42455 points

    Hi Darren,

    I should have realized before, but this device orderable is part of the Redbull project. The data they have provided us shows pretty clearly that some of the devices are the old die with a 1.225V (nom) reference voltage, while the other half of the devices have the 1.2V (nom) reference voltage. 

    When did they order the devices? The PCN expiration date was August 2023, so it's not clear whether the old materials will have been cleared out yet and it seems likely that they ordered them when there were still old materials and they received approximately half old and half new devices.

    Regards,

    Nick

  • 0 in reply to Nick Butts
    TI__Expert 4120 points

    Hi Nick,

    I mail to you to discuss this case.

    Thank you.

    Darren

  • 0 in reply to Darren Chang
    TI__Mastermind 42455 points

    Hi Darren,

    In that case I will close this post to continue offline.

    Regards,

    Nick