• State
  • Locked Locked
  • Replies 4 replies
  • Subscribers 24 subscribers
  • Views 574 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Failure mode by OPEN/SHORT test for LP2951-50-Q1

Atsushi Yamauchi
Genius 4810 points

I would like to confirm the failure mode by OPEN/SHORT test.

Could you please teach OK or NG for OPEN/SHORT test in each pin?

In the case IC has the damage, could you please teach the failure mode?

<OPEN>

Pin#                       Pin name
1                            OUTPUT                                No damege
2                            SENSE
3                            SHUTDOWN                          No damege
4                            GND
5                            /ERROR                                 No damege
6                            VTAP
7                            FEEDBACK
8                            INPUT                                     No damege


<SHORT>

Pin#                        Pin name
1-Thermal PAD      INPUT-Thermal PAD
2-Thermal PAD      SENSE-Thermal PAD
3-Thermal PAD      SHUTDOWN-Thermal PAD
4-Thermal PAD      GND-Thermal PAD                 No damege
5-Thermal PAD      /ERROR-Thermal PAD
6-Thermal PAD      VTAP-Thermal PAD
7-Thermal PAD      FEEDBACK-Thermal PAD
8-Thermal PAD      INPUT-Thermal PAD

Best regards,

Atsushi Yamauchi

  • 0
    TI__Genius 14890 points

    Yamauchi-san,


    I've assigned an apps engineer to this post. They will reply within a few days.

  • 0
    TI__Expert 5675 points

    Hi Atsushi-san,

    1. Set all other pins to 0V.
    2. Force +/- 200uA current to the test pin (some pins may not have positive ESD diode).
    3. Measure voltage at the test pin to identify open/short. Set reasonable clamping voltage to prevent device damage.

    -200uA for open, +200uA for short. Usually clamping voltage shou be a little larger than 1 or 2 diode forward voltage, 1V or 2V.

    Please also note that, thermal pad is not connected to ground GND pin inside the LP2951-50-Q1.

  • 0 in reply to Jason. Liu
    Genius 4810 points

    Dear Jason-san,

    Thank you for your reply.

    I forgot short test condition.

    The short conditions are Pin no 1-2, 2-3, 3-4, 5-6, 6-7, 7-8 too.

    And I want to know the result and failure mode when the device is broken (like FMEA).

    Do you have the data or the matetial?

    Best regards,

    Atsushi Yamauchi

  • 0 in reply to Atsushi Yamauchi
    TI__Expert 5675 points

    Hi Atsushi-san,

    Usually there is an active circuit could be equivalent to one or two diode(s) inside each pin. When the device is broken, it is shorted and  there is no voltage could be detected no matter what current you sink.

    Unfortunately I don't have any data or material of this device.