• State
  • Locked Locked
  • Replies 5 replies
  • Subscribers 64 subscribers
  • Views 505 views
  • Users 0 members are here
Support feedback
Options
Options
Related

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.

TPS7A3301 get damaged after powering on after some time.

Bhupesh Patil
Intellectual 440 points
Other Parts Discussed in Thread: THS4131, TPS7A33

I have used two TPS7A3301  regulators to provide supply for identical circuits on the same board. Layout of both regulators are almost similar. Out of those one regulator get damaged after powering on for some time. 

when i checked the resistance between pin1(output) and 2 (nc), it is zero.

what is the reason?

  • 0
    TI__Guru 55940 points

    Hi Bhupesh,

    Could you share more about your application?  Typically in order to debug a circuit around an LDO, it is important to know Vin, Vout, input capacitors, and output capacitors.  Any information you can share will help!

    Very Respectfully,

    Ryan

  • 0 in reply to Ryan Eslinger
    Intellectual 440 points

    Hi!

    Vin= -15 v, vout = -12 v, cin = 10uf, cout ~ 50 uf

    There are used to supply the opamps circuits using THS4131 (40 nos)

  • 0 in reply to Bhupesh Patil
    TI__Guru 55940 points

    Hi Bhupesh,

    Do you know anything more about the conditions right before failure?  For example, do you know how much current was being drawn?  Also, you mentioned that the damage happens after powering on for "some time."  Could you help ballpark how long the regulator was on?

    Very Respectfully,

    Ryan

  • 0 in reply to Ryan Eslinger
    Intellectual 285 points

    The current drawn was 0.7A at output voltage of -12V. After the regulator got damaged, the output voltage was coming -14.5V. Also, it was repeatedly going in Thermal on/off cycle when kept on for more than 1 min. Also, I observed the same problem coming in the working regulators randomly, but those are working properly at the moment.

    In addition to this, please let me know tha approximate value of the input impedance of the FB pin in TPS7A3301 or any other information that can be used to find out the exact current flowing into the FB pin.

    Regards,

    Anindya

  • 0 in reply to Anindya Chitta Bagchi
    TI__Guru 55940 points

    Hi Anindya,

    You mention that you are running into thermal shutdown.  While TPS7A33 has internal protection circuitry, running the device into thermal shutdown degrades the reliability of the device.  By triggering thermal shutdown, heat is certainly tied to your failures. What methods are being utilized to reduce heat?  Have you checked to ensure an adequate heat sink?

    The impedance of the FB pin is 87.5Mohm (typ).

    Very Respectfully,

    Ryan