• State
  • Locked Locked
  • Replies 2 replies
  • Subscribers 30 subscribers
  • Views 271 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.

LDC1614: Failure and Short Circuit from INxA to GND

Robert Tannhaeuser
Prodigy 20 points
Part Number: LDC1614

We have received an error/failure from our customer that the LDC1614 with a LC sensor is no longer working correctly and only showing 0 MHz. After a more detailed analysis, we measured the following values:

  • Short circuit from IN0A to GND
  • 900 Ohms from IN0B to GND
  • 900 Ohms from IN1-3A and IN1-3B to GND
  • Open on all Inputs INxA and INxB to VDD

In summary, we observe only a short circuit from IN0A to GND. All other inputs seem to work correctly. Now we try to understand what could let to this failure (e.g. ESD).

Therefore I would like to ask the following questions:

  • How are the inputs INx protected with respect to ESD?
  • Is there any information how the CHx drivers look like (internally)?
  • What could have caused a short circuit from IN0A to GND?

I would appreciate any information or a discussion on that.

Many greetings
Robert

  • 0
    TI__Mastermind 40295 points

    Robert,

    The pins are protected by ESD diodes between the pins and the power supply rail, and the pins and ground. 
    One of the ESD may have taken a 'hit' and failed. 
    The CHx drivers are are negative-gm stages; we don't have any details readily available about their topology.

    I will look into any additional guidance we can offer on this and update this thread by COB Monday.

    Regards,
    John

  • 0 in reply to John Miller - Sensing
    TI__Mastermind 40295 points

    Robert,

    Is it a single unit showing the failure, or have you seen it across multiple units?

    If it is a single device, please measure the current drain and sensor frequencies of the failed unit.
    Replace the failed device and measure the current drain and sensor frequencies and post the results to this thread.

    We will determine next steps from there.

    Please consider sharing your schematics and layouts if possible. 
    If you are not comfortable sharing on this public platform, we can arrange a private channel to do this.

    Regards,
    John