• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 46 subscribers
  • Views 403 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.

ADS8326: Over- and Undershooting Conditions

Jejomar Ildefonso
Genius 9700 points

Part Number: ADS8326

Hi Team,

Our customer is currently working on with ADS8326. They are currently experiencing over- and undershooting signal inputs to DCLOCK and CS/SHDN.

VDD = 5V
Overshoot: Max 5.96V against rated 5.3V
Undershoot: Max -1.0V against rated -0.3V

These conditions are specifically experienced during start-up (overshoot) and turn down (undershoot) of a duration of about 2ns. Are these conditions acceptable for the ADS8326? They are currently considering to insert a dumping resistor to the digital inputs. Would really appreciate your inputs. Thanks in advance!


Kind Regards,

Jejomar

  • 0
    TI__Guru 51060 points

    Hello Jejomar,

    These conditions are similar to a fast ESD event.  The internal ESD diodes are definitely turning on, and if the current during this 2nS pulse is high enough, then it will cause damage to the device. We do specify a continuous input current into the ESD diodes of +/-20mA; if the current is less than this, then you will not damage the device.

    Unfortunately, for higher input currents, we do not have any test data that could predict if this specific case is acceptable or not.  

    I agree that the customer should consider adding a damping resistor, external ESD diode, or some type of RC filter to limit the peak over/under shoot.

    Regards,
    Keith Nicholas
    Precision ADC Applications