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Does the ADS5263 HIGH SNR ADC have input protection diodes? If so how much current can they handle in a fault condition?

Prestor Saillant
Intellectual 315 points
Other Parts Discussed in Thread: THS4130, ADS5263

We are driving the the ADS5263 with a fully differential amplifier (THS4130) that is powered with +/-5V.  The circuit is designed such that the ADC input remains within 0.5V to 2.5V as required.  However, in a hardware fault condtion the ADC could be driven by the amplifier with voltages outside of the max range of -0.3V to (AVDD+0.3V).  Rather than adding external clamping diodes I would rather try to limit the current to what the internal input protection diodes for the ADS5263 can handle.

This information is not present in the data sheet.  Can a TI applications engineer provide this information.  The evaluation board for the ADS5263 has a similar design and does not use protection diodes.  So I am hoping to avoid the addtional components if possible. 

Thank you for your assistance as we begin moving our design towards layout next week. 

 

  • 0
    TI__Genius 14540 points

    The device inputs will have an ESD diode to both 3.3V input supply  and analog gnd. So any drive over the 0 and 3.3 will forward bias input diodes. These diodes and the metal connecting  those diodes is designed to take an ESD current which is normally existing only for very short times.

    For sustained DC type of overload the device may not be able to handle more than 10mA of current. Also if more channels in the same device are in overload then it is possible that the per channel current will be lesser than the 10mA rating.