• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 46 subscribers
  • Views 380 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.

Original question:

ADS1112: Input port damage issue

ADS1112: Input port damage issue

JL NEEL
Prodigy 10 points

Part Number: ADS1112

Hello


you specified Analog Inputs, A0, A1, Voltage to GND −0.3V to VDD + 0.3V.

In my application the ADC inputs are connected to a 3V source by a 8k serial resistor.

Could you said me wich is the IIn maximum current sinked on the Analog input (case of the VDD of the device has been lost and the source volage maintened) without damage and lost on the device reliability

Thank you

JL

  • 0
    TI__Guru** 100725 points

    JL,


    In our datasheets, we put in an Absolute Maximum Ratings table. For the ADS1112, this is at the top of page 2. You'll note that the maximum input current is listed 10mA continuous. As you have also done, many will insert a series resistor to limit the input current.

    However as you have also mentioned, the analog input shouldn't go above VDD+0.3V (also listed in the absolute maximum ratings). For that, I would use a reverse biased Schottky diode connected from the input to VDD, to limit the maximum input voltage. If you do lose the VDD supply and there's a voltage on the input, the Schottky should be able to pull up VDD without the input voltage exceeding the maximum.


    Joseph Wu