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ADS7043: Surge Pretection Circuit at AVDD=1.8V

Shinichi Inoue
Guru 20896 points
Part Number: ADS7043

Dear Specialists,

My customer is interested in ADS7043 and has a question.

I would be grateful if you could advise.

---

I'd like to use ADS7043 and AVDD=1.8V

The analog signal is interfaced by 1.8V and is directly received by ADS7043. 

Could you please advise about Surge Protection circuit.

Generally, it uses TVS diode or Zener diode, but there is not 2V clamp diode.

What type of circuit should I use?

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I appreciate  your great help in advance.

Best regards,

Shinichi

  • 0
    TI__Mastermind 24970 points

    Hello,

    You are right, the most common protection is a diode.

    What is driving the ADC input?

    Is there a step down from a higher voltage power supply? Devices usually are limited to the highest voltage they are exposed to. If higher, how much higher is the power supply from 1.8V of the ADC input source?

    Regards

    Cynthia

  • 0 in reply to Cynthia
    Guru 20896 points

    Hi Cynthia,

    Thank you for your reply.

    In this case, ADC input is 0-1.8V directly from outside and power supply is 1.8V.

    It only needs to be able to measure an approcimate value. 

    I couldn't find 1.8V zener diode.

    I appreciate your great help.

    Best regards,

    Shinichi

  • 0 in reply to Shinichi Inoue
    TI__Mastermind 24970 points

    In this case, I would suggest using shunt diodes to protect the ADC inputs.

    When the input goes high, the diodes will turn on and redirect the current to the power supply. Be sure that the power supply the diodes are connected to can sink and source current.

  • 0 in reply to Cynthia
    Guru 20896 points

    Hi Cynthia,

    Thank you for your reply.

    I'll share your suggestion with the customer.

    If he has an additional question, I consult you again.

    I appreciate your great help.

    Best regards,

    Shinichi