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ADS1120-Q1: ADS1120-Q1

Kerem aok
Prodigy 70 points
Part Number: ADS1120-Q1
Other Parts Discussed in Thread: ADS1120

I have a system with an ADC input of 3.3V. I want to protect my processor to max 36V. Do you have a circuit or integrated for this?

  • 0
    TI__Guru** 112765 points

    Hi Kerem,

    Welcome to the E2E forum! I'm not totally sure I understand what you are asking for with respect to the input protection.  Are you wanting to protect specifically the MCU or the combination of the ADS1120 and the MCU?  Is it that 36V could accidentally be applied to the ADC inputs?  Do you have a schematic that you can share?

    Normally we would use a TVS diode to limit the voltage to a specific level.  If 36V would be the level that could be applied to the analog inputs, then you will also need to limit current into the ADC as 36V would exceed the absolute maximum ratings for the ADS1120.  For me to be more specific, I would need to know more information about you system and design.

    Best regards,

    Bob B

  • 0 in reply to Bob Benjamin
    Prodigy 70 points

    Hello Bob, thank you for your attention. In short, I want to make a simple MCU protection. I shared the circuit I designed for this. However, as you said, is there any other system you suggest that can protect the MCU side when a higher voltage is accidentally supplied?

  • 0 in reply to Kerem aok
    TI__Guru** 112765 points

    Hi Kerem,

    The topic thread is based on using the ADS1120, but your diagram is showing the use of the ADC within the micro.  Although the protection circuit would be similar, the protection with respect to the micro would be slightly different.

    In your drawn circuit, you are showing a TVS diode at the input but there is a power rating for the device used so you must make sure that in your design you limit the total current through the TVS diode so that the power rating is not exceeded.  This could be done through a resistor or a PTC fuse.

    Best regards,

    Bob B