high voltage monitoring for AD8212

Hi there,

I have some question's about AD8212 for monitoring high voltage.

According to the datasheet, it says that "7 V to >500 V with external pass transistor ".

#1,Why is the common voltage  limited upt to >500V ?

#2,Is it possible to use this device to monitor high voltage like 1500V?

If it's okay, what designer should consider?

And the datasheet example is using PNP transistor.

#3,Instead of PNP transistor,does the circuit work when Nch-IGBT like GT40WR21 is used?

Thanks in advance.

Best regards,


  • Hi Tarzan,

    Thank you for your interest in using ADI products. Please see below for the answer of your questions.

    1. The common mode voltage was increase  to >500V when using an external PNP transistor and it is dictated and dependent on the VCE breakdown voltage of the external transistor.

    2. Yes, it is might be possible to extend the common mode to some level as long as you have enough VCE break down voltage on the external transistor. We only characterized the part on >500 V so we can't provide any measurements other than that. Few considerations that you need to look into are transistor power dissipations and bias resistor which was also explained on this thread.

    3. Yes, you can try that and it might work but  we don't have available data to show since we didn't characterize the part in that way.


    Best regards,


  • Hi Emman,

    Thank you for your support.

    I'm sorry that I could not reply this.

    Please give me a hand when further questions come up.

    Best regards,