ESD Protection AD7747

Hello at all,

i make measurements in a powder conveyer where we have electrostatic discharge with more than 15kV,

which is killing the ad7747's signal-generator and CAP-inputs.

Inside the tank we use a sensor with three different isolated electrodes on potentials CIN+, CIN- and EXC.

I search for an esd protection circuit for the ad7747 inputs/outputs CIN+, CIN- and EXC.

Hope, that anyone knows a solution which is not influencing the measurement.

Parents
  • 0
    •  Analog Employees 
    on Nov 16, 2012 5:40 PM

    Hello Stefan,

    >15kV is a very high ESD strike. We have not tested our parts to this level and have not devised any circuits that would combat this.

    It should be possible to put a series resistance to minimise the impact of the ESD, but as per the datasheet, additional series resistances will affect the measurement.

    Similar external protection diodes on each input and the excitation pin would add capacitance to the measurement, which can be removed using the CAPDAC of the part. A low resistance will still probably be required.

    Regards,

    Sean

  • Hi

    Regarding to the ESD protection for AD7747, I'm wondering if possible to use same ESD and EMI protection circuits which was illustrated on fig.48 and 49 of AD7150 datasheet?

    Using ultra low capacitance ESD protection diode  (<1pF) might be help, but which breakdown voltage you recommend to be used for the ESD diode?

    Regards,

    Al-Sallami

Reply Children
No Data