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ISO7762-Q1: ISO7762FQDBQQ1

BAGADI RAJA SEKHAR
Prodigy 80 points
Part Number: ISO7762-Q1

Tool/software:

Dear Team,

I am currently working on a gate driver design using the ISO7762FQDBQQ1 digital isolator. In this design, I am utilizing only four channels of the isolator, while leaving two channels unused. According to the datasheet, when the INx pins are open, the corresponding channel output will default to a low logic state.

My concern is regarding the unused input and output pins. The isolator is positioned close to the power ground and the switch node in the circuit. I am wondering whether there could be potential issues with noise coupling or other interference when leaving the unused channels floating, considering the proximity to high-voltage switching areas.

Could you please provide guidance on whether it is safe to leave the unused channels floating, or if there are any recommended design practices to minimize noise or interference in this configuration?

Your assistance and any advice you can offer will be greatly appreciated.

Thanks,

B Raja Sekhar

  • 0
    Guru 298340 points

    The inputs have internal pull-down resistors. If you fear that these high-impedance inputs can pick up noise, then you can simply connect the unused inputs directly to GND.

  • 0 in reply to Clemens Ladisch
    Prodigy 80 points

    in my case input side reference ground is switch node and output side is analog ground , keep floating or connecting to switchnode( input side reference ground) ,which one is better practice for input pins.

  • 0 in reply to BAGADI RAJA SEKHAR
    TI__Intellectual 1965 points

    Hi Raja,

    Thanks for reaching out. Please find my inputs below:

    As Clemens stated, to avoid any unwanted noise coupling unused inputs simply need to be connected to the respective side GND.

    Connecting the INx Pin to the respective side GND will eliminate any High Impedance Noise Coupling.

    Regards
    Varun