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About ISO71xxCC

tsuyoshi tokumoto
Expert 2630 points

Hi team,

  I have a questions about ISO71xxCC.

  Can the ISO71xxCC use under the conditions of negative power supply?

circuit_example.xlsx

Best regards.
Tsuyoshi Tokumoto

  • 0
    TI__Guru 55795 points
    Hello Tokumoto-san,

    ISO71xx will accept all the voltage specifications as mentioned in the datasheet. With the supply voltages you have specified in the attached spreadsheet, the potential at VCC1 is still 5V with respect to GND1 and hence this doesn't violate datasheet specs. Now the logic inputs to the device have to be between -5V (LOW) and 0V (HIGH) to align with the power supply applied. Instead if you try to use 0V to 5V signal as logic inputs the device specs will be violated and device might be damaged.

    The same explanation holds good for VCC2 and GND2 as well. Any particular reason why you would want to use negative power supply for digital isolator?

    Regards,
    Koteshwar Rao
  • 0 in reply to Koteshwar Rao
    Expert 2630 points

    Hello koteshwer_san,

      Thank you very much for your prompt reply and
      I apologise for the delay in replying to you.

      I am considering the isolation circuit for negative power supply
      to suggest to my customer.
      From the above,to use the I/O digital signals levels are 0 to -5V(or -3.3V).

      Your advice is very useful resource for me!


    Best regards.
    Tsuyoshi Tokumoto