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MAX3221E: Protected RS232 transceiver

Jeferson Pehls
Expert 1125 points
Part Number: MAX3221E

Hi.

Please, could I receive a help regarding the RS232 transceiver MAX3221EIPWR?

The schematic is here. I have tried to explain everything I could directly in the PDF, its a single page.

PCB-M9-A-CAN-RS232_01.pdf

Regards.

  • +1
    TI__Mastermind 45917 points

    Hi Jeferson,

    So the RIN pin will be protected with the current scheme that you have - the DOUT pin will not be.

    If the fault  is sustained while the driver is in high impedance mode no practical value of RT will truly protect the device - as the driver will be high impedance - and under normal operation its sending data to a ~5k load - so any series resistance is going to create a voltage divider.

    Ultimately the diode on the DOUT pin needs  to be kept under there absolute maximum always - for short faults - pulse proof resistors at ~10 to 100 ohms should be used -but for sustained as you describe you need a lower clamping voltage.

    Please let me know if you have any other questions and I will see what I can do.

    Best,

    Parker Dodson

  • 0 in reply to Parker Dodson
    Expert 1125 points

    Thanks, Parker.