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ISO1541: schematic check

GARETH OU
Mastermind 8835 points
Part Number: ISO1541
Other Parts Discussed in Thread: ISO6741, ISO1641, ISO6721, ISO6720

Hi 

Could you help check the ISO1541 schematic as below and any need to adjust ,Thanks

  • 0
    TI__Genius 17100 points

    Hi Gareth,

    Thank you for posting to E2E!

    Regarding U44, U45, and U46, the connections all look good. For U48 and U49, it looks like the signals being isolated are SPI, and not open-drain signals like I2C, so a standard digital isolator like ISO6741 can be used instead.

    For the cases where ISO1541 is used, TI's new ISO1641 is a more robust I2C-capable isolator that is pin-to-pin compatible with ISO1541, and we recommend replacing all instances of ISO1541 with ISO1641. 

    Please let us know if you have additional questions.


    Respectfully,
    Manuel Chavez

  • 0 in reply to Manuel Chavez
    Mastermind 8835 points

    Hi Manuel

    Thanks you kindly  reply 

    Does ISO1541 can isolated at UART and SPI interface?

  • 0 in reply to GARETH OU
    TI__Genius 17100 points

    Hi Gareth,

    If ISO1541 is used to isolate UART and SPI signals, pull-up resistors are needed on the signal lines on both sides of the isolator to provide the HIGH signal output states.

    Digital isolators like ISO77xx and ISO67xx devices are recommended instead of an I2C isolator for SPI and UART signals. If package size is a concern, ISO6720 and ISO6721 devices in similar "D" packages are available.


    Thank you,
    Manuel Chavez 

  • 0 in reply to Manuel Chavez
    Mastermind 8835 points

    Hi Manuel

    Could you help to check ISO6741 schematic as below

    Thanks ~

  • 0 in reply to GARETH OU
    TI__Genius 17100 points

    Hi Gareth,

    Thank you for your response! It seems like the ISO6741 is configured correctly, and the only necessary change might be to switch the connections of MISO and MOSI lines on the digital isolator.

    Since MISO is an output to the M90E26, it should drive an input channel of the isolator like IND while MOSI is an input, so it should be connected to an output pin like OUTC to receive data from the MCU. In short, the connection pairs to pins 5 and 12 can be switched with the connections to pins 6 and 11 respectively.

    Please let us know if you have additional questions or concerns.


    Respectfully,
    Manuel Chavez