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BQ75614-Q1: isolation required on UART to MCU?

Part Number: BQ75614-Q1
Other Parts Discussed in Thread: TXS0102, ISO6742

Hi,

on our BQ75614EVM as well as in a couple of other threads, we recommend using ISO7342 on UART connection between MCU and BQ75614:

- why do we recommend an isolation instead of a simple level shifter like TXS0102?

- if isolation is required, could customers use ISO6742 instead of ISO7342?

BR,
Phil

  • Hello Phil,

    No, an insolation device is not strictly required for the BQ75614. We have many automotive customers who require the high voltage isolation to protect their MCU. If this is not a requirement for your system, then a level shifter may be sufficient. We have had some customers who have had concerns with the MCU drawing current when powered off through the UART communication pins. This should be considered when using a level shifter solution and is different depending on the MCU used.

    Both those ISO part numbers seem like they would work. We have not tested using the ISO6742 however.