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LSF0102: Could LSF0102 support 5.25V I/O with Vref_B =4.2V?

Patrick Chen(TPE System & Application)
Expert 3430 points
Part Number: LSF0102

Hi Sir,

Could LSF0102 support 5.25V I/O?

We have an application that need a bi-directional level shifter 1.8V -- 5.25V level shifter.

The 5.25V is a signal coming from another board and it have a pull up resistor on that board.

On my design system, there is only 4.2V power, so we could only provide 4.2V to Vref_B and 1.8V to Vref_A.

On the LSF0102 spec, it says that the VIO Max is 5V, so I think we might not be able to support this application, but I would like to check with you.

Also the Max of Vpu is Vref_B and on our design, the Vref_B is 4.2V while the Vpu is 5.25V.

If you have better fit solution, please also advise.

Thanks,

Patrick

  • 0
    TI__Guru* 97017 points
    Hi Patrick,
    Yes, the LSF0102 can definitely work in your application. The device is rated to operate up to 7V (absolute maximum) so going up to 5.25V won't be any problem.

    As long as the pull-up is to 5.25V on the high side, then the device will work correctly. If you are interested in learning more about how the LSF works, we have a video series that covers it in detail located here: training.ti.com/LogicMinute
  • 0 in reply to Emrys Maier
    TI__Expert 3430 points
    Hi Emrys,
    Thanks for helping, but on the spec, the maximum operating voltage is 5V, will it be ok to support 5.25V?
    Also, the spec define that the Vpu should be Vref_B, will it be ok to pull up 5.25V while Vref_B is 4.2V?
    If answer on above is yes, are we going to change our spec to extend the application that LSF0102 could support?

    Thanks,
    Patrick
  • 0 in reply to Patrick Chen(TPE System & Application)
    TI__Guru* 97017 points
    Hi Patrick,
    The spec is 7V absolute maximum. It is in section 6.1 of the datasheet.

    We will not be updating the recommended operating conditions since this is very clearly stated in the datasheet already. The device will work perfectly fine at 5.25V.

    The pull-up voltage can be any value that is valid for the device (also up to 7V). The typical application operating condition table (Table 3 in the datsheet) is talking about the specific application listed, and does not encompass all possible applications.

    If you watch the video I linked on multi-voltage translation, you will see that you can have many different voltages on a single LSF device without any problems.