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ISO7840: ISO7840's function table

Hirotaka Matsumoto
Guru 27525 points
Part Number: ISO7840

Hi all

Just in case, we would like to confirm ISO7840F's function table.

<ISO7840F's function table which we assume>
Vcci : PU, Vcco : PU, INX : High, EN2 : High or Open -> OUTX : Low
Vcci : PU, Vcco : PU, INX : Low , EN2 : High or Open -> OUTX : High

Is our recognition correct?

Kind regards,

  • 0
    TI__Intellectual 2900 points

    Hi Hirotaka-san,

    The functional table written above is incorrect. I've corrected it below.

    -----------------------------------------------------------------------------------------------
    This functional table is true for both ISO7840 and ISO7840F.
    Vcci : PU, Vcco : PU, INX : Low, EN2 : High or Open -> OUTX : Low
    Vcci : PU, Vcco : PU, INX : High , EN2 : High or Open -> OUTX : High.
    -----------------------------------------------------------------------------------------------

    I understand that the suffix F of the ISO7840F may have caused this confusion. The presence of 'F' indicates the default state of ISO7840F. This is the state that the output will be in if the input is open or if the Vcci is powered down.

    -----------------------------------------------------------------------------------------------
    ISO7840F (Output Default state is Low)
    Vcci : PU, Vcco : PU, INX : Open, EN2 : High or Open -> OUTX : Low
    Vcci : PD, Vcco : PU, INX : PD , EN2 : High or Open -> OUTX : Low
    -----------------------------------------------------------------------------------------------

    -----------------------------------------------------------------------------------------------
    ISO7840 (Output Default state is High)
    Vcci : PU, Vcco : PU, INX : Open, EN2 : High or Open -> OUTX : High
    Vcci : PD, Vcco : PU, INX : PD , EN2 : High or Open -> OUTX : High
    -----------------------------------------------------------------------------------------------

    Please let me know if additional clarity is required.

    Regards,
    Anand Reghunathan

  • 0
    Guru 243820 points

    That is not what I see in the datasheet: