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SN65LVDS100: Receiver Equivalent Schematic

Tomoaki Yoshida91
Genius 5255 points
Part Number: SN65LVDS100

Hi team,

In our usage, the differential input signal may be input while the Vcc pin is in the high impedance state or 0V pulling GND.

At this time, I am going to check whether the device will not be destroyed or whether abnormal output will occur.

So, I am looking at 8.1 Absolute Maximum Ratings(1) and 10.3.1.6 Receiver Equivalent Schematic in the datasheet.

I do not have a risk of breaking if the differential input is less than 4.3 V and I realize that High immpedance does not cause problems especially since the input terminal is only the MOS gate and the diode to the GND side.

However, I am concerned that absolute maximum input voltage is 0.3V higher than Vcc's one that is 4V.

Although there is not in the Receiver Equivalent Schematic, is there a diode in Vcc for ESD protection?

If so, I think that the input voltage always needs to be less than Vcc + Vf.

Best regards,

Tomoaki Yoshida

  • 0
    TI__Mastermind 43795 points

    Hi Tomoaki,

    The ESD structure is to GND.  The II(off) datasheet specification shows that it is okay to have Vi > VCC.

    Regards,

    Lee

  • 0 in reply to Lee Sledjeski
    Genius 5255 points

    Hi Lee-san,

    Thank you for your support.

    I understood that there is no problem our usage.

    I have parts that I do not understand in the datasheet.

    What is the difference between the power dissipation rating and the device power dissipation on the 5th page of the datasheet?

    As SN65LVDS100 has device dissipation of 110 mW and Rθja of DGK package is 263°C /W, is it possible to tolerate temperature increse up to 28.93℃?

    110 mW * 263 °C / W = 28.93 °C

    Is Tj_max 125℃?

    Best regards,

    Tomoaki Yoshida

  • 0 in reply to Tomoaki Yoshida91
    TI__Mastermind 43795 points

    Hi Tomoaki-san,

    The worst case condition for this device is at 85C operating temperature and 110mW power dissipation.  The combination for 85C ambient and thermal increase would be:  85C + 28.93C = 113.93C.  I believe the max Tj is 125C so there is no issue.

    Regards,

    Lee