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SN65HVD1782: imput impedance ri

KANJI SHIBATANI
Mastermind 6205 points
Part Number: SN65HVD1782
Other Parts Discussed in Thread: SN75176B, , SN65HVD75


Hello


My customer see in SN75176B data sheet that

"input impedance ri=12kohm (MIN) ".


However, customer don't find imput impedance spec. in SN65HVD75 and SN65HVD1782 data sheet.


Please let us know input impedance ri of SN65HVD75 and SN65HVD1782.

 
Customer says ri=12kohm is DMX spec, and its important spec for selection.


Best Reagrds

  • 0
    TI__Guru 62910 points
    Hello Shibatani-san,

    Instead of an input resistance, those devices specify a bus input current (which is a specification more in line with TIA-EIA-485). You can translate this into an equivalent input resistance by taking the test voltage defined for this input current and dividing it by the current value, though. Both devices that you mentioned should be able to meet the 12 kOhm specification, since this is equivalent to one "unit load" per the RS-485 standard.

    I hope this is clear. Please let me know if you have any questions.

    Regards,
    Max