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THVD1424: THVD1424RGTR

Harsha K
Prodigy 180 points
Part Number: THVD1424

Tool/software:

Hi Team,

What is the resistor value of internal default pull-down and pull-up used for the DE, SLR, /RE, and other pins in THVD1424RGTR. And what is the external pull-up and pull-down values recommended to change the default status.

Regards,

Harsha

  • 0
    Guru 316690 points

    The current through the resistor is included in the input current specification. So the resistor value must be more than 5.5 V / 5 µA = 1.1 MΩ. To not exceed VIL/VIH even at the lowest supply voltage, the external resistor must be less than 180 kΩ.

  • 0 in reply to Clemens Ladisch
    Prodigy 180 points

    From the above, 1MΩ value used as internal pull/up resistors and to make external, the value must be less than 180KΩ, let me know if my understanding is correct.

  • 0 in reply to Clemens Ladisch
    TI__Guru 72751 points

    Clemens is correct.

    In most systems, customer use values that are 47k ohms or lower. The smaller the resistor, the stronger the bias will be which can help in environments with high electrical noise. The downside to this is higher consumption current which can be bad for systems that rely on batteries. Most customers who use RS485 don't care as much about supply currents though since RS485 in general eats up a bit of power due to communicating by driving ~40mA to 60mA of current.

    Harsha,

    Please let me know if you have follow up questions.

    -Bobby