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THVD1450: How to handle unused pins

Part Number: THVD1450

Dear TI Team

Our customer is considering THVD1450.
If I use only the driver part of THVD1450, how should I handle the unused R and RE pins?
Also, if only the receiver part is used, how should the unused D and DE pins be handled?

Regards,

Y.Ottey

  • This device has integrated pull-up/-down resistors; all unused pins can be left open (see section 9.4.3 of the datasheet).

    If you have a very noisy environment and fear that the resistors might pick up noise, you can connect DE to GND and D and RE to VCC.

  • Y.Ottey,

    You can deactivate either function of the device using the DE and RE pins. Leaving DE floating would disable the driver, as an internal pull-down resistor would bring this to a logic low.

    Similarly, leaving RE floating would disable the receiver, as an internal pull-up resistor would bring this to a logic high.

    I rarely recommend putting floating input pins into a design, so if either portion of the device is to be disabled, I recommend pulling the DE or RE pin to VCC or GND as applicable.

    I especially recommend considering a pull-down for DE if the driver is not used. If a noisy environment somehow causes the driver to become temporarily enabled, it could cause bus contention or data corruption even if D is also left floating.

    Unused digital outputs (pin R) can be left unconnected if necessary.

    Best,

    Danny

  • Dear Danny

    Thank you for your reply.

    I have confirmed what you have described.
    From what you have stated, I have the following perceptions:
    Is there any problem with the following recognition?


    (1) Connection of R and RE pins when using only the driver part of THVD1450

    • R pin ⇒ floating
    • RE pin ⇒ floating or connected to GND

    (2) Connection of D and DE pins when using only the receiver part of THVD1450

    • D pin ⇒ floating
    • DE pin ⇒ Floating or connecting to VCC

    Regards,

    Y.Ottey

  • Y.Ottey,

    Y.Ottey said:

    (1) Connection of R and RE pins when using only the driver part of THVD1450

    • R pin ⇒ floating
    • RE pin ⇒ floating or connected to GND

    (2) Connection of D and DE pins when using only the receiver part of THVD1450

    • D pin ⇒ floating
    • DE pin ⇒ Floating or connecting to VCC

    Looks like we agree. The open RE pin disables the receiver, and the open DE pin disables the driver.

    Best,

    Danny