SN65HVD78: R pin pull up or down resister

Koji Ikeda

Part Number: SN65HVD78

Hello Support team,

My customer inquiries R pin. When they use it as receiver, does SN65HVD78D need pull up or pull down resister? R pin looks like to be push-pull output but Fig.26 uses 10k ohm pull up resister.

Thanks,

Koji Ikeda

over 3 years ago

0 Clemens Ladisch over 3 years ago

Guru 320660 points

The R pin is active only when /RE is low. You need a pull-up resistors if your circuit needs a defined state when /RE is high, or during power-up/-down.

0 Koji Ikeda over 3 years ago in reply to Clemens Ladisch

TI__Expert 6695 points

Hello Clemens-san,

Thank you for your support. Do you have any recommended value for pull up or down resister?

Thanks,

Koji Ikeda

+1 Clemens Ladisch over 3 years ago in reply to Koji Ikeda

Guru 320660 points

See the application report Choosing an Appropriate Pull-up/Pull-down Resistor for Open Drain Outputs, but that still results in a large range of possible values. 10 kΩ is most commonly chosen.

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SN65HVD78: R pin pull up or down resister