SN65HVD24: Schematic review

Moon Wang

Part Number: SN65HVD24

Tool/software:

Hi Team,

My customer want to add a diode DX1 between 5V power and pull up resistor in A line as below picture to avoid the impact of noise from power.

Does it bring any bad influence?

BR,

Moon

over 1 year ago

0 Clemens Ladisch over 1 year ago

Guru 317930 points

This diode has an effect (i.e., blocks current) only when the supply is below the bus voltage. This happens only when the node is powered off, or when there is a large ground shift.

This diode does not hurt, but I cannot see how it would reduce noise impact.

0 Ethan Sempsrott over 1 year ago

TI__Genius 14632 points

Hi Moon,

I would not recommend the diode in your schematic. As Clemens notes, it affects the current on the bus. This can be an issue when switching from driver to receiver mode as the R pin would sees this current draw for a brief time period.

I would consider adding termination resistors as it might improve signal integrity: https://www.ti.com/document-viewer/lit/html/SSZTB23

Best,

Ethan

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SN65HVD24: Schematic review