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SN65HVD3086E: About Vcc pin input current

Tsukui Yusuke
Guru 21930 points

Part Number: SN65HVD3086E

Hi,

Customers are considering SN65HVD3086E for transmitter and receiver.
Customers want to know the input current of 5V power supply.
Transmitter side and receiver side termination resistance is 120Ω.

If the input current depends on the communication speed,
Please tell me the characteristic graph data.

Regards,
Yusuke

  • 0
    TI__Guru 53535 points

    Hi Yusuke,

    Yes, the input current for RS-485 drivers will vary based on resistive load as well as signaling speed because they are driving a the capacitive load created by parasitics. Because different cable networks can introduce varying amounts of bus capacitance, the actual current drawn will depend on your specific application. SN65HVD3086E does provide a Typical Characteristics graph (Figure 15) showing the trend for needed supply current vs data-rate under no-load conditions. 

    Note that the supply current will increase when connecting the node to a bus as well as when a resistive load for termination is introduced. Assuming typical behavior - the DC supply current needed to maintain a typical Vod of 2.3 over two 120-ohm termination would be 38mA. This value will need to be added to the need supply current to drive the AC load. 

    Let me know if this makes sense or if you have any more questions.

    Regards,
    Eric