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TPS2378EVM-105: Power-over-Ethernet Powered Device + Ethernet data transfer

Tim Cruise
Intellectual 841 points
Part Number: TPS2378EVM-105
Other Parts Discussed in Thread: TPS23758, TPS23758EVM-080, TPS23755

Dear TI Engineers,

I am looking for a minimal Power-over-Ethernet solution to power a sensor node through an ordinary LAN cable.

The LAN cable must also power the whole sensor node circuit + MCU.  In addition, sensor data must also be transferred through TCP/IP.

Please advice and introduce some nice choices to me.Relaxed

Yours faithfully,

Timmy

  • 0
    TI__Genius 14555 points

    Hi Timmy,

    How much power is needed for this sensor node? How much power will the system require? I would assume isolation is needed in this system, can you confirm?

    Regards,

    Brandon

  • 0 in reply to Brandon Beader
    Intellectual 841 points

    Hello Brandon,

    I anticipate it to be 5V DC, 1A, driving an 8-bit or 16-bit MCU plus several IoT light weight sensors.

    Isolation is a good alternative for customers who want premium upgrade.

    Thanks for your attention.

  • 0 in reply to Tim Cruise
    TI__Genius 14555 points

    Hi Tim,

    Since the local load is not super heavy, you can go with a Class 3 PD (13W) such as the TPS23758 which is optimized for isolated flyback DCDC converter but also have applications with buck converter. 

    TPS23758EVM-080 is flyback with a 5V output, primary side regulated.

    We also have a reference design with a low-side switching buck converter using TPS23755, but TPS23758 can also be used with this design!

    Therefore, one device for both isolated and non isolated designs.

    Regards,

    Brandon

  • 0 in reply to Brandon Beader
    Intellectual 841 points

    Very nice, thank you Brandon.

    As to a 5V DC Ethernet power + data LAN cable, what is the suggested maximum length of such a cable for it to work?

  • 0 in reply to Tim Cruise
    TI__Genius 14555 points

    Hi Tim,

    Are you referring to 5V on the ethernet cable or the 5V output from the converter? For PoE at 44-57V the max cable length is 100m but for a 5V it would depend on the far end what minimum voltage is needed will determine max cable length since you will assume voltage drop over the cable.

    5V over Ethernet is not standard so I can not recommend a max cable length for this case.

    Regards,

    Brandon