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TL431: IEEE 802.3cg 10BASE-T1L Power over Data Lines Powered Device Design

Marvin Cantos
Expert 6865 points
Part Number: TL431


Hi Experts, 

Good day. I am posting on behalf of the customer.

Below is the customer's full transcript of the inquiry.

"I found an Application notes from TI to implement an IEEE 802.3cg 0r 802.3bu Compliant PoDL PSE and PD. The link is attached below for reference.

How to Implement an IEEE 802.3cg or 802.3bu-Compliant PoDL PSE

IEEE 802.3cg 10BASE-T1L Power over Data Lines Powered Device Design

 

In the application note "IEEE 802.3cg 10BASE-T1L Power over Data Lines Powered Device Design", Figure 3-3, page 6, Shunt is configured to approx. 3.6V. You have mentioned that the total voltage drop will be in the range of 4.05-4.55V including voltage drop at rectifier diodes. Does it also include the voltage drop across the wire due to the resistance of the cable?  IF so which cable (cable diameter) is used for this test? I am referencing the cable diameter given in Table 146B-1 of spec IEEE 802.3cg.

Furthermore, this document was helpful to me in understanding detection and classification circuits. I am trying to simulate the design in PSpice and design a PCB for proof of concept. However, all the components are not given in the application note. Is it possible for TI to provide some documents or the complete circuit design for learning purposes?"

Thank you.

Kind regards, 

Marvin

  • 0
    TI__Mastermind 30440 points

    Hi Marvin,

    I believe that the 4.05-4.55V drop includes the voltage drop over the cables, as the "PD voltage" is measured by the PSE. According to this presentation on IEEE 802.3cg website, 10BASE-T1L uses 18AWG twisted wires; it is safe to assume that that is standard.

    There aren't any designs for PoDL or IEEE 802.3cg, but you may be able to draw inspiration on useful devices from one of these guides or any PoE reference design on ti.com.

    Please let me know if the costumer still does not find what they are looking for.

    Thank you,

    Patrick