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DP83TD510E: Clarification on DP83TD510E CEXT Pin and Power Sequencing

Jefin George
Prodigy 100 points
Part Number: DP83TD510E

Tool/software:

We are designing an Ethernet switch using 10BASE-T1L, where the DP83TD510E is implemented as the Ethernet PHY. During the circuit design, we have a couple of doubts that need clarification:

  1. Does the CEXT pin internally generate 1 V, or should we supply 1 V externally, considering that the datasheet mentions an integrated LDO?

  2. Please review the attached schematics. Should we strictly follow the power-up sequencing as specified in the datasheet?

Your guidance on the above points will help us proceed with the design confidently.

  • 0
    TI__Expert 6475 points

    Hi Jefin, 

    Jefin George said:
    Does the CEXT pin internally generate 1 V, or should we supply 1 V externally, considering that the datasheet mentions an integrated LDO?

    This depends on whether you want to use Single or Dual Supply Modes. For Single Supply Mode, the internal LDO will take care of the 1V supply, in which case all you would need to do is short CEXT to DVDD and add a decoupling cap. In Dual Supply mode, CEXT can be left unconnected while DVDD would need to be connected to an external 1V supply. Dual Supply Mode s usually used if the lowest power consumption is desired. 

    Jefin George said:

    1. Should we strictly follow the power-up sequencing as specified in the datasheet?

    Yes, it is recommended to follow the power-up sequencing listed in the timing section of the datasheet. 

    Best,

    Vivaan