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DP83TD510E-EVM: DP83TD510E - Power supply operations

Rutvik Naik
Prodigy 130 points

Part Number: DP83TD510E-EVM
Other Parts Discussed in Thread: DP83TD510E

Hello team,

We are planning to use the ETH PHY IC DP83TD510E in our new design and have come across a potential misunderstanding related to the Power supply operation.

 

Our use case is to support both 1V p2p and 2.4V p2p operations and thus we would be using 3.3V to supply AVDD. However, we are not clear what this statement mean from datahsheet for DVDD:

----

Digital supply 1.0 V 

• For single-supply operation: Short this pin with CEXT (Pin 2)

 • Optional (dual-supply operation): Connect external 1.0 V to achieve lowest power.

----

 

Does this mean that we would lose the 1V p2p and 2.4V p2p operations if we decide to not provide external 1V and Short DVDD pin with CEXT (Pin 2)? Or is it solely to save power consumption and avoid using internal LDOs to generate the required votlage from single supply of 3.3V? 

  • 0
    TI__Expert 7895 points

    Hi Rutvik, 

    The Digital Supply does not control the MDI output voltage level. As long as you are using 3.3V AVDD, the device can support both 1Vpp and 2.4Vpp modes. The digital core supply can also be generated inside the PHY using an internal LDO, in which case you can short the DVDD pin to CEXT, however, the drawback here is that the internal LDO does not have perfect efficiency, so there will be some slight power losses. If you wish to achieve a more efficient system, and have a 1.0V power supply in your system, this pin can be used to connect a 1V supply to mitigate any LDO power losses. Regardless of your decision to include a 1V power supply, or to use an internal LDO, the device should support both 1Vpp and 2.4Vpp options. 

    Best,

    Vivaan