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DP83620

Ignacio Linares
Expert 1655 points

The power dissipation of 290mW (for Vio=3.3V) or 260mW (for Vio=2.5V) respectively are listed in the datasheet.  I assume those are worst case figures, however it does not specify whether this power  dissipation is for 100Base-T vs. 100Base-FX mode.  My customer wants to know if the power dissipation figures are lower for the 100Base-FX mode?

  • 0
    TI__Mastermind 31600 points

    We have an application note that provides the power consumption in great detail for various operational modes.  The document is AN-1540 (Literature Number:  SNLA089B).  It is available on-line at:
    http://www.ti.com/litv/pdf/snla089b

    The application note was generated for the DP83848 family so the numbers are not exact, but are comparable.

    Regarding your specific questions, the reported power in the datasheet reflects the power dissipation for 100Base-TX.  It includes the power drawn through the transformer center tap due to the transmit and receive signaling.  For worst case power, please refer to the application note.  This will give an indication of the factors that affect power consumption and the impact of those factors. 

    Power consumption for the device is comparable for 100Base-TX and 100Base-FX.  However, the overall 100Base-FX solution will consume considerably more power.  The key is that the fiber optic transceiver and the biasing components for the transceiver will draw more power than the transformer.