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TMDX654GPEVM: TMDX654GPEVM Schematics – SPRR361: Current Consumption DP83867

Genius 12635 points

Part Number: TMDX654GPEVM

Hi Team,

are you sure that your block diagram on page 5 is correct? According the DP83867 data sheet the current consumption for the 1.0V supply is typ. 108mA. 

I can't believe that the 3 PHYs on this EVM draw 1.5A.

Please advise! 

Thanks and Best Regards,

Hans

  • I do not have the original power analysis for the AM65x EVM, so I cannot confirm where the 1.49A originated.  Its possible the DP83867 power estimates changed over time.  Note the power estimate I find for DP83867 are only at 25C.  Temperature will have significant impact on current draw, so possibly that is why additional power was reserved for that device.

    I recommended using the latest power estimates from the DP83867 data sheet in your power estimate, again as they may have changed since AM65x EVM was designed.

  • Well, according to SNLA241 the max current at 105°C for the 1.0V supply has been measured across several parts with 123.78mA. 

    This 1.5A for 3 PHYs is confusing customers who want to power 3 PHYs with 1V @ 1A. Please confirm that ghis also works.

    Thanks and Best Regards, Hans

  • Looking through SNLA241, I see current higher than 123.78mA  (140+mA).  The EVM also connects this power to several expansion interfaces, which might be the reason it has additional capacity. 

  • The additional capacity for several expansion interfaces is included within the 3.7 A  that comes out of the TPS62095 which is a 4 A regulator. (see image in post no.1)

    The 140+ mA in SNLA241 (Oct. 2015) refers to 1.1 V on the VDDA1P0 rail. For 1V at this rail the max. is 124.66 mA @105°C.

    But any ways, even if I use 140+ mA times 3 (or 4 in my case) a 1A regulator should be more than enough when just powering the DP83867 like in my application??? If I use a 2 or more Amps regulator it will get bored pretty soon :-)

    Regards

  • Understood.  Any additional questions on this topic, or can it be closed?

  • Hello, if this is a confirmation, that a 1 Amps regulator is enough for powering 4 PHYs on their 1V rails, then it can be closed. Thanks a lot!

  • This is the processors forum, the PHY device is not supported by our team.  You can open a E2E in the forum supporting the PHY.  Certainly the numbers shown in the datasheet indicate 4 PHYs can be supported with single 1A regulator (with same assumptions as datasheet - like 50% utilization.)  Not indicated in the data manual is if the power measurements are average or peak.  Your design should handle peak currents.