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TPS23880: Schematic Review

chentsu chung
Mastermind 6180 points
Part Number: TPS23880
Other Parts Discussed in Thread: BOOST-PSEMTHR-007

Hi,

Could you please help to check the schematic, thank you.

PS-201G-BT_V1_20181206.pdf

Best Regards,

C.T.

  • 0
    TI__Genius 15655 points

    Hi C.T,

    Please see my comments below:

    1. TPS23880 needs host to load sram code and do basic configuration though I2C even using auto mode. So SCL, SDAO and SDAI can't be left open and they have to be connected to a host.
    2. You probably can get rid of Q1 and Q4 by connecting the LED directly across the port. Please refer to BOOST-PSEMTHR-007 board. 
    3. I can't find T1's datasheet, but I want to make sure you understand that there's a certain polarity Type 3 and Type 4 PSE port needs to follow. See below. If wanting to understand more about BT standard, please check the white paper here:ethernetalliance.org/.../WP_EA_Overview8023bt_FINAL.pdf.

    Best regards,

    Penny

  • 0 in reply to Penny Xu
    Mastermind 6180 points
    Hi Penny,

    Thanks for your notice. May I ask more about the RJ45 pin config?
    1. If didn't follow the type4 pin config of RJ45, how PSE knows about this?
    2. If didn't follow the type4 pin config of RJ45, PD can still work and receive power well, what is the effect?

    Thank you.
    C.T.
  • 0 in reply to chentsu chung
    TI__Genius 15655 points
    Hi C.T,

    The PSE doesn't know about the polarity and PD doesn't care as it usually has rectifier in front. So it should be still functional like Type 3 but it will not pass Type 4 compliance test. Thanks.

    Best regards,
    Penny