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TS3L501E: TS3L501ERUAR design issue

Herbert Wang
Intellectual 675 points
Part Number: TS3L501E


Tool/software:

Dear Expert:

The following are our drawings. We connected the RJ45A and RJ45B to the PC and the router respectively. Theoretically, they should be connected, but in reality, they are not. Could you please check if there is any problem in this application? Thank you

  • 0
    TI__Expert 4675 points

    Hi Herbert,

    The schematic you shared it a little blurry to me, but it appears that both PD & SEL are pulled up to 3.6V through 10k resistors. As you can see from the function table below, if PD is pulled high, the switch will be in a Hi-Z state and no signals will be able to be passed through the switch. I would suggest pulling PD low and then seeing if your signals go through.

    Best,
    Katy

  • 0
    Prodigy 30 points

    Dear

    We have already verified by changing PD to pull-down, but the signal still cannot through it

  • 0 in reply to huang zhi
    TI__Expert 4675 points

    Hi Huang,

    Have you been able to probe the pins themselves to see if the voltage on VCC/ the input pins are as expected? Have you tried soldering new chips onto the board to see if the issue remains?

    Additionally, this shouldn't affect performance of the device, but is there a reason your LED_B and LED_C pins are floating? In high speed applications, we recommend pulling any unused pins to ground through a 50-ohm termination resistor to reduce any noise.

    Lastly, would you be able to post a clearer photo of your schematic?

    Thanks so much!
    Katy

  • 0 in reply to Katy West
    Prodigy 30 points

    Dear Katy：

             The VCC is 3.34V，and this IC welded onto the board，PD pull to GND and SEL is 3.29V，test is faild

    the picture is our design drawings：

  • 0 in reply to huang zhi
    TI__Expert 4675 points

    Hi Huang,

    Thanks so much for the clearer photos! Could you please probe the chip on the PD, SEL, an A pin, and a B pin with an oscilloscope or a multimeter and then send over the scope shots (or multimeter data)? At a high level, I don't see any red flags with the schematic, so I will need more data/information to help you debug this issue.

    Thanks!
    Katy

  • 0 in reply to Katy West
    Prodigy 30 points

    Dear Katy：

          Please review the following image，tks

  • 0 in reply to huang zhi
    TI__Expert 4675 points

    Hi Huang,

    Based on the setting of 2V/ division, it looks like SEL is around 1.8V higher than PD. If PD is at 0V, that means SEL is at 1.8V, which is not high enough to register as a "High," meaning A0 would not be connected to C0. Could you verify what the voltage of SEL is? 

    If SEL is only getting up to1.8V, you may need a smaller pull up to 3.3V.

    Best,
    Katy