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ISOUSB211: [USB isolator] ISOUSB211 schematic review & pinout design discuss

Neil Chen
Prodigy 30 points
Part Number: ISOUSB211

Tool/software:

Hi Sirs, 

Attached file is current usb2 isolator/ISOUSB211 design schematic, have a few question need to asking and need you internal team to clarify & explain more on here : 

whatever EQ10/EQ11/CDPENZ1 pins, are look like adjust eye diagram of usb2 signal interface to implement, but there is no writing about how to use these pins design setting & table description. 

Therfore, could you help to review current schematic is look good at default setting? Or, have any more modify suggestion on here? 

Best Regards 

By Neil Chen

CDU_FANCTRL_DB_USB2 Isolator.ISOUSB211_SCH_20250320.pdf

  • 0
    TI__Genius 13555 points

    Hi Neil,

    Thanks for reaching out. 

    Please give us an additional day to look into your questions.

    Regards,
    Aaditya V

  • 0 in reply to Aaditya V.
    TI__Intellectual 2055 points

    Hi Neil,

    Please find my inputs below:

    Neil Chen said:
    whatever EQ10/EQ11/CDPENZ1 pins, are look like adjust eye diagram of usb2 signal interface to implement, but there is no writing about how to use these pins design setting & table description. 

    Please Refer Section 6.9 for EQ Setting Numbers and section 8.3.9 for explanation of EQ pins: 

    For the Schematics, following are my comments:

    1. Pin6 and Pin23 are output pins and are indication on power up on the other side. I see it's connected to 3.3V LDO Supply, which should be removed.
    2. Pin5 and Pin24 - Caps are currently 0.1uF, they should be replaced with 1uF Vap.
    3. Also, I don't see a way to switch between different power options. Please read section 8.3.1 in datasheet for various options available to power up ISOUSB211.
      1. Each Supply pin has a separate external supply in the schematics currently
      2. Do provide configurability, please refer ISOUSB211 EVM schematics for adding 0ohm options.
    Regards
    Varun
  • 0 in reply to Varun Kumar
    Prodigy 30 points

    Hi Varun, 

    Thanks for your offer adjustment EQ1/EQ0 eye diagram setting table, it's helpful. 

    For review schematic part, please refer to my answer as lists, 

    1. Pin6 and Pin23 are output pins and are indication on power up on the other side. I see it's connected to 3.3V LDO Supply, which should be removed.

    [Neil]  whatever Pin6 & Pin23 pins, both are not have any external power solution to supply it, my original design purpose just need ISOUSB211 internal LDO to supply directly. 

    By the way, the Pin4/Pin11 & Pin25/Pin18 for V1P8 level, also need ISOUSB211 internal LDO to supply directly. 

    2. Pin5 and Pin24 - Caps are currently 0.1uF, they should be replaced with 1uF Vap.

    [Neil] replace to 1uF cap and refer to revision schematic as attached file_v20250326. 

    CDU_FANCTRL_DB_USB2 Isolator.ISOUSB211_SCH_20250326.pdf

    Therefore, please let me know if you have any comments on here, tks you! 

    For 3V3/1V8 internal LDO supply part, it's very confuse after review section 8.3.1, need you double confirm again! 

    Thanks 

    By Neil 

  • 0 in reply to Neil Chen
    TI__Intellectual 2055 points

    Hi Neil,

    Thanks for the updated Schematics. I see that you have updated the decaps to 1uF.

    Neil Chen said:
    my original design purpose just need ISOUSB211 internal LDO to supply directly. 

    V1OK and V2OK are digital output pin. This should not be connected any supply, either external or internally generated 3.3V.

    Also, V3P3 and V1P8 are input supply pins and are not meant to be used to supply power to external circuit. This can damage the device, hence please do not use internal LDO supply for external use.

    As of section 8.3.1, since the VBUSx and VCCx are connected to 5V, device will function properly,

    Regards
    Varun