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ISOUSB211: USB Memory Recognition Problem Inquiry

MJ Jeon
Genius 5240 points
Part Number: ISOUSB211


Hi, TI support team

The ISOUSB211 product is applied to the project developed by the customer and is being reviewed.

Regarding the problems that occurred during the review, we would like to inquire as follows.

[Symptom]

- If you turn on the power of the set with a USB2.0 memory inserted into the set, the USB is recognized normally, and it is recognized normally even if you remove and insert it.

- However, if you turn on the power without USB 2.0 plugged into the set and plug in the USB after Android booting, it will not be recognized.

[Review]

If you remove the ISOUSB211 chipset and directly connect the USB D+, D- lines, it works normally. (Symptoms of the problem do not occur.)

Please advise which part might be the problem.

Below is a link that reviewed the circuit diagram previously.

link : https://e2e.ti.com/support/isolation-group/isolation/f/isolation-forum/1182816/isousb211-citech-schematic-review-request

I will share the current circuit diagram.

Please also review the parts that may be problematic in the circuit diagram.

Thanks.

Regards,

MJ

  • 0
    TI__Guru 55825 points

    Hi MJ,

    Thank you for reaching out and sorry to hear about the issue. To understand the issue better and debug, please help me with the information requested below. Thanks.

    1. Could you please explain what is being referred as "set" here?
      1. From what you have stated, it looks to be an Android based product. Please confirm what product it is.
      2. Please also confirm that ISOUSB211 is used in this customer product where Side1 is connected to the processor while Side2 is connected to the USB connector of the product.
    2. When you mentioned USB 2.0 Memory, I am assuming you are referring to a USB Memory Stick / Flash Drive. Please confirm.
    3. Do you know if the issue is occurring with only this USB Memory device or does it happen with other Memory devices as well?
    4. Do you know if the issue is occurring with only one customer product or does it happen with multiple customer products?
    5. Thanks for sharing the updated schematic.
      1. I see that the schematic has many provisions allow it to be configured in multiple ways. Like the option of 5V or 1.8V to VCC1 and VCC2, pull-up / pull-downs for CDPENZx pins, provision for CMC and others.
      2. Could you please confirm which configuration is being used currently for testing?
    6. It is also important that customer PCB layout follows our guidelines / recommendations from ISOUSB211 datasheet, especially the decoupling capacitors to enable reliable operation of device.
      1. Could you please share customer PCB layout for review?


    Regards,
    Koteshwar Rao

  • 0 in reply to Koteshwar Rao
    TI__Guru 55825 points

    Hi MJ,

    I wanted to check if you are still facing issues. If you do, could you please help me with the information requested which will help me understand and debug the issue better. Thanks.


    Regards,
    Koteshwar Rao