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Hot!Usb2517

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ClemAVT
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2019/04/03 22:54:58 (permalink)
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Usb2517

Hello,
I am using a usb hub : usb2517. The problem is I can't get it works properly :
- when I use it with a 3.3v power supply the hub is not even recognize by the IMX6 (processor).
-when I boost the voltage regulator up to 3.5V, the hub works perfectly (recognized by IMX6 and I can communicate with the usb ports etc...)
Even when no equipement is plugged (so no external load for the Hub and not too much current needed) the 3v3 does not make it works...
I have double and triple tchek the 3.3 (or 3.5V...) power supply, the VDD18, XTAL1 PIN (external oscillator 10ppm, no crystal here), XTAL2 not connected. The reset timing also seems good. The 3v3 is created from a +12V through a Dc/DC then a LDO and the ripple is under datasheet recommandation.
I respected all the implementation note etc...
If anyone knows something about that, please help!
Thank you in advance !
Clément
#1

7 Replies Related Threads

    roundrocktom
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    Re: Usb2517 2019/04/09 11:10:51 (permalink)
    +1 (1)
    Have you submitted the schematic to:
    https://www.microchip.com/design-check-services
    #2
    ClemAVT
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    Re: Usb2517 2019/04/09 23:39:32 (permalink)
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    Not the schematics, but I send a message to the support yes. Waiting for an answer :)
    I though someone here would have encountered the problem :'(
    #3
    qhb
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    Re: Usb2517 2019/04/09 23:59:52 (permalink)
    +1 (1)
    How are they going to check your schematic if you don't send it?
     

    Only 10 to go...
    #4
    ClemAVT
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    Re: Usb2517 2019/04/10 02:46:23 (permalink)
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    I am about to create a support ticket since I do not have any answer here.
    But as I told you, I posted here hoping someone has already encountered this issue before creating a support ticket.
    #5
    roundrocktom
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    Re: Usb2517 2019/04/15 07:57:30 (permalink)
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    when I boost the voltage regulator up to 3.5V, the hub works perfectly (recognized by IMX6 and I can communicate with the usb ports etc...)

     
    I've used that part a few hundred designs. This sound like a PCB issue with too small of a trace.
    Either VDD or VSS (ground slug) via's are undersized. 
     
    What do you measure at Pin25 and Pin62?  Host has to be up and running, and something downstream to see a voltage at the PLL Pin (it goes to sleep when the hub is not active. Not all host support Selective Suspend, but first time I saw that had me scratching my head for a while).
     
    I'd look at the Microchip Reference Design, take a look at the Gerbers.
    https://www.microchip.com...uctDetails/EVB-USB2517
     
    #6
    ClemAVT
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    Re: Usb2517 2019/04/18 03:40:03 (permalink)
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    Thank you for your answer,
    It seems I see 1.8V at those pins (25 and 62) even when nothing downstream

    for the VDD and GND path, i've just tried to reinforce the power by bringing three 220V power cable from GND and 3.3V as close as possible from the HUB. Still nothing.
     
    I have also interrogation about Vbus Detect PIN because the datasheet says that I can tie it to 3.3V but application notes show 5V through 100k divider by 2 so 2.5V. And yes, when 2.6V on this PIN the evalboard is working but when i try to tie this pin to 3.3V, it does not work anymore...
    Clément
    post edited by ClemAVT - 2019/04/18 05:32:09
    #7
    roundrocktom
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    Re: Usb2517 2019/04/22 16:18:35 (permalink)
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    From the Datsheet;
    VBUS_DET 44 I/O12 Detect Upstream VBUS Power
    For self-powered applications with a permanently attached host, this pin must be connected to 3.3V or 5.0V (typically VDD33).
     
    From 8.1 Maximum Guaranteed Ratings
    Voltage on any I/O pin  -0.5  5.5V
     
    I don't see any reason why that device would be shutting down.

    Microchip has that design check, I'd send in your schematic and ask one of the FAE's to take a look.
    https://www.microchip.com/design-check-services
     
    #8
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