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USB 2.0 - 8 way - Multiplexer/Demultiplexer

Giulio Fiscella
Prodigy 20 points
Other Parts Discussed in Thread: TS3USB30, CD74HC4067, TS3DS10224, TS3USB30E

Hi,

I am trying to connect a USB flash drive to more than one USB host.
I have seen from other questions that the TS3USB30 would be one of my best bets.
However, ideally, I would like to be able to connect to around 8 hosts, not just 2.

I have tried using some analogue multiplexers (cd74hc4067) on a prototyping matrix board.
I can make everything work at USB 1.1 speed but the host is only able to identify high speed devices once every twenty tries.

So here are my, probably naive, questions:
1) Are analogue multiplexer a possible solution or can they never work reliably with USB 2.0 requirements?
2) Would building a proper PCB with high speed compliant tracing help/solve the high speed issues?
3) Would using a differential analogue multiplexer improve the situation?

If going with a dedicated USB solution like TS3USB30 is the only option:
4) is it possible to cascade multiple chips?
5) is there any chip in this family that comes in a easy to solder package?

Thanks,

Giulio

  • 0
    TI__Mastermind 45485 points

    Giulio,

    Based on your requirement of switching USB 2.0 one to many,  I suggest looking at the TS3DS10224.  This is a high speed switch with some flexibility in configuration that you can cascade to get you to your 8 port requirment.  

    Are analogue multiplexer a possible solution or can they never work reliably with USB 2.0 requirements?

    There are several analog USB switches/multiplexers that will work reliably with USB 2.0 requirements  

    Would building a proper PCB with high speed compliant tracing help/solve the high speed issues?

    Yes, in higher speed applications such as USB 2.0 the PCB and layout become important for signal integrity.  You can reference this USB 2.0 PCB design guidelines. 

    Is it possible to cascade multiple chips?

    Yes, you may cascade a reasonable amount chips together but there will eventually be a limit since there are slight loss each time a signal passes through the IC

    Is there any chip in this family that comes in a easy to solder package?

    Our package options can very from device to device.  Do you have a specific package in mind?

    Thank you,

    Adam

  • 0 in reply to Adam Torma
    Prodigy 20 points
    Hello,

    As Giulio, I'm searching an 1:8 USB switch, but can't find out any package which can be solder (ex: VSSOP)
  • 0 in reply to etienne soupaseum
    TI__Genius 11665 points

    Hello Etienne,

    The  TS3DS10224 does come in a package that can be soldered. To solder this IC effectively, you would need solder paste and a heat gun since the leads are underneath the IC.  Using the TS3DS10224 would deliever the most straight-forward approach as this would requre the least number of ICs to create 8 ports.

    You can also try cascading the TS3USB30E to meet your 8 port requirement and this IC comes in a VSSOP package. As Adam stated earlier though, you may experience more signal loss as it will require more ICs.

    Please let me know if you have more questions.

    Jared

  • 0 in reply to Jared Becker
    Prodigy 20 points
    Hello Jared,

    Thank you for the answer.
    Unfortunately I am well not equipped.

    In my case I have to switch a USB flash drive in order to write/read in a Flash memory up to 5 USB ports.
    I will try to cascade 3 TS3USB30E.

    Can you advise me an IC that can switch USB signals up to 8 positions ?

    I'm just wondering if it is needed to put the Pull-up and Pull-down resistor on D+ for detection and full speed configuration on every outputs ?

    Etienne.
  • 0 in reply to etienne soupaseum
    TI__Genius 11665 points

    Hello Etienne,

    For advice regarding an IC that can switch USB signals up to 8 positions, please see both Adam's previous post and my previous post.

    As far as pull-up or pull-down resistors go, please see this link. This page will give you some high-level insight to speed identification and how D+ is tied to achieve that.

    Thank you,

    Jared