Because of the holidays, TI E2E™ design support forum responses will be delayed from Dec. 25 through Jan. 2. Thank you for your patience.

  • State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 2 answers
  • Subscribers 16 subscribers
  • Views 318 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Original question:

TMUX1219: Leaving S2 pin floating

TMUX1219: internal switch on/off status when no VDD input supply

Ben Kuo
Expert 7485 points
Part Number: TMUX1219

Dear team,

What are internal switch status of TMUX1219 if there are no VDD input supply?

In our design, D1/S1/S2 may have signal even when no VDD input. And we want to keep D1/S1/S2 isolated in this design condition.

Is there any risk for this design?

Regards,

Ben

  • 0
    TI__Mastermind 46857 points

    Hi Ben,

    Yes there is risk when using the TMUX1219 in this way.

    When VDD is under operational voltage the switch states are undefined - so there is no isolation guaranteed when operating the IC in this way.

    The other issue is that this device is only rated to have an input voltage in the range of -0.5 < Vin < VDD + 0.5 - beyond these voltages the device can be damaged. 

    With all of that being said - what it sounds like your application needs is a multiplexer with powered off protection as this keeps input pins high impedance while VDD = 0V. 

    We do have an option that is similar to the TMUX1219 that has powered off protection it is the TS5A63157. It has similar through channel characteristics as well as adding the powered off protection feature. I'd use a part like this for your application to avoid damage while still meeting the original goal.

    If you have any other questions please let me know!


    Best,

    Parker Dodson

  • 0 in reply to Parker Dodson
    TI__Expert 7485 points

    Hi Parker,

    Did we have P2P compatible solution with TMUX1219 but have power off protection feature?

    Thanks.

    Regards,

    Ben

  • 0 in reply to Ben Kuo
    TI__Mastermind 46857 points

    Hi Ben,

    We don't have a pin to pin part in terms of parametric - but there are a few parts that are the same pinout with similar characteristics.  

    for the DCK package we have the TS4A4624 - one note though is that this device has a lower bandwidth of 90MHz. 

    That is the only part that we have the same pinout and package with powered off protection. If p2p is necessary this is best option but it is only p2p with the DCK package.

    Please let me know if you have any other questions!

    Best,

    Parker Dodson