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TMUX4051: Need design support

Showrya Mohan Avrekad Chandregowda
Prodigy 50 points
Part Number: TMUX4051

Tool/software:

Hello,

I have a few questions regarding the use of the TMUX in my application:

  1. The datasheet mentions 1.8V logic compatibility. Will it also support 5V logic levels without issues?

  2. For unused input channels and the VSS pin, is it advisable to tie them to GND?

  3. When the power supply is not connected, I notice the output pin shows some floating/garbage voltage (around 0.1–0.3V). What could be causing this, and would using a pull-down resistor help? Do you have any suggestions to resolve this behavior?

  4. My setup involves three types of command inputs: 0–5V, 0–10V, and 0–20mA. I convert the 0–20 mA signal to voltage and feed all three signals to the MUX inputs. However, when I try to replicate the setup, I observe voltage drops across the other inputs (0-5 and 0-10 V). What could be causing this interference or drop, and how can it be resolved?

  5. Since I only have three input channels to choose from, I don't require all three select lines. Can I safely tie the A2 (select input) to GND and use only A0 and A1?

Thank you, 

Showrya 

  • 0
    TI__Genius 17595 points

    Hello Showrya,

    Please see answers below:

    1. Yes, the logic high can be up to VDD

    2. Yes, that is correct especially VSS. If you are using the TMUX4051 as a single positive supply, VSS has to be grounded. 

    3. Are you operating the device while it is off? Meaning do you still have a voltage input on the pins when VDD = 0V?

    4. Are you inputting 20mA into the mux? If so you are exceeding the max limitation of the mux and might be damaging it.

    5. Yes, you can tie any unused pins to ground.

    Thanks,

    Nir 

  • 0 in reply to Nir Gilgur
    Prodigy 50 points

    Hello 

     "Are you operating the device while it is off? Meaning, do you still have a voltage input on the pins when VDD = 0V?"

    I tried both approaches—setting all inputs to 0 and also applying voltage to the input pins—but I still observed voltage appearing at the output pin.

  • 0 in reply to Showrya Mohan Avrekad Chandregowda
    TI__Genius 17595 points

    Hello Showrya,

    I do recommend having a termination resistor to ground to provide a path for the stored charge to go. This should clean the floating voltage. 

    Thanks,

    Nir