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TMUX1109: Timing information

Dennis McGlumphy
Expert 1390 points
Part Number: TMUX1109

Dear Sirs

I'm going to use the TMUX1109 analog multiplexer but find the timing in the data sheet to be unclear.  For example, what is the address stable time before applying the enable?  What is the settling time of the switch before the signal is stable?

  • 0
    TI__Expert 3900 points

    Hi Dennis,

    Glad to hear you are planning to use the TMUX1109 in your system! 

    The main timing parameters or the Transition time, and ON/OFF enable times. These are shown in section 7.1.x in the datasheet

    For example, the transition time of the switch is shown below. The timing information specifies the time for the signal to reach 10% of the output value. This is specifying how long the switch takes to toggle between inputs. The amount of time for the signal to be stable depends on how much load you have on output and if signal has any overshoot. The stable time can be calculated as RC time constant with the switch Ron and load capacitance. 

    Regarding the address stable time before applying the enable. The enable pin does not need to be toggled every time while switching the address pins. You can keep the device enabled and toggle the address pins to change the input signal path.

    Here is a link to another E2E post regarding switch timing and the impact of the load on the output timing:

  • 0
    TI__Expert 3900 points

    Hi Dennis,

    Glad to hear you are planning to use the TMUX1109 in your system! 

    The main timing parameters or the Transition time, and ON/OFF enable times. These are shown in section 7.1.x in the datasheet

    For example, the transition time of the switch is shown below. The timing information specifies the time for the signal to reach 10% of the output value. This is specifying how long the switch takes to toggle between inputs. The amount of time for the signal to be stable depends on how much load you have on output and if signal has any overshoot. The stable time can be calculated as RC time constant with the switch Ron and load capacitance. 

    Regarding the address stable time before applying the enable. The enable pin does not need to be toggled every time while switching the address pins. You can keep the device enabled and toggle the address pins to change the input signal path.

    Here is a link to another E2E post regarding switch timing and the impact of the load on the output timing:

  • 0 in reply to Dakotah
    Expert 1390 points

    If I understand correctly, there are not timing requirements for the address lines and the enable.  Would you recommend that the TMUX1109's enable be active all the time?

  • 0 in reply to Dennis McGlumphy
    TI__Expert 3900 points

    Hi Dennis,

    Yes, the timing specifications specify how the time is from a change in the control input pins to the changed state on the output.

    If you do not need to utilize the enable of the TMUX1109 then the enable can be active all the time.

    The enable function is used to disconnect the output from all of the inputs. If there is not need to do this in your circuit then I would recommend to leave the enable active all of the time.