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TS5A9411: What is the minimum power on

Lauren Mayfield
Expert 7985 points
Part Number: TS5A9411


 If the IN Drops below the min. Vcc level while the switch is active (com. connected to “Normally open"), will the switch disengage? (com. connected to "normally closed")

  • 0
    TI__Genius 9132 points

    Hi Lauren,

    How are you driving the "IN" pin and what is your supply voltage?

    If IN is high, COM is connected to NO.

    With a 5 V on the supply pin the minimum voltage on the digital input IN pin that the device will recognize as a logic "high" is 2.4 V.  

    With supplies 4.5 V or below on the supply pin the minimum voltage on the digital input IN pin that the device will recognize as a logic "high" is 2 V. 

    Regards

    Saminah

  • 0 in reply to Saminah C
    TI__Expert 7985 points

    Hi Saminah,

    OK, so say the voltage dropped below the minimum level required to be considered a logic high (which you said is 2V). So say it drops to 1.5V or so. Will the switch disengage and connect to normally closed?

  • 0 in reply to Lauren Mayfield
    TI__Genius 9132 points

    Hi Lauren,,

    CMOS logic devices depend on their inputs being at either a logic HIGH or a logic LOW.

    For 4.5V supply or below, To guarantee a logic low (VIL) the max voltage is 0.8V to connect NC to COM, and to connect NO to COM , the MIN voltage for logic High is 2V. 

     When the input is 'somewhere in the middle,' then both MOSFETs on the input can be turned on, which can cause a significant amount of shoot-through current. It is best to transition through this voltage region as quickly as possible to prevent shoot-through current. See FAQ here.

    Check out the link to the TI Precision lab video that explains the logic levels in more details and details in this application report for  Preventing Excess Current Consumption on Analog Switches.

    Thanks

    Saminah

  • 0 in reply to Saminah C
    TI__Expert 7985 points

    Hi Saminah,

    So it *won't* disengage, but it'll cause shoot-through. Got it.

    Thank you!

    Lauren

  • 0 in reply to Lauren Mayfield
    TI__Genius 9132 points

    Hi Lauren,

    Yes, to simplify it, the switch will be in "unknown" state when the Control signal is operating in the undefined region between VIL and VIH that can result in issues  (like shoot-through current) related to slow changing across the threshold voltage.

    TI application report on “Slow or floating CMOS Inputs”  has detail explanation of the impact this can have on device performance.

    Regards

    Saminah