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SN74LV4051A-Q1: I/O Pin Capacitances (for pins Y1:Y7)

Part Number: SN74LV4051A-Q1

My customer is trying to understand input pin capacitance of this device (specifically for pins Y1, Y2, Y4, Y5, Y6 and Y7) assuming the switch is not closed to the COM port. I don’t see a good drawing for the defined capacitance. For instance if the multiplexer is routing Y1 to the COM pin, would the total capacitance seen by the driving element of Y1 be Cis+Cos? Can you supply the ratings over temperature?

Also, what is the capacitance of the Y1,Y2,Y4,Y5,Y6 and Y7 pins if the switch is not closed to the COM pin?

  • Hi Whitney:

    Definition as below with graph:  

    Cic: Control ( enable)  pin input capacitance

    Cf:  feedthrough capacitance

    Cis: Com pin capacitance

    Cos: Yx pin capacitance

    The COM pin capacitance is higher than the Yx capacitance because the COMMON pin has the several FETs drains tied together to the one pin to create the 8:1 configuration. 

    The capacitances (except feedthrough capacitance) are with respect to ground and are in parallel so you may add them together to get the total capacitance. The capacitances are normally measured while the switches are open.

    Thank you,