offset voltage of ADG5412

sir:

   I use four ADG5412 in my design, but two of them do not work correctly. When the channel is on, the ADG5412 work OK, but when the channel is in off state, the output of the channel has a offset voltage. One of the breaken ADG5412 has a offset voltage of 1.62V, and the other has a offset voltage of -0.117V.  What is the possible reason for these unwanted voltages?

Besides, I provide the ADG5412 with a supply of +/-12V.

Thank you!

best wishes

  • 0
    •  Analog Employees 
    on Sep 5, 2012 3:18 PM

    Hello Jacky,

    What voltages are you applying to the pins when the channel is on and when the channel is off? What is driving the signal and what is the load?

    Can you show me a schematic of your circuit?

    Regards,

    Sean

  • Sean:

           I produce the Digital control signal of ADG5412 from FPGA, and I use the LVCMOS3V3 level. The driving signal is a 1MHz sinewave with amplitude of 1 Vpp.  The load is Resisitor of 50ohm, 800ohm, and 13k ohm individually.  A schematic is shown below.

    Thank you!

    regards.

    Jacky

  • 0
    •  Analog Employees 
    on Sep 5, 2012 8:38 PM

    Hello Jacky,

    Can you confirm that that it is two separate ADG5412 that are displaying the issue you describe, or is it two of the switches on one ADG5412?

    If it is on separate parts, does the voltage show up on all switches or just one?

    Regards,

    Sean

  • Sean:

           Thank you for your attention.

           I am very sure that it is two separate ADG5412 that are displaying the issue. For one ADG5412, all the four switches have a offset voltage of 1.62V when in off state;for the other ADG5412, all four switches have a offset voltage of -0.117 when in off state.

    Thank you!

    Regards

    Jacky

  • 0
    •  Analog Employees 
    on Sep 6, 2012 1:06 PM

    Hello Jacky,

    Does the voltage persist even when the external circuitry is disconnected from the part?

    Have you tried replacing the two problem parts with new ones?

    Regards,

    Sean