Parameters I can change Spice models - ADG408/ADG409 to match behavior - ADG1408/ADG1409?

Are there some parameters I can change in the models for the ADG408/ADG409 parts to match how an ADG1408/ADG1409 would operate?

I have both spice models downloaded: AGD408/ADG409

I would like to simulate ADG1408/ADG1409

Thanks.

  • 0
    •  Analog Employees 
    on Apr 26, 2016 5:56 PM

    Hi Matthew,

    I'll look into this. I'll get back to you soon.

    Best Regards,

    May

  • 0
    •  Analog Employees 
    on Apr 28, 2016 12:39 AM

    Hi Matthew,

    I've had a look at the difference between the ADG1408 and ADG408, these two devices does not have similar parametric values. On resistance for instance is from 4.7 ohms to 40 ohms respectively. Now, if you plan to change the ADG408 spice model to match the ADG1408 behavior I'm afraid you have to change the values of the component used in each parameter. Please be reminded that changing the component values inside the model would not necessarily mean a proportional outcome.

    Best Regards,

    May

  • 0
    •  Analog Employees 
    on Apr 28, 2016 9:56 PM

    Hi Matthew,

    Here are some points you might want to consider in editing the ADG408 spice model to make it close to the ADG1408 behavior.

    • On Resistance:
      • The Lines below is a voltage controlled voltage source used to manipulate the on resistance parameter by computing for the particular nodes (73,500) and (421,500). This replicates the NMOS and PMOS region of the part.

                   *     Main Series Switch combination

                   E_1_E     611  14         VALUE = {(10*V(73,500))/(V(421,500)+0.005)}

                   E_1_F     612  14         VALUE = {(10*V(73,500))/(V(500,422)+0.005)}

    • Cin, Digital Input Capacitance:

                   *          Input capacitances

                   *

                   C_A0_1      4  14         8E-12

                   *...

    • Off Isolation:
      • There is no concrete formula for the values of the capacitors and resistors used for this parameter.
      • Please be reminded that this parameter is caused by parasitic capacitance and resistance formed in the die. Having this kind of configuration in the spice model replicates close behavior of the off isolation parameter.
      • COI - capacitor
      • ROI - resistor

                   *   OFF Isolation

                   *

                   COI_1      4  8           1E-13

                   *...

                   ROI_1        4 1901         1.6E9

                   COI_1A    1901    8         10E-12

    If you want to push through in editing the ADG408 spice file to make it close to the behavior of the ADG1408, I'm afraid you'd have to change every component values of the model. Also as mentioned from the previous reply, changing the values in the spice file does not mean proportional parameter outcome.

    Best Regards,

    May

  • I see that the parametric values are indeed different. I would like to edit the ADG408 spice model in order to achieve something that is closer to what I would see with an ADG1408.  I am having a hard time interpreting the spice file to know what to change to achieve my goal. There are headers for sections but - line by line are unknown characteristics. Can you help me with that part? I am having a hard time correlating from SPEC sheet to SPICE MODEL If what I am looking for is unfeasible then I will move on.  Thank you for your help!

    Example: (A few lines from the Spice file)

    *          Input capacitances

    *

    C_A0_1      4  14         8E-12

    *...

    *   OFF Isolation

    *

    COI_1      4  8           1E-13

    *...

    ROI_1        4 1901         1.6E9

    COI_1A    1901    8         10E-12

              

    PART Data Width Voltage Typ On ohms ohms Typ On Flatness Cs OFF pF Cs OFF pF Cs ON pF
    ADG1408 8ch MUX +/-5V TYP 4 0.5 14 80 135
    MAX 4.7 0.72 14 80 135
    ADG408 8ch MUX +/-5V TYP 40 60 11 40 54
    MAX 100 85 ~11 ~40 ~54