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ADG612 Spice model error: Ron/Roff greater than 1/Gmin

Thread Summary

The user encountered an 'RON or ROFF greater than 1/GMIN' error in PSpice when simulating the ADG612 in a 4:1 mux configuration. The final answer suggests updating the spice model and reducing the Roff parameter from 1E20 to 1E11 for the vswitches. The user confirmed that tying all drain nodes together is necessary for the design, and the error persists even after disconnecting irrelevant drains and adding a 1k load to ground.
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I downloaded the spice model from the AD website for ADG612. I need to run an ac sweep with the part as part of a larger simulation. I am starting with just a basic simulation of the part to show that it works. When I run the simulation in PSpice, I get the following error: "ERROR(ORPSIM-15159): RON or ROFF greater than 1/GMIN for VSWITCH model X_U1.X1.x1.SMOD2."

The same error comes up several times in a row in the simulation window with different SMODs, for example: "ERROR(ORPSIM-15159): RON or ROFF greater than 1/GMIN for VSWITCH model X_U1.X2.X2.SMOD4."

I am new to PSpice, so my apologies if I am missing something basic. 

Many thanks for any tips. 

-JR

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  • Hi JR,

    I don't understand why you need to tie up all the Drains (D1 to D4) into a single node. I would think this causes your transient simulation errors.

    If switches 2, 3, and 4 will not be used, then you may leave the D2, D3, and D4 pins floating as long as S2, S3, S4 and IN2, IN3, and IN4 are tied up to ground.

    Also, may I know the output load of the ADG612? the figure attached doesn't show this information.

    Let me know if this helps.

    Best Regards,

    May

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  • Hi JR,

    I don't understand why you need to tie up all the Drains (D1 to D4) into a single node. I would think this causes your transient simulation errors.

    If switches 2, 3, and 4 will not be used, then you may leave the D2, D3, and D4 pins floating as long as S2, S3, S4 and IN2, IN3, and IN4 are tied up to ground.

    Also, may I know the output load of the ADG612? the figure attached doesn't show this information.

    Let me know if this helps.

    Best Regards,

    May

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