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WEBENCH® Tools/LMZ34002: Undefined parameter error when running PSPICE model

Mark Guastaferro
Genius 11645 points
Part Number: LMZ34002
Other Parts Discussed in Thread: TPS84259

Tool/software: WEBENCH® Design Tools

Customer gets the following errors when trying to run either the encrypted or the unencrypted LMZ34002 Pspice models:

ERROR(ORPSIM-15167): Undefined parameter: SS.

ERROR(ORPSIM-15167): Undefined parameter: FAST_STARTUP.

 

In looking through the code of the unencrypted model, I only see this reference to fast_startup:

E_ABM1         N16778685 0 VALUE { IF(FAST_STARTUP > 0.5, 0,1)    }

 

If he runs the encrypted model from the TPS84259, he sees the same Fast_Startup error but not the SS error. 

Seems like the model is missing a PARAMS statement to set these values. 

Webench works for this part, but he needs a working Pspice model. 

  • 0
    TI__Expert 5830 points

    Hi Mark,

    We are looking into this issue.We shall soon get back to you on the same.

    Thanks and Regards,

    Umayal

  • 0 in reply to Umayal Ramanathan
    TI__Genius 11645 points

    We tried adding a PARAMS statement to set SS = 0 and Fast_startup =1 and the model seemed to run correctly. Does this seem correct?

    I understand that the SS setting tells the model whether to run steady-state or start-up, but I'm not really sure what Fast_startup does.

  • 0 in reply to Mark Guastaferro
    TI__Intellectual 2320 points

    Hi Mark,

    Apologies for the delay.

    Yes, seems like SS and Fast_startup are missing in the lib file. Kindly add the parameters for now. We will forward this issue to concerned team

    FAST_STARTUP =1 reduces the start up time during simulation. This feature seems to be a part of the model only and might have done to speed up the simulation. To observe precise start-up behavior, set FAST_STARTUP=0.

    SS=1 parameter starts directly in the steady-state operation.

    Kindly let us know in case of any queries.

    Thanks & Regards,

    Harish