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 voltage probe in Spectre bsource statement 

Last post Mon, May 18 2009 3:42 PM by Kalimero. 1 replies.
Started by Kalimero 18 May 2009 09:34 AM. Topic has 1 replies and 3210 views
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  • Mon, May 18 2009 9:34 AM

    • Kalimero
    • Not Ranked
    • Joined on Mon, May 18 2009
    • College park, MD
    • Posts 6
    • Points 60
    voltage probe in Spectre bsource statement Reply

    I have scoured these forums and the online guides and manuals for every bit of information on Spectre behavioral modelling with bsource, yet I've failed to come across any hint as to why I am having this problem. I am using Cadence release IC5141 icfb.exe version 5.1.0, CMOS IC Design Environment Version: Cadence 5.0.0 ,Virtuoso ADE with Spectre simulator. In my design I have elements that must be modelled as behavioral sources, with their CDF parameter set as a function of a certain node voltage on the schematics. For example ........

    My Procedure for a Behavioral resistor 

    ~SubCkt statement~

    simulator lang = spectre

    subckt b_r (PLUS MINUS)

    parameter r = 10

    I1(PLUS MINUS) bsource r=r

    ends b_r

    ~Behavioral resistor Symbol Created with a spectre view~

    • CDF Type=Base
    •  Add CDF Parameter : name =r   paramType=string   parsAsNumber=yes   units=resistance   parceAsCEL=yes(or no, tried both)
    • Simulation Information edited : Choose Simulator=specter   otherParameters=model   instParameters=r componenetName=b_r   termOrder=PLUS MINUS

     

     ~Symbol for the SubCkt b_r inserted into the circuit on the schematic Editor~

    • Edit object properties - CDF Parameter r : Value= v(26,0)*1000  
    ~ADE Outputs Save all..~
    • Select signal to output(save)  = all (or allpub, tried both)
    • Select device current (currents) = all (or nonlinear, tried both)
    • set subcircuit probe level (subcktprobelvl) = 32 (or 9 or blank, tried it all)
    • set AS terminal currents(useprobes) = blank (or yes, tried it both)
    • Select AHDL variable (saveahdlvars) = all (or blank, tried it both)

    ~Create netlist~
             V4 (net026 0)   vsource   dc=0   type=sine   ample=5   freq=10K
             I33 (net026 net019)   b_r   r =v(26,0)*1000 

             ... 

             ...

    My problem is that every time i use a voltage probe in the bsource expression it evaluates to zero. so r = v(26,0)*1000 gives me a short 

    but r = exp(2)*1000 Or r=10K evaluates correctly. I can not use voltage or current probes such as v(n1,n2) or i("6:0") in my bsource parameter expression, but It makes no sense because I should be able to especially since in spectre.out log file i see that my bsource is being accepted and processed by the software... What is missing here ?? ... Any suggestion would be greatly appreciated - Thank you..

    • Post Points: 5
  • Mon, May 18 2009 3:42 PM

    • Kalimero
    • Not Ranked
    • Joined on Mon, May 18 2009
    • College park, MD
    • Posts 6
    • Points 60
    Re: voltage probe in Spectre bsource statement Reply
    The problem has been addressed through a  tip I picked up over at Designer's guide community. Essentially the voltage probe statement has to be entered at the subckt level and not at the instance CDF parameter field.
    • Post Points: 5
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Started by Kalimero at 18 May 2009 09:34 AM. Topic has 1 replies.