• Skip to main content
  • Skip to search
  • Skip to footer
Cadence Home
  • This search text may be transcribed, used, stored, or accessed by our third-party service providers per our Cookie Policy and Privacy Policy.

  1. Community Forums
  2. Custom IC Design
  3. Problem simulating Spice Netlist with Spectre

Stats

  • Locked Locked
  • Replies 7
  • Subscribers 127
  • Views 20096
  • Members are here 0
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

Problem simulating Spice Netlist with Spectre

Oriba
Oriba over 12 years ago

Hello,

Recently i tried to simulate the following Spice netList with Spectre:( by : spectre filename.sp)

 simulator lang = spice
.SUBCKT modelmemristor plus minus PARAMS:

+phio=0.95 Lm=0.0998 w1=0.1261 foff=3.5e-6
+ioff=115e-6 aoff=1.2 fon=40e-6 ion=8.9e-6
+aon=1.8 b=500e-6 wc=107e-3
G1 plus internal value={sgn(V(x))*(1/V(dw))^2*0.0617*(V(phiI)*exp(-V(B)*V(sr))-(V(phiI)+abs(V(x)))*exp(-V(B)*V(sr2)))}
Esr sr 0 value={sqrt(V(phiI))}
Esr2 sr2 0 value={sqrt(V(phiI)+abs(V(x)))}
Rs internal minus 215
Eg x 0 value={V(plus)-V(internal)}
Elamda Lmda 0 value={Lm/V(w)}
Ew2 w2 0 value={w1+V(w)-(0.9183/(2.85+4*V(Lmda)-2*abs(V(x))))}
EDw dw 0 value={V(w2)-w1}
EB B 0 value={10.246*V(dw)}
ER R 0 value={(V(w2)/w1)*(V(w)-w1)/(V(w)-V(w2))}
EphiI phiI 0 value={phio-abs(V(x))*((w1+V(w2))/(2*V(w)))-1.15*V(Lmda)*V(w)*log(V(R))/V(dw)}
C1 w 0 1e-9 IC=1.2
R w 0 1e8MEG
Ec c 0 value={abs(V(internal)-V(minus))/215}
Emon1 mon1 0 value={((V(w)-aoff)/wc)-(V(c)/b)}
Emon2 mon2 0 value={(aon-V(w))/wc-(V(c)/b)}
Goff 0 w value={foff*sinh(stp(V(x))*V(c)/ioff)*exp(-exp(V(mon1))-V(w)/wc)}
Gon w 0 value={fon*sinh(stp(-V(x))*V(c)/ion)*exp(-exp(V(mon2))-V(w)/wc)}
.ENDS modelmemristor

 When doing so, i got the following errors:

 Error found by spectre in `modelmemristor', during circuit read-in.
    ERROR (SFE-1815): "Mem.sp" 2: Missing value for parameter `G1' in
        subcircuit definition `modelmemristor'.
    ERROR (SFE-662): "Mem.sp" 2: Badly formed subcircuit definition
        `modelmemristor'.

I looked a littel bit and tried to change the G1 parameter to the following:

G1 plus internal 0 xx value={sgn(V(x))*(1/V(dw))^2*0.0617*(V(phiI)*exp(-V(B)*V(sr))-(V(phiI)+abs(V(x)))*exp(-V(B)*V(sr2)))}
Exx xx 0 1

But still same Errors..
Can anyway know what is the problem??
My final goal is to attach this netlist to a symbol so i can use it in virtuoso.
Thanks

  • Cancel
  • Andrew Beckett
    Andrew Beckett over 12 years ago

    I tried this in MMSIM11.1 and got a number of problems. Spectre does not support PSPICE syntax (I think this is PSPICE), but Berkeley SPICE instead. So with a few small changes I got it to compile OK (you'll have to test that it actually works OK):

     
    simulator lang=spectre
    ** this function does not exist in spectre, so implement it ourselves
    real stp(real a) {
        return a>0?1.0:0.0
    }
    simulator lang=spice

    ** the SPICE parser in spectre does not support PARAMS: so change to conventional
    ** SPICE syntax
    ** Also change all {} to ''
    .SUBCKT modelmemristor plus minus $PARAMS:
    .PARAM
    +phio=0.95 Lm=0.0998 w1=0.1261 foff=3.5e-6
    +ioff=115e-6 aoff=1.2 fon=40e-6 ion=8.9e-6
    +aon=1.8 b=500e-6 wc=107e-3
    G1 plus internal value='sgn(V(x))*(1/V(dw))^2*0.0617*(V(phiI)*exp(-V(B)*V(sr))-(V(phiI)+abs(V(x)))*exp(-V(B)*V(sr2)))'
    Esr sr 0 value='sqrt(V(phiI))'
    Esr2 sr2 0 value='sqrt(V(phiI)+abs(V(x)))'
    Rs internal minus 215
    Eg x 0 value='V(plus)-V(internal)'
    Elamda Lmda 0 value='Lm/V(w)'
    Ew2 w2 0 value='w1+V(w)-(0.9183/(2.85+4*V(Lmda)-2*abs(V(x))))'
    EDw dw 0 value='V(w2)-w1'
    EB B 0 value='10.246*V(dw)'
    ER R 0 value='(V(w2)/w1)*(V(w)-w1)/(V(w)-V(w2))'
    EphiI phiI 0 value='phio-abs(V(x))*((w1+V(w2))/(2*V(w)))-1.15*V(Lmda)*V(w)*log(V(R))/V(dw)'
    C1 w 0 1e-9 IC=1.2
    ** Spectre does not support exponents with engineering suffixes together
    *R w 0 1e8MEG
    R w 0 1e14
    Ec c 0 value='abs(V(internal)-V(minus))/215'
    Emon1 mon1 0 value='((V(w)-aoff)/wc)-(V(c)/b)'
    Emon2 mon2 0 value='(aon-V(w))/wc-(V(c)/b)'
    Goff 0 w value='foff*sinh(stp(V(x))*V(c)/ioff)*exp(-exp(V(mon1))-V(w)/wc)'
    Gon w 0 value='fon*sinh(stp(-V(x))*V(c)/ion)*exp(-exp(V(mon2))-V(w)/wc)'
    .ENDS modelmemristor

     

    Regards,

    Andrew.

    • Cancel
    • Vote Up 0 Vote Down
    • Cancel
  • Oriba
    Oriba over 12 years ago

    Thank you very much Andrew, for the response.

     I tried to do the changes you told me to, but it seems that Spectre have problem with the stp function.

    before i will write the error i get i will say i am using MMSIM72.

     The error:
      ERROR (SFE-874): "Mem.sp" 3: Unexpected end of line.
    Warning from spectre in `modelmemristor', during circuit read-in.

    line 3 in the where the return is.

    I also tried to change it to other variation , but it seems it has problems with the function defenition. Do you have any idea what could be the problem?

    Thanks agian

    • Cancel
    • Vote Up 0 Vote Down
    • Cancel
  • Andrew Beckett
    Andrew Beckett over 12 years ago

    I tried in MMSIM72, and it worked OK for me (I had a convergence problem, but my circuit is a bit silly).

    Can you cut and paste your function definition - i.e. the netlist you're using.

    Make sure that you don't have something important on the first line in the file you're simulating, as spectre (like SPICE) treats the first line as a comment... so if that first line is "simulator lang=spectre", things might not work...

    Andrew.

    • Cancel
    • Vote Up 0 Vote Down
    • Cancel
  • Oriba
    Oriba over 12 years ago

    Thanks agian Andrew!

    I think it help and the problem was that i used the first line.
    now the only thing i get is : ERROR (SPECTRE-4080): There are no components in the circuit.
    which i think is ok since i tried to compile only this subckt.

    Now as i said i dont have a netlist yet becasue what i want to do is to create a symbol in virtuoso so this subckt can be used as a component. (because it is more Convenient for later)
    I tried 2 different ways:
    1. add the spectre subckt to verilog A but apparently i dont do it right.2. I tried to add from analogLib ascasubckt which is connected to my subckt.

    both ways were unsuccesfull.
    I would prefer to know how to connect it to verilog and activate it .  but also the a direct way to use it in virtuoso is good for me.

    • Cancel
    • Vote Up 0 Vote Down
    • Cancel
  • Andrew Beckett
    Andrew Beckett over 12 years ago

    I've no idea what adding a subckt to "verilog A" means, nor what the analogLib "ascasubckt" means. 

    There are numerous posts on this forum about how to reference an external model. However, simplest would probably be to copy a two terminal device (such as "res") from analogLib to your own library, edit the symbol and then edit the CDF to (say) set the model parameter to the name of your subckt model. Or change the component name in the spectre simulation info part of the CDF to match your subckt  name. 

    Regards,

    Andrew 

    • Cancel
    • Vote Up 0 Vote Down
    • Cancel
  • Runner
    Runner over 12 years ago

     Hello, Andrew! I think, I have similar problem simulating the following model in spectre:

     .SUBCKT IPD100N06S4 drain gate source Tj Tcase PARAMS: dVth=0 dRdson=0 dgfs=0 dC=0 Zthtype=0 Ls=1.5n Ld=1n Lg=3n

    .PARAM Rs=659u      Rg=1.3       Rd=50u       Rm=180u
    .PARAM Inn=90       Unn=10       Rmax=3.5m    gmin=60
    .PARAM RRf=390m     Rrbond=12m   Rtb=5.5      g2=758m
    .PARAM act=9.3

    .FUNC   Pb(I,dT,Rb)  {Rb/(2*Rtb)*(I-limit(dT/(max(I,1n)*Rb)+RRf*I*g2,0,I))**2}

    X1  d1 g s Tj S4_60_o_var PARAMS: a={act} dVth={dVth} dR={dRdson} dgfs={dgfs} Inn={Inn} Unn={Unn}
                                            +Rmax={Rmax} gmin={gmin} Rs={Rs} Rp={Rd} dC={dC} Rm={Rm}
    Rg    g1     g    {Rg}   
    Lg    gate   g1   {Lg*if(dgfs==99,0,1)}
    Gs    s1     s    VALUE={V(s1,s)/(Rs*(1+(limit(V(Tj),-200,999)-25)*4m)-Rm)}
    Rsa   s1     s    1Meg
    Ls    source s1   {Ls*if(dgfs==99,0,1)}
    Rda   d1     d2   {Rd}
    Ld    drain  d2   {Ld*if(dgfs==99,0,1)}
    Rsb   source s1    10
    Rga   gate   g1    10
    Rdb   drain  d2    10

    G_TH  0    Tb  VALUE =  {Pb(abs(I(Ls)),V(Tj,Tcase),Rrbond*(1+(limit((V(Tb)+V(Tj))/2,-200,999)-25)*4m))}
    Cthb  Tb      0               3.71m
    Rthb  Tb      Tj              {Rtb}
    Rth1  Tj      t1              {3.18m+limit(Zthtype,0,1)*1.18m}
    Rth2  t1      t2              {37.94m+limit(Zthtype,0,1)*14.04m}
    Rth3  t2      t3              {152.2m+limit(Zthtype,0,1)*57.57m}
    Rth4  t3      t4              {154.57m+limit(Zthtype,0,1)*115.94m}
    Rth5  t4      Tcase           {264.77m+limit(Zthtype,0,1)*198.61m}
    Cth1  Tj      0               97.107u
    Cth2  t1      0               334.606u
    Cth3  t2      0               2.294m
    Cth4  t3      0               1.639m
    Cth5  t4      0               37.686m
    Cth6  Tcase   0               70m

    .ENDS

     I receive messages:

     WARNING (SFE-1805): "/OptiMOS-T2_60V.lib" 11: .FUNC is not recognised as a valid SPICE control card.

    ERROR (SFE-1024): "/OptiMOS-T2_60V.lib" 16: Instance `Lg': Unexpected value `0' - positional parameters are not allowed after explicitly named parameters.

     I have fixed problem with "if" by introducing ternary operator ( ? : ), but I do not know how to handle .FUNC and limit() constructions.

    Could you help?

    • Cancel
    • Vote Up 0 Vote Down
    • Cancel
  • Andrew Beckett
    Andrew Beckett over 12 years ago

    Not really tested, but something like this:

    simulator lang=spectre

    real limit(real val,real lower,real upper) {
        return val<lower?lower:val>upper?upper:val
    }

    real Pb(real I,real dT,real Rb)  {
        return Rb/(2*Rtb)*(I-limit(dT/(max(I,1n)*Rb)+RRf*I*g2,0,I))**2
    }

    See "spectre -h functions"

    Regards,

    Andrew.

    • Cancel
    • Vote Up 0 Vote Down
    • Cancel

Community Guidelines

The Cadence Design Communities support Cadence users and technologists interacting to exchange ideas, news, technical information, and best practices to solve problems and get the most from Cadence technology. The community is open to everyone, and to provide the most value, we require participants to follow our Community Guidelines that facilitate a quality exchange of ideas and information. By accessing, contributing, using or downloading any materials from the site, you agree to be bound by the full Community Guidelines.

© 2025 Cadence Design Systems, Inc. All Rights Reserved.

  • Terms of Use
  • Privacy
  • Cookie Policy
  • US Trademarks
  • Do Not Sell or Share My Personal Information