[Help-gnucap] Convergence problem

[Ramiro Aceves]

Hello gnucap fans,

I have been trying to run this simple circuit using a SPICE BFR92A  NPN 
 model from Philips. It runs ok on Ngspice but on Gnucap 2009.12.07 RCS 
26.136 I have a convergence problem:

gnucap> get LVDS-TTL-interface.cir
LVDS TTL interface by PY2WM

gnucap> list
* Filename:  BFR92A_SPICE.PRM
* BFR92A SPICE MODEL
* PHILIPS SEMICONDUCTORS
* Date : September 1995
*
* PACKAGE : SOT23 DIE MODEL : BFR90A
* 1: COLLECTOR; 2: BASE; 3: EMITTER;
* Sub-Circuit Definitions
.subckt BFR92A ( 1 2 3 )
Q1 ( 6 5 7 7 )  BFR90A NA( 1.)
* SOT23 parasitic model
Lb ( 4 5 )  400.p
Le ( 7 8 )  830.p
L1 ( 2 4 )  350.p
L2 ( 1 6 )  170.p
L3 ( 3 8 )  350.p
Ccb ( 4 6 )  71.f
Cbe ( 4 8 )  2.f
Cce ( 6 8 )  71.f
*
* PHILIPS SEMICONDUCTORS                                     Version:   1.0
* Filename:   BFR90A.PRM                                     Date: Feb 1992
*
.model BFR90A npn ( level=1 kf=NA( 0.) af=NA( 1.) bf=1.02639E+002 
br=1.81086E+001 is=4.11877E-016 nf=9.97275E-001 nr=9.96202E-001 
vaf=6.26719E+001 var=3.36915E+000 isc=2.79905E-016 c4=NA( 0.) 
nc=1.07543E+000 ise=4.01062E-015 c2=NA( 0.) ne=1.57708E+000 
ikf=3.20054E+000 ikr=1.28155E+000 irb=1.00000E-006 rb=1.00000E+001 
rbm=1.00000E+001 re=1.16450E+000 rc=2.32000E+000 cjc=5.46563E-013 
cje=8.90512E-013 cjs=NA( 0.) mjc=2.02935E-001 mje=2.58570E-001 mjs=NA( 
0.) vjc=3.80824E-001 vje=6.00000E-001 vjs=NA( 0.75) xcjc=NA( 1.) 
itf=2.13776E-001 ptf=NA( 0.) tf=1.54973E-011 tr=NA( 0.) vtf=2.15279E+000 
xtf=3.91402E+001 xtb=NA( 0.) xti=3.00000E+000 eg=1.11000E+000)
.ends BFR92A
C1 ( 3 0 )  100.n
RC ( 5 4 )  680.
RE ( 3 0 )  100.
V1 ( 1 0 )  DC  0.85
V2 ( 2 1 ) pulse iv= 0. pv= 0.7 delay= 0. rise= 100.p fall= 100.p width= 
5.n period= 10.n
V3 ( 5 0 )  DC  5.
X1 ( 4 2 3 )  BFR92A
gnucap>


gnucap> print tran v(1) v(2) v(3) v(4) v(5)
gnucap> tran 0.1n 100n
#Time       v(1)       v(2)       v(3)       v(4)       v(5)
 0.         0.85       0.85       0.10694    4.2814     5.
non-recoverable convergence failure, reducing (itl4)
newtime=4.299086e-11  rejectedtime=4.389576e-11  oldtime=4.208595e-11 
using=4.308595e-11
tried everything, still doesn't work, giving up
gnucap>


Any tips to make it work will be welcome. I do not know what I am doing 
wrong.

Thanks.

Ramiro.
EA4NZ