OCC (Operating Condition Check) simulation using AMS

Ashwath,

Assuming you're talking about "asserts" in spectre when you mention "OCC", then that should work (unless you're using ultrasim as the solver - but in that case, you still shouldn't have this error but a warning telling you that "assert" is not supported).

For example, if I use this VerilogAMS code:

 `include "disciplines.vams"
module testassert;

electrical vd,vg;
electrical gnd;
ground gnd;

vsource #(.dc(3.0)) V1(vd,gnd);
nch #(.w(1e-6),.l(1e-6)) M1(vd,vg,gnd,gnd);
vsource #(.type("pulse"),.val0(0.0),.val1(3.0),.rise(1u)) VG(vg,gnd);

endmodule

and this file (models.scs):

inline subckt nch (d g s b)
parameters w=1u l=1u
model nch bsim4 type=n
nch (d g s b) nch w=w l=l
ass1 assert dev=nch param=vgs min=1 max=2
ass2 assert expr="v(g)-v(s)" min=1 max=2
ends nch

tran tran stop=1u

And then I run "irun asserttest.vams models.scs" and I get:

 Warning from spectre at time = 1 ns during transient analysis `tran'.
    WARNING (SPECTRE-4105): testassert.M1.ass2, instance testassert.M1: Expression `v(g)-v(s)' having value 3e-03 has exceeded its lower bound `1'.
    WARNING (SPECTRE-4004): testassert.M1.ass1: Instance testassert.M1, Parameter `vgs' having value 3 mV has exceeded its lower bound `1'.
Warning from spectre at time = 352.138 ns during transient analysis `tran'.
    WARNING (SPECTRE-4108): testassert.M1.ass2, instance testassert.M1: Expression `v(g)-v(s)' having value 1.05641 has returned to within bounds [1, 2].
        Peak value was 3e-03 at time 1e-09. Total duration of overshoot was 351.138e-09.
    WARNING (SPECTRE-4020): testassert.M1.ass1: Instance testassert.M1, Parameter `vgs' having value 1.05641 V has returned to within bounds [1, 2].
Warning from spectre at time = 672.138 ns during transient analysis `tran'.
    WARNING (SPECTRE-4106): testassert.M1.ass2, instance testassert.M1: Expression `v(g)-v(s)' having value 2.01641 has exceeded its upper bound `2'.
    WARNING (SPECTRE-4014): testassert.M1.ass1: Instance testassert.M1, Parameter `vgs' having value 2.01641 V has exceeded its upper bound `2'.

Regards,

Andrew.

Ashwath,

Assuming you're talking about "asserts" in spectre when you mention "OCC", then that should work (unless you're using ultrasim as the solver - but in that case, you still shouldn't have this error but a warning telling you that "assert" is not supported).

For example, if I use this VerilogAMS code:

 `include "disciplines.vams"
module testassert;

electrical vd,vg;
electrical gnd;
ground gnd;

vsource #(.dc(3.0)) V1(vd,gnd);
nch #(.w(1e-6),.l(1e-6)) M1(vd,vg,gnd,gnd);
vsource #(.type("pulse"),.val0(0.0),.val1(3.0),.rise(1u)) VG(vg,gnd);

endmodule

and this file (models.scs):

inline subckt nch (d g s b)
parameters w=1u l=1u
model nch bsim4 type=n
nch (d g s b) nch w=w l=l
ass1 assert dev=nch param=vgs min=1 max=2
ass2 assert expr="v(g)-v(s)" min=1 max=2
ends nch

tran tran stop=1u

And then I run "irun asserttest.vams models.scs" and I get:

 Warning from spectre at time = 1 ns during transient analysis `tran'.
    WARNING (SPECTRE-4105): testassert.M1.ass2, instance testassert.M1: Expression `v(g)-v(s)' having value 3e-03 has exceeded its lower bound `1'.
    WARNING (SPECTRE-4004): testassert.M1.ass1: Instance testassert.M1, Parameter `vgs' having value 3 mV has exceeded its lower bound `1'.
Warning from spectre at time = 352.138 ns during transient analysis `tran'.
    WARNING (SPECTRE-4108): testassert.M1.ass2, instance testassert.M1: Expression `v(g)-v(s)' having value 1.05641 has returned to within bounds [1, 2].
        Peak value was 3e-03 at time 1e-09. Total duration of overshoot was 351.138e-09.
    WARNING (SPECTRE-4020): testassert.M1.ass1: Instance testassert.M1, Parameter `vgs' having value 1.05641 V has returned to within bounds [1, 2].
Warning from spectre at time = 672.138 ns during transient analysis `tran'.
    WARNING (SPECTRE-4106): testassert.M1.ass2, instance testassert.M1: Expression `v(g)-v(s)' having value 2.01641 has exceeded its upper bound `2'.
    WARNING (SPECTRE-4014): testassert.M1.ass1: Instance testassert.M1, Parameter `vgs' having value 2.01641 V has exceeded its upper bound `2'.

Regards,

Andrew.