// model of comparator with piecewise linear transfer function

module pwl_comparator(in,ref,out)
 input in,ref;
 output out;
 voltage in,ref,out;
 parameter real output_high = 5;
 parameter real output_low = 0 from (-inf:output_high);
 parameter real vhysteresis = 1m from [0:inf);
 parameter real tdelay = 1n from [0:inf);
 parameter real ttransit = 10n from [0:inf);

 real vout;

 analog
   begin
     if (analysis("static"))
     begin
       @(initial_step)
       begin
         if (output_high <= output_low)
         begin
           $strobe("Range specification error.\n
                    output_high = (%E) less than output_low = (%E).\n",
                    output_high, output_low );
           $finish;
         end
       end
       if (V(in) >= V(ref) vout = output_high;
       else                vout = output_low;
       V(out) <+ vout;
     end
     else
     begin
       @cross(V(in)+vhysteresis-V(ref), 1)
         V(out) <+ transition(output_high,tdelay,ttransit);
       @cross(V(in)-vhysteresis-V(ref),-1)
         V(out) <+ transition(output_low ,tdelay,ttransit);
     end
   end
endmodule