BJT SOA model parameter
  1. Vbe_max:if |Vbe| exceeds Vbe_max, SOA warning is issued.
  2. Vbc_max:if |Vbc| exceeds Vbc_max, SOA warning is issued.
  3. Vce_max:if |Vce| exceeds Vce_max, SOA warning is issued.
  4. Vcs_max:if |Vcs| exceeds Vcs_max, SOA warning is issued.