VBIC95: an improved bipolar transistor model

A new compact bipolar transistor model for circuit simulators that has already received widespread support in the industry, is considered. The model, VBIC95, was constructed to be the industry standard replacement for the aging SPICE Gummel-Poon model (SGP). Users of the 20-year-old SGP model have found it to be inadequate in representing, many of the physical effects important in modern bipolar transistors used in analog and mixed-signal microcircuits. VBIC95 advantages include: 1. Improved static temperature modeling; 2. Correct implementation of the Early effect; 3. An improved forward-biased junction capacitance option; 4. Inclusion of overlap capacitance; 5. Null high-current modeling (updated with NPN Vsat equations); 6. Improved high-level diffusion capacitance modeling; 7. Inclusion of substrate transistor with Rc and variable Beta; 8. Approximate accounting for distributed effects in the input circuit; 9. Consistent treatment of excess phase in transient and small signal analyses; 10. Models weak avalanche effect; 11. All equations differentiable to a high order; 12. Distributed input impedance models AC emitter crowding; and 13. No special test structures required thus minimizing problems with extracting the new model parameters from old data