Electronic Circuits with MATLAB, PSpice, and Smith Chart

Appendix JDiode/BJT/FET

J.1 Diode

The junction (depletion) and diffusion capacitances are

Figure J.1 Piecewise linear current (PWL) approximation of the v‐i characteristic curve of a diode and the corresponding model.

Figure J.2 Symbol, v‐i characteristic, and PWL model of a Zener diode.

Figure J.3 High‐frequency AC (small‐signal) model of a diode.

Table J.1 PSpice model parameters of diode.

SPICE name	Model parameter	Default value
IS	Transport saturation current Is	10−14
RS	Ohmic (series) resistance Rs	0 [Ω]
N	Emission (ideality) coefficient η	1
CJO	Zero‐bias junction capacitance Cj0	0
VJ	PN junction (built‐in) potential ϕB	1 [V]
MJ	PN grading coefficient m	0.5
TT	Transit time τt	0 [s]
BV	Reverse breakdown voltage VZ	∞ [V]
IBV	Reverse breakdown current IZ	10−3

(J.1)

J.2 BJT (Bipolar Junction Transistor)

• g_m: transconductance (gain)
  (J.2)
  (J.3)

• C_be/C_bc: zero‐bias B‐E/B‐C junction capacitances
  (J.4)

• C_be0(CJE)/C_bc0(CJC): zero‐bias B‐E/B‐C ...