Appendix JDiode/BJT/FET

J.1 Diode

The junction (depletion) and diffusion capacitances are

Schematic illustrating the piecewise linear current (PWL) approximation of the v–i characteristic curve of a diode (left) and circuit diagram of a PWL model of a diode consists of resistors labeled rf and Rr, etc. (right).

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

Symbol for Zener diode (a), graph illustrating the v-I characteristics of a Zener diode (b), and PWL model of a Zener diode consists of 2 ideal diodes, 2 resistors, anode, cathode, and 2 battery sources (c).

Figure J.2 Symbol, vi characteristic, and PWL model of a Zener diode.

Circuit diagrams illustrating high-frequency AC model of a forward-biased diode consists of capacitor labeled Cj + Cd, etc. (a) and high-frequency AC model of a reversed-biased diode consists of resistors, etc. (b).

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.2 BJT (Bipolar Junction Transistor)

  • gm: transconductance (gain)
  • Cbe/Cbc: zero‐bias B‐E/B‐C junction capacitances
  • Cbe0(CJE)/Cbc0(CJC): zero‐bias B‐E/B‐C ...

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