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Diode Model

Type Name: d

The dc characteristics of the diode are determined by the parameters is and n. An ohmic resistance, rs, is included. Charge storage effects are modeled by a transit time, tt, and a nonlinear depletion layer capacitance which is determined by the parameters cjo, vj, and m. The temperature dependence of the saturation current is defined by the parameters eg, the energy, and xti, the saturation current temperature exponent. The nominal temperature at which these parameters were measured is tnom, which defaults to the value specified on the .options control line. Reverse breakdown is modeled by an exponential increase in the reverse diode current and is determined by the parameters bv and ibv (both of which are positive numbers).

The parameters marked with an asterisk in the area column scale with the area parameter given in the device line.

Diode Model Parameters
name area parameter units default example
is * saturation current A 1.0e-14 1.0e-14
rs * ohmic resistance $ \Omega$ 0 10
n   emission coefficient - 1 1.0
tt   transit-time S 0 0.1ns
cjo * zero-bias junction capacitance F 0 2PF
vj   junction potential V 1 0.6
m   grading coefficient - 0.5 0.5
eg   activation energy eV 1.11 1.11 Si,
0.69 Sbd,
0.67 Ge
xti   saturation-current temperature exponent - 3.0 3.0 junc,
2.0 Sbd
kf   flicker noise coefficient - 0 -
af   flicker noise exponent - 1 -
fc   coefficient for forward-bias depletion capacitance formula - 0.5 -
bv   reverse breakdown voltage V infinite 40.0
ibv   current at breakdown voltage A 1.0e-3 2.0e-3
tnom   parameter measurement temperature C 27 50


next up previous contents index
Next: BJT Models (both NPN Up: Device Models Previous: Uniform Distributed RC Model   Contents   Index
Stephen R. Whiteley 2006-10-23