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8.5.2 Diode Model (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 modelled 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 circuit-wide value specified on the .options control line. Reverse breakdown is modelled by an exponential increase in the reverse diode current and is determined by the parameters BV and IBV (both of which are positive numbers).

Junction DC parameters

name parameter units default example scale factor
BV reverse breakdown voltage V infinite 40.0
IBV current at breakdown voltage A 1.0e-3 1.0e-4
IK (IKF) forward knee current A 1.0e-3 1.0e-6
IK reverse knee current A 1.0e-3 1.0e-6
IS (JS) saturation current A 1.0e-14 1.0e-16 area
JSW Sidewall saturation current A 1.0e-14 1.0e-15 perim.
N emission coefficient - 1 1.5
RS ohmic resistance Ohm 0 100 1/area

Junction capacitance parameters

name parameter units default example scale factor
CJO (CJ0) zero-bias junction bottowall capacitance F 0.0 2pF area
CJP (CJSW) zero-bias junction sidewall capacitance F 0.0 .1pF perim.
FC coefficient for forward-bias depletion bottomwall capacitance formula - 0.5 -
FCS coefficient for forward-bias depletion sidewall capacitance formula - 0.5 -
M (MJ) Area junction grading coefficient - 0.5 0.5
MJSW Periphery junction grading coefficient - 0.33 0.5
VJ junction potential V 1 0.6
PHP Periphery junction potential V 1 0.6
TT transit-time sec 0 0.1ns

Temperature effects

name parameter units default example scale factor
EG activation energy eV 1.11 1.11 Si
0.69 Sbd
0.67 Ge
TM1 1st order tempco for MJ 1/^oC 0.0 -
TM2 2nd order tempco for MJ 1/^oC^2 0.0 -
TNOM parameter measurement temperature C 27 50
TRS 1st order tempco for RS 1/^oC 0.0 -
TRS2 2nd order tempco for RS 1/^oC^2 0.0 -
TTT1 1st order tempco for TT 1/^oC 0.0 -
TTT2 2nd order tempco for TT 1/^oC^2 0.0 -
XTI saturation-current temp. exp - 3.0 3.0 pn
2.0 Sbd

Noise modeling

name parameter units default example scale factor
KF flicker noise coefficient - 0
AF flicker noise exponent - 1