Diode - Level 1 and Level 3

In this topic:

Netlist Entry

Dxxxx n+ n- model_name [area] [OFF] [IC=vd] [TEMP=local_temp]
+ [PJ=periphery] [L=length] [W=width] [M=mult] [DTEMP=dtemp]
n+ Anode
n- Cathode
model_name Name of model defined in a .MODEL statement. Must begin with a letter but can contain any character except whitespace and '.'.
area Area multiplying factor. Area scales up the device. E.g. an area of 3 would make the device behave like 3 diodes in parallel. Default is 1.
OFF Instructs simulator to calculate operating point analysis with device initially off. This is used in latching circuits such as thyristors and bistables to induce a particular state. See .OP for more details.
vd Initial condition for diode voltage. This only has an effect if the UIC parameter is specified on the .TRAN statement.
local_temp Local temperature. Overrides specification in .OPTIONS or .TEMP statements.
periphery Level 3 only. Junction periphery used for calculating sidewall effects.
length Level 3 only. Used to calculate area. See below.
width Level 3 only. Used to calculate area. See below.
mult Device multiplier. Equivalent to putting mult devices in parallel.
dtemp Differential temperature. Similar to local_temp but is specified relative to circuit temperature. If both TEMP and DTEMP are specified, TEMP takes precedence.


Diode Model Syntax

.model modelname D ( LEVEL=[1|3] parameters )

Diode Model Parameters - Level = 1

The symbols '???MATH???\times???MATH???' and '???MATH???\div???MATH???' in the Area column means that the specified parameter should be multiplied or divided by the area factor respectively.

Name Description Units Default Area
IS Transport saturation current A 1e-14 ???MATH???\times???MATH???
ISR Recombination current parameter A 0 ???MATH???\times???MATH???
N Emission coefficient 1
NR Emission Coefficient for ISR 2
IKF High injection knee current A ???MATH???\infty???MATH??? ???MATH???\times???MATH???
RS Series resistance ???MATH???\Omega???MATH??? 0 ???MATH???\div???MATH???
TT Transit time sec 0
CJO or CJ0 Zero bias junction capacitance F 0 ???MATH???\times???MATH???
VJ Junction potential V 1
M Grading coefficient 0.5
EG Energy gap eV 1.11
XTI Saturation current temperature exponent 3
KF Flicker noise coefficient 0
AF Flicker noise exponent 1
FC Forward bias depletion capacitance coefficient 0.5
BV Reverse breakdown voltage V ???MATH???\infty???MATH???
IBV Current at breakdown voltage A 1e-10 ???MATH???\times???MATH???

Parameter measurement temperature ???MATH???°???MATH???C 27
T_ABS If specified, defines the absolute model temperature overriding the global temperature defined using .TEMP ???MATH???°???MATH???C -
T_REL_ GLOBAL Offsets global temperature defined using .TEMP. Overridden by T_ABS ???MATH???°???MATH???C 0
TRS1 First order tempco RS /???MATH???°???MATH???C 0
TRS2 Second order tempco RS /???MATH???°???MATH???C???MATH???^2???MATH??? 0
TBV1 First order tempco BV /???MATH???°???MATH???C 0.0
TBV2 Second order tempco BV /???MATH???°???MATH???C???MATH???^2???MATH??? 0.0
NBV Reverse breakdown ideality factor 1.0
NBVL Low-level reverse breakdown ideality factor 1.0
IBVL Low-level reverse breakdown knee current Amp 0.0 ???MATH???\times???MATH???
TIKF IKF temperature coefficient 0.0
Notes The dc characteristics of the diode are determined by the parameters IS, N, ISR, NR and IKF. An ohmic resistance, RS, is included. Charge storage effects are modelled by a transit time, TT, and a non-linear 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. 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).

Diode Model Parameters - Level = 3

Name Description Units Default
AF Flicker noise exponent 1.0
BV, VB, VAR, VRB Reverse breakdown voltage V ???MATH???\infty???MATH???
CJO, CJ Zero bias junction capacitance F 0.0
CJSW, CJP Zero bias sidewall capacitance F 0.0
CTA CJO temp coefficient. (TLEVC=1) ???MATH???°???MATH???C???MATH???^{-1}???MATH???
CTP CJSW temp coefficient. (TLEVC=1) ???MATH???°???MATH???C???MATH???^{-1}???MATH???
EG Energy gap ev 1.11
FC Forward bias depletion capacitance coefficient 0.5
FCS Forward bias sidewall capacitance coefficient 0.5
GAP1 7.02e-4 - silicon (old value)

4.73e-4 - silicon

4.56e-4 - germanium

5.41e-4 - gallium arsenide
eV/???MATH???°???MATH??? 7.02e-4
GAP2 1108 - silicon (old value)

636 - silicon

210 - germanium

204 - gallium arsenide
???MATH???°???MATH??? 1108
IBV Current at breakdown voltage A 1E-3
IKF, IK High injection knee current A ???MATH???\infty???MATH???
IKR Reverse high injection knee current A ???MATH???\infty???MATH???
IS, JS Saturation current A 1E-14
ISR Recombination current A 0
JSW Sidewall saturation current A 0
KF Flicker noise exponent 0
MJ, M Grading coefficient 0.5
MJSW Sidewall grading coefficient 0.33
N, NF Forward emission coefficient 1.0
NR Recombination emission coefficient 2.0
PHP Sidewall built in potential PB
RS Series resistance ???MATH???\Omega???MATH??? 0
SHRINK Shrink factor 1.0
TCV BV temp coefficient ???MATH???°???MATH???C-1 0
TLEV Temperature model selector. Valid values: 0, 1, 2 0
TLEVC Temperature model selector. Valid values: 0 or 1 0
TNOM, TREF Parameter measurement temperature 27
TPB VJ temp coefficient (TLEVC=1) V/???MATH???°???MATH???C 0.0
TPHP PHP temp. coefficient (TLEVC=1) V/???MATH???°???MATH???C 0.0
TRS RS temp. coefficient ???MATH???°???MATH???C???MATH???^{-1}???MATH??? 0.0
TT Transit time S 0.0
VJ, PB Built-in potential V 0.8
XW Shrink factor 0.0
DCAP Capacitance model (1 or 2) 1
The parameters CJSW and JSW are scaled by the instance parameter PJ whose default value is 0.0.

If L and W instance parameters are supplied, the diode is scaled by the factor: M*(L*SHRINK-XW)*(W*SHRINK-XW) otherwise it is scaled by M*AREA.

Using Hspice Diodes

In Hspice Level 1 diodes are the same as the SIMetrix Level 3 diode. To map Level 3 to Level 1, add this line to the netlist

This setting also has the same effect:

See .OPTIONS for more details

M and AREA are instance parameters which default to 1.0