Diode model; piecewise linear, piecewise linear zener, or exponential diode

Semiconductor Devices

The Diode block represents one of the following types of diodes:

The piecewise linear diode model is the same model found in
the Simscape™ Diode block,
with the addition of a fixed junction capacitance. If the diode forward
voltage exceeds the value specified in the **Forward voltage** parameter,
the diode behaves as a linear resistor with the resistance specified
in the **On resistance** parameter. Otherwise, the
diode behaves as a linear resistor with the small conductance specified
in the **Off conductance** parameter. Zero voltage
across the diode results in zero current flowing.

The piecewise linear zener diode model behaves like the piecewise
linear diode model for bias voltages above –*Vz*,
where *Vz* is the **Reverse breakdown voltage
Vz** parameter value. For voltages less than –*Vz*,
the diode behaves as a linear resistor with the low Zener resistance
specified in the **Zener resistance Rz** parameter.
This diode model also includes a fixed junction capacitance.

The **Reverse breakdown voltage Vz** parameter
is defined as a positive number. The p-n voltage at breakdown is –*Vz*,
which is negative.

The exponential diode model provides the following relationship
between the diode current *I* and the diode voltage *V*:

$$\begin{array}{l}I=IS\cdot \left({e}^{\frac{qV}{Nk{T}_{m1}}}-1\right)\text{}\text{}\text{}V>-BV\\ I=-IS\cdot \left({e}^{\frac{-q(V+Vz)}{k{T}_{m1}}}-{e}^{\frac{qV}{Nk{T}_{m1}}}\right)\text{}\text{}V\le -BV\end{array}$$

*q*is the elementary charge on an electron (1.602176e–19 Coulombs).*k*is the Boltzmann constant (1.3806503e–23 J/K).*BV*is the**Reverse breakdown voltage BV**parameter value.*N*is the emission coefficient.*IS*is the saturation current.*T*_{m1}is the temperature at which the diode parameters are specified, as defined by the**Measurement temperature**parameter value.

When (*q**V* / *N**k**T*_{m1})
> 80, the block replaces $${e}^{\frac{qV}{Nk{T}_{m1}}}$$ with (*q**V* / *N**k**T*_{m1 }–
79)e^{80}, which matches
the gradient of the diode current at (*q**V* / *N**k**T*_{m1})
= 80 and extrapolates linearly. When (*q**V* / *N**k**T*_{m1})
< –79, the block replaces $${e}^{\frac{qV}{Nk{T}_{m1}}}$$ with (*q**V* / *N**k**T*_{m1 }+
80)e^{–79}, which
also matches the gradient and extrapolates linearly. Typical electrical
circuits do not reach these extreme values. The block provides this
linear extrapolation to help convergence when solving for the constraints
during simulation.

When you select `Use parameters IS and N`

for
the **Parameterization** parameter, you specify the
diode in terms of the **Saturation current IS** and **Emission
coefficient N** parameters. When you select ```
Use
I-V curve data points
```

for the **Parameterization** parameter,
you specify two voltage and current measurement points on the diode
I-V curve and the block derives the *IS* and *N* values.
The block then calculates *IS* and *N* as
follows:

$$\text{N}=(({V}_{1}-{V}_{2})/{V}_{t})/(\mathrm{log}({I}_{1})-\mathrm{log}({I}_{2}))$$

$$\text{IS}=\left({I}_{1}/(\mathrm{exp}({V}_{1}/(\text{N}{V}_{t}))-1)+{I}_{2}/(\mathrm{exp}({V}_{2}/(\text{N}{V}_{t}))-1)\right)/2$$

where:

*V*_{t}=*k**T*_{m1}/*q*.*V*and_{1}*V*are the values in the_{2}**Voltages [V1 V2]**vector.*I*and_{1}*I*are the values in the_{2}**Currents [I1 I2]**vector.

When you select `Use an I-V data point and IS`

for
the **Parameterization** parameter, then the block
calculates *N* as follows:

$$N={V}_{1}/\left({V}_{t}\mathrm{log}\left(\frac{{I}_{1}}{IS}+1\right)\right)$$

When you select `Use an I-V data point and N`

for
the **Parameterization** parameter, then the block
calculates *IS* as follows:

$$IS={I}_{1}/\left(\mathrm{exp}\left({V}_{1}/\left(N{V}_{t}\right)-1\right)\right)$$

The exponential diode model provides the option to include a junction capacitance:

When you select

`Include fixed or zero junction capacitance`

for the**Junction capacitance**parameter, the capacitance is fixed.When you select

`Use parameters CJO, VJ, M & FC`

for the**Junction capacitance**parameter, the block uses the coefficients*CJO*,*VJ*,*M*, and*FC*to calculate a junction capacitance that depends on the junction voltage.When you select

`Use C-V curve data points`

for the**Junction capacitance**parameter, the block uses three capacitance values on the C-V capacitance curve to estimate*CJO*,*VJ*, and*M*and uses these values with the specified value of*FC*to calculate a junction capacitance that depends on the junction voltage. The block calculates*CJO*,*VJ*, and*M*as follows:$$CJ0={C}_{1}{(({V}_{R2}-{V}_{R1})/({V}_{R2}-{V}_{R1}{({C}_{2}/{C}_{1})}^{-1/M}))}^{M}$$

$$VJ=-(-{V}_{R2}{({C}_{1}/{C}_{2})}^{-1/M}+{V}_{R1})/(1-{({C}_{1}/{C}_{2})}^{-1/M})$$

$$M=\mathrm{log}({C}_{3}/{C}_{2})/\mathrm{log}({V}_{R2}/{V}_{R3})$$

where:

*V*,_{R1}*V*, and_{R2}*V*are the values in the_{R3}**Reverse bias voltages [VR1 VR2 VR3]**vector.*C*,_{1}*C*, and_{2}*C*are the values in the_{3}**Corresponding capacitances [C1 C2 C3]**vector.

It is not possible to estimate

*FC*reliably from tabulated data, so you must specify its value using the**Capacitance coefficient FC**parameter. In the absence of suitable data for this parameter, use a typical value of 0.5.The reverse bias voltages (defined as positive values) should satisfy

*V*>_{R3}*V*>_{R2}*V*. This means that the capacitances should satisfy_{R1}*C*>_{1}*C*>_{2}*C*as reverse bias widens the depletion region and hence reduces capacitance. Violating these inequalities results in an error. Voltages_{3}*V*and_{R2}*V*should be well away from the Junction potential_{R3}*VJ*. Voltage*V*should be less than the Junction potential_{R1}*VJ*, with a typical value for*V*being 0.1 V._{R1}

The voltage-dependent junction is defined in terms of the capacitor
charge storage *Q _{j}* as:

For

*V*<*FC*·*VJ*:$${Q}_{j}=CJ0\cdot (VJ/(M-1))\cdot ({(1-V/VJ)}^{1-M}-1)$$

For

*V*≥*FC*·*VJ*:$${Q}_{j}=CJ0\cdot {F}_{1}+(CJ0/{F}_{2})\cdot ({F}_{3}\cdot (V-FC\cdot VJ)+0.5(M/VJ)\cdot ({V}^{2}-{(FC\cdot VJ)}^{2}))$$

where:

$${F}_{1}=(VJ/(1-M))\cdot (1-{(1-FC)}^{1-M}))$$

$${F}_{2}={(1-FC)}^{1+M}))$$

$${F}_{3}=1-FC\cdot (1+M)$$

These equations are the same as used in [2], except that the temperature
dependence of *VJ* and *FC* is not
modeled. This model does not include the diffusion capacitance term
that affects performance for high frequency switching applications.

For applications such as commutation diodes it can be important to model diode charge dynamics. When a forward-biased diode has a reverse voltage applied across it, it takes time for the charge to dissipate and hence for the diode to turn off. The time taken for the diode to turn off is captured primarily by the transit time parameter. Once the diode is off, any remaining charge then dissipates, the rate at which this happens being determined by the carrier lifetime.

The Diode block uses the model of Lauritzen and Ma [3] to capture these effects. The three defining equations are:

$$I=\frac{{q}_{E}-{q}_{M}}{TT}$$

$$\frac{d{q}_{M}}{dt}+\frac{{q}_{M}}{\tau}-\frac{{q}_{E}-{q}_{M}}{TT}=0$$

$${q}_{E}=\left(\tau +TT\right)IS\left(\mathrm{exp}\left(\frac{V}{N\cdot {V}_{t}}\right)-1\right)$$

where:

*I*is the diode current.*V*is the diode voltage.*N*is the emission coefficient.*q*_{E}is the junction charge.*q*_{M}is the total stored charge.*TT*is the transit time.*τ*is the carrier lifetime.

Datasheets do not typically provide values for *TT* and *τ*.
Therefore the Diode block provides an alternative parameterization
in terms of **Peak reverse current, Irrm** and **Reverse
recovery time, trr**. Equivalent values for *TT* and *τ* are
calculated from these values, plus information on the initial forward
current and rate of change of current used in the test circuit when
measuring *I*_{rrm} and *t*_{rr}.
The test circuit can consist of a series voltage source, resistor,
inductor and the diode. The polarity of the voltage source is switched
so as to move the diode from forward conduction to reverse biased.
The following figure shows an idealized diode current response.

The value of the series resistor and applied voltage value determine
the initial current *I*_{F}.
The value of the series inductance and the applied reverse voltage
value determine the current gradient, *a*.

The precise values of peak reverse current and reverse recovery time depend on the test circuit used. Also, junction capacitance has some effect on the current recovery characteristic. However, a junction capacitor value that dominates the response is physically unrealistic.

Only the exponential diode supports modeling of the diode charge
dynamics. If you select the `Exponential`

for
the **Diode model** parameter, then the **Capacitance** tab
contains an additional parameter called **Charge dynamics**.
Select between the three options:

`Do not model charge dynamics`

`Use peak reverse current and reverse recovery time`

`Use transit time and carrier lifetime`

The default behavior for the Diode is that dependence on temperature is not modeled, and the device is simulated at the temperature for which you provide block parameters. The Exponential diode model contains several options for modeling the dependence of the diode current-voltage relationship on the temperature during simulation. Temperature dependence of the junction capacitance is not modeled, this being a much smaller effect.

When including temperature dependence, the diode defining equation
remains the same. The measurement temperature value, *T*_{m1},
is replaced with the simulation temperature, *T*_{s}.
The saturation current, *IS*, becomes a function
of temperature according to the following equation:

$$I{S}_{Ts}=I{S}_{Tm1}\cdot {({T}_{s}/{T}_{m1})}^{XTI/N}\cdot \mathrm{exp}\left(-\frac{EG}{Nk{T}_{s}}(1-{T}_{s}/{T}_{m1})\right)$$

where:

*T*_{m1}is the temperature at which the diode parameters are specified, as defined by the**Measurement temperature**parameter value.*T*_{s}is the simulation temperature.*IS*_{Tm1}is the saturation current at measurement temperature.*IS*_{Ts}is the saturation current at simulation temperature. This is the saturation current value used in the standard diode equation when temperature dependence is modeled.*EG*is the energy gap for the semiconductor type measured in Joules. The value for silicon is usually taken to be 1.11 eV, where 1 eV is 1.602e-19 Joules.*XTI*is the saturation current temperature exponent. This is usually set to 3.0 for pn-junction diodes, and 2.0 for Schottky barrier diodes.*N*is the emission coefficient.*k*is the Boltzmann constant (1.3806503e–23 J/K).

Appropriate values for *XTI* and *EG* depend
on the type of diode and the semiconductor material used. Default
values for particular material types and diode types capture approximate
behavior with temperature. The block provides default values for common
types of diode.

In practice, the values of *XTI* and *EG* need
tuning to model the exact behavior of a particular diode. Some manufacturers
quote these tuned values in a SPICE Netlist, and you can read off
the appropriate values. Otherwise you can determine improved estimates
for *EG* by using a datasheet-defined current-voltage
data point at a higher temperature. The block provides a parameterization
option for this. It also gives the option of specifying the saturation
current at a higher temperature *IS _{Tm2}* directly.

You can also tune the values of *XTI* and *EG* yourself,
to match lab data for your particular device. You can use Simulink^{®}
Design Optimization™ software
to help tune the values for *XTI* and *EG*.

Device temperature behavior is also dependent on the emission
coefficient. An inappropriate value for the emission coefficient can
give incorrect temperature dependence, because saturation current
is a function of the ratio of *EG* to *N*.

If defining a finite reverse breakdown voltage *BV*,
then the value of the reverse breakdown voltage is modulated by the
reverse breakdown temperature coefficient *TCV* (specified
using the **Reverse breakdown voltage temperature coefficient,
dBV/dT** parameter):

*BV*_{Ts} = *BV*_{Tm1} – *TCV*·
(*T*_{s} – *T*_{m1})

The block has an optional thermal port, hidden by default. To
expose the thermal port, right-click the block in your model, and
then from the context menu select **Simscape** > **Block
choices** > **Show thermal port**.
This action displays the thermal port H on the block icon, and adds
the **Thermal Port** tab to the block dialog box.

Use the thermal port to simulate the effects of generated heat
and device temperature. For more information on using thermal ports
and on the **Thermal Port** tab parameters, see Simulating Thermal Effects in Semiconductors.

Use the **Variables** section of the block
interface to set the priority and initial target values for the block
variables prior to simulation. For more information, see Set Priority and Initial Target for Block Variables (Simscape).

The Exponential diode model has the following limitations:

When you select

`Use I-V curve data points`

for the**Parameterization**parameter, choose a pair of voltages near the diode turn-on voltage. Typically, this is in the range from 0.05 to 1 Volt. Using values outside of this region may lead to numerical issues and poor estimates for*IS*and*N*.The block does not account for temperature-dependent effects on the junction capacitance.

You may need to use nonzero ohmic resistance and junction capacitance values to prevent numerical simulation issues, but the simulation may run faster with these values set to zero.

**Diode model**Select one of the following diode models:

`Piecewise Linear (Foundation Library)`

— Use a piecewise linear model for the diode, as described in Piecewise Linear. This is the default method.`Piecewise Linear Zener`

— Use a piecewise linear model with reverse breakdown characteristics for the diode, as described in Piecewise Linear Zener.`Exponential`

— Use a standard exponential model for the diode, as described in Exponential.

**Forward voltage**Minimum voltage that needs to be applied for the diode to become forward-biased. This parameter is only visible when you select

`Piecewise Linear (Foundation Library)`

or`Piecewise Linear Zener`

for the**Diode model**parameter. The default value is`0.6`

V.**On resistance**The resistance of the diode when it is forward biased. This parameter is only visible when you select

`Piecewise Linear (Foundation Library)`

or`Piecewise Linear Zener`

for the**Diode model**parameter. The default value is`0.3`

Ω.**Off conductance**The conductance of the diode when it is reverse biased. This parameter is only visible when you select

`Piecewise Linear (Foundation Library)`

or`Piecewise Linear Zener`

for the**Diode model**parameter. The default value is`1e-08`

1/Ω.**Parameterization**Select one of the following methods for model parameterization:

`Use two I-V curve data points`

— Specify measured data at two points on the diode I-V curve. This is the default method.`Use parameters IS and N`

— Specify saturation current and emission coefficient.`Use an I-V data point and IS`

— Specify measured data at a single point on the diode I-V curve in combination with the saturation current.`Use an I-V data point and N`

— Specify measured data at a single point on the diode I-V curve in combination with the emission coefficient.

This parameter is only visible when you select

`Exponential`

for the**Diode model**parameter.**Currents [I1 I2]**A vector of the current values at the two points on the diode I-V curve that the block uses to calculate

*IS*and*N*. This parameter is only visible when you select`Exponential`

for the**Diode model**parameter and`Use two I-V curve data points`

for the**Parameterization**parameter. The default value is`[ 0.0137 0.545 ]`

A.**Voltages [V1 V2]**A vector of the voltage values at the two points on the diode I-V curve that the block uses to calculate

*IS*and*N*. This parameter is only visible when you select`Exponential`

for the**Diode model**parameter and`Use two I-V curve data points`

for the**Parameterization**parameter. The default value is`[ 0.6 0.7 ]`

V.**Current I1**A current value at the point on the diode I-V curve that the block uses for calculations. This parameter is only visible when you select

`Exponential`

for the**Diode model**parameter and either`Use an I-V data point and IS`

or`Use an I-V data point and N`

for the**Parameterization**parameter. Depending on the**Parameterization**value, the block uses this parameter to calculate either*N*or*IS*. The default value is`0.07`

A.**Voltage V1**A voltage value at the point on the diode I-V curve that the block uses for calculations. This parameter is only visible when you select

`Exponential`

for the**Diode model**parameter and either`Use an I-V data point and IS`

or`Use an I-V data point and N`

for the**Parameterization**parameter. Depending on the**Parameterization**value, the block uses this parameter to calculate either*N*or*IS*. The default value is`0.7`

V.**Saturation current, IS**The magnitude of the current that the ideal diode equation approaches asymptotically for very large reverse bias levels. This parameter is only visible when you select

`Exponential`

for the**Diode model**parameter and either`Use parameters IS and N`

or`Use an I-V data point and IS`

for the**Parameterization**parameter. The default value is`1e-14`

A.**Emission coefficient, N**The diode emission coefficient or ideality factor. This parameter is only visible when you select

`Exponential`

for the**Diode model**parameter and either`Use parameters IS and N`

or`Use an I-V data point and N`

for the**Parameterization**parameter. The default value is`1`

.**Ohmic resistance, RS**The series diode connection resistance. This parameter is only visible when you select

`Exponential`

for the**Diode model**parameter. The default value is`0.01`

Ω.**Measurement temperature**The temperature

*T*_{m1}at which IS or the I-V curve was measured. This parameter is only visible when you select`Exponential`

for the**Diode model**parameter. The default value is`25`

°C.

This section is not applicable for Piecewise Linear diode models.

**Zener resistance Rz**The resistance of the diode when the voltage is less than the

**Reverse breakdown voltage Vz**value. This parameter is only visible when you select`Piecewise Linear Zener`

for the**Diode model**parameter. The default value is`0.3`

Ω.**Reverse breakdown voltage Vz**The reverse voltage below which the diode resistance changes to the

**Zener resistance Rz**value. This parameter is only visible when you select`Piecewise Linear Zener`

for the**Diode model**parameter. The default value is`50`

V.**Reverse breakdown voltage BV**The reverse voltage below which to model the rapid increase in conductance that occurs at diode breakdown. This parameter is only visible when you select

`Exponential`

for the**Diode model**parameter. The default value is`Inf`

V, which effectively omits reverse breakdown from the model.

**Junction capacitance**When you select

`Piecewise Linear (Foundation Library)`

or`Piecewise Linear Zener`

for the**Diode model**parameter, the**Junction capacitance**parameter is the fixed junction capacitance value. The default value is`5`

pF.When you select

`Exponential`

for the**Diode model**parameter, the**Junction capacitance**parameter lets you select one of the following options for modeling the junction capacitance:`Include fixed or zero junction capacitance`

— Model the junction capacitance as a fixed value.`Use C-V curve data points`

— Specify measured data at three points on the diode C-V curve.`Use parameters CJ0, VJ, M & FC`

— Specify zero-bias junction capacitance, junction potential, grading coefficient, and forward-bias depletion capacitance coefficient.

**Zero-bias junction capacitance CJ0**The value of the capacitance placed in parallel with the exponential diode term. This parameter is only visible when you select

`Exponential`

for the**Diode model**parameter and`Include fixed or zero junction capacitance`

or`Use parameters CJ0, VJ, M & FC`

for the**Junction capacitance**parameter. The default value is`5`

pF.**Reverse bias voltages [VR1 VR2 VR3]**A vector of the reverse bias voltage values at the three points on the diode C-V curve that the block uses to calculate

*CJ0*,*VJ*, and*M*. This parameter is only visible when you select`Exponential`

for the**Diode model**parameter and`Use C-V curve data points`

for the**Junction capacitance**parameter. The default value is`[ 0.1 10 100 ]`

V.**Corresponding capacitances [C1 C2 C3]**A vector of the capacitance values at the three points on the diode C-V curve that the block uses to calculate

*CJ0*,*VJ*, and*M*. This parameter is only visible when you select`Exponential`

for the**Diode model**parameter and`Use C-V curve data points`

for the**Junction capacitance**parameter. The default value is`[ 3.5 1 0.4 ]`

pF.**Junction potential VJ**The junction potential. This parameter is only visible when you select

`Exponential`

for the**Diode model**parameter and`Use parameters CJ0, VJ, M & FC`

for the**Junction capacitance**parameter. The default value is`1`

V.**Grading coefficient M**The grading coefficient. This parameter is only visible when you select

`Exponential`

for the**Diode model**parameter and`Use parameters CJ0, VJ, M & FC`

for the**Junction capacitance**parameter. The default value is`0.5`

.**Capacitance coefficient FC**Fitting coefficient that quantifies the decrease of the depletion capacitance with applied voltage. This parameter is only visible when you select

`Exponential`

for the**Diode model**parameter and`Use C-V curve data points`

or`Use parameters CJ0, VJ, M & FC`

for the**Junction capacitance**parameter. The default value is`0.5`

.**Charge model**Select one of the following methods for charge dynamics parameterization:

`Do not model charge dynamics`

— Do not include charge dynamics modeling. This is the default method.`Use peak reverse current and reverse recovery time`

— Model charge dynamics by providing values for peak reverse current,*I*_{rrm}, and reverse recovery time,*t*_{rr}, plus information on the initial forward current and rate of change of current used in the test circuit when measuring*I*_{rrm}and*t*_{rr}. Use this option if the manufacturer datasheet does not provide values for transit time,*TT*, and carrier lifetime,*τ*.`Use transit time and carrier lifetime`

— Model charge dynamics by providing values for transit time,*TT*, and carrier lifetime,*τ*.

**Peak reverse current, Irrm**The peak reverse current measured in a test circuit. This parameter is only visible when you select

`Exponential`

for the**Diode model**parameter and`Use peak reverse current and reverse recovery time`

for the**Charge model**parameter. The default value is`7.15`

A.**Starting forward current when measuring Irrm**The initial forward current when measuring peak reverse current. This parameter is only visible when you select

`Exponential`

for the**Diode model**parameter and`Use peak reverse current and reverse recovery time`

for the**Charge model**parameter. The default value is`4`

A.**Rate of change of current when measuring Irrm**The rate of change of current when measuring peak reverse current. This parameter is only visible when you select

`Exponential`

for the**Diode model**parameter and`Use peak reverse current and reverse recovery time`

for the**Charge model**parameter. The default value is`-750`

A/us.**Reverse recovery time, trr**The time between the point where the current initially goes to zero when the diode turns off, and the point where the current falls to less than ten percent of the peak reverse current. This parameter is only visible when you select

`Exponential`

for the**Diode model**parameter and`Use peak reverse current and reverse recovery time`

for the**Charge model**parameter. The default value is`115`

ns.**Transit time, TT**A measure of how long it takes carriers to cross the diode junction. This parameter is only visible when you select

`Exponential`

for the**Diode model**parameter and`Use transit time and carrier lifetime`

for the**Charge model**parameter. The default value is`50`

ns.**Carrier lifetime, tau**A measure of how long it takes for the carriers to dissipate once the diode is no longer conducting. This parameter is only visible when you select

`Exponential`

for the**Diode model**parameter and`Use transit time and carrier lifetime`

for the**Charge model**parameter. The default value is`100`

ns.

This section is applicable for Exponential diode models only.

**Parameterization**Select one of the following methods for temperature dependence parameterization:

`None — Simulate at parameter measurement temperature`

— Temperature dependence is not modeled, or the model is simulated at the measurement temperature*T*_{m1}(as specified by the**Measurement temperature**parameter on the**Main**tab). This is the default method.`Use an I-V data point at second measurement temperature`

— If you select this option, you specify a second measurement temperature*T*_{m2}, and the current and voltage values at this temperature. The model uses these values, along with the parameter values at the first measurement temperature*T*_{m1}, to calculate the energy gap value.`Specify saturation current at second measurement temperature`

— If you select this option, you specify a second measurement temperature*T*_{m2}, and saturation current value at this temperature. The model uses these values, along with the parameter values at the first measurement temperature*T*_{m1}, to calculate the energy gap value.`Specify the energy gap, EG`

— Specify the energy gap value directly.

**Current I1 at second measurement temperature**Specify the diode current

*I1*value when the voltage is*V1*at the second measurement temperature. This parameter is only visible when you select`Use an I-V data point at second measurement temperature`

for the**Parameterization**parameter. The default value is`0.245`

A.**Voltage V1 at second measurement temperature**Specify the diode voltage

*V1*value when the current is*I1*at the second measurement temperature. This parameter is only visible when you select`Use an I-V data point at second measurement temperature`

for the**Parameterization**parameter. The default value is`0.5`

V.**Saturation current, IS, at second measurement temperature**Specify the saturation current

*IS*value at the second measurement temperature. This parameter is only visible when you select`Specify saturation current at second measurement temperature`

for the**Parameterization**parameter. The default value is`1.25e-7`

A.**Second measurement temperature**Specify the value for the second measurement temperature. This parameter is only visible when you select either

`Use an I-V data point at second measurement temperature`

or`Specify saturation current at second measurement temperature`

for the**Parameterization**parameter. The default value is`125`

°C.**Energy gap parameterization**This parameter is only visible when you select

`Specify the energy gap, EG`

for the**Parameterization**parameter. It lets you select a value for the energy gap from a list of predetermined options, or specify a custom value:`Use nominal value for silicon (EG=1.11eV)`

— This is the default.`Use nominal value for 4H-SiC silicon carbide (EG=3.23eV)`

`Use nominal value for 6H-SiC silicon carbide (EG=3.00eV)`

`Use nominal value for germanium (EG=0.67eV)`

`Use nominal value for gallium arsenide (EG=1.43eV)`

`Use nominal value for selenium (EG=1.74eV)`

`Use nominal value for Schottky barrier diodes (EG=0.69eV)`

`Specify a custom value`

— If you select this option, the**Energy gap, EG**parameter appears in the dialog box, to let you specify a custom value for*EG*.

**Energy gap, EG**Specify a custom value for the energy gap,

*EG*. This parameter is only visible when you select`Specify a custom value`

for the**Energy gap parameterization**parameter. The default value is`1.11`

eV.**Saturation current temperature exponent parameterization**Select one of the following options to specify the saturation current temperature exponent value:

`Use nominal value for pn-junction diode (XTI=3)`

— This is the default.`Use nominal value for Schottky barrier diode (XTI=2)`

`Specify a custom value`

— If you select this option, the**Saturation current temperature exponent, XTI**parameter appears in the dialog box, to let you specify a custom value for*XTI*.

**Saturation current temperature exponent, XTI**Specify a custom value for the saturation current temperature exponent,

*XTI*. This parameter is only visible when you select`Specify a custom value`

for the**Saturation current temperature exponent parameterization**parameter. The default value is`3`

.**Reverse breakdown voltage temperature coefficient, dBV/dT**This coefficient modulates the reverse breakdown voltage

*BV*. If you define the reverse breakdown voltage*BV*as a positive quantity, a positive value for*TCV*implies that the magnitude of the reverse breakdown voltage decreases with temperature. The default value is`0`

V/K.**Device simulation temperature**Specify the value for the temperature

*T*_{s}, at which the device is to be simulated. The default value is`25`

°C.

The block has the following ports:

`+`

Electrical conserving port associated with the diode positive terminal

`-`

Electrical conserving port associated with the diode negative terminal

[1] MH. Ahmed and P.J. Spreadbury. *Analogue
and digital electronics for engineers*. 2nd Edition, Cambridge
University Press, 1984.

[2] G. Massobrio and P. Antognetti. *Semiconductor
Device Modeling with SPICE*. 2nd Edition, McGraw-Hill,
1993.

[3] Lauritzen, P.O. and C.L. Ma. “A Simple Diode Model
with Reverse Recovery.” *IEEE ^{®} Transactions on
Power Electronics*. Vol. 6, No. 2, April 1991.

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