# Diode - Soft Recovery

In this topic:

## Netlist Entry

Dxxxx n+ n- model_name [TEMP=local_temp]
 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 '.'. local_temp Local temperature. Overrides specification in .OPTIONS or .TEMP statements.

## Diode Model Syntax

.model modelname SRDIO ( parameters )

## Soft Recovery Diode Model Parameters

 Name Description Units Default CJO Zero bias junction capacitance F 0.0 EG Energy gap ev 1.11 FC Forward bias depletion capacitance coefficient 0.5 IS Saturation current A 1E-15 MJ Grading coefficient 0.5 N Forward emission coefficient 1.0 RS Series resistance $\Omega$ 0 TNOM Parameter measurement temperature 27 TT Diffusion transit time S 5e-6 TAU Minority carrier lifetime 1e-5 VJ Built-in potential V 1 XTI Saturation current temperature exponent 3

## Basic Equations

The model is based on the paper "A Simple Diode Model with Reverse Recovery" by Peter Lauritzen and Cliff Ma. (See references). The model's governing equations are quite simple and are as follows:

$i_d = \frac{q_e - q_m}{TT}$

$\frac{dq_m}{dt} + \frac{q_m}{TAU} - \frac{q_e - q_m}{TT} = 0$

$q_e = IS \cdot TAU \cdot \left(\exp\left(\frac{v_d}{N\cdot V_t}\right)-1\right)$

In addition the model uses the standard SPICE equations for junction capacitance and temperature dependence of IS.

## References

Peter O. Lauritzen, Cliff L. Ma, A Simple Diode Model with Reverse Recovery, IEEE Transactions on Power Electronics, Vol. 6, No 2, pp 188-191, April 1991.