Zener Diode

The Zener Diode models the DC characteristics of most zeners. This model differs from the Diode/Rectifier by providing a user-defined dynamic resistance in the reverse breakdown region. The forward characteristic is defined by only a single point, since most data sheets for zener diodes do not give detailed characteristics in the forward region.

The first three parameters define the DC characteristics of the zener in the breakdown region and are usually explicitly given on the data sheet.

The saturation current refers to the relatively constant reverse current that is produced when the voltage across the zener is negative, but breakdown has not been reached. The reverse leakage current determines the slight increase in reverse current as the voltage across the zener becomes more negative. It is modeled as a resistance parallel to the zener with value v_breakdown / i_rev.

Note that the limit_switch parameter engages an internal limiting function for the zener. This can, in some cases, prevent the simulator from converging to an unrealistic solution if the voltage across or current into the device is excessive. If use of this feature fails to yield acceptable results, the convlimit option should be tried.

Port Table

Description Direction Default Type Allowed Types Vector Vector Bounds Null Allowed
zener INOUT gd gd NO   NO

Parameter Table

Name Description Data Type Default Value Limits Vector Vector Bounds Null Allowed
v_breakdown Breakdown voltage Real   1.0e-6 / 1.0e6; NO   NO
i_breakdown Breakdown current Real 2.0e-2 1.0e-9 / - NO   YES
r_breakdown Breakdown resistance Real 1.0 1.0e-12 / - NO   YES
i_rev Reverse current Real 1.0e-6 1.0e-9 / - NO   YES
i_sat Saturation current Real 1.0e-12 1.0e-15 / - NO   YES
n_forward Forward emission coefficient Real 1.0 0.1 / 10 NO   YES
limit_switch switch for on-board limiting (convergence aid) Boolean FALSE   NO   YES


a9 3 4 vreflO

.model vreflO zener(v_breakdown=10.0 i_breakdovn=0.02 r_breakdown=l.0 i_rev=le-6 i_sat=le-12)

See also

XSPICE Devices
XSPICE Code Models