Looking for zener diode model.

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While you are waiting to find one if one exists. It might be quicker to roll your own approximation from the datasheet. From the LTspice Help file:

D. Diode
A diode requires a .model card to specify its characteristics. There are two types of diodes available. One is a conduction region-wise linear model that yields a computationally light weight representation of an idealized diode. It has three linear regions of conduction: on, off and reverse breakdown. Forward conduction and reverse breakdown can non-linear by specifying a current limit with Ilimit(revIlimit). tanh() is used to fit the slope of the forward conduction to the limit current. The parameters epsilon and revepsilon can be specified to smoothly switch between the off and conducting states. A quadratic function is fit between the off and on state such that the diode's I-V curve is continuous in value and slope and the transition occurs over a voltage specified by the value of epsilon for the off to forward conduction and revepsilon for the transition between off and reverse breakdown.

Below are the model parameters for this type of diode:

NameDescriptionUnitsDefault
RonResistance in forward conduction1.0
RoffResistance when offΩ1/Gmin
VfwdForward threshold voltage to enter conductionV0.0
VrevReverse breakdown voltageVInfin.
RrevBreakdown impedanceΩRon
IlimitForward current limitAInfin.
RevilimitReverse current limitAInfin.
EpsilonWidth of quadratic regionV0.0
RevepsilonWidth of reverse quad. regionV0.0
This idealized model is used if any of Ron, Roff, Vfwd, Vrev or Rrev is specified in the model.
 
Sure. It's all up to your level of motivation. The piecewise linear conduction model is easier to deal with than the alternative.
 
Papabravo what do you think about this:

.MODEL 1N4109 D BV=15 IS=5.72393f CJO=73.3167p IBV=50u VJ=0.75

I got it from my LTspice group.
 
Papabravo what do you think about this:

.MODEL 1N4109 D BV=15 IS=5.72393f CJO=73.3167p IBV=50u VJ=0.75

I got it from my LTspice group.
If you're happy, then so am I. You might want to check on the default values for the other parameters to avoid surprises. In particular there is the emission coefficient, N, which defaults to 1.0
 
Why would you choose 1N4109's?

They are rather old/unpopular and many better choices for cost, performance and availability exist.
 
Why would you choose 1N4109's?

They are rather old/unpopular and many better choices for cost, performance and availability exist.
It is not clear that the TS needs to obtain them. More likely he has some and wants to investigate their suitability.
 
You might approach the need for a spice model differently. What zener characteristic is critical to your circuit design?
That is why I suggested he use the piecewise linear diode model available in LTspice and perhaps other spice packages as well. See the description in post #2
 
Be sure to compare it with the model in your post #6 for good measure. You should be able to get what you need with a DC sweep from -17V to +2V and some current limiting. this is simulation and you can stress the hell out of model without the agony of letting out the magic smoke
 
I believe I found a more modern device to replace the 1N4109. The BZX55C15-TAP, but still no model.
 
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