• Analog Custom Design & Analysis Examples

opt_ex05 : Level 1 Diode Model Extraction

Requires: Utmost IV, SmartSpice, SmartView

Minimum Versions: Utmost IV 1.10.6.R, SmartSpice 4.10.2.R, SmartView 2.28.2.R

This example describes how to extract a level 1 diode model given typical forward and reverse current and reverse capacitance measurement data. A diode is a device with two terminals (nodes), the anode (A) and cathode (C). In forward operation, the anode bias is more positive than the cathode and in reverse operation the inverse is true.

The project file opt_ex05.prj and the data file diode.uds for this example should be loaded into your database. When opened, the project will look as shown in opt_ex05_01.png and when plotted, the example measured data will look as shown in opt_ex05_02.png .

The optimization sequence, which fully automates the extraction of this level1 diode model example, has three sections. The objective of each section is to isolate a device characteristic and then to optimize only those model parameters which account for this device behavior.

The first section, takes the reverse current characteristic and extracts the parameters BV and IBV associated with the reverse breakdown. Also included is the RS parameter representing the device series resistance.

The second section extracts the forward diode current parameters, IS and N . It also adjusts the series resistance parameter, RS , since the fit in the high forward current region is often more important than that in reverse operation.

In the final section, the reverse bias capacitance parameters, CJ0 , MJ and VJ are optimized.

Note that the Levenberg-Marquardt optimization method was used throughout this example, except for the fwd1 optimization setup where a more advanced Parallel-Tempering optimization is required.

Once the sequence is complete, the final model fit is as shown in opt_ex05_03.png . The model card can then be exported into an external model library file as shown in the output file opt_ex05.lib.

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