Categories of CAD Models
There are several categories of CAD models available for Spansion Flash memory devices.

• For digital circuit simulation and timing verification, the most common model formats are VHDL and Verilog.
• For signal integrity tests and transition response, the preferred model is IBIS format.

VHDL and Verilog Models
These models are used to perform circuit simulation. They replicate command inputs and outputs as found in the device datasheet.

Denali Software
VHDL and Verilog behavioral simulation models are now available from Denali Software in Palo Alto, California.

Denali is a company that focuses only on model support for memory devices. Their model creation system builds models in 'C' that can be ported to work with all the major Verilog and VHDL simulators. They have committed to create model files for all our single power supply Flash devices and to support and verify their model files in all major simulator environments. They also have the capability of creating model files for devices from datasheet specifications so customers can simulate a new device in their system before first silicon.

Denali models for some Spansion devices are available for download from the Spansion FTP site. For further information on Denali models and support for other Spansion Flash memory devices, visit their web site at www.denalisoft.com.

IBIS
IBIS (I/O Buffer Information Specification) is a behavioral description of the I/O buffers and package characteristics of a semiconductor device. IBIS models use a standard format to make it easier to import data into circuit simulation software packages. A consortium of semiconductor companies developed the IBIS model format for the express purpose of giving customers the data they needed without sharing proprietary H-SPICE models.

Customers can use IBIS to check/verify:

• Signal Integrity
• EMI
• Transition response

To download IBIS models for various Spansion memory devices, select the IBIS model links on the right.

H.A.S. Electronics
IBIS models for the Am29F040-150JC are available for $288 from H.A.S. Electronics, Inc. Other models may be available on request.

Other Third-Party EDA Models
Synopsys (formerly Logic Modeling Corporation) in Beaverton, Oregon, compiles behavioral Models in a binary file format. They are available only through a licensing agreement that must be executed between the customer and Synopsys. Flash and EPROM datasheets were provided to Synopsys and they generated the models for placement in their SmartModel Library for memory devices. These models can be configured for use at multiple sites on a wide variety of CAD platforms.

For more information on Synopsys products, please contact the company directly at (503) 531-2279, or at www.synopsys.com.