Product: 		ICAP/4Windows
Description: 		Analog and mixed signal circuit design software available from Intusoft
Price:				$2595, available immediately
Compatibility:	Windows 3.1x, Windows95, Windows NT (x86, Alpha, and Mips CPUs)
Contacts:			Charles Hymowitz - Vice President intusoft   (310) 833-0710, FAX (310) 833-9658, 
					E-mail 74774.2023@compuserve.com

New SPICE Adds Native Mixed Mode and HDL Support


	The ICAP/4Windows Virtual Circuit Design Lab has been updated with several major new features including native mixed mode simulation, support for user defined C subroutines (C Code Models), support for a public domain AHDL and a library of over 40 HDL models.

	Unlike SPICE 3, which is designed mainly for analog simulation, the new IsSpice4 program includes BOTH analog and event-driven digital simulation capabilities in the same executable. This means that any simulation may contain components that are analog, event driven, or a combination of both. An entire mixed signal analysis can be driven from one integrated schematic. All the digital models allow accurate specification of propagation time and rise/fall time delays. 

	The event driven algorithm in IsSpice4 is unique. It is general purpose and supports non-digital types of data. For example, elements can use real or integer values to simulate DSP functions or sampled data filters. Because the event driven algorithm is faster than the standard SPICE matrix solution simulation time is greatly reduced for circuits that use event driven models in place of analog models. 

Digital Modeling on Three Levels
	In IsSpice4, mixed mode simulation is handled on three levels; (a) with primitive digital elements that use timing models and the built-in 12 state digital logic simulator, (b) with subcircuit models that use the actual transistor topology of the integrated circuit, and finally, (c) with In-line Boolean logic expressions. 

	Exact representations are used mainly in the analysis of transmission line and signal integrity problems where a close inspection of an IC's I/O characteristics is needed. Boolean logic expressions are delayless functions that are used to provide efficient logic signal processing in an analog environment. These two modeling techniques use SPICE to solve a problem while the third method, digital primitives, uses IsSpice4's new native mixed mode capability. Each of these methods has its merits and target applications. In fact, many simulations call for the combination of all three approaches. No one approach alone is sufficient.

IsSpice4 Supports HDL Modeling For Top-Down Design
	IsSpice4 also supports XDL (XSPICE eXtended Description Language), a non-proprietary HDL (Hardware Description Language) based on the C programming language. XDL modeling, also called "Code Modeling" is a new approach to making SPICE models. It allows the designer to add new analog, digital, or mixed analog/digital models to SPICE very easily. The code modeling architecture is based on XSPICE, a derivative of Berkeley SPICE produced by the Georgia Institute of Technology. 

	XDL models are an extension of the standard devices offered in SPICE programs. They provide the designer with an enriched set of modeling primitives with which to perform system and board level top-down design, mixed mode simulation, and simulation of mixed domain (electrical-physical) systems. XDL models are basically C code that is compiled and linked to IsSpice4 via a Windows DLL. Since the source code is readily available, users can create new models or modify existing ones.

	Users can develop their own SPICE models with an additional "Code Model Software Development Kit", (CM-SDK list price $3500, special introductory price $2500 until 4/15/95). Once created, code models behave exactly like traditional SPICE models such as a diode or BJT. Along with support for C code modeling, IsSpice4 includes an expanding set of over 40 new analog, hybrid (mixed analog/digital), and digital models developed with XDL. The following XDL models are of particular significance:

Digital XDL Models: logic gates, flip-flops, Latches, State Machine, frequency divider, RAM, MIDI controlled oscillator

Analog XDL Models: s-domain (Laplace) transfer function, magnetic core, hysteresis, inductive coupling, table model, controlled oscillators

Mixed/Other XDL Models: digitally controlled oscillator, real gain, and real Z transform

ICAP/4: A Complete System
	The new ICAP/4Windows system includes an integrated schematic entry program, interactive SPICE 3/XSPICE based simulator (IsSpice4), Real time waveform display and analysis, and over 1000 new SPICE models bringing the total to over 6000. The DC and transient convergence properties of IsSpice4 have been greatly improved due to the addition and enhancement of gmin stepping/source stepping algorithms, independent supply ramping (Pseudo-Transient) algorithms, and automatic conductance from every node to ground.

Price And Availability
	Even though the update provides two major enhancements the list price for new purchases, $2595, has not been increased. Current ICAP/4Windows owners may update to the new version for $295. ICAP/4Windows requires Windows 3.1x, Windows 95, or Windows NT and 8 megabytes of RAM.