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Introduction to SIMetrix Demo Version

  Limitations

Features:

All features of the full production version are enabled except:

  1. The command line is not present. This effectively inhibits any features that require the command line. There are, however, very few of these.
  2. User scripts.
  3. Custom menu and key definitions.
  4. Currently the "User Defined" goal functions for histogram plots and performance analysis don't work in SIMetrix Intro. This is actually a bug not a deliberate limitation and will be corrected at the next minor upgrade. This bug does not apply to the full production version.
  5. The PSpice translator is limited to small schematics.
The symbol editor limitations of earlier versions have now been lifted.

Circuit Size Limits

There is a limit to the size of circuit that can be simulated. The exact limits are:

  • 120 analog nodes
  • 36 digital nodes
  • 72 digital ports
  • 24 digital components
  • 36 digital outputs
Although the number of allowed digital nodes is small, there is no limit to the size of definition for an arbitrary logic block. This in practice means that quite large digital circuits can be simulated.

There is also a limit to the number of some analog components. The limit can be worked out by multiplying the number of each type of component by the score given in the table below then summing all the results. The total must be 384 or less for the circuit to be accepted.

 
BJT 21
Diode 5
JFET 13
GaasFET 13
MOS devices other than BSIM3 and MOS9 17
Capacitor 2
Inductor 2
BSIM3 18
Laplace 2 + 2 X (order of denominator)
Philips Devices:
MOS9 6
JUNCAP 2
Mextram 12
 
All other devices 0
 

Examples:
18 BJT's + 10 resistors: score 378 - OK
18 BJT's + 4 capacitors: score 386 - fail
2 MOS1 2 BJT 10 capacitors: score 96 - OK

The number of opamps you can use is usually limited by the maximum number of nodes. These are usually composed of a collection of controlled sources which score zero. In practice you can usually simulate circuits that have three opamps.

 

 Other Limitations

The schematic symbol library supplied has 170 symbols compared with 340 for the full product (SIMetrix AD).
Only a handful of device models are supplied, sufficient to run the example circuits.
 

 There are no Limits on...

...the complexity of arbitrary source expressions or arbitrary logic block definitions. There are also no limits on the size of schematic that can be drawn or printed. Unlike earlier versions of SIMetrix Intro, there is no simulation run time limit and all devices and analysis modes are enabled.
 

 Documentation

The help file contains virtually all the documentation provided in the printed "User's Manual" that is supplied with the full product. A second manual - the "Simulator Reference Manual" - also supplied with the full product - is available as a PDF file. Click here to download it.
 
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