Digital Signal Processing Reference
In-Depth Information
Some 3D solvers have
wizards
or template files that make it easy to setup com-
monly found problems such as vias or differential pair traces (or differential vias).
This valuable feature can save significant time and is especially important if the SI
engineer is not using the simulator on a daily basis.
Generally S-parameters are the default output model type, but RLGC files or
W line models can also sometimes be created. The electrical parameters calculated
are of the complete geometry. For instance, a structure might have a capacitance of
3 pF, but it would not have a value of 3 pF/inch.
3.6 Main Points
I/O models are either transistor based or behavioral.
•
Transistor level models are most accurate but run significantly slower than
IBIS models.
•
Transistor level models may be encrypted to protect intellectual property.
This can make the SI debug more difficult.
•
IBIS models are the most common behavioral type model and run signifi-
cantly faster than transistor level models.
•
Field solvers calculate the resistance, capacitance, inductance, and conduc-
tance of physical structures.
•
Two-dimensional field solvers are used to create circuit models of regular
structures such as uniform traces.
•
Three-dimensional field solvers are used to create circuit models such as vias
and irregular structures.
•
Some 3D simulators are difficult to set up and to properly run and should be
thoroughly tested to verify that the operation is intuitive.
•
The output from 2D and 3D field solvers can be tabular data, circuit models
of various forms, or S-parameters.
•
References
[1]
IBIS version 5.0, ratifi ed August 2008 by the IBIS Open Forum, http://www.eigroup.org/
ibis/specs.htm.
[2]
Thierauf, S. C.,
High-Speed Circuit Board Signal Integrity
, Norwood, MA: Artech House,
2004.
[3]
Proakis, J. G.,
Digital Communications
, New York: McGraw-Hill, 2000.
[4]
Bateman, A.,
Digital Communications
, Reading, MA: Addison-Wesley, 1998.
[5]
Bissell, C. C., et al.,
Digital Signal Transmission
, Cambridge: Cambridge University Press,
1996.
[6]
Horowitz, M., et al., “High-Speed Electrical Signaling: Overview and Limitations,”
IEEE
Micro
., Vol. 18, No. 1, January/February 1998.
[7]
Dally, W., et al., “Transmitter Equalization for 4-Gbps Signaling,”
IEEE Micro
, Vol. 17,
No. 1, January/February 1997.
