Layout Guidelines for SmartFusion2- and IGLOO2-Based Board Design
AC393 Application Note Revision 14.0 59
3.9 Considerations for Simulation
Microsemi recommends simulations to confirm the quality of the received signal. The following files are
required to simulate the serial channel:
• IBIS: AMI files for SmartFusion2/IGLOO2 and any other devices that are connected to SerDes
• Package: files (optional). S-parameter of package improves the accuracy instead of using package
parameters in the IBIS file
• Board traces model file including via models
• Connector models, if required
The following steps describe how to run the serial channel simulations:
3.9.1 Step 1: Gathering the Required Files
3.9.1.1 IBIS-AMI Models
The IBIS-AMI models of SmartFusion2/IGLOO2 and the IBIS-AMI models of IC that will be interfaced
with SmartFusion2/IGLOO2 can be downloaded from the Microsemi website:
• www.microsemi.com/soc/download/ibis/SmartFusion2.aspx
• www.microsemi.com/soc/download/ibis/IGLOO2.aspx
3.9.1.2 Package Models
The package models (S-parameter models) of SmartFusion2/IGLOO2 can be downloaded from the
Microsemi website:
• www.microsemi.com/soc/download/ibis/SmartFusion2.aspx
• www.microsemi.com/soc/download/ibis/IGLOO2.aspx
Accuracy of simulation improves with S-parameter model of package file instead of using package
models available in the IBIS file. If S-parameter models for package are used, the package details in IBIS
should be commented.
3.9.1.3 PCB Trace Models
The PCB file should be converted into a compatible format of simulator software. For example, the
.HYP file format of PCB is required to be simulated in Hyperlynx, and
.SPD file format of PCB is required
to be simulated in Sigrity. Once the PCB file is loaded in the simulation tool, the stack-up that matches
the PCB stack-up should be checked. The dielectric constant, Dk and dissipation factor, and Df of PCB
material should be defined. The tool extracts incorrect models, if the above points are not defined
properly.
The SerDes traces should be identified and ports on both the sides of the traces need to be assigned.
The S-parameter models of traces should be extracted. The following tools can be used to extract S-
parameter models of PCB traces:
• Agilents ADS
• Mentors Hyperlynx
• Sigritys PowerSI
It is not mandatory to use the above mentioned tools, many other tools are available in the market which
can extract S-parameter models.
3.9.2 Step 2: Creating Simulation Topology
The typical topology, as shown in the following figure, shows the blocks involved in the serial link
analysis. These blocks are taken from the Sigrity tool. All simulations related to SerDes are done on
Sigritys SystemSI tool in this document. Topology is same in any tool. This can be done in any tool that
supports the serial link analysis.
The typical topology for SLA simulation is done as following:
• AMI: AMI models of TX and RX
• TX_PRIMARY: IBIS model of TX I/O
• Pkg1 and Pkg2: Package model of TX and RX I/O
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