SIwave: Everything You Need to Know About the SIwizard (HD Version)

SI Wave is a power integrity and signal integrity tool. The Signal Integrity Wizard, which is this solver, is the main tool for signal integrity analysis. Signal Integrity Wizard is used to study the signal integrity of RF clock and control traces. Using this tool, the user can check if the bandwidth is sufficient and if the group delay deficiency is tolerable in any trace.

Key Features of Signal Integrity Wizard

• Transient analysis
• Eye analysis
• Bit error calculations
• S-parameter calculations

Users can add IBIS and IBIS-MI models to the TX and RX side. SI Wave supports NRZ as well as PAM for signals.

Important Considerations

SI Wave should not be used to build PCBs. While this is possible, it's not the best way to use SI Wave. SI Wave can import all kinds of files in different formats.

File Import Recommendations

• Users of Allegro and Altium can install ANSYS ADB translator to produce ADB files.
• For ORCAD users, it is recommended to use IPC 2581.
• Mentor Expedition users should use ODB++ files.
• Cadence users should generate BRD files and import them to SIWave. Cadence must be installed on the same computer, and the extractor from Cadence must also be installed with its location in the path environment variable.

Working with Differential Traces

Before launching the Signal Integrity Wizard, ensure that SI Wave recognizes the differential traces:

1. Select the differential tab. It might be empty initially.
2. Click auto-identify. SI Wave will show the notations it uses to recognize differential lines, such as _P and _N.
3. If correct, click auto-identify again to populate the table with differential lines.

You can also manually select two nets with _P and _N and create differential pairs.

Creating Extended Nets

For traces made of many sections due to DC blocks or components like resistors or inductors, you can create an extended net:

1. Click auto-identify in the extended net tab. SI Wave uses the letter R to recognize nets that can be combined.
2. To create an extended net, edit the net name to include R at the end.
3. Use auto-identify to recognize and combine the nets.

There are three ways to create extended nets:

• Auto-identify based on naming conventions.
• Manually select and unite nets from the screen.
• Enter a new name and select nets from the board.

Setting Up the Signal Integrity Wizard

Once signals are identified as single, differential, or extended, proceed to the solver:

1. Select the Signal Integrity Wizard.
2. Choose single-ended, differential, or extended traces for analysis.
3. Understand the schematic created by the solver, which includes I sources and I probes.

Understanding the Dialog Box

The dialog box contains several columns:

• Individual Nets: Lists the nets.
• Pin: Specifies if a port is needed on that pin.
• Component Name: Name of the component.
• Reference Designator: Unique identifier for each component on the PCB.
• Driver/Receiver: Specify if the net is a driver or receiver.
• IBIS Models: Add IBIS models if needed.
• Excitation: Define the signal type (e.g., default pulse, PRBS).

Defining Signals

In the Manage Sources dialog box, define your signals:

• Specify voltage, type, bit list, seed, period, duty cycle, bit rate, delay, rise time, fall time, and internal impedance.
• For PRBS, enter random in the seed field for automatic random bit sequence generation.

Receiver Termination and Solver Setup

Define the impedance of the receiver and specify power planes connected to the components:

1. Enter the project name and choose to generate a net list or schematic.
2. Define transient solver settings, including step size and stop time.
3. Select the desired actions for SI Wave after creating the schematic.
4. Configure S-parameter settings, including signal and power net impedance.

Advanced Solver Options

Access additional solver options for accuracy, temperature, multiprocessing, and net processing.

Solving and Analyzing Results

Once setup is complete, start solving:

1. View transient solver results, including voltage at the driver and receiver.
2. Generate eye diagrams using different methods:
• Rectangular plot
• Stacked eye diagram plot
• Statistical eye plot
3. Perform statistical analysis with the verify eye feature to generate bathtub analysis.

Using IBIS Models

To add IBIS models:

1. Select the receiver and driver, then choose the appropriate IBIS model and update.
2. Review the schematic with IBIS models and adjust settings as needed.

For more detailed information on IBIS models, a special session will be provided to explain their setup and options.