# Setting Up Translation Options

Choose Options from the Translate menu to open the Translation Command Settings dialog. It takes over 2000 Java statements to initialize this dialog, so please be patient while it opens. Settings made here will be saved in a control file that will provide input to s2ibis2. The control file is named after the SPICE file, but with a .s2i extension. For example, if the SPICE file is iobuff.sp, then s2ibis2 options are saved in iobuff.s2i in the project directory when OK is clicked.

### Importing an s2ibis Control File

You can save time by reading settings from an existing s2ibis2 control file. This may have been manually prepared for use with s2ibis2, or it may reside in another SpiTran project directory. Click the Import Settings from File button to open a file browser. Selecting a .s2i file will import the settings. The import file is read, but will not be modified.

### Editing the Settings

For more details on the usage of items edited in this dialog, see the s2ibis2 documentation. Every item in this dialog is saved as an s2ibis2 control parameter, following the command language defined for this file. Some items written to the control file are not edited, but are determined by SpiTran. For example, the [IBIS Ver] is always "2.1" and the date is always the current date.

First set the buffer type by selecting one of the standard IBIS model types from the Buffer Type popup:

- Input
- Input_ECL
- I/O
- I/O_ECL
- I/O_open_drain
- I/O_open_sink
- I/O_open_source
- Open_drain
- Open_sink
- Open_source
- Output_ECL
- 0utput
- 3-state

Then select items from the hierarchical tree menu to display the various settings pages. The items with folder icons must be double-clicked to expand the subitems. The following sections discuss the settings pages.

### Node Options

Select the Nodes tab to display the Nodes options page. This is the page that is shown when the dialog opens. Note that the popup menus are currently inoperative, so each field must be typed.

IBIS Model Name | The name of the buffer Model to create. This will be the [Model] entry in the IBIS file.
Buffer | The name of the node for buffer input/output.
Power | The name of the node for positive power supply.
Ground | The name of the node for negative power supply.
Buffer Input | The name of the node for controlling the buffer logic state.
Buffer Enable | The name of the node for controlling the buffer enable state.

### Mode Options

Select the Mode tab to display the Mode options page.

SPICE Type | s2ibis2 allows HSpice, PSpice, Spice2, Spice3, or Spectre
Iterate | Check this to save time when multiple iterations are required to achieve successful translation. If set, s2ibis2 will not repeat simulations for which an output file already exists in the project directory.
Cleanup | If set, s2ibis2 will remove all simulation files as it proceeds, leaving the project directory relatively clean.
Summarize | This makes s2ibis2 more verbose, and causes it to require interactive user input to proceed.

### Model Information Options

Select the Model Information tab to display the Model Information page.

These parameters are passed into the IBIS file. The Inverting and Active-High parameters control the generation of stimulus voltages as well.

Low Input Threshold | Enter the Low state input threshold voltage.
High Input Threshold | Enter the High state input threshold voltage.
C_comp | Enter the die capacitance.
Inverting Polarity | Set this if a High input voltage induces a Low logic output state.
Active-High Enable | Set this if a High input voltage puts the buffer output into the High-Z state.

### Voltage Options

Select the Voltage tab to display the Voltage page.

VoltageRange is a convenient means for setting both PullUp and PowerClamp to a power supply reference voltage, and assuming 0V for the PullDown and GroundClamp references. If you set VoltageRange leave the other fields blank. Otherwise, leave VoltageRange blank and set specific voltages for the other fields. For each parameter that you set, enter typical, minimum, and maximum values for the parameter.

Voltage Range | If set, these values are used for PullUp and PowerClamp voltages, and 0V is assumed for the PullDown and GroundClamp voltages.
PullUp | If VoltageRange is not set, set this to the reference voltage for the PullUp.
PullDown | If VoltageRange is not set, set this to the reference voltage for the PullDown.
PowerClamp | If VoltageRange is not set, set this to the reference voltage for the PowerClamp.
GroundClamp | If VoltageRange is not set, set this to the reference voltage for the GroundClamp.

### Stimulus Options

Select the Stimulus tab to display the Stimulus page.

These parameters are used by s2ibis2 to insert stimulus elements into the test circuits, and to run the simulation.

Simulation Time | Enter the amount of time that must be simulated to adequately show the buffer making a full swing logic transition.
Rise Time | The 0 to 100% rise time for the stimulus voltage that will be applied to the buffer input control for output buffers, or to the buffer input for receivers.
Fall Time | The 0 to 100% fall time for the stimulus voltage that will be applied to the buffer input control for output buffers, or to the buffer input for receivers.
Low V | The voltage that is applied to the buffer input control to force a logic low condition.
High V | The voltage that is applied to the buffer input control to force a logic high condition.

### VT Waveform(1) Options

Select the VT-1 tab to display the VT-1 page.

The test fixtures for rising and falling waveform characterization are similar to those for BufferDelay measurement. Although an L element is allowed in addition to a C element in the fixture, neither of these are recommended. To insure that your IBIS model will simulate accurately and consistently in all IBIS simulators, your test fixtures should have only V_fix and R values set. Enter typical, minimum, and maximum values for the V_fix parameters. The DUT (Device Under Test) fields are currently unused; leave them blank. The first VT test fixture usually uses the PullDown reference voltages for V_fix.

Rising Waveform V_fix | The voltage that Fixture R is terminated to for the rising waveform test fixture.
Rising Waveform Fixture R | The resistive load for the rising waveform test fixture.
Rising Waveform Fixture L | An inductor connecting the buffer to the Fixture R for the rising waveform test fixture.
Rising Waveform Fixture C | The capacitive load for the rising waveform test fixture.
Falling Waveform V_fix | The voltage that Fixture R is terminated to for the falling waveform test fixture.
Falling Waveform Fixture R | The resistive load for the falling waveform test fixture.
Falling Waveform Fixture L | An inductor connecting the buffer to the Fixture R for the falling waveform test fixture.
Falling Waveform Fixture C | The capacitive load for the falling waveform test fixture.

### VT Waveform(2) Options

Select the VT-2 tab to display the VT-2 page.

The second VT test fixture usually uses the PullDown reference voltages for V_fix. The parameters are the same as described above for the first VT test fixture.

### Ramp Load Options

Select the Ramp Load tab to display the Ramp Load page.

To fill in the Ramp data in the IBIS file, s2ibis performs simulations with a simple resistive load and measures the 20%-80% times.

Rload | A resistive load that will be used to determine Ramp rates.

### Buffer Delay Options

Select the Buffer Delay tab to display the Buffer Delay page.

These parameters are passed into the IBIS file. They are used for BufferDelay calculation, which s2ibis2 does not perform.

Vmeas | The voltage threshold used for BufferDelay time measurements.
Vref | The voltage that Rref is terminated to.
Cref | The capacitive load for the BufferDelay test fixture.
Rref | The resistive load for the BufferDelay test fixture.

### Temperature Options

Select the Temperature tab to display the Temperature page.

The temperature values are inserted into the SPICE files for simulation, and are passed into the IBIS file as well.

Temperature Range | Enter the buffer temperatures that best represent typical, minimum, and maximum operating conditions. Note that CMOS buffers usually operate better at higher temperatures, while the opposite is true for other technologies.

### Post Processing Options

Select the Post Processing tab to display the Post Processing page.

Set these parameters only if you need s2ibis2 to derate IBIS data to achieve an adjusted model. This is for experts. Consult the s2ibis2 documentation before using these.

Derate VI | Enter the percentage to reduce each current value in the VI curves.
Derate Ramp | Enter the percentage to reduce the Ramp rate values.
Clamp Tolerance | Enter the current below which s2ibis2 should not generate clamp curve values.

### Saving the Settings

Click OK to save the settings in an s2ibis2 control file. This file resides in the project directory. It has the same root name as the SPICE buffer file, with a .s2i extension. Here is a sample s2ibis2 control file produced by Spitran.