14 

VST/VAVO/VAEO Interfaces

This chapter describes the Virtuoso^® VoltageStorm Transistor (VST), Virtuoso Analog VoltageStorm Option (VAVO), and Virtuoso Analog ElectronStorm Option (VAEO) interfaces for the Virtuoso UltraSim^™ simulator.

VST Interface

The Cadence VoltageStorm Transistor-Level PGS tool is used to analyze the power distribution network for IR voltage drop and metal electromigration failure for a circuit design. The Virtuoso UltraSim simulator supports the following flows:

The Virtuoso UltraSim usim_ir command is designed to be used with these flows. For more information about this tool, refer to the VoltageStorm Transistor-Level PGS User Guide.

VAVO/VAEO Interface

Spectre Syntax

usim_emir type=all format=[vavo] [start=time] [stop=time]

SPICE Syntax

.usim_emir type=all format=[vavo] [start=time] [stop=time]

Note: A period (.) is required when using SPICE language syntax (for example, .usim_emir).

Description

To improve the efficiency and capability of the Virtuoso UltraSim simulator and VAVO/VAEO flow, the simulator calculates the information needed for electromigration (EM) and IR drop analysis, including maximum, root mean square (RMS), and average voltage values for each node, and average current values for each resistor. The information is saved in a binary database that can be read into VAVO/VAEO for post-processing.

The usim_emir command can be added to the netlist file, so that the Virtuoso UltraSim simulator saves the binary database, and VAVO/VAEO continues to run uninterrupted.

Arguments

 

format	The Virtuoso UltraSim simulator saves the voltage and current information in a binary database (vavo keyword is specified for Virtuoso UltraSim and VAVO/VAEO flow). Note: The usim_emir command can also be used with the Virtuoso UltraSim netlist-based EM/IR flow.
start/stop	Specifies the time window start and stop times. The start time default is the beginning of the transient simulation and the stop time default is the end of the transient simulation.