Let's quickly discuss design checks and asserts in the Spectre Simulator Platform. Asserts (also called device checks) help design and verification engineers identify the critical design issues in their circuit, such as extreme voltages, excessive currents and current densities, unreasonable device model parameters (transistor width or length, for example), or erroneous design conditions, with the help of expressions using design parameters, terminal voltages, element currents, model parameters, or OP parameters.
Asserts have been used to detect voltage overshoot, forward-biased diodes in the entire circuit, high current density, current surges through devices, and irregular physical dimensions of a transistor.
Design checks (also known as circuit checks) are separated into dynamic checks and static checks. These two checks have different syntaxes to run the checks and with varying intervals of simulation.
Here is an example of how to use a dynamic check statement:
hz1 dyn_highz node=["*"] duration=2e-09 time_window=[1e-09 1e-08]
In this example, the above command will report all nodes that were in a high impedance state for a duration longer than 2e-09s within the time window between 1e-09s and 1e-08s.
When a netlist or the model files may contain multiple assert checks, the checklimit feature lets the user control which assert is enabled or disabled and what time window is checked.
Checks and assertions can be run from both the command line and the Virtuoso ADE GUI. This small clip shows how to determine voltage level using the Assert Statement.
Watching checks and asserts in action might be more helpful than just reading about them. Therefore, I recommend checking out our Training Bytes video channel. It offers many helpful videos that guide you through launching and using the software.
All related videos are grouped in a channel for easy access and viewing.
Want to Learn More?
For lab instructions and a downloadable design, enroll in the online training courses of your interest:
Design Checks and Asserts in Spectre Simulator SPECTRE 24.1 (Online)
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Related Resources
Training Bytes (Video Channel)
Online Courses
- Virtuoso Schematic Editor Training
- Virtuoso ADE Explorer and Assembler S1: ADE Explorer and Single Test Corner Analysis Training
- Virtuoso ADE Explorer and Assembler S2: ADE Assembler and Multi Test Corner Analysis Training
- Spectre Simulator Fundamentals S1: Spectre Basics Training
- Spectre Simulator Fundamentals S4: Measurement Description Language Training
About Knowledge Booster Training Bytes
"Knowledge Booster Training Bytes" is an online journal that provides information about Cadence Training videos, online courses, and upcoming webinars that are available on the Cadence Learning and Support portal. This blog category offers direct links to these videos, courses, and other related materials on a regular basis.
Sai Darshan S Nishani, Sr. Education Application Engineer