Digital Logic Circuit Design Simulation Software

November 4, 2019 Cadence PCB Solutions

Woman driving a racing simulation

 

As a huge fan of Star Trek in all of its iterations, I have always found the logic and appeal of the use of simulators (Holodeck) as a means to arrive at a viable conclusion. The "smart" virtual reality system was an invaluable tool with uses that includes personal stress relief, scientific simulation, tactical or even covert training.

These various simulations all had one thing in common, they all afforded an unparalleled level of situational examination without the penalty of failure. Although the actual technology does not exist today, it has certainly had a profound influence on the direction of our technological advancements.

The logic behind the use of simulations cannot be disputed. Having the ability to create a virtual exact replication of various components and circuit designs without actual expenditures being incurred is priceless. In addition, the ability to test various designs and configurations through the use of simulations, reduces development time, costs, and it greatly improves your designs overall.

What is Digital Circuit Design Simulation?

As you may know, electronic circuit simulation uses mathematical models to replicate the behavior of an actual electronic device or circuit. The actual simulation software itself allows for modeling of circuit operation and is an invaluable analysis tool.

In today’s cost laden design and manufacturing process, software tools for designing and simulating digital circuits has become an intricate part of the overall process. The need to shorten design times and limit costs has made digital circuit design and simulation software as important as the product being produced.

However, it is not just about shortened design times and lowering costs. The true benefit of using digital circuit design and simulation software is the fact that it improves designs.

What is Digital Logic Circuit Simulation?

When working on integrated circuits or on circuit design in general, logic simulation is here to determine the correctness of this circuit. The three fundamental logic gates are AND, OR, and NOT gates. When determining how to simulate logic, you’ll want to have a circuit and work through the potential outputs of a switch or other gates you’ll be using. 

Digital logic simulation primarily functions through either compiled-code or event-driven logic simulation techniques. In logic simulation, designers are looking to determine if their circuit contains any design errors (as is the case in most simulation efforts). SPICE simulators and logic simulators will be looking for digital cell libraries, memory, and AMS or analog and mixed-signal circuits.

What these circuits are looking for is to maintain precision timing to support their proper function. As timing-sensitive designs can be tricky to nail down, especially with the oftentimes painful distance between simulation software and hardware-capabilities, logic simulators are undeniably necessary for the design engineer’s pocket. 

Team Design vs Digital Circuit Design and Simulation Software

I am sure you have heard the term, “Paper Champion.” There have been very few true representatives of those words in the world of the NBA than the Clyde Drexler led Portland Trail Blazers. The Portland Trail Blazers was a team loaded with talent and on paper, they were an unstoppable force.

However, in actuality, the team went to back to back championships in the ’90s, only to lose both times. The Governor of the team spent millions of dollars bringing his design to fruition only to discover afterward that this particular configuration was flawed.

I am sure he would have welcomed the opportunity to test out his design before actually assembling his so-called championship contender. This sentiment holds an equal degree of truth in the world of electronics. One of the biggest benefits of using digital circuit design and simulation software is the ability to test your designs before actually building it.

SPICE bandpass waveform frequency gains

SPICE modeling can help from everything between and beyond SMPS and filters.

 

How Digital Circuit Design and Simulation Software Affects Quality

Digital circuit design and simulation software afford engineers the opportunity to test various configurations and designs without incurring associated component costs. Aside from the obvious time and money this saves, it also improves overall design quality.

The term perfection means that you have discovered how to do or create something free of flaws. It also points to the fact that it is equally important to know all of the incorrect ways to do something as it is to know all of the correct ways to do something.

In essence, practice still makes perfect and simulation in its purest form is precisely that. The ability to simulate the component or circuit and observe its behavior and functionality before actually building it is crucial in the development process as well as design. So it stands to reason that simulating a circuit’s behavior before actually building it can greatly improve design efficiency and overall design itself. Thus, highlighting faulty designs and providing greater insight into the behavior of electronic circuit designs as a whole.

Combining EDA and Digital Circuit Design and Simulation Software

Electronic design automation (EDA), also referred to as electronic computer-assisted design, is a class of software tools used for designing electronic systems such as integrated circuits (IC) and printed circuit boards (PCB).

It is no secret that EDA (electronic design automation) tools have made PCB design easier and more efficient. Mainly because it provides schematic capture tools that allow you to generate a circuit diagram as an interactive schematic from a library of digital components. After which, you can transfer the resulting netlist to a layout editor where you can build your board.

Furthermore, the EDA software suite keeps everything catenated, allowing the designer to make changes to one file such as a schematic, and see it reflected in the other, such as the layout. This same level of efficiency, integration, and interactivity provided by EDA tools (software) can also be applied to the prototyping and testing phases of the PCB design process. This is achieved through the use of electronic circuit simulation with SPICE.

What is SPICE and How is it Used?

SPICE or Simulation Program with Integrated Circuit Emphasis is the industry standard for open-source analog electronic circuit simulation. Within SPICE, you simply provide a netlist of the circuit you wish to simulate, and SPICE takes care of the rest, allowing you to generate waveform plots for analysis.

Overall, one of the most beneficial aspects of using SPICE is the fact that it gives you a way to verify the performance of your circuit without touching a single breadboard or physical component.

Hysteresis curve modeled in PSpice

PSpice even helps with measuring and modeling things like hysteresis.

 

In addition, SPICE also allows you to change component values (resistance, voltage, capacitance) and check frequency response across a range of tolerances or time periods. More advanced SPICE software even lets you run Monte Carlo analysis, perform smoke and stress tests, and create parametric plots.

In conclusion, when approaching digital circuit design and simulation software, it is imperative that you understand that its use is no longer optional. Take, for example, integrated circuits (ICs). The tooling (photomasks) is expensive, breadboards are impractical, and probing the behavior of internal signals is extremely difficult. Therefore, almost all IC designs rely heavily on, you guessed it, simulation. 

Provide your designers and production teams with Cadence’s suite of design and analysis tools, for the best digital circuit design simulation software for any of your circuits. PSpice simulator is available to exceed any of your needs in terms of circuit simulation, modeling, and analysis. 

If you’re looking to learn more about how Cadence has the solution for you, talk to us and our team of experts

About the Author

Cadence PCB solutions is a complete front to back design tool to enable fast and efficient product creation. Cadence enables users accurately shorten design cycles to hand off to manufacturing through modern, IPC-2581 industry standard.

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