Introducing QSPICE: The Next Generation Mixed-Mode Simulation Tool for Advanced Circuit Design

Introducing QSPICE: The Next Generation Mixed-Mode Simulation Tool for Advanced Circuit Design


The original Simulation Program with Integrated Circuit Emphasis (SPICE) was introduced in 1973. Engineer Mike Engelhardt began developing his version of SPICE a quarter-century after its inception. Fast forward another 25 years and Qorvo has unveiled QSPICE, the company’s latest advancement in mixed-mode SPICE simulation.

“Basically, QSPICE is what I would have written 25 years ago when I wrote LTspice had I known then what I know now.” — Mike Engelhardt

In the real world, many circuits aren’t purely analog or digital. They’re a mix of both. For instance, imagine a power control chip: it might have analog components for managing voltage and current, but also digital parts for controlling the overall operation. These are mixed-mode circuits.

Now, traditional SPICE tools have often focused on either analog or digital circuits, not both. This can be a problem for companies like Qorvo, whose components are used in mixed-mode designs. Regular SPICE tools might not handle these mixed circuits well, leading to inaccurate simulations or poor performance.

That’s where QSPICE comes in. It’s specifically designed to handle mixed-mode circuits effectively. It’s like a more advanced version of SPICE that can accurately simulate both analog and digital parts of a circuit, ensuring better performance and reliability for engineers working with Qorvo’s components.

SMPS with a controller IC written in C++

QSPICE stands out due to its comprehensive support for mixed-mode simulations. A notable example is its capability to simulate Switched-Mode Power Supplies (SMPS) featuring a controller IC written in C++. This demonstrates QSPICE’s proficiency in integrating complex logic. Before the simulation, QSPICE compiles C++ and Verilog models into native code, resulting in simulations that run faster than the actual integrated circuits, according to Engelhardt. This tight integration also allows for the inclusion of significant amounts of digital logic within analog simulations.

In addition to its advancements in mixed-mode simulation, QSPICE underwent significant re-architecting of its analog analysis compared to Engelhardt’s previous work. The primary objective was to address singularities and discontinuities in IV curves. Moreover, the numerical methods inherited from the original Berkeley SPICE have been extensively updated to leverage modern PC architectures.

Despite being in Beta status, QSPICE boasts many features and tools. For instance, it includes a comprehensive plotting engine with cursor functionalities. Users familiar with Engelhardt’s previous simulator will find the schematic editor’s user experience instantly recognizable. However, new users are encouraged to watch a QSPICE quick-start video, as basic functionality may not be immediately apparent due to the absence of conventional menus or context clues typically found in modern software interfaces.

QSPICE, developed by Qorvo, includes models for Qorvo’s silicon carbide devices and advanced power management solutions. It also supports third-party models, allowing users to directly paste “.model” and “.subckt” models into the software. QSPICE’s schematic editor generates appropriate symbols automatically. It’s a fast, powerful simulation tool, particularly suited for mixed-mode designs like switch-mode power supplies. Available for Windows only, it’s free for commercial use but requires registration at

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1. There is a typo in the title: QPSICE should be QSPICE

2. QSPICE is NOT free! You must surrender your personal and private information to Qorvo and agree to let Qorvo (and others that Qorvo decides) SPAM you – forever. Read Qorvo’s Privacy Policy first – it is here:

The following information is mandatory if you want to download and use QSPICE from Qorvo:

First Name:
Last Name:
Email Address:
[X] Yes, I agree to receive periodic emails from Qorvo related to products and services and can unsubscribe at any time. I accept the Qorvo Privacy Policy.

3. The nonsense required in Item-2 above by Qorvo to download and use QSPICE is NOT required by Analog Devices Incorporated (ADI) to download and use LTspice. Get LTspice (Fast • Free • Unlimited) here:

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