Introduction
Modern electronic products aren’t just PCBs and components anymore. A motor drive blends switching power semiconductors, magnetics, and thermal management; a sensor front end contains analog amplifiers and digital logic. Engineers need to ensure that all these domains—electrical, magnetic, mechanical, thermal—work together, often before hardware exists. Traditional SPICE simulators excel at transistor-level detail but fall short when you try to simulate an entire system across multiple domains or test a controller algorithm early in the design process.
That’s where Synopsys Saber comes in. Saber bridges detailed circuit simulation with broad system-level modeling. SaberRD, the production version, lets you combine accurate circuit models, high-level behavioral descriptions, and multi-physics components in a single environment. Engineers can integrate electrical, magnetic, mechanical, thermal, and even hydraulic models and describe control logic directly using hardware-description languages. The result is a “virtual prototype” that supports early concept exploration, cross-domain analysis, and final validation—all within one tool. Saber has been refined in demanding automotive, aerospace, and industrial applications for more than 25 years, demonstrating both robustness and reliability.
This post explains why SaberRD is valuable to both technical teams and business stakeholders, highlights its key capabilities, and shows how its behavioral modeling and extensive libraries accelerate analog and digital design. We’ll also touch briefly on SaberEXP, its companion tool for rapid conceptual design, and provide an example of SaberRD in action.
Why System-Level Simulation with Saber?
In complex projects, engineers often need to verify system behaviour long before each component’s transistor-level details are finalized. For example, you might want to ensure a sensor’s front-end analog circuit, a microcontroller’s firmware, and a mechanical motor load all play well together. Traditional SPICE struggles here: simulating a large mixed-signal, multi-domain system with full transistor models can be painfully slow or fail to converge. Saber was designed to address exactly this problem.
Two Flavors of Saber—SaberEXP and SaberRD
In short, SaberEXP is for prototyping quickly; SaberRD is for finishing the job with full fidelity.
More Than SPICE
SaberRD doesn’t replace SPICE for low-level transistor validation; it builds on it. Within one schematic you can mix abstraction levels—a detailed physics-based MOSFET model for power transistors alongside a high-level controller model—without worrying about convergence. Multi-domain support is built in, so you can co-simulate an electrical circuit driving a mechanical motor that heats up and interacts with a thermal management model. That holistic view exposes issues that would be missed if each domain were simulated in isolation.
From a business standpoint, this reduces costly hardware prototypes by letting you catch problems in simulation, and it shortens development cycles by enabling early validation. Saber’s cross-domain strengths make it especially attractive to markets where reliability is paramount, like automotive electrification, industrial automation, and aerospace..
Key Capabilities of SaberRD
SaberRD offers a unified platform with a rich feature set. Some highlights include:
Fig1. Key capabilities of Synopsys SaberRD: a single unified platform combining multi-domain modeling, rich model libraries with HDL support, seamless co-simulation with external tools, and advanced reliability analysis.
Capture electrical, magnetic, mechanical, thermal, hydraulic, and other physical domains in one environment. For example, you can model how heat affects motor torque, or how a fluid system interacts with an electronic valve, without leaving the tool.
You get access to more than 30 000 component models covering IGBTs, MOSFETs, diodes, sensors, motors, and more. Both behavioural and physics‑based models are characterised from real data. SaberRD supports MAST and VHDL‑AMS for analog and mixed‑signal modeling, and you can import models written in C, C++, Fortran, and standard SPICE. Functional Mock‑up Units via the FMI standard are also supported. This means you can reuse proven parts and write new models at the right level of abstraction..
Using standards like FMI, SaberRD exchanges data with other simulators (e.g. MATLAB/Simulink for controls, ModelSim or VCS for digital logic). Its built‑in event‑driven digital simulator schedules logic alongside analog signals and runs digital blocks far faster than forcing a SPICE engine to handle digital timing..
Look beyond nominal operation by running parametric sweeps, Monte Carlo and sensitivity studies, and worst‑case stress analysis. Inject shorts, opens, and stuck‑at faults to evaluate functional safety (for example, for ISO 26262 compliance). Automated fault campaigns highlight weak points early, helping teams design safer systems
Taken together, these capabilities translate into faster time‑to‑market and reduced costs. Multi‑domain modeling cuts down on cross-discipline guesswork; libraries encourage IP reuse; co‑simulation aligns analog and digital teams early; and robustness analysis catches problems before they appear in hardware.
Behavioral Modeling and HDL Flexibility in Saber
One of Saber’s greatest strengths is its support for behavioural modeling—describing components using equations or logic instead of full transistor schematics. High‑level models run orders of magnitude faster than detailed SPICE models yet still capture essential behaviour. Saber’s roots are in MAST, and it fully supports IEEE VHDL‑AMS for analog and mixed‑signal modeling. If you’ve written VHDL or Verilog for FPGAs, VHDL‑AMS will feel familiar—only it also handles continuous-time analog behaviour.
Choosing the Right Abstraction
Behavioural models let you decide how detailed you need to be:
You can mix and match these levels in one schematic. Start with high‑level models for speed, then refine only the parts of the design that require accuracy.
Fig2. Demonstrating the power of behavioral modeling with an op-amp example.
Example (MAST op-amp):
This model captures differential gain, finite input resistance, and offset, yet it runs far faster than a full transistor‑level op‑amp. If you need more accuracy later, simply swap it with a detailed SPICE model without touching the rest of your circuit.
Saber’s digital engine completes the picture. You can embed a microcontroller algorithm or state machine in VHDL‑AMS or Verilog alongside power electronics, and the simulation remains fast because the event‑driven logic engine handles digital timing efficiently.
HDL vs. Software Programming
If you haven’t used hardware description languages before, they may look like software—but they work differently. An HDL model describes hardware behaviour: for analog, that might mean writing Kirchhoff’s laws or state equations; for digital, it means specifying logic networks or state machines. These descriptions execute in parallel, like real circuit elements. Saber’s simulation engine uses numerical methods for analog and event scheduling for digital. This allows complex closed‑loop systems—transistors, sensors, firmware, mechanical loads—to be modelled and solved together. An engineer comfortable with HDLs can code a PID controller or fault‑detection routine in VHDL‑AMS and drop it into the system simulation, accelerating development and helping cross‑functional teams collaborate more effectively.
Example: Combining Analog and Digital
Consider a voltage‑controlled current source with digital enable logic and built‑in protection—a mixed‑domain design. The sensor and current source are analog, while the enable logic is digital (e.g. an FPGA), and the system closes the loop via feedback. Traditionally, each domain would be tested separately—analog in SPICE, digital in an HDL simulator, and protection logic on the bench.
Figure 3. Smart Voltage-Controlled Current Source (VCCS) example modeled in SaberRD, showing integration of sensor input, FPGA control logic, ASIC core, and load.
SaberRD lets you capture the whole system and simulate it together:
A Saber simulation of this circuit shows both analog waveforms (load current, sensor voltage) and digital events (enable toggling, comparator output) on the same time axis. You can observe timing effects, switching delays, and fault behaviour without building hardware. This demonstrates how SaberRD handles the entire loop—sensor → digital logic → mixed‑signal circuit → load → feedback—giving you confidence in regulation, timing, and safety before prototypes are built
Accelerating Design with Reusable Models and Templates
Another way Saber accelerates your workflow is through its extensive library of reference designs and templates, especially for power electronics. SaberEXP comes with pre‑built models of common converter topologies, control structures, and support circuits that give engineers a head start on new projects.
For instance, SaberEXP includes ready‑to‑use templates for DC‑DC converters such as buck, boost, buck‑boost, SEPIC, forward, and phase‑shifted full bridge. Each topology includes realistic component models and control loops so you can simulate performance immediately and then customise for your application.
To support these topologies, the library also provides analog filter and compensator examples. The Type II and Type III compensator templates help you shape control‑loop poles and zeros quickly for converters. These behavioural models let engineers tune parameters quickly without hand‑calculating every component.
Once verified in SaberEXP, these blocks can be exported to SaberRD for integration with detailed device models and reliability analysis. The library extends beyond converters and filters: it includes motor drive examples (e.g. SRM drives, SPWM inverters, EV powertrains) that combine electrical and mechanical models. Engineers can study torque ripple, efficiency, and dynamic response in a single environment.
The ability to reuse proven models means less time reinventing basic circuits and more time focusing on system integration. For new engineers, these templates also serve as a learning resource, illustrating best practices in power electronics and control design.
Conclusion
Synopsys SaberRD bridges the gap between high‑level system exploration and detailed circuit implementation. It enables engineers to model complete systems—blending electrical circuits, digital controllers, and multi‑physics components—with accuracy and speed that traditional tools can’t match. Behavioural modeling lets you run simulations orders of magnitude faster than transistor‑level SPICE when appropriate, while you retain the option to add device‑level detail as needed. You don’t have to choose between speed and depth: start with high‑level models and refine where necessary, all in one environment.
For organisations, adopting SaberRD encourages more innovative and robust designs. Teams can experiment rapidly in SaberEXP, then carry designs through to a reliable finish in SaberRD with confidence in cross‑domain performance and safety. Multi‑domain and multi‑language support makes Saber a collaborative platform where electrical, mechanical, and control engineers can work together on a virtual prototype.
In short, SaberRD offers speed, flexibility, and rigor. It enables workflows where an idea can be prototyped in the morning and stress‑tested by the afternoon—without building hardware. Whether you’re an engineer looking to streamline your design process or a sales specialist positioning a best‑in‑class solution, Saber provides the capabilities to win in today’s complex system designs.