Tool · Verification & Validation
ZeBu (Zero Bugs)
Synopsys's FPGA-based hardware emulation system, acquired with EVE in 2012. It targets high emulation capacity and throughput for large SoC and AI accelerator designs.
- Also known as
- ZeBu Server, ZeBu EP
- Type
- Tool
- Domain
- Verification & Validation, Emulation & prototyping
Notes
Paired with HAPS prototyping in the Synopsys flow so a design can move between the two with a common front end.
Overview
ZeBu is Synopsys's family of hardware emulation systems, which map a chip design onto large arrays of commercial FPGAs so that it runs far faster than it would in a software simulator. Verification teams and software developers use it to run long tests, boot operating systems and measure power on designs of billions of gates before any silicon exists. The product line came to Synopsys in 2012 with its acquisition of Emulation and Verification Engineering (EVE), the company that developed it.
How it works
The design's RTL is compiled for the emulator: synthesised, partitioned across many FPGAs and connected through the system's interconnect, with debug instrumentation added so that signals can be captured. The emulator then runs the design as hardware, cycle by cycle, under control of a host computer. Testbenches and real-world interfaces connect through transactors, speed adaptors and virtual models, so the design can talk to simulated software environments or slowed-down physical devices.
Synopsys sells several systems. ZeBu Server 5 is aimed at the largest SoCs and is quoted as scaling to about 30 billion gates. ZeBu EP is a unified platform for both emulation and prototyping, and ZeBu-200 extends capacity to about 23 billion gates with faster compile and runtime than ZeBu EP. ZeBu Empower uses emulation for power profiling, analysing switching activity across long software workloads to find power bugs and the time windows that matter for power signoff. Systems are also offered through a cloud service.
Common use modes include simulation acceleration, in which a simulator offloads the design to the emulator; hybrid emulation, in which processors run as fast virtual models alongside the emulated hardware; software bring-up; and performance and power analysis.
Examples
- Booting Linux and running application software on an emulated mobile SoC months before tapeout.
- Using ZeBu Empower to profile the power of a large AI accelerator running a real workload and pass the critical windows to signoff power tools.
- Hybrid emulation in which the CPU subsystem runs as a fast virtual model while the rest of the design runs on the emulator.
- Renting emulation capacity through a cloud service for a peak verification period instead of buying hardware.
Why it matters
Emulation engineers, verification teams and software developers depend on ZeBu or its competitors for workloads that are far too long for simulation, such as booting an operating system, running an AI model or exercising a full protocol stack. Finding hardware and software bugs at this stage avoids costly respins and lets software be ready when silicon arrives.
In the chip lifecycle, ZeBu is used once RTL is stable enough to compile, through subsystem and full-chip verification, software bring-up and power analysis before tapeout; it is often kept after first silicon for debugging and for verifying derivatives.
It matters most to: EDA R&D Engineer, Hardware Emulation and Prototyping, Emulation Engineer, Emulation-to-Silicon Correlation Engineer, Hardware-Software Co-Verification Engineer, SoC Verification Engineer
Common confusions
- Not the same as Palladium
- Palladium is Cadence's emulation platform and a direct competitor. It is a separate product with its own architecture, compiler and debug tools.
- Not the same as Veloce
- Veloce is the emulation family from Siemens EDA, formerly Mentor Graphics. Like ZeBu it targets large SoC verification but is a different system.
- Not the same as HAPS
- HAPS is Synopsys's FPGA-based prototyping line, used mainly for software development and system validation. ZeBu systems are emulators, although platforms such as ZeBu EP are designed to serve both uses.
Sources
- Emulation Systems (opens in a new tab), Synopsys, 2026-10-22
- ZeBu Server 5: High-Capacity Emulator for Fast SoC Bring-Up (opens in a new tab), Synopsys, 2026-10-22
- ZeBu Empower (opens in a new tab), Synopsys, 2026-10-22
- Legal Battlefield In Emulation (Brian Bailey, 23 October 2014) (opens in a new tab), Semiconductor Engineering, 2026-10-22
- Hardware emulation (Wikipedia) (opens in a new tab), Wikimedia Foundation, 2026-10-22
Related terms
Part of the Verification & Validation glossary, with every term in the topic and the lifecycles, tools and standards that use them.
Where it appears on the Hub
Used on 6 pages of the Hub. In each group, the pages that mention it most come first.
Suggest an improvement
Suggest an improvement to this entry
A clearer definition, an example, a correction or a source an editor can check. Editors review every suggestion before the entry changes.
Last reviewed . Written by The Semiconductor Hub editorial team. The full glossary