[FPGA](https://www.ampheo.com/c/fpgas-field-programmable-gate-array) simulation is essential for verifying digital designs before deployment on hardware. Below are the most widely used tools categorized by their primary use cases.

**1. Industry-Standard Simulation Tools**
**A. Xilinx (AMD) Tools**
Vivado Simulator (XSim)

* Built into Vivado Design Suite
* Supports VHDL, Verilog, SystemVerilog
* Best for: [Xilinx/AMD FPGA](https://www.vemeko.com/product/#xilinx) designs

**ModelSim (Mentor Graphics, now Siemens)**

Often bundled with Vivado

Features:

* Waveform debugging
* Code coverage analysis

**B. Intel (Altera) Tools**
**ModelSim Intel® FPGA Edition**

* Free version included with Quartus Prime
* Supports mixed-language simulation

**Questa Simulator (Advanced version of ModelSim)**

Used for complex ASIC/[FPGA](https://www.onzuu.com/category/fpgas) verification

**C. Siemens EDA (Formerly Mentor Graphics)**
**QuestaSim**

* Advanced debug features (UVM support)
* Used in high-reliability designs (aerospace, medical)

**ModelSim**

Lightweight, good for beginners

**2. Open-Source & Free Simulators**

**3. High-Level Synthesis (HLS) & Co-Simulation**
**Xilinx Vitis HLS**

Simulates C/C++ designs before RTL conversion

**MATLAB/Simulink (with HDL Coder)**

Used for [DSP](https://www.ampheo.com/c/dsp-digital-signal-processors)/control system FPGA designs

**SystemC**

For system-level modeling

**4. Specialized Verification Tools**
**Cadence Xcelium**

High-performance simulation for ASIC/FPGA

**Synopsys VCS**

Used in large-scale verification

**UVM (Universal Verification Methodology)**

Framework for complex testbenches

**5. Waveform Debugging Tools**
**Vivado Logic Analyzer (ILA)**

Real-time [FPGA](https://www.ampheoelec.de/c/fpgas-field-programmable-gate-array) debugging

**SignalTap (Intel Quartus)**

Similar to Xilinx ILA

**GTKWave**

Open-source waveform viewer

**6. Which Simulator Should You Use?**

**Conclusion**
* For beginners: Start with Vivado Simulator (XSim) or ModelSim.
* For open-source projects: Use GHDL + GTKWave (VHDL) or Icarus Verilog.
* For advanced verification: QuestaSim or Synopsys VCS.