IEEE 1051 is a standardised extension to the Verilog hardware description language (HDL) that allows the modelling and simulation of analogue, digital, and mixed-signal systems within a unified framework. It builds upon Verilog-AMS, a language developed to bridge the gap between purely digital simulations and real-world analogue behaviour.
Full Title: IEEE 1051 – Standard for Verilog Analogue and Mixed-Signal Extensions
Also Known As: Verilog-AMS Standard
Status: Active IEEE Standard (as of the latest available revision)
Why is IEEE 1051 Important?
In modern semiconductor design, it’s rare to find purely digital systems. Most real-world electronic systems involve both digital and analogue components—for example, Analogue-to-Digital Converters (ADCs), Phase-Locked Loops (PLLs), RF front ends, and power management circuits. Without a unified language:
Designers are forced to use different tools for digital (Verilog/VHDL) and analogue (SPICE).
Integration between analogue and digital models is error-prone and time-consuming.
Mixed-signal behaviour is difficult to simulate accurately and consistently.
IEEE 1051 solves these issues by enabling:
Unified Modeling: Model analog, digital, and mixed-signal components in one file.
Top-Down Design: High-level abstractions support early system validation.
Behavioral Simulation: Fast simulation for analog components using behavioral models.
Cross-Domain Interaction: Digital and analog signals can interact naturally, improving test coverage and accuracy.
Key Features of IEEE 1051 (Verilog-AMS)
1. Analogue Behavioural Modelling
IEEE 1051 introduces constructs such as analog, electrical, and ground that enable the definition of continuous-time analogue behaviour using differential equations and Laplace transforms.
2. Discipline and Nature
Discipline definitions associate physical properties (e.g., voltage, current) with signals. nature defines what kind of physical quantity is being modeled.
discipline electrical
potential Voltage;
flow Current;
enddiscipline
Seamless signal conversions between analog and digital domains.
analog begin
analog_value = V(in);
end
always @(analog_value)
digital_value = analog_value * 255;
4. Strong Event-Driven and Continuous-Time Simulation
Supports both discrete-time (event-driven) and continuous-time (analogue) simulation engines working together.
5. Support for Real-Number Modelling
Simplifies high-speed AMS simulation with real data types (real, wreal), especially useful for ADC/DAC behavioral models.
Benefits of Adopting IEEE 1051 in Design Flows
🚀 Accelerated Time-to-Market: Rapid prototyping and system-level validation.
🔍 Improved Verification Coverage: Simulate analogue behaviours alongside digital testbenches.
🛠️ Toolchain Compatibility: Supported by leading EDA tools like Cadence Spectre, Synopsys CustomSim, and Siemens Questa ADMS.
📏 Model Reuse: Consistent models can be reused across projects and teams.
IEEE 1051 vs. Other Standards
| Feature | IEEE 1051 (Verilog-AMS) | VHDL-AMS | SPICE |
|---|---|---|---|
| Digital Modeling | ✔ | ✔ | ✘ |
| Analog Modeling | ✔ | ✔ | ✔ |
| Mixed-Signal Co-Simulation | ✔ | ✔ | ✘ |
| Learning Curve | Moderate | High | Low |
| Speed (Behavioural Sim.) | Fast | Moderate | Slow |
Use Cases and Applications
IEEE 1051 is ideal for:
SoC Design and Verification.
Power Management ICs.
High-Speed Interface Modelling (e.g., USB, HDMI, DDR).
Sensor Integration.
Analog Front-End (AFE) for Data Acquisition Systems