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Electrical Rule Check

Key Takeaways

  • An electrical rule check (ERC) ensures that integrated circuits work as they should.

  • ERC tools can detect potential circuit errors that lead to reduced yields or circuit malfunctions after delivery.

  • The ERC ensures the functionality, reliability, and manufacturability of PCBs.

 An electrical design check makes sure integrated circuits work correctly

An electrical design check ensures integrated circuits work properly

An electrical rule check (ERC) ensures that integrated circuits work as they should. ERC makes sure a design follows a set of electrical rules defined by the designer or industry standards. ERC errors can lead to reduced yields or circuit malfunctions after delivery, so product success depends on finding and fixing them. Using connectivity and device information, ERC reviews electrical design rules. These checks are enabled by design rule checking (DRC) and layout versus schematic (LVS) verification tools.

DRC ensures that an integrated circuit layout complies with the design rules and guidelines specified by the foundry or design team. These rules define layout constraints such as minimum and maximum dimensions, spacing between components, and wiring widths. The LVS process verifies the consistency between an integrated circuit's physical layout and logical schematic. This makes sure the layout accurately reflects the circuit connectivity the engineers intended. 

Errors Detected by ERC Review

Short circuits, voltage violations, and other errors can cause malfunctions, overheating, and even catastrophic failures. ERC tools can detect potential errors by analyzing the circuit's electrical characteristics and connectivity.

Circuit Errors Detected by Electrical Rule Checks

Process-Independent Errors

Process-Dependent Errors

Short circuits

Process-Dependent Errors

Open circuits

Improper implant types

Floating nodes

Improper substrate bias

Improper power and ground connections

Singular notes

When designers perform ERC before fabrication or production, they can catch and fix potential electrical problems, lowering the risk of costly mistakes and improving quality.

It is much cheaper to fix design problems early in the development process than after production has started. By catching problems early, ERC minimizes rework and development costs. Early detection and resolution of design issues help prevent project delays. This can speed up development and get products to market faster.

Electrical Rule Checks and PCB Design

ERC ensures the functionality, reliability, and manufacturability of PCBs. Verifying connections and circuit characteristics, adherence to design constraints, and industry standards are all part of ERC.  Below are some key aspects of ERC’s role in PCB design.

In designing PCBs, ERC helps to:

  • Ensure Power Distribution Network (PDN) Integrity: ERC tests power and ground connections to ensure that PDNs are stable, which prevents voltage drops and noise.

  • Detect Electrical Errors: ERC tools check PCB design for short circuits, open circuits, and unconnected pins. These errors can cause malfunctions or even damage components during fabrication and assembly.

  • Check Voltage Levels: ERC ensures every pin is connected to the correct voltage level (e.g., power supply or ground). The wrong voltage connection can damage components or cause circuit malfunctions.

  • Verify Net Connectivity: ERC verifies that all nets (electrical connections between components and traces) are connected and there are no floating pins. 

  • Check Current-Carrying Capacity: ERC checks the trace widths and copper pours to make sure they can handle the current without overheating. Adequate trace widths are crucial to preventing overheating and potential failures.

  • Analyze Signal Integrity: Signal integrity checks can identify signal reflections, crosstalk, and impedance violations. The checks are crucial to maintaining signal integrity and preventing issues with data transmission.

  • Check Clearance and Creepage Requirements: ERC ensures compliance with safety standards by checking clearances between traces, pads, and components.

  • Verify Design Rules Compliance: ERC ensures the PCB design adheres to design rules defined by the manufacturer, industry standards, or specific project requirements. These rules include minimum trace widths, clearances, and solder mask requirements.

ERC checks can help designers identify and fix electrical issues early on, which reduces the risk of costly re-spins and ensures that the PCB works correctly once manufactured. ERC also reduces delays and manufacturing defects, thereby streamlining the manufacturing process.

Modern PCB Design Software Provides ERC and Other Checks

Incorporating ERC into your PCB design process can prevent issues during production, saving you time and money. Modern PCB design software, such as OrCAD PCB Designer,  walks you through ERC and other checks you can run on your designs. Check out Cadence’s suite of PCB design and analysis tools today.

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