Electrical Rules Check (ERC) in PCB Design - Real Business Scenario

Scenario Mode

👤 Your Role: You are a PCB design engineer working on a new circuit board layout.

📋 Request: Your manager wants a report showing all electrical rule violations found in the latest PCB design to ensure the board meets quality standards before manufacturing.

📊 Data: You have a dataset listing all electrical nets, their connected components, pin types, and any detected ERC violations such as unconnected pins, conflicting pin types, or missing power connections.

🎯 Deliverable: Create a dashboard report summarizing the number and types of ERC violations by net and component, highlighting critical errors that must be fixed.

Sample Data

Net Name	Component	Pin	Pin Type	ERC Violation
NET1	U1	Pin1	Input	None
NET1	U2	Pin3	Output	None
NET2	U3	Pin2	Input	Unconnected Pin
NET3	U4	Pin5	Power	Missing Power Source
NET4	U5	Pin4	Output	Conflicting Pin Types
NET4	U6	Pin1	Output	Conflicting Pin Types
NET5	U7	Pin3	Input	None
NET6	U8	Pin2	Input	Unconnected Pin

1

Step 1: Load the ERC dataset into your BI tool.

Import the table with columns: Net Name, Component, Pin, Pin Type, ERC Violation.

Expected Result

Dataset loaded with 8 rows representing pins and their ERC status.

2

Step 2: Create a calculated measure to count total ERC violations.

Count of rows where ERC Violation is not 'None'.

Expected Result

Total ERC violations count = 5.

3

Step 3: Create a pivot table with Rows = ERC Violation, Values = Count of Pins.

Group by ERC Violation and count pins per violation type.

Expected Result

Pivot shows: Unconnected Pin = 2, Missing Power Source = 1, Conflicting Pin Types = 2.

4

Step 4: Create a pivot table with Rows = Net Name, Columns = ERC Violation, Values = Count of Pins.

Show ERC violations per net for detailed analysis.

Expected Result

NET2 has 1 Unconnected Pin, NET3 has 1 Missing Power Source, NET4 has 2 Conflicting Pin Types, NET6 has 1 Unconnected Pin.

5

Step 5: Build a dashboard visualization with a bar chart showing counts of each ERC violation type.

Bar chart: X-axis = ERC Violation, Y-axis = Count of Pins.

Expected Result

Bar chart clearly shows Unconnected Pin and Conflicting Pin Types as the most frequent issues.

6

Step 6: Add a table listing all nets with their ERC violations and affected components for detailed review.

Table with columns: Net Name, Component, Pin, Pin Type, ERC Violation filtered to show only violations.

Expected Result

Table lists 5 rows with violations for quick identification of problem areas.

7

Step 7: Highlight critical errors (e.g., Missing Power Source) in red on the dashboard for urgent attention.

Conditional formatting on the bar chart and table for 'Missing Power Source' violations.

Expected Result

Missing Power Source violations stand out visually for priority fixing.

Final Result

|||||||| 2

↓

|| 1

↓

|||||||| 2

✓There are 5 total ERC violations in the design.

✓Unconnected Pins and Conflicting Pin Types are the most common issues.

✓NET3 has a critical Missing Power Source violation that needs urgent fixing.

✓NET4 has conflicting output pins connected, which can cause circuit errors.

✓NET2 and NET6 have unconnected input pins that should be reviewed.

Bonus Challenge

Create a calculated measure to identify nets with multiple types of ERC violations and visualize them separately.

Show Hint

Use grouping and filtering to find nets appearing in more than one violation category, then create a filtered chart or table.

Practice

1. What is the main purpose of Electrical Rules Check (ERC) in PCB design?

easy

A. To generate the bill of materials automatically

B. To check the physical dimensions of the PCB

C. To find electrical mistakes like unconnected pins early in the schematic

D. To simulate the circuit's electrical behavior

Solution

1. Step 1: Understand ERC's role in PCB design

   ERC is used to detect electrical issues such as unconnected pins or conflicting connections in the schematic.

2. Step 2: Differentiate ERC from other checks

   Physical dimension checks and simulations are separate processes, not part of ERC.

3. Final Answer:

   To find electrical mistakes like unconnected pins early in the schematic -> Option C

4. Quick Check:

   ERC = Find electrical mistakes early [OK]

Hint: ERC finds electrical errors in schematics before layout [OK]

Common Mistakes:

• Confusing ERC with physical layout checks
• Thinking ERC simulates circuit behavior
• Assuming ERC generates manufacturing files

2. Which of the following is the correct way to run an ERC in most PCB design software?

easy

A. Click the 'Run ERC' button after completing schematic edits

B. Export the schematic as PDF and review manually

C. Run a 3D visualization of the PCB

D. Generate Gerber files before running ERC

Solution

1. Step 1: Identify the ERC execution method

   Most PCB tools have a dedicated 'Run ERC' button or menu option to start the electrical rules check.

2. Step 2: Eliminate incorrect options

   Exporting PDFs, 3D visualization, and generating Gerber files are unrelated to running ERC.

3. Final Answer:

   Click the 'Run ERC' button after completing schematic edits -> Option A

4. Quick Check:

   Run ERC via dedicated button [OK]

Hint: Run ERC using the software's dedicated button [OK]

Common Mistakes:

• Thinking ERC runs automatically without user action
• Confusing ERC with file export or visualization
• Running layout checks instead of ERC

3. After running ERC, you see an error: Pin 'IN' on U1 is unconnected. What does this mean?

medium

A. The pin 'IN' is connected correctly and no action is needed

B. The pin 'IN' is connected to multiple nets causing a short

C. The component U1 is missing from the PCB layout

D. The pin named 'IN' on component U1 has no wire connected to it

Solution

1. Step 1: Interpret the ERC error message

   The message says the pin 'IN' on component U1 is unconnected, meaning no wire or net is attached to it.

2. Step 2: Understand implications

   An unconnected pin usually indicates a missing connection that may cause circuit malfunction.

3. Final Answer:

   The pin named 'IN' on component U1 has no wire connected to it -> Option D

4. Quick Check:

   Unconnected pin means no wire attached [OK]

Hint: Unconnected pin means no wire attached to that pin [OK]

Common Mistakes:

• Assuming unconnected means short circuit
• Confusing missing PCB part with schematic connection
• Ignoring ERC errors thinking they are warnings

4. You ran ERC and got multiple errors about conflicting pin connections. Which step should you take to fix this?

medium

A. Ignore the errors and proceed to PCB layout

B. Check the schematic for pins connected to multiple nets and correct wiring

C. Delete the entire schematic and start over

D. Run a 3D model check instead

Solution

1. Step 1: Analyze ERC conflict errors

   Conflicting pin connections mean pins are wired to more than one net, which is invalid.

2. Step 2: Correct schematic wiring

   Review and fix the wiring in the schematic to ensure each pin connects to only one net.

3. Final Answer:

   Check the schematic for pins connected to multiple nets and correct wiring -> Option B

4. Quick Check:

   Fix wiring conflicts in schematic before layout [OK]

Hint: Fix wiring conflicts in schematic, don't ignore ERC errors [OK]

Common Mistakes:

• Ignoring ERC errors and continuing
• Deleting schematic unnecessarily
• Confusing ERC errors with layout issues

5. You have a complex schematic with multiple power nets. ERC reports a warning that a power pin is connected to a net with a different voltage level. What is the best approach to resolve this?

hard

A. Verify the power net assignments and ensure pins connect only to nets with matching voltage levels

B. Ignore the warning if the circuit works in simulation

C. Connect all power pins to a single net regardless of voltage

D. Remove the power pins from the schematic

Solution

1. Step 1: Understand power net voltage warnings

   ERC warns when a power pin connects to a net with a different voltage, which can cause damage or malfunction.

2. Step 2: Verify and correct net assignments

   Check that each power pin connects only to the correct net matching its voltage level to avoid conflicts.

3. Step 3: Avoid unsafe shortcuts

   Ignoring warnings or connecting all power pins to one net can cause serious issues.

4. Final Answer:

   Verify the power net assignments and ensure pins connect only to nets with matching voltage levels -> Option A

5. Quick Check:

   Match power pins to correct voltage nets [OK]

Hint: Match power pins only to nets with correct voltage [OK]

Common Mistakes:

• Ignoring ERC voltage warnings
• Connecting different voltage nets together
• Removing essential power pins