Creating custom symbols in PCB Design - Business Scenario Walkthrough

Scenario Mode

👤 Your Role: You are a PCB design engineer working on a new electronic product.

📋 Request: Your manager wants you to create custom schematic symbols for unique components not available in the standard library.

📊 Data: You have a list of components with their pin configurations and electrical characteristics.

🎯 Deliverable: Create custom schematic symbols for these components and prepare a report showing the symbol visuals and pin details.

Sample Data

Component	Pin Number	Pin Name	Pin Type
SensorX	1	VCC	Power
SensorX	2	GND	Ground
SensorX	3	OUT	Output
ControllerY	1	IN1	Input
ControllerY	2	IN2	Input
ControllerY	3	VDD	Power
ControllerY	4	GND	Ground
ControllerY	5	OUT	Output

1

Step 1: Organize the component pin data by component name to prepare for symbol creation.

Group data by 'Component' and list pins with their 'Pin Number', 'Pin Name', and 'Pin Type'.

Expected Result

Two groups: SensorX with 3 pins, ControllerY with 5 pins.

2

Step 2: Open your PCB design software's symbol editor to start creating a new symbol for SensorX.

Create new symbol named 'SensorX'. Add pins: Pin 1 as Power named 'VCC', Pin 2 as Ground named 'GND', Pin 3 as Output named 'OUT'.

Expected Result

Symbol 'SensorX' with three pins correctly placed and labeled.

3

Step 3: Create a new symbol for ControllerY with its pins and types.

Create new symbol named 'ControllerY'. Add pins: 1-IN1(Input), 2-IN2(Input), 3-VDD(Power), 4-GND(Ground), 5-OUT(Output).

Expected Result

Symbol 'ControllerY' with five pins correctly placed and labeled.

4

Step 4: Arrange pins logically on the symbol: inputs on left, outputs on right, power pins on top, ground pins on bottom.

Position pins accordingly in the symbol editor for clarity and standard practice.

Expected Result

Symbols with clear, standard pin placement improving readability.

5

Step 5: Save the custom symbols and export a report showing each symbol with pin details.

Export symbol images and create a table listing pins with their numbers, names, and types.

Expected Result

Report with visuals of 'SensorX' and 'ControllerY' symbols and their pin configurations.

Final Result

  SensorX Symbol
  +-----------+
  | VCC (1)   |
  |           |
  | GND (2)   |
  |           |
  | OUT (3)   |
  +-----------+

  ControllerY Symbol
  +-----------------+
  | IN1 (1)   IN2 (2)|
  |                 |
  | VDD (3)   GND (4)|
  |                 |
  |      OUT (5)    |
  +-----------------+

✓Custom symbols for SensorX and ControllerY were created with correct pin assignments.

✓Pins are arranged following standard conventions for easy understanding.

✓The report provides clear visuals and pin details for use in schematic design.

Bonus Challenge

Create a parameterized symbol template that can be reused for similar components by changing pin count and names.

Show Hint

Use the symbol editor's template or scripting features to define variable pins and labels.

Practice

1. What is the main purpose of creating custom symbols in PCB design?

easy

A. To make schematics clearer and tailored to specific components

B. To increase the size of the PCB board

C. To automatically route PCB traces

D. To generate 3D models of the PCB

Solution

1. Step 1: Understand the role of symbols in schematics

   Symbols represent components visually in schematics to improve clarity.

2. Step 2: Identify why custom symbols are used

   Custom symbols help tailor the schematic to specific or unique components, making it clearer.

3. Final Answer:

   To make schematics clearer and tailored to specific components -> Option A

4. Quick Check:

   Custom symbols improve clarity [OK]

Hint: Custom symbols improve schematic clarity and fit unique parts [OK]

Common Mistakes:

• Confusing symbols with PCB size or routing
• Thinking symbols create 3D models
• Assuming symbols automatically route traces

2. Which step is essential when creating a custom symbol in a PCB design tool?

easy

A. Running the autorouter to connect pins

B. Exporting the PCB layout as a PDF

C. Adding pins to represent electrical connections

D. Changing the board thickness settings

Solution

1. Step 1: Identify key elements of a custom symbol

   A symbol must have pins to show where connections happen.

2. Step 2: Recognize irrelevant steps for symbol creation

   Autorouting, exporting layout, or board thickness are unrelated to symbol creation.

3. Final Answer:

   Adding pins to represent electrical connections -> Option C

4. Quick Check:

   Pins are essential in symbols [OK]

Hint: Pins define connections in symbols, always add them [OK]

Common Mistakes:

• Confusing symbol creation with routing or export steps
• Skipping pin placement
• Changing unrelated board settings

3. Consider this symbol creation process:
1. Draw rectangle shape
2. Add 4 pins at edges
3. Save symbol as 'MyIC'
What will happen if you reuse 'MyIC' in multiple schematics?

medium

A. The symbol cannot be reused once saved

B. Each schematic shows a different random symbol

C. The symbol loses pins when reused

D. The symbol appears consistently with 4 pins in all schematics

Solution

1. Step 1: Understand symbol saving behavior

   Saving a symbol stores its shape and pins for reuse.

2. Step 2: Predict reuse effect

   Reusing the saved symbol inserts the exact same symbol with all pins intact.

3. Final Answer:

   The symbol appears consistently with 4 pins in all schematics -> Option D

4. Quick Check:

   Saved symbols reuse consistently [OK]

Hint: Saved symbols keep pins and shape consistent when reused [OK]

Common Mistakes:

• Thinking symbols change randomly on reuse
• Assuming pins disappear after saving
• Believing symbols cannot be reused

4. You created a custom symbol but when placing it in the schematic, pins do not connect to wires. What is the likely cause?

medium

A. The symbol shape is a rectangle

B. Pins were not assigned electrical pin numbers or names

C. The PCB board size is too small

D. The schematic grid is turned off

Solution

1. Step 1: Check pin properties in custom symbols

   Pins must have electrical numbers or names to connect properly.

2. Step 2: Identify why pins don't connect

   Without pin numbers/names, the tool cannot recognize pins for wiring.

3. Final Answer:

   Pins were not assigned electrical pin numbers or names -> Option B

4. Quick Check:

   Pin numbering enables connections [OK]

Hint: Always assign pin numbers/names to enable wire connections [OK]

Common Mistakes:

• Blaming symbol shape for connection issues
• Ignoring pin numbering importance
• Thinking grid affects pin connectivity

5. You want to create a custom symbol for a new sensor with 6 pins arranged in two rows. Which approach best ensures clarity and reusability?

hard

A. Draw the symbol shape, add 6 pins with correct numbers, group pins logically, then save as a reusable symbol

B. Draw the symbol shape only and add pins later in each schematic

C. Use a generic symbol with fewer pins to simplify the schematic

D. Create separate symbols for each pin and place them individually

Solution

1. Step 1: Plan symbol layout with correct pins

   Arrange all 6 pins logically in two rows with correct numbering.

2. Step 2: Save the complete symbol for reuse

   Saving the full symbol ensures consistent use and clarity in schematics.

3. Final Answer:

   Draw the symbol shape, add 6 pins with correct numbers, group pins logically, then save as a reusable symbol -> Option A

4. Quick Check:

   Complete, numbered, reusable symbol [OK]

Hint: Complete and save symbols with all pins for clarity and reuse [OK]

Common Mistakes:

• Adding pins later in each schematic causing inconsistency
• Using generic symbols missing needed pins
• Splitting pins into separate symbols causing confusion