Manual trace routing in PCB Design - Real Business Scenario

Scenario Mode

👤 Your Role: You are a PCB design engineer at an electronics manufacturing company.

📋 Request: Your manager wants you to manually route the traces on a new PCB layout to optimize signal integrity and minimize interference.

📊 Data: You have a PCB layout with component placements and a netlist showing which pins need to be connected. The board has multiple layers and design rules for trace width and spacing.

🎯 Deliverable: A detailed PCB layout showing manually routed traces that meet design rules and optimize signal paths.

Sample Data

Net	Pin Start	Pin End	Layer	Trace Width (mil)	Min Spacing (mil)
Net1	U1-1	R1-1	Top	10	6
Net2	U1-2	C1-1	Top	8	6
Net3	U2-1	J1-1	Bottom	12	8
Net4	U2-2	R2-1	Inner1	10	6
Net5	U3-1	C2-1	Top	10	6
Net6	U3-2	J2-1	Bottom	8	6
Net7	U4-1	R3-1	Top	10	6
Net8	U4-2	C3-1	Inner2	12	8

1

Step 1: Review the netlist and component placement to understand which pins need connection and their physical locations on the PCB.

No formula needed; visually inspect the PCB layout and netlist.

Expected Result

Clear understanding of all nets and their start and end points.

2

Step 2: Set up design rules in the PCB design software for trace width and minimum spacing according to the sample data.

Configure trace width and spacing: For example, Net1 trace width = 10 mil, spacing = 6 mil; Net3 trace width = 12 mil, spacing = 8 mil.

Expected Result

Design rules are active and prevent routing violations.

3

Step 3: Manually route Net1 on the Top layer from U1-1 to R1-1, keeping trace width 10 mil and spacing 6 mil from other traces.

Use manual routing tool; draw trace following shortest path avoiding obstacles and respecting spacing.

Expected Result

Net1 trace is routed cleanly on Top layer without spacing violations.

4

Step 4: Manually route Net3 on the Bottom layer from U2-1 to J1-1 with trace width 12 mil and spacing 8 mil.

Use manual routing tool; route trace avoiding vias and other traces, maintaining spacing.

Expected Result

Net3 trace is routed on Bottom layer meeting width and spacing rules.

5

Step 5: Route remaining nets (Net2, Net4, Net5, Net6, Net7, Net8) on their specified layers with correct trace widths and spacing, using manual routing.

Follow same manual routing process for each net, layer, and design rule.

Expected Result

All nets are routed manually with no design rule violations.

6

Step 6: Perform a design rule check (DRC) to verify no trace width or spacing violations exist after manual routing.

Run DRC tool in PCB software.

Expected Result

No errors or warnings reported; routing meets all design rules.

7

Step 7: Review the routed traces for signal integrity considerations, such as minimizing trace length and avoiding sharp angles.

Visually inspect traces; adjust routing if needed to smooth corners and shorten paths.

Expected Result

Optimized trace routing for signal quality.

Final Result

PCB Layout Manual Routing Summary

+----------------+----------------+----------------+
| Net            | Layer          | Trace Width    |
+----------------+----------------+----------------+
| Net1 (U1-1-R1-1) | Top            | 10 mil        |
| Net2 (U1-2-C1-1) | Top            | 8 mil         |
| Net3 (U2-1-J1-1) | Bottom         | 12 mil        |
| Net4 (U2-2-R2-1) | Inner1         | 10 mil        |
| Net5 (U3-1-C2-1) | Top            | 10 mil        |
| Net6 (U3-2-J2-1) | Bottom         | 8 mil         |
| Net7 (U4-1-R3-1) | Top            | 10 mil        |
| Net8 (U4-2-C3-1) | Inner2         | 12 mil        |
+----------------+----------------+----------------+

All traces routed manually with correct widths and spacing.
No design rule violations detected.
Signal integrity optimized by minimizing trace length and smoothing corners.

✓Manual routing allowed precise control of trace paths to avoid interference.

✓All nets meet the required trace width and spacing design rules.

✓Signal integrity improved by minimizing trace length and avoiding sharp angles.

✓Design rule check confirmed no violations after manual routing.

Bonus Challenge

Create a layer stackup visualization showing how manual routing on different layers affects signal integrity and crosstalk.

Show Hint

Use color coding for layers and highlight critical nets to show their routing paths and proximity.