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Haythemjls , 09-17-2026, 01:09 PM

According to these images, which standard should be used to design the courtyard of electronic components? When should I use IPC-7351B, and when should I use IPC-7351C?

, 09-17-2026, 01:13 PM

🤖 In the meantime, here’s a response from the [FEDEVEL AI HW Assistant]().
It helps to find relevant resources for your question, but it may make mistakes as it’s still in early development.

This is the response from the AI Assistant:
For courtyard design in component footprints, **IPC-7351C** is the current recommendation for new designs. Here's how to decide:

1. **IPC-7351B (2005)**
- Uses three density levels:
• **Most** (hand soldering)
• **Nominal** (standard SMT production)
• **Least** (RF/analog designs)
- Contains outdated courtyard rules where "most density" was later found ineffective for reliability in automated processes ([source](https://www.youtube.com/watch?v=cMxXea16Hxc&t=1576))

2. **IPC-7351C (2017)**
- Removed "most density" for automated assembly (now only for hand soldering)
- Made courtyard calculations more practical using updated industry data
- Aligns with modern manufacturing realities like 0201 components and ultra-fine pitch BGAs
- Now classified as a *guideline* rather than a strict standard ([source](https://www.youtube.com/watch?v=cMxXea16Hxc&t=958))

**When to use which:**
• **Use 7351C** for all new designs - it incorporates lessons from Japanese reliability studies and modern SMT lines
• **Use 7351B** only if maintaining legacy designs where:
- You need backward compatibility with old CAD libraries
- Working with manufacturers still using 2005-era processes
- Required by specific automotive/military specs frozen to B-revision

Key difference: 7351C simplifies courtyard rules by eliminating redundant "most density" requirements while maintaining the core nominal/least distinction that works for 99% of modern designs ([source](https://www.youtube.com/watch?v=cMxXea16Hxc&t=3955)).

You can continue chatting with the AI Assistant here:
https://fedevel.com/hw-assistant

Robert Feranec , 09-18-2026, 05:46 AM

Has C been approved? Last time I think it was only a suggestion

QDrives , 09-22-2026, 07:58 PM

That is up to you.
There is no mandatory element to the courtyard.
A square courtyard is easy, the minimum one (as shown as version C) is much more work to create/draw.
I only use the courtyard for documentation purposes and simply use a rectange.