Routing power traces to power input on 2 layer board ideas [noob question] - Page 1
Forum section: electronics / general

author: newtekuser
author_rank: Frequent Contributor
timestamp: March 26, 2023, 08:41:31 pm
content: I am working with 2 layer boards, where I designate the bottom layer as ground plane and top layer for signal and power. My applications are 5V, no high speed signals, typically consisting of an LCD display, 8bit PIC MCU + buttons and an occasional i2c IC.When I lay out the traces I typically end up with a hub and spoke design where each 5V power trace goes up to the 5V power input similarly to the attached screenshot.My projects do work, but I'm not happy with the design. Is there a better way of routing power within the constrains of a 2 layer design?

author: John B
author_rank: Frequent Contributor
timestamp: March 26, 2023, 10:34:59 pm
content: The empty space in between the tracks is wasted space since all the nets are +5V. So you have essentially taken up the space of a several mm wide trace, without the benefits of said trace. I would normally route a thicker bus track going to the top left, and off to the right. You can also remove the redundant GND trace with via. the KiCAD DRC will detect when components are connected through a filled zone.

author: SiliconWizard
author_rank: Super Contributor
timestamp: March 26, 2023, 10:50:22 pm
content: I would also route one thick trace and distribute it closer to what it powers. This kind of "star" connection probably doesn't make much sense here.Just avoid making full loops with power traces, that's pretty nasty EMI-wise.

author: PlainName
author_rank: Super Contributor
timestamp: March 26, 2023, 10:56:07 pm
content: QuoteThat's true, but I always route a track anyway - partly habit (from tape days) but also because it lets me know there is a good route to a pin without having to check ERC errors all the time. Obviously doesn't (or shouldn't) apply to planes, but for fills...

author: newtekuser
author_rank: Frequent Contributor
timestamp: March 26, 2023, 11:19:39 pm
content: Quote from: John B on March 26, 2023, 10:34:59 pmI was wondering about GND tracks as well. When I first started with PCB design I used to drop in vias to the ground plane and not route tracks for them, but after a long break of a few years and having to re-learn stuff I forgot that this was the way to go with ground planes.

author: Benta
author_rank: Super Contributor
timestamp: March 26, 2023, 11:39:16 pm
content: What you seem to be doing is routing the "rat's nest" lines by straightening them out. Totally wrong approach.Like others said, just make a "fat" supply line and attach the other supply traces to that.Stop believing the Interwebs and buy a book on PCB design instead.

author: newtekuser
author_rank: Frequent Contributor
timestamp: March 26, 2023, 11:55:53 pm
content: Quote from: Benta on March 26, 2023, 11:39:16 pmSadly I was using the following printed book as reference : "Kicad6 Fundamentals and Projects" by Peter Dalmaris (ISBN 978-3-89576-496-7) and I could not find a single example where the power was routed the "correct way" for a single/dual layer board. All projects from the book use the same pattern using either loops for or go to power plane using vias.Attached an example from that book.

author: newtekuser
author_rank: Frequent Contributor
timestamp: April 19, 2023, 01:45:38 am
content: I was thinking, can't I just create a filled zone on the top layer and tie it to the +5V net, or will this create a giant antenna? That will eliminate the need to add any individual power traces.

author: newtekuser
author_rank: Frequent Contributor
timestamp: April 30, 2023, 11:46:53 pm
content: Quote from: newtekuser on April 19, 2023, 01:45:38 amAnswering my own question: Yes. (modified my previous design and just finished assembling the newly arrived PCB and everything works)