Trace Width - Page 1
Forum section: electronics / beginners

author: Nikos A.
author_rank: Regular Contributor
timestamp: April 11, 2019, 11:33:43 am
content: Hi every one,I design a PCB which power trace should be cable to carry 16A. I found two online calculators claims that their calculations based on IPC-2221 standard.However inserting the same parameters in both calculators there is significant deviation between the resultsCalculator 1https://www.4pcb.com/trace-width-calculator.htmlCalculator 2https://www.digikey.com/en/resources/conversion-calculators/conversion-calculator-pcb-trace-widthI attach the screenshots from the resultsThanks in advance

author: Moriambar
author_rank: Unknown
timestamp: April 11, 2019, 11:51:00 am
content: Hi.In your digikey screenshot you screwed up the unit of measure (mil vs mm). I tried with mms and the results are comparable

author: Nikos A.
author_rank: Regular Contributor
timestamp: April 11, 2019, 11:53:38 am
content: What an idiot!!Thank you Moriambar

author: Moriambar
author_rank: Unknown
timestamp: April 11, 2019, 11:56:47 am
content: Quote from: Nikos A. on April 11, 2019, 11:53:38 amIt happens

author: Nikos A.
author_rank: Regular Contributor
timestamp: April 11, 2019, 12:52:14 pm
content: The PCB looks like the attachedIt is correct the traces to be wider than the through hole plated pads?

author: pix3l
author_rank: Regular Contributor
timestamp: April 11, 2019, 01:14:40 pm
content: Quote from: Nikos A. on April 11, 2019, 12:52:14 pmYes that's fine! You could also consider using a GND plane (if appliccable)

author: Nikos A.
author_rank: Regular Contributor
timestamp: April 11, 2019, 01:24:43 pm
content: This board is intended to mound a DC/DC converter.https://eu.mouser.com/ProductDetail/TDK-Lambda/PAH300S2428?qs=sGAEpiMZZMvGsmoEFRKS8PKj03Y0BBZ9U9Zmx%252b%2F9di4%3DThis is an isolated converter meaning that I cannot apply common ground in both input and output..I am not sure whether or not is preferable to create power and negative planes instead of traces..

author: pelule
author_rank: Frequent Contributor
timestamp: April 11, 2019, 02:09:43 pm
content: I get same result for both calculators at the same conditions.../PeLuLe

author: T3sl4co1l
author_rank: Super Contributor
timestamp: April 12, 2019, 04:56:00 am
content: A note, IPC-2221 is quite old, and known to be off by a good bit. This one uses IPC-2152:https://www.smps.us/pcb-calculator.htmlMore discussion here:https://www.ourpcb.com/trace-width-calculator.htmlNote that trace width doesn't mean much over short distances, where component pins act as heatsinks keeping the trace cool, or where current is still spreading out from the pins themselves (a trace width of say 200 mils is not even meaningful for a length of 100 mils), or for pours/polygons that have arbitrary shapes.For polygons in particular, the area of the shape matters as much as the width of the current path through it. Even if current doesn't spread out over the whole area, heat does. It helps to have wide pours, even if the added area isn't carrying any current as such!You can also get 2 and 3 (and even 4) ounce copper for not much added cost these days. You can also use identical traces/pours routed on both copper layers (assuming no trace crossings are needed), in which case merely 1 or 2 ounce will do.Tim

author: Nikos A.
author_rank: Regular Contributor
timestamp: April 13, 2019, 04:32:46 pm
content: Thank you for your answer Tim!! The guide is really informative!!