PCB Libraries Forum : Decimal Precision in Physical Description https://www.PCBLibraries.com/forum/ Sun, 05 Apr 2026 15:03:22 +0000 Sun, 21 Oct 2012 14:46:58 +0000 http://blogs.law.harvard.edu/tech/rss Web Wiz Forums 12.07 360 https://www.PCBLibraries.com/forum/RSS_post_feed.asp?TID=298 <![CDATA[PCB Libraries Forum]]> https://www.PCBLibraries.com/forum/forum_images/PCBLForumLogo.gif https://www.PCBLibraries.com/forum/ <![CDATA[Decimal Precision in Physical Description : If the package is originally...]]> https://www.PCBLibraries.com/forum/decimal-precision-in-physical-description_topic298_post2063.html#2063 Author: Tom H
Subject: 298
Posted: 21 Oct 2012 at 2:46pm

If the package is originally a Inch Based part, the millimeter values are sometimes carried out 3 places to the right of the decimal point.
 
Eventually all packages will be metric based parts and this will automatically correct itself.
 
]]> Sun, 21 Oct 2012 14:46:58 +0000 https://www.PCBLibraries.com/forum/decimal-precision-in-physical-description_topic298_post2063.html#2063 <![CDATA[Decimal Precision in Physical Description : I have noticed in the physical...]]> https://www.PCBLibraries.com/forum/decimal-precision-in-physical-description_topic298_post482.html#482 Author: AGONZ67
Subject: 298
Posted: 25 May 2012 at 1:21pm

I have noticed in the physical description field most dimensions are two places past the decimal, ie 3.20 x 1.60 x1.40, but there are several that are carried out to three places. This only refers to the description field as the examples shown below. IPC Standard is two places past the decimal point and include trailing zeros

PLCC127P1244X1244X457-28 Plastic Leaded Chip Carrier (PLCC), 1.27mm pitch;square,7 pin X 7 pin,12.445mm L X 12.445mm W X 4.57mm H body

TO254P1054X203-4 Transistor Outline (TO, DPAK),2.54 pitch;;3 pin,10.54mm L X 9.395mm W X 2.03mm Hbody

LEDDFN120X77X40-4 LED, Dual Flat No-Lead (DFN 4 Pins), 0.75mm pitch;4 pin,1.20mm L X 0.775mm W X 0.40mm H body

DIOMELF3515   Diode, Metal Electrode Face (MELF);3.50mm L X 1.525mm Dia
 
RESMELF3515   Resistor, Metal Electrode Face (MELF);3.50mm L X 1.525mm Dia
 
 
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