How to pick which pattern to start with for TLC2274

Making your own components and patterns, organizing and using libraries.
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jdolecki
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Joined: 29 Mar 2011, 09:15

How to pick which pattern to start with for TLC2274

#1 Post by jdolecki » 01 May 2019, 12:35

in pattern editor i want to create a new component for a TLC2274 ( http://www.ti.com/lit/ds/symlink/tlc2274.pdf)

So in my choice for SOIC-14, I have three choices 150mil, 209mil, 300mil.

I'm not exactly sure what those numbers mean or which one to use. (this is my first time doing this)

I look at the datasheet and it don't make sense.

please advise which one to use.

thanks john

Tomg
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Posts: 1375
Joined: 20 Jun 2015, 14:39

Re: How to pick which pattern to start with for TLC2274

#2 Post by Tomg » 02 May 2019, 09:25

On the first page of the Texas Instruments datasheet there is a Device Information chart. Notice the first number in the "BODY SIZE (NOM)" column. This number represents the nominal width of each package. The 14-pin SOIC width is listed as 3.91mm, which is roughly equivalent to 154 mils. For a little more detail you can refer to the note at the bottom of the chart that reads "For all available packages, see the orderable addendum at the end of the data sheet."
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Starting on page 31 of the datasheet is a PACKAGE OPTION ADDENDUM featuring a PACKAGING INFORMATION chart. When scrolling down through this chart you will see a reference to Package Drawing "D" for all 14-pin SOIC packages.
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Package Drawing "D" can be found on page 42. Package Drawing "D" calls out a 14-pin SOIC package width of 0.150" to 0.157" (150 mils to 157 mils, or 3.80mm to 4.00mm). Notice that this encompasses the nominal 14-pin SOIC package width listed in the Device Information chart.
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Three 14-pin SOIC packages named "SOIC-14/150mil", "SOIC-14/209mil" and "SOIC-14/300mil" can be found in the DipTrace pattern libraries. The "XXXmil" suffix of the pattern name represents the package width in mils, so the pattern you most likely need is named "SOIC-14/150mil".

A document called Pattern Names Help details DipTrace pattern naming conventions and can be found here - https://diptrace.com/books/Pattern_names_help.pdf.
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Tom

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