PCB Libraries Forum : IPC-7351 Padstack Naming Convention

IPC-7351 Padstack Naming Convention : Updated Pad Stack Naming Convention...

Sun, 07 Apr 2024 14:30:10 +0000

Author: Tom H
Subject: 36
Posted: 07 Apr 2024 at 2:30pm

Updated Pad Stack Naming Convention released in IPC-7352.

The first letter in the pad stack name describes the shape of the pad on the outer layers of the circuit board. Small letters are used. Note: “b” = Oblongs, because the letter “o” could easily be confused with the number “0”.

IPC-7351 Padstack Naming Convention : Thanks! So I will name my padstack...

Wed, 29 Apr 2020 10:43:57 +0000

Author: AleksMK
Subject: 36
Posted: 29 Apr 2020 at 10:43am

Thanks! So I will name my padstack xc120mx130px0.

Cheers!

Aleks

IPC-7351 Padstack Naming Convention : Modifiers that are used when...

Wed, 29 Apr 2020 10:08:56 +0000

Author: Tom H
Subject: 36
Posted: 29 Apr 2020 at 10:08am

Modifiersthat are used when pad stack features are different than the defaults

In instances where shapes are different thisbecomes a two letter code with the "modifier" first followed by the land shapeletter.

x = Special modifierused alone or following other modifiers for lands on opposite side to primarylayer land dimension

So the "x" comes before the shape character.

IPC-7351 Padstack Naming Convention : Hi Tom,Thanks for all the info,...

Wed, 29 Apr 2020 09:44:28 +0000

Author: AleksMK
Subject: 36
Posted: 29 Apr 2020 at 9:44am

Hi Tom,

Thanks for all the info, although a bit unrelated to my question :-) The application for which I need this padstack is creating test points in OrCAD PCB Designer Professional, where the padstack need to be defined on the layer where you are creating the test point. So if I want a test point on the bottom layer, I need to have the bottom layer defined in my padstack. The padstack is not being mirrored when adding testpoints, hence this requirement.

If I may re-iterate my question: using the padstack naming convention that I have downloaded from PCB Libraries, what is the correct name to name a padstack which will have a circular land patter on the bottom layer only 1.2mm in size, with a solder mask on the bottom layer only with 1.3mm opening and no bottom paste mask layer?

Cheers

IPC-7351 Padstack Naming Convention : There is a pad stack naming issue...

Wed, 29 Apr 2020 09:34:13 +0000

Author: Tom H
Subject: 36
Posted: 29 Apr 2020 at 9:34am

There is a pad stack naming issue with the current V2019 Library Expert for SMD pads that are defined on both the Top and Bottom layers. This issue will be fixed in V2020 coming out next month.

To create a complex pad stack, you need the FP Designer feature and that does not come with the free Library Expert Pro (yet), but next month when V2020 is released, the Library Expert Pro will have 100% full featured program (just like the Enterprise version) and support these CAD tools -

CADint
DesignSpark
DipTrace
Eagle
KiCad
Pantheon
Proteus
Pulsonix
McCAD
SoloPCB
Target 3001!
Ultiboard

So even if you don't use any of these CAD tools you can still download the program for free and use it as an advanced Land Pattern Calculator.

Also, starting next week we start giving away the full featured Library Expert Enterprise for free. Just pay the yearly maintenance to get all the updates and technical support for the year. Pick any CAD tool and get our new Cloud License for a yearly lease at 20% of list price.

Bottom line is that you need FP Designer to create custom pad stacks and we're either going to give that away for free or lease it at an affordable price point.

The software program needs to work perfect to take away any guessing and confusion.

Also, putting a SMD pad on the top & bottom layers is rare. What application is this for?

IPC-7351 Padstack Naming Convention : Hi Tom,Yes, I do have the document,...

Wed, 29 Apr 2020 07:56:35 +0000

Author: AleksMK
Subject: 36
Posted: 29 Apr 2020 at 7:56am

Hi Tom,

Yes, I do have the document, the question arose from reading that document. As I quoted, It's not very clear to me how the naming for my padstack should be? Any advice on that?

Thanks!

Aleks

IPC-7351 Padstack Naming Convention : AleksMK, do you have a copy of...

Wed, 29 Apr 2020 07:31:27 +0000

Author: Tom H
Subject: 36
Posted: 29 Apr 2020 at 7:31am

AleksMK, do you have a copy of the pad stack naming convention document?

You can download it here - www.pcblibraries.com/downloads

IPC-7351 Padstack Naming Convention : Hi everyone,I have a question...

Wed, 29 Apr 2020 06:50:09 +0000

Author: AleksMK
Subject: 36
Posted: 29 Apr 2020 at 6:50am

Hi everyone,

I have a question on the use of the special x modifier. This is it's definition:

"x = Special modifierused alone or following other modifiers for lands on opposite side to primarylayer land dimension"

And later on there are three examples:

mxc = Solder MaskOpposite Side Circular

mx0 = Solder MaskOpposite Side No Solder Mask

xc = Opposite SideCircular

As the x-modifier is defined that it is following other modifier, is the last "xc" example wrong? Should it not be "cx"?

I need to create a padstack, which will have a circular land patter on the bottom layer only 1.2mm in size, with a solder mask on the bottom layer only with 1.3mm opening and no bottom paste mask layer. Which of the following namings (or none?) will be the correct one for this padstack?

1. cx120mx130px0

2. xc120mx130px0

3. xc120xm130xp0

Thanks!

Aleks

IPC-7351 Padstack Naming Convention : Another example of padstyle of...

Mon, 05 Oct 2015 05:45:34 +0000

Author: jameshead
Subject: 36
Posted: 05 Oct 2015 at 5:45am

Another example of padstyle of the top "layer 1" may be different to the inner and bottom layers is a TO-220 horizontal where you have a rectangular pad to connect with the heatsink of the device and have only a round pad on inner and the bottom layer.

I've interpreted the standard to have:

r1599_1039r25o510xc580zc580h385

Rectangular 15.99 mm x 10.39 mm, radius 0.25 mm corners for a pad on layer 1, where the centre of the rectangular pad is off-set 5.1 mm from the centre of the hole. Hole size is 3.85 mm. Pads on inner layers and the bottom size is a round 5.80 mm.

Not all CAD systems allow you do this easily though.

IPC-7351 Padstack Naming Convention : Cheers Tom.

Mon, 05 Oct 2015 04:39:48 +0000

Author: Matthew Lamkin
Subject: 36
Posted: 05 Oct 2015 at 4:39am

Cheers Tom.