Strange footprint pad location error after creating it

Layout Footprints
1

I created a footprint for a TDK low pass filter according to its data sheet here at:

https://product.tdk.com/system/files/dam/doc/product/rf/rf/filter/catalog/rf_lpf_dlf162500lt-5028a1_en.pdf

The pads and land pattern diagram are shown as below:

Screenshot from 2025-11-13 18-21-12
Screenshot from 2025-11-13 18-21-121144×744 37.9 KB

Using the footprint editor, I created a footprint for this part. The setup of the footprint is as below for pads 2 and 4:

2
2927×691 55.7 KB

4
4931×692 58.3 KB

Pads 1 and 3 are at y =0 for both and pad 1 is at x = -0.6125mm while pad2 is at x= 0.6125mm. Please see that pads 2 and 4 are at y = 0.2275mm and y = -0.2275mm and at x=0 for both. From this, pad 2 should be on top of pad 4 but pad 2 is appearing down and pad 4 is appearing up as shown in this diagram.

footprint
footprint1280×982 147 KB

The footprint is shown as below in the schematic.

footprint
footprint694×622 7.65 KB

The footprint should look like that but pads 2 and 4 are reversed in position.

Is this a bug in the footprint editor?

Attached is the footprint.

DLF162500LT-5028A1.kicad_mod (2.9 KB)

Attached is the barebone project containing the footprint:

opa1641.zip (524.6 KB)

Please tell me why the orientation of pads 2 and 4 is reversed in the footprint editor even though their X and Y positions were given correctly?

KiCAD version info:

Application: KiCad Schematic Editor x86_64 on x86_64
Version: 9.0.5+1, release build
Libraries:
wxWidgets 3.2.8 , FreeType 2.13.3, HarfBuzz 10.2.0, FontConfig 2.15.0 , libcurl/8.14.1 OpenSSL/3.5.1 zlib/1.3.1 brotli/1.1.0 zstd/1.5.7 libidn2/2.3.8 libpsl/0.21.2 libssh2/1.11.1 nghttp2/1.64.0 nghttp3/1.8.0 librtmp/2.3 OpenLDAP/2.6.10

Platform: Debian GNU/Linux 13 (trixie), 64 bit, Little endian, wxGTK, X11, cinnamon, x11
OpenGL: Intel, Mesa Intel(R) HD Graphics 2500 (IVB GT1), 4.2 (Compatibility Profile) Mesa 25.0.7-2

Build Info:
Date: Oct 11 2025 10:45:10 , wxWidgets: 3.2.8 (wchar_t,wx containers) GTK+ 3.24 ,Boost: 1.83.0
OCC: 7.8.1 ,Curl: 8.14.1 , ngspice: 44.2, Compiler: GCC 14.2.0 with C++ ABI 1019, KICAD_IPC_API=ON

Locale:
Lang: en_IN ,Enc: UTF-8, Num: 1,234.5 ,Encoded кΩ丈: D0BACEA9E4B888 (sys), D0BACEA9E4B888 (utf8)

2

By default, Y coordinates increment while going downwards. You can change this in the preferences, or you can just change the pad numbers.

But at the moment your footprint is already the same as in the datasheet (by coincidence). Look closer at the datasheet. It shows the bottom view of the part. I was alerted to this, as the normal convention is to number pads counter clockwise when seen from above.

For the symbol editor, you can simply rotate the pins. KiCad is a bit confusing sometimes with left / right / top / bottom. As an alternative, you can also give both GND pads the same number in the footprint editor, and then only use one GND pin the schematic. KiCad simply assumes that pads with the same pad number always have to be connected to each other, and this cleans up the schematic a bit.

On a sidenote, you also have very little clearance between the pads. Certainly less then the 0.25mm in the “recommended land pattern”.

3

Where is this located in preferences? Usually, positive Y means going upwards as seen by the viewer with view towards the part on the PCB. I follow this convention.

4

Preferences / Preferences / PCB Editor / Origins & Axes / Y-Axis / Increases up

Having (0, 0) in the upper left corner is a common convention for programming, as that is the native origin for most monitor programs. It’s also where the cursor starts in text boxes etc. But it’s indeed not common for programs used by users, or mathematics.

5

In math, mechanic and in PCB but not in screen and graphics.

I suppose that someone experienced in graphics was designing KiCad coordinates :slight_smile:

6

I chose origin (0,0) as the point at which the vertical and horizontal lines intersect.

7

But KiCad origin is at top left sheet corner.

I work above (or around) this point (I have modified my PCB sheet frame to contain only a small cross at 0,0 coordinates (I wanted to left it empty but then default sheet frame was shown).

9

This fixed the positions of pads 2 and 4. Now 2 is up and 4 is down as required for the top view of the part in datasheet.

10

Huh? The top of your screenshot states: [Bottom view], as I already mentioned earlier. (sigh).

12

TDK created that spec. I’m aware of the small clearance between pads 2 and 4 which is 0.21mm. It appears that the PCB manufacturer would change it if the part has a different clearance.

13

Just as you have done, I see it as correct.

A bug? Why? You can orient the symbol pins however you want. They don’t have to match the orientation of the footprint pads.

1 Like
14

I changed the origin and direction of Y axis as pointing upwards. Now, pads 2 and 4 are as in the datasheet with pad 2 up and pad 4 down. The default settings in KiCad had Y-axis pointing downwards.