I’m creating a footprint, RDE03 Series DC/DC converter. The datasheet shows the pin layout as a bottom view (left). When building the footprint in my EDA tool, does this mean the pin arrangement needs to be mirrored (for example, along the X-axis)?
What you’re looking at is a mechanical drawing, not a recommended PCB footprint or land pattern. For through-hole parts, manufacturers often present pin layouts as a bottom view to describe the physical component, not how it appears from the PCB top side.
When creating the footprint, you place the holes based on those dimensions but interpreted from the PCB’s top view, which usually means mentally flipping or mirroring the drawing. If flipping the image helps, that’s fine. Bottom-view drawings are common for mechanical clarity, even though they’re not ideal for direct footprint creation.
A useful way to think about it is that pin numbering is absolute and doesn’t depend on how the drawing is shown. The bottom view exists so you can identify pins correctly when looking at the physical part during handling or inspection.
When creating the footprint, focus on ensuring that, once the part is mounted on the top side of the PCB, the pin numbers line up correctly with the schematic, not on making the footprint visually match the datasheet drawing.
It is not just datasheets that provide bottom views. Assembly drawings are also like this since assemblies are not transparent. If you are holding an assembly, when you rotate it to the bottom side, you want the drawing view to reflect what the user actually is seeing in that view. The bottom view is mirrored of what you would see if the assembly were transparent and you are looking from the top side down through the unit.
One practical check that often helps here is orientation validation, not just mirroring logic. After you’ve created the footprint, place it on a test PCB, assign pin 1 in the schematic, and then imagine (or physically mock up) inserting the real part from the top side. Verify that pin 1 on the actual component lands in the correct hole relative to your board origin and silkscreen marker. Bottom views exist mainly for physical handling and inspection. In CAD, the goal is correct pin-to-net mapping after assembly, regardless of how the drawing is shown.
You don’t design the footprint to visually match the datasheet view. The only requirement is that, once the part is mounted on the PCB top side, each pin number connects to the correct schematic net. Bottom views are provided for physical identification and inspection, not as a direct footprint template.
Footprints are always defined from the PCB top side. You don’t mirror a footprint just because the datasheet shows a bottom view. The key is that each pad maps to the correct pin number when the component is inserted from the top. If the pin numbering is correct, the footprint will work regardless of how the drawing looks.
