Do boards have to be rectangular?

We get this question often: do PCBAs need to be rectangular? The answer is no. We’ve designed boards in many different shapes, from rectangular to donut shape. The shape is limited only by the PCB manufacturing capabilities. Generally shorter than 23.5” in any direction and not narrower than 0.25”. It’s important to note that the price of a PCB is based on the overall X & Y dimension, not just the surface area. So in the case of the donut shaped PCB, it had a 3.5 inch outer diameter and 3 inch inner diameter. Surface area of this board is about 2 square inches (the proof is left as an exercise for the reader) but since you pay based on the overall X & Y space, you will need to pay for a 3.5” square, or about 12 square inches. So if you are aiming for the lowest cost PCBA then you will want it to be rectangular shaped.

Boards are often shaped differently to fit a mechanical requirement. Consider the board shown below:

This board was designed to illuminate the inside of a channel; if you look closely you can see six LEDs pointed inwards. The board also needed to contain the LED driver and a proximity sensor. The final board shape was a negotiation between the mechanical engineer and myself. Most PCBAs are generally rectangular like the small wrist mounted medical device shown below.