The PCB layout design for the OPT3005 requires a couple of considerations. Bypass the power supply with a capacitor placed close to the OPT3005. Note that optically reflective surfaces of components also affect the performance of the design. The three-dimensional geometry of all components and structures around the sensor must be taken into consideration to prevent unexpected results from secondary optical reflections. Placing capacitors and components at a distance of at least twice the height of the component is usually sufficient. The best optical layout is to place all close components on the opposite side of the PCB from the OPT3005. However, this approach is not practical for the constraints of every design.

Electrically connecting the thermal pad to ground is recommended. This connection can be created either with a PCB trace or with vias to ground directly on the thermal pad itself. If the thermal pad contains vias, then the vias are recommended to be of a small diameter (< 0.2 mm) to prevent them from wicking the solder away from the appropriate surfaces.

An example PCB layout with the OPT3005 is shown in Figure 9-6.