SBOS745A May 2016 – June 2016 OPT3002
The PCB layout design for the OPT3002 requires a couple of considerations. Bypass the power supply with a capacitor placed close to the OPT3002. 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 most optimal optical layout is to place all close components on the opposite side of the PCB from the OPT3002. However, this approach may not be 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, they 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 OPT3002 is shown in Figure 24.