Disclosed examples include integrated circuits with a leadframe structure, a first circuit structure including a light source configured to generate a light signal along an optical path, a second circuit structure including a light sensor facing the optical path to receive the light signal, and a molded package structure enclosing portions of the leadframe structure, the molded package structure having a cavity defined by an interior surface of the molded package structure, the optical path extending in the cavity between the first and second circuit structures.