The battery in a mobile phone or smartphone has to support multiple functions, one of which is the camera’s high-power LED flash. Any noise generated by one load therefore affects all others, of which some—such as the RF receiver and power amplifier—are sensitive to noise. As long as the noise generated by the load stays on a known fixed frequency, the use of appropriately specified EMC filters and shields will block it. Unfortunately, the noise generated by typical LED flash driver ICs is not at a fixed frequency.