The SFH 7773 from OSRAM Opto Semiconductor (www.osrram-os.com) combines a digital ambient light sensor and a proximity sensor (emitter + detector) within one package. Additionally the sensor provides an I2C-bus interface and an interrupt pin to connect it to an e.g. microcontroller.
This application note describes the basic technical features and the components operation, allowing the user to achieve the full functionality of the sensor. At the end a simple software code illustrates an example for the implementation of the SFH 7773 into a mobile phone environment.
Please note that this guide is only a brief introduction. For more detailed information and the latest products and updates please visit www.osram-os.com or contact your local sales office to get technical assistance during your design-in phase.
Applications Typical application areas are mobile phones, PDAs, notebooks, cameras and other consumer products. Common tasks for the integrated ambient light sensor are display brightness adjustments, whereas the proximity sensor is usually employed to detect objects and motions.
This single component integrates several distinct functionalities and greatly simplifies the design-in process in consumer as well as industrial applications. The dark black look of the SFH 7773 makes it ideally suitable for implementation behind a cover glass.
The ultra-low power consumption of the SFH 7773 makes the devices especially suited for mobile applications, where conservation of battery power is a critical point.
The SFH 7773 The SFH 7773 consists of an 850 nm infrared (IR) LED and an ultra-low power ASIC which performs the signal processing and provides the I2C-bus interface as well as an interrupt alert function. Additionally the ASIC contains the two photodiodes for proximity resp. ambient light sensing.
The key features of the SFH 7773 include:
Proximity Sensor (PS)
- detection-range up to 150 mm
- optimized for the integrated 850nm emitter
- superior ambient light suppression (> 50 klx) - immunity to crosstalk - fast access to PS signal - high power (stacked) emitter version for extended detection range are available on request