Ambient light sensors bring energy efficiency

The sensors are ideal solutions for a variety of portable devices that require UV sensing, proximity sensing, or gesture detection functionality.     

The sensors which are available at Mouser Electronics, are offered in two product varieties: the Si1133 and Si1153. The Si1133 is an ambient light sensor with an optional high-accuracy ultraviolet (UV) index sensor. The UV sensor features a unique on-die filter that closely resembles an erythema curve to help monitor the effects of ultraviolet radiation.     

By contrast, the Si1153 is a touchless sensor IC designed for proximity detection adjustable from under 1 cm up to 200 cm. With 30 current settings from 5.6mA to 360mA for each LED driver, the Si1153’s proximity detector operates in direct sunlight with an optional on-die 940nm band pass filter that rejects unwanted visible light and IR from daylight and other sources.

The photodiode response and associated digital conversion circuitry on the Si1153 provides excellent immunity to artificial light flicker and natural light flutter noise. With two or more LEDs, the Si1153 is also capable of supporting multiple-axis proximity motion detection.

The Si1153 also features three integrated LED drivers with programmable drive levels that make it an attractive solution for proximity detection, and wearable monitoring and wrist applications.

Other features include a heart rate and blood oxygen monitor with a broad sensitivity from green to 940nm.      

Silicon Labs’ Si1133 and Si1153 ambient light sensor ICs provide less than 100mlx resolution, allowing each device to be operated under dark glass covers, and both offer up to 128klx of dynamic range across two ADC range settings.

The sensors use a supply voltage range of 1.62 V to 3.6 V, and boast one of the industry’s lowest power consumption ratings of under 500 nA (standby). The sensors feature a flexible I²C digital interface with data rate up to 3.4Mbps, and a programmable-event interrupt output feature.

Available in compact package options (a 10-pin QFN for the Si1133, and both a 10-pin QFN and 10-pin module with integrated 940nm LED for the Si1153), the Silicon Labs’ Si11x3 family of ambient light sensors are ideally suited toward a broad array of sensor aplications including wearables, handsets, display backlighting, and consumer electronics.

In addition, the Si1153 is also supported by an expansion board, the 115XOPT-EXP-EVB, also available through the Mouser Electronics website.