The VCNL4040 from Vishay is a fully integrated proximity and ambient light sensor that combines an IR emitter, photo-detectors for proximity and ambient light sensing, a signal-processing IC and a 16-bit ADC in a single chip.
When used in battery-powered products that have a touchscreen display, the Vishay Semiconductors VCNL4040 reduces power consumption, because its proximity sensor function lets the system automatically disable the display until a user is detected.
At the same time, the ambient light sensor supports adaptive brightness control of display and keypad backlighting, also helping to reduce power consumption while improving the user experience.
Because the VCNL4040 includes all of the circuitry needed for these applications in a single device, it eliminates the need for additional light barriers and for optical alignment of the IR emitter and photodiode.
Measuring just 4mm x 2mm x 1.1mm, the VCNL4040 gives design engineers great flexibility in the placement of the sensor. It can function at any depth or air gap below the glass window, unlike sensors with resolution of 8-, 10- or 12-bits, which require a depth of 1.5mm or less. Lower-resolution devices must also be placed away from other components on a costly and dedicated flexible circuit, while the 16-bit resolution of the VCNL4040 allows it to be assembled on the main PCB.
The VCNL4040’s ambient light and proximity sensors operate in a parallel structure; each offers a programmable Interrupt function with high and low thresholds. The use of patented Filtron™ technology provides for ambient light sensitivity that very closely matches the response of the human eye. The device also offers an excellent temperature-compensation capability to keep the output stable in all conditions.
The VCNL4040 measures ambient light with an accuracy of ±10% across a broad range from very dark (0.01lux) conditions up to bright sunlight (5.2klux). This means that it can be used equally well behind a dark or a transparent window. The sensor is immune to fluorescent light flicker.
- I²C bus interface
- Proximity function has selectable 12-bit and 16-bit outputs
- Intelligent cancellation eliminates crosstalk in proximity sensor
- 940nm emitter wavelength with no visible ‘red tail’
- Supply voltage range: 2.5V to 3.6V
- Digital cameras
- Handheld consumer electronics devices