Date: 20/02/2011

1.1µW power consuming ambient light sensor ICs from Maxim

Maxim Integrated Products has rolled out the new MAX44007/MAX44009, digital ambient-light sensor (ALS) ICs with a unique adaptive-gain block. These sensor chips which are made using BiCMOS process integrate two optical sensors, an ADC, and digital functionality with in a package size of 2mm x 2mm x 0.6mm.

Maxim claims MAX44007/MAX44009 consume 100x less power than the nearest competitive product. The light measurement is made continuously and reports to the microcontroller when the measurement passes the threshold. These chips extend power savings by reducing the frequency of I²C communications.

The MAX44007/MAX44009 are suggested for applications such as tablet and notebook PCs, smartphones, TVs, digital lighting-management systems, and light-intensity monitoring applications. Where the display brightness or any such lighting source intensity can be controlled by continuously sensing the ambience light.

MAX44007/MAX44009 feature maximum total gain error of 15% and the digital interface from sensor to device is immune from parasitic electrical noise.

MAX44007/MAX44009 integrates two photodiodes along with an optical filter to reject ultraviolet and infrared light enabling precision sensing of light intensity close to human eye. Spectra variations between light sources are corrected using advanced algorithms.

The built in ADC integration time of the sensors can be adjusted from 6.25ms to 800ms. A default integration time of 100ms ensures excellent 50Hz/60Hz rejection.

The tinted or black glass issue is taken care by MAX44007 by providing access to two different optical sensors: a visible-plus-infrared photodiode and an infrared photodiode. Once the designer knows the response of the black glass, it can be factored into the light sensor's measurement for superior accuracy and sensitivity (down to 0.025 lux).

The MAX44007/MAX44009 with wide dynamic range feature an integrated adaptive-gain block that automatically selects the optimum gain range. This capability relieves designers of the time-consuming process of manually programming the device, and it offloads work from the application processor or microcontroller. The MAX44009 can measure light levels from 0.045 lux to 188,000 lux, yielding a dynamic range of more than 4,000,000 to 1. Maxim states this technology provides the most precise lux measurements over the widest range of ambient-light conditions.

The MAX44007/MAX44009 consume low operating current (0.65µA) and operate from an industry-low 1.7V to 3.6V supply voltage.
The devices' low supply voltage allows them to use the same 1.8V supply for both the supply voltage and the I²C interface.

Package: UTDFN-Opto-EP
Price: Start at $1.20 (1000-up, FOB USA).