LX1977

WWW.Microsemi .COM LX1977 TM ® SMBus Ambient Light Sensor PRODUCTION DATASHEET DESCRIPTION The LX1977 is a CMOS based Ambient Light Sensor (ALS) with an I2C compatible SMBus interface. This device is ideal for controlling display back lighting systems of low cost consumer products such as TV, portable computers, handheld devices, or medical devices. The LX1977 is optimized for a linear, accurate, and very repeatable input and output transfer function. The device also features adjustable input range and gain. The LX1977 has a spectral response that emulates the human eye. Specially designed circuitry produces peak spectral response at 555 nm, with IR response less than 10% above 810 nm. Input dynamic range of this device is adjustable via SMBus command. It can be set to either 0 ~ 500 lux, 0 ~ 1000 lux, 0 ~ 2500 lux or 0 ~ 5000 lux. ALS internal compensation ensures photodiode dark current are at very low levels, providing high output accuracy at low ambient light levels. The LX1977 integrates a 12-bit SigmaDelta A/D converter that converts the ALS photodiode output into a digital word. This value is read via the I2C compatible SMBus interface. The LX1977 ALS is internally optimized to an accuracy of approximately 5% over temperature. The high accuracy and repeatability of this device eliminates the need of calibration during product production, which results in reduced assembly time and lower production cost. The LX1977 is available in an 8-pin MSOP package, and is opera...