TAOS Inc. is now ams AG The technical content of this TAOS datasheet is still valid. Contact information: Headquarters: ams AG Tobelbaderstrasse 30 8141 Unterpremstaetten, Austria Tel: +43 (0) 3136 500 0 e-Mail: ams sales ams.com Please visit our website at www.ams.com TSL2550 AMBIENT LIGHT SENSOR WITH SMBus INTERFACE TAOS029L OCTOBER 2007 PACKAGE D Converts Light Intensity to Digital Signal 8-LEAD SOIC Infrared Compensation to Approximate (TOP VIEW) Human Eye Response V 1 8 SMBData DD Companding A/D for Wide Dynamic Range NC 2 7 NC Rejects 50 Hz/60 Hz Lighting Ripple Two-Wire SMBus Serial Interface NC 3 6 NC Single Supply Operation (2.7 V to 5.5 V) GND 4 5 SMBCLK Low Active Power (1 mW typ) Power Down Mode Low-Profile Surface-Mount Packages PACKAGE T RoHS Compliant 4-LEAD SMD (TOP VIEW) Description V 1 4 SMBData DD The TSL2550 is a digital-output light sensor with GND 2 3 SMBCLK a two-wire, SMBus serial interface. It combines two photodiodes and a companding analog-to- digital converter (ADC) on a single CMOS integrated circuit to provide light measurements over an effective 12-bit dynamic range with a response similar to that of the human eye. The TSL2550 is designed for use with broad wavelength light sources. One of the photodiodes (channel 0) is sensitive to visible and infrared light, while the second photodiode (channel 1) is sensitive primarily to infrared light. An integrating ADC converts the photodiode currents to channel 0 and channel 1 digital outputs. Channel 1 digital output is used to compensate for the effect of the infrared component of ambient light on channel 0 digital output. The ADC digital outputs of the two channels are used to obtain a value that approximates the human eye response in the commonly used unit of Lux. This device is intended primarily for use in applications in which measurement of ambient light is used to control display backlighting such as laptop computers, PDAs, camcorders, and GPS systems. Other applications include contrast control in LED signs and displays, camera exposure control, lighting controls, etc. The integrating conversion technique used by the TSL2550 effectively eliminates the effect of flicker from AC-powered lamps, increasing the stability of the measurement. Functional Block Diagram Integrating Channel 0 A/D Converter Photodiode Channel 1 Photodiode V = 2.7 V to 5.5 V DD Control Logic Output Registers SMBCLK Two-Wire Serial Interface SMBData Copyright 2007, TAOS Inc. The LUMENOLOGY Company Texas Advanced Optoelectronic Solutions Inc. 1001 Klein Road Suite 300 Plano, TX 75074 (972) 673-0759 www.taosinc.com 1 ams AG Technical content still valid