| Along with the IC, the vendor offers an evaluation kit, which consists of a pc board with sensor, choice between RS-232 interface or PCMCIA interface to the board, and a CD ROM with exercise code. The TSL2550 is US$1.59 (1000 pieces) while each evaluation kit is US$110. | 
The TSL2550 sensor plus interface IC controls display backlighting and saves system power. |
How much backlighting you need in a given ambient light condition for PDAs, handheld instrumentation, camcorders, and similar products is not a minor issue—it affects power consumption, which is always critical. The TSL2550 from Texas Advanced Optoelectronic Solutions, Inc (TAOS) promises to make the judgment easier. This light sensor provides an SMBus-compatible output derived from the readings on two integral sensors, one for visible plus infrared light and one for infrared only. By combining the two readings and digitizing the result, it approximates the response of the eye, thus letting you assess the visible light intensity along with the effect of infrared, so you can adjust the backlighting accordingly. The internal, 12-bit companding ADC provides necessary dynamic range, while the design rejects unavoidable 50-/60-Hz ripple from ambient lighting sources. The 1 mW 8-lead IC operates from a 2.7- to 5.5-V supply, and needs just two wires for the SMBus serial interface. 
