1 low power ambient light and proximity sensor with enhanced infrared rejection ISL29038 the ISL29038 is a low power am bient light sensor (als) and proximity (prox) sensor. it has a built-in ir-led driver for proximity function. the als func tion measures the amount of light (in the visible spectrum) incident on the ISL29038. the als function has a programmable ambient ir-rejection, which allows fine tuning of light source variations and is ideal for light sensor applications under dark protective glass. the als provides a 12-bit measurement. a passive optical filter removes unwanted wavelengths (ir or ultraviolet) to ensure accurate als measurement. the proximity function includes a new offset adjustment to compensate for the ir light re flected off the inside of the protective glass cover and back to the ISL29038 sensor. this offset adjustment allows the sensor to compensate for these internal reflections and preserve the dynamic range of the proximity measurement. the built-in current-driver pulses an external infrared led at a programmed current for 90s. the infrared light that is reflected and received by ISL29038 is digitized by an 8-bit adc. the proximity sensor also has a passive optical filter designed to pass ir and reject visible wavelengths. the ISL29038 provides a hardware pin to indicate an interrupt event. the interrupt pin saves po wer as the host micro-controller can ?wake-up? on an interrupt event and does not need to poll the device for an interrupt event. the interrupt generator is user configurable and provides several options for als and prox trigger configurations. the ISL29038 supports an smbus compatible i 2 c interface for configuration and control. features ? ideal for applications un der dark or tinted glass ? enhanced ambient sunlight rejection to 40k lux ? programmable proximity sleep time between proximity measurements optimizes power consumption ? hardware interrupt - no polling required ? programmable ir compensation to fine tune als performance for various glass compositions ? up to 4000 lux, four selectable als ranges ? programmable ir led drive current to 250ma ? operates from 2.25v to 3.63v v dd ?power down i dd, typical 0.2a dc ? tiny 2.1x2.0x0.7 (mm) odfn package applications ? display dimming and adjustment - mobile devices: smart phones, pda, gps - computing: monitors, laptops, notebooks - picture frames, tablet-pcs, lcd-tv ? object detection - touchscreen disabling -smart power-saving figure 1. typical applications circuit vdd_irled vdd_analog r 2 100 c 1 1f c 2 1f r 1 499k 1 2 3 4 8 7 6 5 gndir avdd agnd rext irdr int sda scl d 1 irled u1 ISL29038 vdd_pullup scl, sda and int sda scl int pullups smbus master r 1 : 499k 1% resistor r 2 : 100 ? 5% resistor c 1 , c 2 : 1f ceramic 10v capacitor d 1 : osram sfh4650 infrared led october 12, 2012 fn7851.0 caution: these devices are sensitive to electrostatic discharge; follow proper ic handling procedures. 1-888-intersil or 1-888-468-3774 | copyright intersil americas inc. 2012. all rights reserved intersil (and design) is a trademark owned by intersil corporation or one of its subsidiaries. all other trademarks mentioned are the property of their respective owners.
ISL29038 2 intersil products are manufactured, assembled and tested utilizing iso9000 quality systems as noted in the quality certifications found at www.intersil.com/en/suppor t/qualandreliability.html intersil products are sold by description only. intersil corporat ion reserves the right to make changes in circuit design, soft ware and/or specifications at any time without notice. accordingly, the reader is cautioned to verify that data sheets are current before placing orders. information furnished by intersil is believed to be accurate and reliable. however, no responsi bility is assumed by intersil or its subsid iaries for its use; nor for any infringem ents of patents or other rights of third parties which may result from its use. no license is granted by implication or otherwise under any patent or patent rights of i ntersil or its subsidiaries. for information regarding intersil corporation and its products, see www.intersil.com fn7851.0 october 12, 2012 for additional products, see www.intersil.com/en/products.html pin configuration ISL29038 (8 ld odfn) top view figure 2. ISL29038 block diagram vdd rext gnd scl ir photodiode photodiode 4 3 5 2 fosc iref irdr array als photodiode amplifiers (als and ir) array dual channel adcs 8 int 7 command register data register i 2 c ir driver interrupt sda 6 gndir 1 1 2 3 8 7 6 gndir vdd gnd irdr int sda 4 5 rext scl thermal pad pin description pin# name description 1 gndir ground for irdr led current. 2 vdd positive supply: 2.25v to 3.63v. 3gndground. 4 rext external resistor, connect to gnd pin through a 499k ? , 1% resistor. 5scli 2 c serial clock input. 6sdai 2 c serial data input/output. 7int active low, open-drain output. 8 irdr ir-led driver sink - connect to ir led cathode. - tpad thermal pad - connect to gnd.
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