Application Note 1741 Author: Xiaoying Shi ISL76671 Low Power, <100 Lux Optimized, Analog Output Ambient Light Sensor Evaluation Hardware User Guide Description Hardware Setup The ISL76671 is a low light optimized analog output sensor. In normal operation, the device is intended to be mounted behind a smoked glass/plastic bezel which normally significantly attenuates received light. The ISL76671 will typically saturate at full scale with an incident illumination of around 150 lux, which is a fair deal lower than normal indoor ambient light conditions (2k to 10k lux). The small ISL76671 evaluation board comprises the sensor device itself and a 100k resistor which sets the output scaling for the sensor. The part was characterized with the 100k resistor. Larger or smaller values can be used, however, Intersil found that the 100k value worked well under a variety of conditions. Note that with larger scale setting resistors the sensor is likely to prematurely saturate at relatively low light levels. Please check Page 7 of the ISL76671 datasheet for a description of the output scaling factor relative to incident ambient light. The ISL76671EVAL1Z evaluation board is an RoHS compliant evaluation board prepared to speed up part evaluation. Note that the sensing range for this device is from 0.01 lux to 100 lux typically and the device has been optimized for use with a 100k output scaling resistor (REXT). The device and the evaluation board will work from a 3V supply. Evaluation Package The jumpers and components on the printed circuit board (PCB) are as shown in Table 1. TABLE 1. JUMPERS, COMPONENTS ON PCB JUMPER DESCRIPTION * Evaluation Board ISL76671EVAL1Z, populated with all required components JP1 REXT = 100k(Default) JP2 REXT = 47k * AN1741: "ISL76671 Low Power, <100 Lux Optimized, Analog Output Ambient Light Sensor Evaluation Hardware User Guide" (see Technical Documentation on the ISL76671 product information page) JP3 REXT = 147k JP4 RLOAD = 10k (Optional, Do not populate) JP5 RLOAD = 100k (Optional, Do not populate) JP6 RLOAD = 1M (Optional, Do not populate) C1 0.1F D1 Optional L1 Optional March 14, 2012 AN1741.0 1 CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. 1-888-INTERSIL or 1-888-468-3774 | Copyright Intersil Americas LLC 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. Application Note 1741 U1 VCC L1 VCC D1 BAT42 ISL76671 TP1 1 BEAD C1 0.1uF 2 3 VOUT GND NC2 NC1 REXT VOUT 6 5 JP4 JP5 JP6 4 R4 10k R5 100k R6 1M 7 TP GND1 VCC GND2 JP1 R1 100k JP2 R2 47k JP3 R3 147k FIGURE 1. ISL76671EVAL1Z EVALUATION BOARD SCHEMATIC Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without notice. Accordingly, the reader is cautioned to verify that the Application Note or Technical Brief is current before proceeding. For information regarding Intersil Corporation and its products, see www.intersil.com 2 AN1741.0 March 14, 2012 Mouser Electronics Authorized Distributor Click to View Pricing, Inventory, Delivery & Lifecycle Information: Intersil: ISL76671EVAL1Z