ISL29001 ® Data Sheet December 21, 2005 FN6166.0 Ambient Light Sensor Features The ISL29001 is an integrated ambient light sensor with ADC and I2C interface. With a spectral sensitivity curve matched to that of the human eye, the ISL29001 provides 15-bit effective resolution while rejecting 50Hz and 60Hz flicker caused by artificial light sources. • Human eye response In normal operation, the ISL29001 consumes less than 300µA of supply current. A software power-down mode controlled via the I2C interface disables all but the I2C interface. A power-down pin is also provided which reduces power consumption to less than 1µA. • Simple output code, directly proportional to lux The ISL29001 includes an internal oscillator which provides 100ms automatic integration periods, or can be externally timed by I2C commands. Both the internal timing and the illuminance resolution can be adjusted with an external resistor. • I2C interface Designed to operate on supplies from 2.5V to 3.3V, the ISL29001 is specified for operation over the -40°C to +85°C ambient temperature range. It is packaged in a clear 6-pin ODFN package. • 15-bit effective resolution • Adjustable resolution: 3 to 15 counts per lux • 0.3 lux to 10,000 lux range • IR rejection • 50Hz/60Hz rejection • 2.5V to 3.3V supply • 6-pin ODFN (2.1mm x 2mm) • Pb-Free plus anneal available (RoHS compliant) Applications • Ambient light sensing • Ambient backlight control Ordering Information • Temperature control systems PART NUMBER PACKAGE TAPE & REEL PKG. DWG. # ISL29001IROZ (See Note) 6-Pin ODFN (Pb-Free) - MDP0052 • Contrast control • Camera light meters • Lighting controls Pinout ISL29001 (6-PIN ODFN) TOP VIEW VDD 1 6 SDA THERMAL PAD • HVAC Block Diagram TEMPERATURE COMPENSATED LIGHT SENSOR VDD PD 50Hz/60Hz REJECTION 16-bit ADC GND REXT I2C INTERFACE NOTE: Intersil Pb-free plus anneal products employ special Pb-free material sets; molding compounds/die attach materials and 100% matte tin plate termination finish, which are RoHS compliant and compatible with both SnPb and Pb-free soldering operations. Intersil Pb-free products are MSL classified at Pb-free peak reflow temperatures that meet or exceed the Pb-free requirements of IPC/JEDEC J STD-020. GND 2 • Temperature compensated SDA SCL 5 SCL 4 PD REXT 3 1 CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. 1-888-INTERSIL or 1-888-468-3774 | Intersil (and design) is a registered trademark of Intersil Americas Inc. Copyright © Intersil Americas Inc. 2005. All Rights Reserved. All other trademarks mentioned are the property of their respective owners. ISL29001 Absolute Maximum Ratings (TA = 25°C) Maximum Supply Voltage between VDD and GND . . . . . . . . . . 3.6V I2C Bus Pin Voltage (SCL, SDA) . . . . . . . . . . . . . . . . . -0.2V to 5.5V I2C Bus Pin Current (SCL, SDA) . . . . . . . . . . . . . . . . . . . . . . <10mA Rext Pin Voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.2V to 3.6V Operating Temperature . . . . . . . . . . . . . . . . . . . . . . .-45°C to +85°C Maximum Die Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . +125°C Storage Temperature . . . . . . . . . . . . . . . . . . . . . . . .-45°C to +100°C ESD Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2kV CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied. IMPORTANT NOTE: All parameters having Min/Max specifications are guaranteed. Typical values are for information purposes only. Unless otherwise noted, all tests are at the specified temperature and are pulsed tests, therefore: TJ = TC = TA Electrical Specifications PARAMETER VDD = 3V, TA = 25°C, REXT = 100kΩ, internally controlled integration timing (Note 1), unless otherwise specified. DESCRIPTION CONDITION MIN VDD Power Supply Range IDD Supply Current IDD1 Supply Current Software disabled IDD2 Supply Current PD = 3V FUPD Internal Update Time Mode 1 & Mode 2 (Note 2) Fosc Internal Oscillator Frequency FI2C I2C Clock Rate DATA0 ADC Code Ev = 0 lux DATA1 ADC Code Full scale ADC count value DATA2 ADC Code Ev = 300 lux, fluorescent light, Mode 1 DATA3 ADC Code Ev = 300 lux, fluorescent light, Mode 2 VREF Voltage of REXT Pin TYP MAX UNIT 3.63 V 0.28 0.33 mA 0.09 0.10 mA 0.5 µA 126 ms 2.25 85 105 312 1 738 983 kHz 400 kHz 1 Counts 32768 Counts 1247 Counts 98 0.487 0.51 Counts 0.532 V NOTES: 1. See Principle of Operation 2. There are three modes of the ADC’s operations. In Mode 1, the ADC integrates the current of the photodiode which is sensitive to visible and infrared light. In Mode 2, the ADC integrates the current of the photodiode which is sensitive only to infrared light. Pin Descriptions PIN NUMBER PIN NAME 1 VDD Positive supply. Connect this pin to a clean 2.5V to 3.3V supply. 2 GND Ground pin 3 PD 4 REXT 5 SCL I2C serial clock 6 SDA I2C serial data 2 DESCRIPTION Power-down pin. This pin is active-high. Applying a logic “high” to this pin will put the device into power down mode. External resistor pin for ADC reference. Connect this pin to ground through a (nominal) 100kΩ resistor. FN6166.0 December 21, 2005 ISL29001 Typical Performance Curves (Rext = 100kΩ) SUPPLY CURRENT (µA) 306 10 Ta = 27oC COMMAND = 00H 5000 lux 292 278 200 lux 264 250 2.0 2.3 2.6 2.9 3.2 SUPPLY VOLTAGE (V) 8 OUTPUT CODE (COUNTS) 320 3.5 6 4 2 0 2.0 3.8 FIGURE 1. SUPPLY CURRENT vs SUPPLY VOLTAGE 1.000 200 lux 0.995 2.3 2.6 2.9 3.2 SUPPLY VOLTAGE (V) 3.5 3.8 FIGURE 3. OUTPUT CODE vs SUPPLY VOLTAGE 3.8 Ta = 27oC 319.5 319.0 318.5 318.0 2.0 2.3 2.6 2.9 3.2 SUPPLY VOLTAGE (V) 3.5 3.8 10 Vdd = 3V COMMAND = 00H OUTPUT CODE (COUNTS) SUPPLY CURRENT (µA) 3.5 FIGURE 4. OSCILLATOR FREQUENCY vs SUPPLY VOLTAGE 5000 lux 295 285 200 lux 275 265 -60 OSCILLATOR FREQUENCY (kHz) OUTPUT CODE RATIO (% FROM 3V) 5000 lux 1.005 305 2.6 2.9 3.2 SUPPLY VOLTAGE (V) 320.0 Ta = 27oC COMMAND = 00H 1.010 315 2.3 FIGURE 2. OUTPUT CODE FOR 0 LUX vs SUPPLY VOLTAGE 1.015 0.990 2.0 Ta = 27oC COMMAND = 00H 0 lux -20 20 60 TEMPERATURE ( oC) FIGURE 5. SUPPLY CURRENT vs TEMPERATURE 3 100 8 Vdd = 3V COMMAND = 00H 0 lux 6 4 2 0 -60 -20 20 60 TEMPERATURE ( oC) 100 FIGURE 6. OUTPUT CODE FOR 0 LUX vs TEMPERATURE FN6166.0 December 21, 2005 ISL29001 Typical Performance Curves (Rext = 100kΩ) 1.048 5000 lux 1.016 200 lux 0.984 0.952 0.920 -60 -20 20 60 TEMPERATURE ( oC) FIGURE 7. OUTPUT CODE vs TEMPERATURE 100 100 Vdd = 3V 329 328 327 326 325 -60 -20 20 60 TEMPERATURE ( oC) 100 FIGURE 8. OSCILLATOR FREQUENCY vs TEMPERATURE Diode 1 R AD IAT ION P AT T E R N 75 LUMINO S IT Y ANG LE 50 25 0 428 444 460 476 492 508 524 540 556 572 588 604 620 636 652 668 RELATIVE SENSITIVITY (%) OUTPUT CODE RATIO (% FROM 25oC) 330 Vdd = 3V COMMAND = 00H OSCILLATOR FREQUENCY (kHz) 1.080 (Continued) SPECTRAL WAVELENGTH (nm) FIGURE 9. RELATIVE SENSITIVITY 4 R E LA T IV E S E N S IT IV IT Y FIGURE 10. RADIATION PATTERN FN6166.0 December 21, 2005 ISL29001 Principles of Operation Photodiodes and ADC The ISL29001 contains two photodiodes. One of the photodiodes is sensitive to visible and infrared light (Diode 1) and the other is sensitive primarily to infrared light (Diode 2). The ISL29001 also contains an on-chip integrating analogto-digital converter (ADC) to convert photodiode currents into digital data. The ADC has three operating modes with two timing controls. (Please consult Table 1 for a complete list of modes.) In the first operating mode, the ADC only integrates Diode 1's current, and the digital output format is 16-bit unsigned-magnitude. In second operating mode, the ADC's operation is the same, except Diode 2's current is integrated. In the third operating mode, the ADC integrates Diode 2's current first, then Diode 1's current. The total integration time is doubled, and the digital output is the difference of the two photodiode currents (Diode 1’s current - Diode 2’s current). In this mode, the digital output format is 16-bit 2'scomplement. Any of the three operating modes can be used with either of the two timing controls (either internally or externally controlled integration timing). The interface to the ADC is implemented using the standard I2C interface. I2C Interface The ISL29001 contains a single 8-bit command register that can be written via the I2C interface. The command register defines the operation of the device, which does not change until the command register is overwritten. The ISL29001 contains four 8-bit data registers that can be read via the I2C interface. The first two data registers contain the ADC's latest digital output, while the second two registers contain the number of clock cycles in the previous integration period. master always drives the SCL (clock) line, while either the master or the slave can drive the SDA (data) line. Every I2C transaction begins with the master asserting a start condition (SDA falling while SCL remains high). The following byte is driven by the master, and includes the slave address and read/write bit. The receiving device is responsible for pulling SDA low during the acknowledgement period. Any writes to the ISL29001 overwrite the command register, changing the device’s mode. Any reads from the ISL29001 return two or four bytes of sensor data and counter value, depending upon the operating mode. Neither the command register nor the data registers have internal addresses, and none of the registers can be individually addressed. Every I2C transaction ends with the master asserting a stop condition (SDA rising while SCL remains high). For more information about the I2C standard, please consult the Philips® I2C specification documents. Command Register The command register is used to define the ADC's operations. Table 1 shows the primary commands used to control the ADC. Note that there are two classes of operating commands: three for internal timing, and three for external (arbitrary) timing. When using any of the three internal timing commands, the device self-times each conversion, which is nominally 100ms (with REXT = 100kΩ). When using any of the three external timing commands, each command received by the device ends one conversion and begins another. The integration time of the device is thus the time between one I2C external timing command and the next. The integration time can be between 1 and 100 milliseconds. The external timing commands can be used to The ISL29001’s I2C address is hardwired internally as 1000100. Figure 11 shows a sample one-byte read. (A typical application will read two to four bytes, however.) The I2C bus SDA DRIVEN BY MASTER SDA DRIVEN BY ISL29002 SDA SCL START 1-7 8 9 ADDRESS R/W ACK 1-7 8 DATA 9 ACK STOP FIGURE 11. I2C TIMING DIAGRAM 5 FN6166.0 December 21, 2005 ISL29001 synchronize the ADC’s integrating time to a PWM dimming frequency in a backlight system in order to eliminate noise. TABLE 1. COMMAND FUNCTION 8cH ADC is powered-down. 0cH ADC is reset. 00H ADC converts Diode 1’s current (IDIODE1) into unsigned-magnitude 16-bit data. The integration is internally timed at 100ms per integration. 04H ADC converts Diode 2’s current (IDIODE2) into unsigned-magnitude 16-bit data. The integration is internally timed at 100ms per integration. 08H ADC converts IDIODE1-IDIODE2 into 2’scomplement 16-bit data. The total integration is internally timed at 200ms per integration. 30H ADC converts Diode 1’s current (IDIODE1) into unsigned-magnitude 16-bit data. The integration is externally timed; each 30H command sent to the device ends one integration period and begins another. 34H ADC converts Diode 2’s current (IDIODE1) into unsigned-magnitude 16-bit data. The integration is externally timed; each 34H command sent to the device ends one integration period and begins another. 38H ADC converts IDIODE1-IDIODE2 into 2’scomplement 16-bit data. The integration is externally timed; each 38H command sent to the device ends one integration period and begins another. I2C communication test. The value written to the command register can be read back via the I2C bus. 1xxx_xxxxB Data Registers The ISL29001 contains four 8-bit data registers. These registers cannot be specifically addressed, as is conventional with other I2C peripherals; instead, performing a read operation on the device always returns all available registers in ascending order. See Table 2 for a description of each register. TABLE 2. ADDRESS CONTENTS 00H Least-significant byte of most recent sensor reading. 01H Most-significant byte of most recent sensor reading. 02H Least-significant byte of integration counter value corresponding to most recent sensor reading. 03H Most-significant byte of integration counter value corresponding to most recent sensor reading. 6 The first two 8-bit data registers contain the most recent sensor reading. The meaning of the specific value stored in these data registers depends on the command written via the I2C interface; see Table 1 for information on the various commands. The first byte read over the I2C interface is the least-significant byte; the second is the most significant. This byte ordering is often called “little-endian” ordering. The third and fourth 8-bit data registers contain the integration counter value corresponding to the most recent sensor reading. The ISL29001 includes a free-running oscillator, each cycle of which increments a 16-bit counter. At the end of each integration period, the value of this counter is made available in these two 8-bit registers. Like the sensor reading, the integration counter value is read across the I2C bus in little-endian order. Note that the integration counter value is only available when using one of the three externally-timed operating modes; when using internally-timed modes, the device will NAK after the two-byte sensor reading has been read. Internal Timing When using one of the three internal timing modes, each integration period of the ISL29001 is timed by 32,768 clock cycles of an internal oscillator. The nominal frequency of the internal oscillator is 327.6kHz, which provides 100ms internally-timed integration periods. The oscillator frequency is dependent upon an external resistor, Rext, and can be adjusted by selecting a different resistor value. The resolution and maximum range of the device are also affected by changes in Rext; see below. The oscillator frequency can be calculated with the following equation: 100kΩ f osc = 327.6kHz ⋅ -----------------R ext Rext is nominally 100kΩ, and provides 100 millisecond internal timing and a 1-10,000 lux range for Diode 1. Doubling this resistor value to 200kΩ halves the internal oscillator frequency, providing 200ms internal timing. In addition, the maximum lux range of Diode 1 is also halved, from 10,000 lux to 5,000 lux, and the resolution is doubled, from 3.3 counts per lux to 6.6 counts per lux. The acceptable range of this resistor is 50kΩ (providing 50ms internal timing, 100,000 lux maximum reading, ~1.6 counts per lux) to 500kΩ (500ms internal timing, 2,000 lux maximum reading, ~16 counts per lux). When using one of the three internal timing modes, the ISL29001’s resolution is determined by the ratio of the max lux range to 32,768, the number of clock cycles per integration. FN6166.0 December 21, 2005 ISL29001 longer fixed at 32,768, but varies with the chosen integration time. The following equations describe the light intensity as a function of the sensor reading, and the integration time as a function of the external resistor. The number of clock cycles in the previous integration period is provided in the third and fourth bytes of data read across the I2C bus. This two-byte value is called the integration counter value. 10, 000lux 1 L = ---------------- ⋅ --------------------------------------- ⋅ Data1 32768 ( R ext ⁄ 100kΩ ) When using one of the three external timing modes, the ISL29001’s resolution varies with the integration time. The resolution is determined by the ratio of the max lux range to the number of clock cycles per integration. R ext T = 100ms ⋅ -----------------100kΩ where L is the measured light intensity, Data1 is the sensor reading, T is the integration time, and Rext is external resistor value. The following equations describe the light intensity as a function of sensor reading, integration counter value, and integration time: External Timing When using one of the three external timing modes, each integration period of the ISL29001 is determined by the time which passes between consecutive external timing commands received over the I2C bus. 10, 000lux Data1 L = --------------------------------------- ⋅ ----------------( R ext ⁄ 100kΩ ) Data2 The internal oscillator operates identically in both the internal and external timing modes, with the same dependence on Rext. However, when using one of the three external timing modes, the number of clock cycles per integration is no where L is the measured light intensity, Data1 is the sensor reading, Data2 is the integration counter value, T is the integration time, and Rext is external resistor value. T = Time Interval between external time commands Typical Circuit A typical application circuit is shown in Figure 12. MICROCONTROLLER ISL29002 2.53.3V VDD + 4.7µF SDA SDA SCL SCL 0.1µF VSS PD REXT 100k FIGURE 12. TYPICAL CIRCUIT 7 FN6166.0 December 21, 2005 ISL29001 Suggested PCB Footprint See Figure 13. Footprint pads should be a nominal 1-to-1 correspondence with package pads. The large, exposed central die-mounting paddle in the center of the package requires neither thermal nor electrical connection to the PCB, and such connection should be avoided. 0.3 0.65 0.65 2.05 All dimensions in millimeters. FIGURE 13. SUGGESTED PCB FOOTPRINT Layout Considerations The ISL29001 is relatively insensitive to layout. Like other I2C devices, it is intended to provide excellent performance even in significantly noisy environments. There are only a few considerations that will ensure best performance. Route the supply and I2C traces as far as possible from all sources of noise. Use two power-supply decoupling capacitors, 4.7µF and 0.1µF, placed close to the device. Soldering Considerations Convection heating is recommended for reflow soldering; direct-infrared heating is not recommended. The ISL29001’s plastic ODFN package does not require a custom reflow soldering profile, and is qualified to 260°C. A standard reflow soldering profile with a 260°C maximum is recommended. 8 FN6166.0 December 21, 2005 ISL29001 ODFN Package Outline Drawing 9 FN6166.0 December 21, 2005 ISL29001 All Intersil U.S. products are manufactured, assembled and tested utilizing ISO9000 quality systems. Intersil Corporation’s quality certifications can be viewed at www.intersil.com/design/quality Intersil products are sold by description only. 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 data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements 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 Intersil or its subsidiaries. For information regarding Intersil Corporation and its products, see www.intersil.com 10 FN6166.0 December 21, 2005