ISL29011 ® Data Sheet May 14, 2009 Digital Ambient Light Sensor and Proximity Sensor with Interrupt Function The ISL29011 is an integrated ambient and infrared light to digital converter with a built-in IR LED driver and I2C Interface (SMBus Compatible). This device provides not only ambient light sensing to allow robust backlight/display brightness control but also infrared sensing to allow proximity estimation featured with interrupt function. For ambient light sensing, an internal ADC has been designed based on the charge-balancing A/D conversion technique. The ADC conversion time is nominally 90ms and is user adjustable from 11µs to 90ms, depending on oscillator frequency and ADC resolution. This ADC is capable of rejecting 50Hz and 60Hz flicker noise caused by artificial light sources. The lux-range-select feature allows users to program the lux range for optimized counts/lux. For proximity sensing, the ADC is used to digitize the output signal from the photodiode array when the internal IR LED driver is turned on and off for the programmed time periods under user-selected modulation frequency to drive the external IR LED. As this proximity sensor employs a noise cancellation scheme to highly reject unwanted IR noise, the digital output of proximity sensing decreases with distance. The driver output current is user selectable up to 100mA to drive different types of IR emitters LEDs. Six different modes of operation can be selected via the I2C interface: Programmable ALS once with auto power-down, programmable IR sensing once, programmable proximity sensing once, programmable continuous ALS sensing, programmable continuous IR sensing and programmable continuous proximity sensing. The programmable one-time operation modes greatly reduce power because an immediate automatic shutdown reduces overall supply current less than 0.5µA. The ISL29011 supports both hardware and software interrupts that remain asserted until the host clears it through I2C interface for ambient light sensing and proximity detection. Designed to operate on supplies from 2.5V to 3.63V, the ISL29011 is specified for operation over the -40°C to +85°C ambient temperature range. It is packaged in a clear, Pb-free 8 Ld ODFN package. FN6467.2 Features Proximity Sensing • Ambient IR Cancellation During Proximity Sensing - Works Under Direct Sunlight • IR LED Driver with Programmable Source Current - Adjustable Current Drive from 100mA to 12.5mA • Programmable LED current Modulation Frequency • Variable Conversion Resolution Ambient Light Sensing • Simple Output Code Directly Proportional to lux • Adjustable Sensitivity up to 65 Counts per lux • Selectable Range (via I2C) - Range 1 = 0.015 lux to 1,000 lux - Range 2 = 0.06 lux to 4,000 lux - Range 3 = 0.24 lux to 16,000 lux - Range 4 = 0.96 lux to 64,000 lux • Integrated 50/60Hz Noise Rejection • Works Under Various Light Sources, Including Sunlight Ideal Spectral Response for Light and Proximity Sensor • Light Sensor Close to Human Eye Response - Excellent Light Sensor IR and UV Rejection • Proximity sensor range from 850nm to 950nm - Can use either 850nm or 950nm LED solution Ultra Low Power • 90μA Max Operating Current • Software Shutdown and Automatic Shutdown - 0.5μA Max Shutdown Current Easy to Use • I2C (SMBus Compatible) Output • No Complex Algorithms Needed • Temperature Compensated • Small Form Factor - 8 Ld 2.0mmx2.1mmx0.7mm ODFN Package Additional Features • I2C and SMBus Compatible • 1.7V to 3.63V Supply for I2C Interface • 2.25V to 3.63V Sensor Power Supply • Pb-Free (RoHS compliant) Applications • Display and Keypad Dimming Adjustment and Proximity Sensing for: - Mobile Devices: Smart Phone, PDA, GPS - Computing Devices: Notebook PC, Webpad - Consumer Devices: LCD-TV, Digital Picture Frame, Digital Camera • Industrial and Medical Light and Proximity Sensing 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. 2009. All Rights Reserved. All other trademarks mentioned are the property of their respective owners. ISL29011 Ordering Information PART NUMBER (Note) TEMP. RANGE (°C) ISL29011IROZ-T7* PACKAGE (Pb-Free) -40 to +85 ISL29011IROZ-EVALZ 8 Ld ODFN PKG. DWG. # L8.2.1x2.0 Evaluation Board *Please refer to TB347 for details on reel specifications. NOTE: These Intersil Pb-free plastic packaged products employ special Pb-free material sets; molding compounds/die attach materials and NiPdAu plate - e4 termination finish, which is 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. Pinout ISL29011 (8 LD ODFN) TOP VIEW) VDDD 1 8 IRDR VDDA 2 7 INT GND 3 6 SDA REXT 4 5 SCL EXPOSED PAD CAN BE CONNECTED TO GND OR ELECTRICALLY ISOLATED Pin Descriptions PIN NUMBER PIN NAME DESCRIPTION 1 VDDD Positive digital supply: 2.5V to 3.63V. 2 VDDA Positive analog supply: 2.5V to 3.63V, VDDA and VDDD should be externally shorted. 3 GND Ground. The thermal pad is also connected to the GND pin. 4 REXT External resistor pin setting the internal reference current and the conversion time. 499kΩ with 1% tolerance resistor is recommended. 5 SCL I2C serial clock line 6 SDA I2C serial data line 7 INT Interrupt pin; LO for interrupt/alarming. The INT pin is an open drain. 8 IRDR The I2C bus lines can be pulled from 1.7V to above VDD, 3.63V max. IR LED driver pin connecting to the anode of the external IR LED. The source current of the IR LED driver can be programmed through I2C. Exposed pad connected to ground or electrically isolated. 2 FN6467.2 May 14, 2009 ISL29011 Block Diagram VDDD 1 VDDA 2 PHOTODIODE ARRAY COMMAND REGISTER LIGHT DATA PROCESS ALS AND IR INTEGRATION ADC DATA REGISTER 6 SDA 5 SCL INTERRUPT 7 INT IR DRIVER 8 IRDR I2C IR PHOTODIODE ARRAY IREF FOSC 4 3 REXT GND ISL29011 3 FN6467.2 May 14, 2009 ISL29011 Absolute Maximum Ratings (TA = +25°C) Thermal Information VSUP(VDDD,VDDA) Supply Voltage between VDD and GND . . . . . .4V VDDA Supply Voltage between VDDA and GND . . . . VDDD +/- 0.5V I2C Bus (SCL, SDA) and INT Pin Voltage . . . . . . . . . . . . -0.2V to 4V I2C Bus (SCL, SDA) and INT Pin Current . . . . . . . . . . . . . . . <10mA IRDR Pin Voltage . . . . . . . . . . . . . . . . . . . . . . . . -0.2V to VDD + 0.5V REXT Pin Voltage . . . . . . . . . . . . . . . . . . . . . . . . -0.2V to VDD + 0.5V ESD Rating Human Body Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2kV Thermal Resistance (Typical, Note 1) θJA (°C/W) 8 Ld ODFN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 Maximum Die Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . +90°C Storage Temperature . . . . . . . . . . . . . . . . . . . . . . . .-40°C to +100°C Operating Temperature . . . . . . . . . . . . . . . . . . . . . . .-40°C to +85°C Pb-Free Reflow Profile. . . . . . . . . . . . . . . . . . . . . . . . .see link below http://www.intersil.com/pbfree/Pb-FreeReflow.asp CAUTION: Do not operate at or near the maximum ratings listed for extended periods of time. Exposure to such conditions may adversely impact product reliability and result in failures not covered by warranty. NOTE: 1. θJA is measured in free air with the component mounted on a high effective thermal conductivity test board with “direct attach” features. See Tech Brief TB379. 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 VSUP(VDDD,VDDA) = 3V, TA = +25°C, REXT = 499kΩ 1% tolerance, 16-bit ADC operation, unless otherwise specified. Electrical Specifications PARAMETER DESCRIPTION CONDITION VSUP Power Supply Range for VDDD, VDDA (Note 2) Software disabled or auto power-down MIN ISUP(OFF) Supply Current when Powered Down Supply Current of Ambient Light and IR Sensing VI2C Supply Voltage Range for I2C Interface 1.7 fOSC Internal Oscillator Frequency 675 tint ADC Integration/Conversion Time FI2C I2C Clock Rate Range DATA_0 Count Output When Dark 16-bit ADC data E = 0 lux Full Scale ADC Code ΔDATA DATA Count Output Variation Over Three Light Sources: Fluorescent, Incandescent and Sunlight Ambient light sensing DATA_1 Light Count Output With LSB of 0.015 lux/count E = 300 lux, Fluorescent light (Note 3), Ambient light sensing, Range 1 (1k lux) DATA_2 Light Count Output With LSB of 0.06 lux/count DATA_3 MAX UNIT 3.63 V 0.1 0.5 µA 70 90 µA 3.63 V 825 kHz 2.25 ISUP(ON) DATA_FS TYP 750 90 ms 1 to 400 kHz 1 5 Counts 65535 Counts ±10 15000 % 20000 25000 Counts E = 300 lux, Fluorescent light (Note 3), Ambient light sensing, Range 2 (4k lux) 5000 Counts Light Count Output With LSB of 0.24 lux/count E = 300 lux, Fluorescent light (Note 3), Ambient light sensing, Range 3 (16k lux) 1250 Counts DATA_4 Light Count Output With LSB of 0.96 lux/count E = 300 lux, Fluorescent light (Note 3), Ambient light sensing, Range 4 (64k lux) 312 Counts DATA_IR1 Infrared Count Output E = 210 lux, Sunlight (Note 4), IR sensing, Range 1 DATA_IR2 Infrared Count Output DATA_IR3 DATA_IR4 20000 25000 Counts E = 210 lux, Sunlight (Note 4), IR sensing, Range 2 5000 Counts Infrared Count Output E = 210 lux, Sunlight (Note 4), IR sensing, Range 3 1250 Counts Infrared Count Output E = 210 lux, Sunlight (Note 4), IR sensing, Range 4 312 Counts VREF Voltage of REXT Pin VIL SCL and SDA Input Low Voltage VIH SCL and SDA Input High Voltage 4 15000 0.52 V 0.55 1.25 V V FN6467.2 May 14, 2009 ISL29011 Electrical Specifications PARAMETER VSUP(VDDD,VDDA) = 3V, TA = +25°C, REXT = 499kΩ 1% tolerance, 16-bit ADC operation, unless otherwise specified. (Continued) DESCRIPTION CONDITION ISDA, IINT SDA and INT Current Sinking Capability IIRDR1 IRDR Source Current IS<1:0> = 0 (Note 5) IIRDR2 IRDR Source Current IS<1:0> = 1 (Note 5) IIRDR3 IRDR Source Current IS<1:0> = 2 (Note 5) IIRDR4 IRDR Source Current IS<1:0> = 3 (Note 5) VIRLED Voltage Head Room of IRDR Pin MIN 4 15Ω at IRDR pin 44 TYP MAX UNIT 5 mA 100 mA 50 58 mA 25 mA 12.5 mA VDD - 0.6 V tr Rise Time for IRDR Source Current RLOAD = 15Ω at IRDR pin, 20% to 80% 35 ns tf Fall Time for IRDR Source Current RLOAD = 15Ω at IRDR pin, 80% to 20% 10 ns fIRLED1 IR LED Modulation Frequency Freq = 0 (Note 5) DC kHz fIRLED2 IR LED Modulation Frequency Freq = 1 (Note 5) 360 kHz ISUP (IRLED1) Supply Current of Proximity Sensing IS<1:0> = 0, Freq = 0 (Note 5) 101 mA ISUP (IRLED2) Supply Current of Proximity Sensing IS<1:0> = 0, Freq = 1 (Note 5) 51 mA Duty Cycle Duty Cycle of IR LED Modulation 50 % PROX-IR PROX Differential ADC Output of IR and Proximity IR and proximity sensing with Range 2 and Scheme 0; Sensing With Object Far Away to Provide 15Ω @ IRDR pin, IS<1:0> = 0, Freq = 0; E = 210 lux, No Reflection Sunlight. 1.0 % NOTES: 2. VSUP is the common voltage to VDDD and VDDA. 3. 550nm green LED is used in production test. The 550nm LED irradiance is calibrated to produce the same DATA count against an illuminance level of 300 lux fluorescent light. 4. 850nm infrared LED is used in production test. The 850nm LED irradiance is calibrated to produce the same DATA_IR count against an illuminance level of 210 lux sunlight at sea level. 5. See “Register Set” on page 7. Principles of Operation Photodiodes and ADC The ISL29011 contains two photodiode arrays which convert light into current. The spectral response for ambient light sensing and IR sensing is shown in Figure 6 in the performance curves section. After light is converted to current during the light signal process, the current output is converted to digital by a built-in 16-bit Analog-to-Digital Converter (ADC). An I2C command reads the ambient light or IR intensity in counts. The converter is a charge-balancing integrating type 16-bit ADC. The chosen method for conversion is best for converting small current signals in the presence of an AC periodic noise. A 100ms integration time, for instance, highly rejects 50Hz and 60Hz power line noise simultaneously. See “Integration and Conversion Time” on page 9. The built-in ADC offers user flexibility in integration time or conversion time. Integration time is determined by an internal oscillator (fOSC), and the n-bit (n = 4, 8, 12,16) counter inside the ADC. A good balancing act of integration time and resolution depending on the application is required for optimal results. The ADC has I2C programmable range select to dynamically accommodate various lighting conditions. For very dim conditions, the ADC can be configured at its lowest range 5 (Range 1) in the ambient light sensing. For very bright conditions, the ADC can be configured at its highest range (Range 4) in the proximity sensing. Low-Power Operation The ISL29011 initial operation is at the power-down mode after a supply voltage is provided. The data registers contain the default value of 0. When the ISL29011 receives an I2C command to do a one-time measurement from an I2C master, it will start ADC conversion with light or proximity sensing. It will go to the power-down mode automatically after one conversion is finished and keep the conversion data available for the master to fetch anytime afterwards. The ISL29011 will continuously do ADC conversion with light or proximity sensing if it receives an I2C command of continuous measurement. It will continuously update the data registers with the latest conversion data. It will go to the power-down mode after it receives the I2C command of power-down. Ambient Light, IR and Proximity Sensing There are six operational modes in ISL29011: Programmable ALS once with auto power-down, programmable IR sensing once with auto power-down, programmable proximity sensing once with auto power-down; programmable continuous ALS sensing, programmable continuous IR sensing and programmable continuous proximity sensing. These six modes can be programmed in series to fulfill the application FN6467.2 May 14, 2009 ISL29011 of the interrupt. This reduces the possibility of false triggers, such as noise or sudden spikes in ambient light conditions. An unexpected camera flash, for example, can be ignored by setting the persistency to 8 integration cycles. needs. The detailed program configuration is listed in “Register Set” on page 7. When the part is programmed for ambient light sensing, the ambient light with wavelength within the “Ambient Light Sensing” spectral response curve in Figure 6 is converted into current. With ADC, the current is converted to an unsigned n-bit (up to 16 bits) digital output. I2C Interface There are eight 8-bit registers available inside the ISL29011. The two command registers define the operation of the device. The command registers do not change until the registers are overwritten. The two 8-bit data Read Only registers are for the ADC output and the Timer output. The data registers contain the ADC's latest digital output, or the number of clock cycles in the previous integration period. The four 8-bit interrupt registers hold 16-bit interrupt high and low thresholds. When the part is programmed for infrared (IR) sensing, the IR light with wavelength within the “IR or Proximity Sensing” spectral response curve on Figure 6 is converted into current. With ADC, the current is converted to an unsigned n-bit (up to 16 bits) digital output. When the part is programmed for proximity sensing, the external IR LED is turned on by the built-in IR LED driver through the IRDR pin. The amplitude of the IR LED current and the IR LED modulation frequency can be programmed through Command Register II. When the IR from the LED reaches an object and gets reflected back, the reflected IR light with wavelength within the “IR or Proximity Sensing” spectral response curve in Figure 6 is converted into current. With ADC, the current is converted to an unsigned n-bit (up to 16 bits) digital output. The output reading is inversely proportional to the square of the distance between the sensor and the object. The ISL29011’s I2C interface slave address is internally hard-wired as 1000100. When 1000100x with x as R or W is sent after the Start condition, this device compares the first seven bits of this byte to its address and matches. Figure 1 shows a sample one-byte read. Figure 2 shows a sample one-byte write. The I2C bus master always drives the SCL (clock) line, while either the master or the slave can drive the SDA (data) line. Figure 2 shows a sample write. 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. Every I2C transaction ends with the master asserting a stop condition (SDA rising while SCL remains high). Interrupt Function The active low interrupt pin is an open drain pull-down configuration. There is also an interrupt bit in the I2C register. The interrupt serves as an alarm or monitoring function to determine whether the ambient light level or the proximity detection level exceeds the upper threshold or goes below the lower threshold. The user can also configure the persistency I2C DATA I2C SDA IN I2C SDA OUT I2C CLK DEVICE ADDRESS START For more information about the I2C standard, please consult the Philips™ I2C specification documents. REGISTER ADDRESS W A A6 A5 A4 A3 A2 A1 A0 W A R7 R6 R5 R4 R3 R2 R1 R0 A 1 2 3 4 5 6 SDA DRIVEN BY MASTER A SDA DRIVEN BY MASTER 7 8 9 1 2 3 4 5 6 DEVICE ADDRESS STOP START 7 A 8 9 A6 A5 A4 A3 A2 A1 A0 W SDA DRIVEN BY MASTER 1 2 3 4 5 6 DATA BYTE0 A SDA DRIVEN BY ISL29011 A A D7 D6 D5 D4 D3 D2 D1 D0 7 8 9 1 2 3 4 5 6 7 8 9 FIGURE 1. I2C READ TIMING DIAGRAM SAMPLE 6 FN6467.2 May 14, 2009 ISL29011 START DEVICE ADDRESS W A W A R7 R6 R5 R4 R3 R2 R1 R0 A B7 B6 B5 B4 B3 B2 B1 B0 A SDA DRIVEN BY MASTER A SDA DRIVEN BY MASTER A REGISTER ADDRESS A FUNCTIONS STOP I2C DATA I2C SDA IN A6 A5 A4 A3 A2 A1 A0 A I2C SDA OUT SDA DRIVEN BY MASTER A I2C CLK IN 1 3 2 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 FIGURE 2. I2C WRITE TIMING DIAGRAM SAMPLE Register Set There are eight registers that are available in the ISL29011. Table 1 summarizes their functions. TABLE 1. REGISTER SET BIT ADDR REG NAME 7 6 5 4 3 2 1 0 DEFAULT 00h COMMANDI OP2 OP1 OP0 0 0 FLAG PRST1 PRST0 00h 01h COMMANDII Scheme FREQ IS1 IS0 RES1 RES0 RANGE1 RANGE0 00h 02h DATALSB D7 D6 D5 D4 D3 D2 D1 D0 00h 03h DATAMSB D15 D14 D13 D12 D11 D10 D9 D8 00h 04h INT_LT_LSB TL7 TL6 TL5 TL4 TL3 TL2 TL1 TL0 00h 05h INT_LT_MSB TL15 TL14 TL13 TL12 TL11 TL10 TL9 TL8 00h 06h INT_HT_LSB TH7 TH6 TH5 TH4 TH3 TH2 TH1 TH0 FFh 07h INT_HT_MSB TH15 TH14 TH13 TH12 TH11 TH10 TH9 TH8 FFh Command Register I 00(hex) The first command register has the following functions: 1. Operation Mode: Bits 7, 6, and 5.These three bits determines the operation mode of the device. TABLE 2. OPERATION MODE BITS 7 TO 5 TABLE 3. INTERRUPT FLAG BIT 2 OPERATION 0 Interrupt is cleared or not triggered yet 1 Interrupt is triggered OPERATION 000 Power-down the device 001 ALS once 010 IR once 011 Proximity once 100 Reserved (Do not use) 101 ALS continuous 110 IR continuous 111 high. Both interrupt pin and the status bit are automatically cleared at the end of Command Register I transfer. Proximity continuous 2. Interrupt flag; Bit 2. This is the status bit of the interrupt. The bit is set to logic high when the interrupt thresholds have been triggered, and logic low when not yet triggered. Once triggered, INT pin stays low and the status bit stays 7 3. Interrupt persist; Bits 1 and 0. The interrupt pin and the interrupt flag is triggered/set when the data sensor reading is out of the interrupt threshold window after m consecutive number of integration cycles. The interrupt persist bits determine m. TABLE 4. INTERRUPT PERSIST BITS 1 TO 0 NUMBER OF INTEGRATION CYCLES 00 1 01 4 10 8 11 16 FN6467.2 May 14, 2009 ISL29011 Command Register II 01(hex) The second command register has the following functions: 1. Proximity Sensing Scheme: Bit 7. This bit programs the function of the proximity detection. Logic 0 of this bit, Scheme 0, makes full n (4, 8, 12, 16) bits (unsigned) proximity detection. The range of Scheme 0 proximity count is from 0 to 2n. Logic 1 of this bit, Scheme 1, makes n-1 (3, 7, 11, 15) bits (2’s complementary) proximity_less_ambient detection. The range of Scheme 1 proximity count is from -2(n-1) to 2(n-1). While Scheme 0 has wider dynamic range, Scheme 1 proximity detection is less affected by the ambient IR noise variation. TABLE 5. PROXIMITY SENSING SCHEME BIT 7 OPERATION 0 Sensing IR from LED and ambient 1 Sensing IR from LED with ambient IR rejection 2. Modulation Frequency: Bits 6. This bit sets the IR LED driver’s modulation frequency. TABLE 6. MODULATION FREQUENCY BITS 6 MODULATION FREQUENCY (kHz) 0 DC 1 360 TABLE 9. RANGE/FSR LUX BITS 1:0 k RANGE(k) FSR (LUX) @ ALS SENSING FSR @ IR SENSING 00 1 Range1 1,000 Refer to page 4 01 2 Range2 4,000 Refer to page 4 10 3 Range3 16,000 Refer to page 4 11 4 Range4 64,000 Refer to page 4 Data Registers (02 hex and 03 hex) The device has two 8-bit read-only registers to hold the data from LSB to MSB for ADC. The most significant bit (MSB) is accessed at 03 hex, and the least significant bit (LSB) is accessed at 02 hex. For 16-bit resolution, the data is from D0 to D15; for 12-bit resolution, the data is from D0 to D11; for 8-bit resolution, the data is from D0 to D7. The registers are refreshed after every conversion cycle. TABLE 10. DATA REGISTERS ADDRESS (hex) 3. Amplitude of IR driver current: Bits 5 and 4. This device provides current source to drive an external IR LED. The drive capability can be programmed through Bits 5 and 4. For example, the device sources 12.5mA out of the IRDR pin if Bits 5 and 4 are 0. TABLE 7. CURRENT SOURCE CAPABILITY AT IRDR PIN BITS 5 TO 4 5. Range: Bits 1 and 0. The Full Scale Range (FSR) can be adjusted via I2C using Bits 1 and 0. Table 9 lists the possible values of FSR for the 499kΩ REXT resistor. IRDR PIN SOURCE CURRENT CONTENTS 02 D0 is LSB for 4, 8, 12 or 16-bit resolution, D3 is MSB for 4-bit resolution, D7 is MSB for 8-bit resolution 03 D15 is MSB for 16-bit resolution, D11 is MSB for 12-bit resolution Interrupt Registers (04, 05, 06 and 07 hex) Registers 04 and 05 hex set the low (LO) threshold for the interrupt pin and the interrupt flag. 04 hex is the LSB and 05 hex is the MSB. By default, the Interrupt threshold LO is 00 hex for both LSB and MSB. 00 12.5mA IR LED driver 01 25mA IR LED driver 10 50mA IR LED driver Registers 06 and 07 hex set the high (HI) threshold for the interrupt pin and the interrupt flag. 06 hex is the LSB and 07 hex is the MSB. By default, the Interrupt threshold HI is FF hex for both LSB and MSB. 11 100mA IR LED driver Calculating Lux 4. Resolution: Bits 3 and 2. Bits 3 and 2 determine the ADC’s resolution and the number of clock cycles per conversion in Internal Timing Mode. Changing the number of clock cycles does more than just change the resolution of the device. It also changes the integration time, which is the period the device’s analog-to-digital (A/D) converter samples the photodiode current signal for a measurement. . TABLE 8. RESOLUTION/WIDTH BITS 3 TO 2 NUMBER OF CLOCK CYCLES n-BIT ADC 00 216 = 65,536 16 01 12 10 212 = 4,096 28 = 256 11 24 = 16 4 8 The ISL29011’s ADC output codes, DATA, are directly proportional to lux in the ambient light sensing. (EQ. 1) E cal = α × DATA Here, Ecal is the calculated lux reading. The constant α is determined by the Full Scale Range and the ADC’s maximum output counts. The constant is independent on the light sources (fluorescent, incandescent and sunlight) because of the light sources’ IR component is removed during the light signal process. The constant can also be viewed as the sensitivity: the smallest lux measurement the device can measure as shown in Equation 2. Range ( k ) α = ---------------------------Count max (EQ. 2) Here, Range(k) is defined in Table 9. Countmax is the maximum output counts from the ADC. 8 FN6467.2 May 14, 2009 ISL29011 The transfer function used for n-bit ADC becomes Equation 3: Range ( k ) E cal = --------------------------- × DATA n 2 (EQ. 3) Here, n = 4, 8, 12 or 16. This is the number of ADC bits programmed in the command register. 2n represents the maximum number of counts possible from the ADC output. Data is the ADC output stored in the data registers (02 hex and 03 hex). The ADC resolution and fOSC determines the integration time, tint as shown in Equation 4. R EXT n n 1 t int = 2 × -------------- = 2 × ---------------------------------------------725kHz × 499kΩ f OSC (EQ. 4) where n is the number of bits of resolution and n = 4, 8, 12 or 16. 2n, therefore, is the number of clock cycles. n can be programmed at the command register 01(hex) bits 3 and 2. TABLE 11. INTEGRATION TIME OF n-BIT ADC REXT (kΩ) n = 16-BIT (ms) n = 12-BIT (ms) n = 8-BIT (µs) n = 4-BIT (µs) 250 45 2.812 175.5 10.8µs 499** 90 5.63 351 21.6µs **Recommended REXT resistor value External Scaling Resistor REXT for fOSC and Range The ISL29011 uses an external resistor REXT to fix its internal oscillator frequency, fOSC and the light sensing range, Range. fOSC and Range are inversely proportional to REXT. For user simplicity, the proportionality constant is referenced to 499kΩ as shown in Equations 5 and 6: 499kΩ Range = ------------------ × Range ( k ) R EXT (EQ. 5) 499kΩ f OSC = ------------------ × 725 kHz R EXT (EQ. 6) Noise Rejection In general, integrating type ADC’s have excellent noise-rejection characteristics for periodic noise sources whose frequency is an integer multiple of the conversion rate. For instance, a 60Hz AC unwanted signal’s sum from 0ms to k*16.66ms (k = 1,2...ki) is zero. Similarly, setting the device’s integration time to be an integer multiple of the periodic noise signal, greatly improves the light sensor output signal in the presence of noise. ADC Output in IR Sensing The ISL29011’s ADC output codes, DATA, are directly proportional to the IR intensity received in the IR sensing. (EQ. 7) 9 ADC Output in Proximity Sensing In the proximity sensing, the ADC output codes, DATA, are directly proportional to the total IR intensity from the background IR noise and from the IR LED driven by the ISL29011. DATA PROX = β × E IR + γ × E LED Integration and Conversion Time DATA IR = β × E IR Here, EIR is the received IR intensity. The constant β changes with the spectrum of background IR noise like sunlight and incandescent light. The β also changes with the ADC’s range and resolution selections. (EQ. 8) Here, β and EIR have the same meanings as in Equation 7. The constant γ depends on the spectrum of the used IR LED and the ADC’s range and resolution selections. ELED is the IR intensity which is emitted from the IR LED and reflected by a specific objector to the ISL29011. ELED depends on the current to the IR LED and the surface of the object. ELED decreases with the square of the distance between the object and the sensor. If background IR noise is small, EIR can be neglected, and the ADC output directly decreases with the distance. If there is significant background IR noise, ISL29011 offers two schemes to reduce the effect. The first way is do a proximity sensing using Scheme 0, immediately followed by an IR sensing. The differential reading of ADC outputs from the proximity and IR sensing will then reduce the effect of background IR noise and directly decrease with the distance between the object and the sensor. The second way is to do a proximity sensing using Scheme 1 to do on-chip background IR noise subtraction. While Scheme 0 has wider dynamic range, Scheme 1 proximity detection is faster but with half the resolution. Please refer to “Typical Performance Curves” on page 12 for ADC output versus distance using Scheme 0 detection. Figure 9 shows ISL29011 configured at 12-bit ADC resolution and sensitivity range select at 16000 (range 3) for the proximity reading. A 12.5mA external LED current at 360kHz modulation frequency detects three different sensing objects: 92% brightness paper, 18% gray card and ESD black foam. Figure 10 shows ISL29011 configured at 12-bit ADC resolution and sensitivity range select at 1000 (range 1) for the proximity reading, with a programmed external LED at 360kHz modulation frequency, detecting the same sensing object: 18% gray card under four different external LED current: 12.5mA, 25mA, 50mA and 100mA to compare the proximity readout versus distance. ISL29011 Proximity sensing relies on the amount of IR reflected back from the objects to be detected. Clearly, it can not detect an optically black object that reflects no light. However, ISL29011 is sensitive enough to detect a black ESD foam, which reflects slightly less than 1% of IR, as shown in Figure 9 on page 12. For biological objects, blonde hair reflects more than brunette hair, as expected and shown in FN6467.2 May 14, 2009 ISL29011 Figure 11. Also notice that skin tissue is much more reflective than hair. IR penetrates into the skin and is reflected or scattered back from within. As a result, the proximity count peaks at contact and monotonically decreases as skin moves away. This characteristic is very different from that of a plain paper reflector. Suggested PCB Footprint It is important that the users check the “Surface Mount Assembly Guidelines for Optical Dual FlatPack No Lead (ODFN) Package” before starting ODFN product board mounting. http://www.intersil.com/data/tb/TB477.pdf Interrupt Function Depending on the mode of operation set by Bits 7, 6 and 5 of command register 00 hex, the upper and lower interrupt thresholds are for either ambient light level or proximity detection. After each change of mode of operation, it is expected a new set of thresholds are loaded to interrupt registers 04, 05, 06 and 07 hex for proper interrupt detection. Also, the interrupt persist counter will be reset to 0 when the mode of operation is changed. LED Modulation for Proximity Detection ISL29011 offers two ways to modulate the LED in the Proximity Detection mode - DC or 360kHz (with 50% duty cycle) by bit 6 of register 01h. At the IRDR pin, there are four different IRDR LED currents; 12.5, 25, 50, and 100mA outputs selectable by bits 4 and 5 of register 01h. With the LED running in the DC mode, the proximity detection is twice as sensitive but consumes 2 times more current. The sensitivity of LED 50mA, DC 50mA is identical to that of 100mA, 360kHz modulation. Please note that the ISL29011 does not include a LED. Current Consumption Estimation The low power operation is achieved through sequential readout in the serial fashion, as shown in Figure 3, the device requires three different phases in serial during the entire detection cycle to do ambient light sensing, infrared sensing and proximity sensing. The external IR LED will only be turned on during the proximity sensing phase under user program controlled current at modulated frequency depends on user selections. Figure 3 also shows the current consumption during each ALS, IR sensing and Proximity sensing phase. For example, at 8-bit ADC resolution the integration time is 0.4ms. If user programed 50mA current to supply external IR LED at 360kHz modulated frequency, during the entire operation cycle that includes ALS, IR sensing and Proximity sensing three different serial phases, the detection occurs once every 30ms, the average current consumption including external IR LED drive current can be calculated from Equation 9: Layout Considerations The ISL29011 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 1uF and 0.1µF and place them close to the VDDA and VDDD pins of the device. Typical Circuit A typical application for the ISL29011 is shown in Figure 4. The ISL29011’s I2C address is internally hardwired as 1000100. The device can be tied onto a system’s I2C bus together with other I2C compliant devices. Soldering Considerations Convection heating is recommended for reflow soldering; direct-infrared heating is not recommended. The 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. [ ( 0.05mA + 0.05mA + 1mA + (50mA∗ 50%))∗ 0.4ms ) ]/30ms = 0.35mA (EQ. 9) If at a 12-bit ADC resolution where the integration time for each serial phase becomes 7ms and the total detection time becomes 100ms, the average current can be calculated from Equation 10: [ ( 0.05mA + 0.05mA + 1mA + (50mA∗ 50%))∗ 7 ms ) ]/100ms = 1.83mA (EQ. 10) 10 FN6467.2 May 14, 2009 ISL29011 30ms 1µA ALS 50µA 0.4ms IR 50µA 0.4ms PROXIMITY 0.4ms 1mA IR LED 50mA 360 kHz FIGURE 3. CURRENT CONSUMPTION FOR EACH INTEGRATION PHASE AND DETECTION CYCLE 1.7V TO 3.63V R1 10kΩ R2 10kΩ I2C MASTER R3 10kΩ MICROCONTROLLER INT SDA SCL 2.25V TO 3.63V SLAVE_0 1 2 C1 1µF C2 0.1µF 3 4 REXT 499k VDDD IRDR VDDA INT GND SDA REXT SCL SLAVE_1 8 7 I2C SLAVE_n SDA SDA SCL SCL 6 5 ISL29011 FIGURE 4. ISL29011 TYPICAL CIRCUIT 11 FN6467.2 May 14, 2009 ISL29011 Typical Performance Curves VSUP (VDDD, VDDA) = 3V, REXT = 499kΩ 1.2 SUN 1.0 INCANDESCENT 1.0 0.8 NORMALIZED RESPONSE HALOGEN 0.6 FLUORESCENT 0.4 0.2 HUMAN EYE RESPONSE IR AND PROXIMITY SENSING 0.8 0.6 0.4 0.2 0 0 300 400 500 600 700 800 WAVELENGTH (nm) 900 1000 -0.2 300 1100 20° 10° 0° 10° 20° 30° 40° 50° 50° 60° 60° 70° 70° 80° 80° 90° 0.2 0.4 0.6 0.8 RELATIVE SENSITIVITY 90° 1.0 CALCULATED ALS READING (LUX) RADIATION PATTERN LUMINOSITY 30° ANGLE 40° 500 600 700 800 900 WAVELENGTH (nm) 1000 1100 1000 65535 VDD = 3V RANGE = 1000 LUX 16-BIT ADC 900 800 700 INCANDESCENT HALOGEN 600 500 32768 400 FLUORESCENT 300 200 Ecal = 100 0 0 1000 LUX 216 x DATA 0 100 200 300 400 500 600 700 800 900 1000 LUX METER READING (LUX) FIGURE 7. RADIATION PATTERN FIGURE 8. SENSITIVITY TO THREE LIGHT SOURCES 4500 DATAPROX-DATAIR (COUNT) 10000 92% BRIGHTNESS PAPER 1000 18% GRAY CARD 100 10 ESD BLACK FOAM 1 400 FIGURE 6. SPECTRAL RESPONSE FOR AMBIENT LIGHT SENSING AND PROXIMITY SENSING FIGURE 5. SPECTRUM OF FOUR LIGHT SOURCES DATAPROX-DATAIR AMBIENT LIGHT SENSING ADC OUTPUT (COUNT) NORMALIZED LIGHT INTENSITY 1.2 0 20 40 60 DISTANCE (mm) 80 100 FIGURE 9. ADC OUTPUT vs DISTANCE WITH DIFFERENT OBJECTS IN PROXIMITY SENSING 12 4000 3500 IIRLED = 100mA 3000 IIRLED = 50mA IIRLED = 25mA 2500 IIRLED = 12.5mA 2000 1500 1000 500 0 0 10 20 30 40 50 60 DISTANCE (mm) 70 80 90 FIGURE 10. ADC OUTPUT vs DISTANCE WITH DIFFERENT LED CURRENT AMPLITUDES IN PROXIMITY SENSING FN6467.2 May 14, 2009 ISL29011 Typical Performance Curves VSUP (VDDD, VDDA) = 3V, REXT = 499kΩ (Continued) 10 12-BIT ADC RANGE 3 fLED = 328kHz ILED = 12.5mA 4mm CENTER-TO-CENTER FOR ISL29011 AND SFH4650, ISOLATED BY BARRIER AND BEHIND A 65% IR TRANSMITTING GLASS 300 PIG'S SKIN 250 200 150 18% GRAY 130 CTS = 500 CTS x 65% x 65% = 211 CTS 100 50 0 ALS SENSING 0 Lux OUTPUT CODE (COUNTS) DATAPROX - DATAIR (COUNT) 350 0 10 BLOND HAIR BRUNETTE HAIR 20 40 30 50 8 6 4 2 0 -60 60 -20 DISTANCE (mm) FIGURE 11. PROXIMITY DETECTIONS OF VARIOUS BIOLOGICAL OBJECTS 60 100 FIGURE 12. OUTPUT CODE FOR 0 LUX vs TEMPERATURE 1.10 105.0 300 Lux FLUORESCENT LIGHT ALS SENSING IRDR OUTPUT CURRENT (mA) 104.5 1.05 1.00 0.95 0.90 -60 -20 20 TEMPERATURE (°C) 60 PROXIMITY SENSING IS<1:0> = 0 104.0 103.5 103.0 102.5 102.0 101.5 101.0 100.5 100.0 -40 100 FIGURE 13. OUTPUT CODE vs TEMPERATURE -20 0 20 40 60 TEMPERATURE (°C) 80 100 120 FIGURE 14. OUTPUT CURRENT vs TEMPERATURE IN PROXIMITY SENSING 90 85 SUPPLY CURRENT (µA) OUTPUT CODE RATIO (FROM +30°C) 20 TEMPERATURE (°C) ALS SENSING 10,000 Lux 80 75 70 65 60 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (°C) FIGURE 15. SUPPLY CURRENT vs TEMPERATURE IN ALS SENSING 13 FN6467.2 May 14, 2009 ISL29011 FIGURE 16. 8 LD ODFN SENSOR LOCATION OUTLINE 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 14 FN6467.2 May 14, 2009 ISL29011 Package Outline Drawing L8.2.1x2.0 8 LEAD OPTICAL DUAL FLAT NO-LEAD PLASTIC PACKAGE (ODFN) Rev 0, 10/08 2.10 6 A PIN #1 INDEX AREA B 6 PIN 1 INDEX AREA 0.50 2.00 1.50 1.50 0.20±0.05 (2X) 0.10 M C A B 0.10 8X 0 . 35 ± 0 . 05 TOP VIEW 0.75 BOTTOM VIEW SEE DETAIL "X" 0.10 C 0.70±0.05 C BASE PLANE SEATING PLANE 0.08 C SIDE VIEW (6x0.50) (1.50) (8x0.20) C 0 . 2 REF 5 (8x0.55) (0.75) 0 . 00 MIN. 0 . 05 MAX. TYPICAL RECOMMENDED LAND PATTERN DETAIL "X" NOTES: 1. Dimensions are in millimeters. Dimensions in ( ) for Reference Only. 2. Dimensioning and tolerancing conform to AMSE Y14.5m-1994. 3. Unless otherwise specified, tolerance : Decimal ± 0.05 4. Dimension b applies to the metallized terminal and is measured between 0.25mm and 0.35mm from the terminal tip. 5. Tiebar shown (if present) is a non-functional feature. 6. The configuration of the pin #1 identifier is optional, but must be located within the zone indicated. The pin #1 indentifier may be either a mold or mark feature. 15 FN6467.2 May 14, 2009