Low Power Ambient Light and Proximity Sensor with Enhanced Infrared Rejection ISL29038 Features The ISL29038 is a low power Ambient Light Sensor (ALS) and proximity (PROX) sensor. It has a built-in IR-LED driver for proximity function. The ALS function measures the amount of light (in the visible spectrum) incident on the ISL29038. • Ideal for applications under dark or tinted glass 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 reflected 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 90µs. 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 power 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 I2C interface for configuration and control. • 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 VDD • Power Down IDD, typical 0.2µADC • 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 100 90 VDD_IRLED R2 100 VDD_ANALOG C2 1µF C1 1µF D1 IRLED U1 1 8 GNDIR IRDR 2 7 AVDD INT 3 6 SDA AGND 4 5 SCL REXT SCL, SDA AND INT PULLUPs SMBus MASTER INT SDA SCL R1 ISL29038 499k R1: 499k 1% RESISTOR R2: 100Ω 5% RESISTOR C1, C2: 1µF CERAMIC 10V CAPACITOR D1: OSRAM SFH4650 INFRARED LED FIGURE 1. TYPICAL APPLICATIONS CIRCUIT October 12, 2012 FN7851.0 1 FULL SCALE RANGE (%) VDD_PULLUP 80 250mA 70 125mA 60 50 62.5mA 40 30 31.25mA 20 10 0 0 20 40 60 18% GREY CARD PROXIMITY DISTANCE (mm) 80 FIGURE 2. PROXIMITY SENSITIVITY 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 VDD 2 ALS PHOTODIODE ARRAY COMMAND REGISTER PHOTODIODE AMPLIFIERS (ALS AND IR) DUAL CHANNEL ADCs DATA REGISTER 1 I2C IR PHOTODIODE ARRAY SCL 6 SDA INTERRUPT 7 INT IR DRIVER 8 IRDR IREF FOSC 4 3 REXT GND GNDIR 5 FIGURE 3. ISL29038 BLOCK DIAGRAM Pin Configuration Pin Description ISL29038 (8 LD ODFN) TOP VIEW GNDIR 1 8 IRDR VDD 2 7 INT GND 3 6 SDA REXT THERMAL PAD 4 5 SCL PIN# NAME DESCRIPTION 1 GNDIR 2 VDD Positive supply: 2.25V to 3.63V. 3 GND Ground. 4 REXT External Resistor, Connect to GND pin through a 499kΩ, 1% resistor. 5 SCL I2C Serial Clock Input. 6 SDA I2C Serial Data Input/Output. 7 INT Active Low, Open-Drain Output. 8 IRDR IR-LED Driver Sink - Connect to IR LED Cathode. - TPAD Thermal Pad - Connect to GND. Ground for IRDR LED Current. Ordering Information PART NUMBER (Notes 1, 2, 3) PART MARKING ISL29038IROZ-T7 N/A ISL29038IROZ-EVALZ Evaluation Board VDD RANGE (V) TEMP RANGE (°C) 2.25 to 3.63 -40 to +85 PACKAGE 8 Lead ODFN PKG. DWG. # L8.2.1x2.0 NOTES: 1. Refer to TB347 for details on reel specifications. 2. 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. 3. For Moisture Sensitivity Level (MSL), see device information page for ISL29038. For more information on MSL see techbrief TB477. 2 FN7851.0 October 12, 2012 ISL29038 Absolute Maximum Ratings Thermal Information VDD Supply Voltage between VDD and GND . . . . . . . . . . . . . . . . . . . . . .4.0V I2C Bus Pin Voltage (SCL, SDA). . . . . . . . . . . . . . . . . . . . . . . . . -0.5V to 4.0V I2C Bus Pin Current (SCL, SDA). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . <10mA REXT Pin Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .-0.5V to VDD + 0.5V IRDR Pin Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5.5V INT Pin Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.5V to 4.0V INT Pin Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . <10mA ESD Rating Human Body Model (Note 6). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2kV Thermal Resistance (Typical) θJA (°C/W) θJC (°C/W) 8 Ld ODFN (Notes 4, 5) . . . . . . . . . . . . . . . . 88 10 Maximum Die Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +90°C Storage Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .-40°C to +100°C Operating Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -40°C to +85°C Pb-Free Reflow Profile (*) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . see TB477 *Peak temperature during solder reflow +260°C max 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. NOTES: 4. 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. 5. For θJC, the “case temp” location is the center of the exposed metal pad on the package underside. 6. Tested per JESD22-A114E, ESD on all pins is 2kV except IRDR, which is 1.5kV. 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 = 3.0V, TA = +25°C, REXT = 499kΩ 1% tolerance. DESCRIPTION CONDITION MIN TYP MAX UNIT 2.25 3.0 3.63 V INPUT POWER VDD IDD_OFF IDD_NORM IDD_PRX_SLP IDD_ALS Power Supply Range Supply Current when Powered Down ALS_EN = 0; PROX_EN = 0 0.2 1.0 µA Supply Current for ALS+Prox in Sleep Time ALS_EN = 1; PROX_EN = 1 125 140 µA Supply Current for Prox in Sleep Time ALS_EN = 0; PROX_EN = 1 95 µA Supply Current for ALS ALS_EN = 1; PROX_EN = 0 95 µA ADC (ALS & PROX) tINTGR_ALS 12-bit ALS Conversion Time 80 95 110 ms tINTGR_PROX 8-bit Prox Conversion Time 0.4 0.50 0.6 ms DATAALS_0 ALS Result when Dark EAMBIENT = 0 Lux, 2k range DATAALS_F Full Scale ALS ADC Code EAMBIENT > selected range maximum Lux ΔDATA1 DATA Output Variation Over Light Sources: Fluorescent, Incandescent and Sunlight Ambient light sensing, no cover glass After programmable active IR compensation (Note 7) ±10 % ΔDATA2 DATA Output Variation Over Light Sources: Fluorescent, Incandescent and Sunlight Ambient light sensing under cover glass After programmable active IR compensation (Note 7) ±10 % Linearity ALS ADC Data Linearity 20% - 80% of full range ±5 % DATAALS_0 Light Count, ALS_Range 125 Lux E = 50 Lux (Note 8), ALS_RANGE = 0 1555 1767 1979 Counts DATAALS_1 Light Count, ALS_Range 250 Lux E = 50 Lux (Note 8), ALS_RANGE = 1 771 876 981 Counts DATAALS_2 Light Count, ALS_Range 2000 Lux E = 300 Lux (Note 8), ALS_RANGE = 2 585 665 745 Counts DATAALS_3 Light Count, ALS_Range 4000 Lux E = 300 Lux (Note 8), ALS_RANGE = 3 292 331 371 Counts DATAPROX_0 Prox Data without Object in Path 3 1 Counts 4095 1 Counts Counts FN7851.0 October 12, 2012 ISL29038 Electrical Specifications PARAMETER VDD = 3.0V, TA = +25°C, REXT = 499kΩ 1% tolerance. (Continued) DESCRIPTION DATAPROX_F CONDITION MIN TYP Full Scale Prox ADC Code ProxWASH Washout Bit Activation Level Norwood Solar Emulator UNIT 255 Counts 40k ProxOffsetMax Maximum PROX Offset, Referenced to Proximity ADC Range ProxOffsetInc MAX Lux 512 Proximity Offset Adjust Increment Referenced to Proximity ADC Range LSB 27 LSB LED DRIVER (IRDR PIN) tr Rise Time for IRDR Sink Current RLOAD = 15Ω at IRDR pin, 20% to 80% 25 ns tf Fall time for IRDR Sink Current RLOAD = 15Ω at IRDR pin, 80% to 20% 15 ns IIRDR_0 IRDR Sink Current PROX_DR = 0; VIRDR = 0.5V 31.25 mA IIRDR_1 IRDR Sink Current PROX_DR = 1; VIRDR = 0.5V 62.5 mA IIRDR_2 IRDR Sink Current PROX_DR = 2; VIRDR = 0.5V 125 mA IIRDR_3 IRDR Sink Current PROX_DR = 3; VIRDR = 0.5V 250 mA IRDR Leakage Current PROX_EN = 0; VIRDR = 3.63V 0.001 VIRDR IRDR Pin Voltage Compliance Register bit PROX_DR = 0 tPULSE IIRDR On Time Per PROX Reading IIRDR_LEAK 0.50 1 µA 4.3 V 90 µs 0.52 V MISCELLANEOUS VREF Voltage of REXT Pin ALS_EN = 1 or PROX_EN = 1 I2C Electrical Specifications For SCL and SDA unless otherwise noted, VDD = 3V, TA = +25°C, REXT = 499kΩ 1% tolerance (Note 10). SYMBOL PARAMETER MAX UNITS 3.63 V SCL Clock Frequency 400 kHz VIL SCL and SDA Input Low Voltage 0.55 V VIH SCL and SDA Input High Voltage Vhys Hysteresis of Schmitt Trigger Input VOL Low-level Output Voltage (open-drain) at 4mA Sink Current VI2C Supply Voltage Range for fSCL Ii I2C TEST CONDITIONS Interface MIN 1.7 Input Leakage for each SDA, SCL Pin TYP 1.25 V 0.05VDD V -10 0.4 V 10 µA tSP Pulse Width of Spikes that must be Suppressed by the Input Filter 50 ns tAA SCL Falling Edge to SDA Output Data Valid 900 ns 10 pF Ci tHD:STA Capacitance for each SDA and SCL Pin Hold Time START Condition After this period, the first clock pulse is generated 600 ns tLOW LOW Period of the SCL Clock Measured at the 30% of VDD crossing 1300 ns tHIGH HIGH period of the SCL Clock 600 ns tSU:STA Set-up Time for a START Condition 600 ns tHD:DAT Data Hold Time 30 ns tSU:DAT Data Set-up Time 100 ns 4 FN7851.0 October 12, 2012 ISL29038 I2C Electrical Specifications For SCL and SDA unless otherwise noted, VDD = 3V, TA = +25°C, REXT = 499kΩ 1% tolerance (Note 10). (Continued) SYMBOL PARAMETER TEST CONDITIONS MIN TYP MAX UNITS tR Rise Time of both SDA and SCL Signals (Note 11) 20 + 0.1xCb ns tF Fall Time of both SDA and SCL Signals (Note 11) 20 + 0.1xCb ns Set-up Time for STOP Condition 600 ns Bus Free Time Between a STOP and START Condition 1300 ns tSU:STO tBUF Cb Capacitive Load for Each Bus Line 400 Maximum determined by tR and tF 1 pF Rpull-up SDA and SCL System Bus Pull-Up Resistor kΩ tVD;DAT Data Valid Time 0.9 µs tVD:ACK Data Valid Acknowledge Time 0.9 µs VnL Noise Margin at the LOW Level 0.1VDD V VnH Noise Margin at the HIGH Level 0.2VDD V NOTES: 7. Cover glass assumes fixed infrared/visible light transmissivity ratio of 10. 8. The LED light source irradiance is calibrated to produce the same ALS count as a fluorescent light source of the same Lux level. 9. An 850nm infrared LED is used in production test for proximity/IR sensitivity testing. 10. All parameters in I2C Electrical Specifications table are guaranteed by design and simulation. 11. Cb is the capacitance of the bus in pF. FIGURE 4. I2C TIMING DIAGRAM 5 FN7851.0 October 12, 2012 ISL29038 Each I2C transaction ends with the master asserting a stop condition (SDA rising while SCL remains high). For more information about the I2C standard, consult the Philips™ I2C specification documents. ISL29038 Configuration and Control I2C Interface ISL29038 configuration and control is performed using the I2C or SMBus. The ISL29038’s I2C interface slave address is internally hard wired as 8’b1000100x, where x denotes the R/W bit. Timing specifications are included in “I2C Electrical Specifications” on page 4. The timing parameters are defined in Figure 4. Every I2C transaction begins with the master asserting a start condition (SDA falling while SCL remains high). The first transmitted byte is initiated by the master and includes 7 address bits and a R/W bit. The slave is responsible for pulling SDA low during the ACK time after every transmitted byte. The I2C interface on the ISL29038 supports single and multiple byte read and write transfers using the random-read/write protocol. The ISL29038 does not support I2C ‘Repeat Start’ protocol. Note that in most system implementations, the ISL29038 is connected to a single I2C master with one or more slave devices, consequently, absence of ‘Repeat Start’ function does not adversely affect I2C bus system performance. Figure 5 shows a sample one-byte read. The I2C bus master always drives the SCL (clock) line, while either the master or the slave can drive the SDA (data) line. I2C DATA DEVICE ADDRESS START I2C SDA MASTER REGISTER ADDRESS W A A6 A5 A4 A3 A2 A1 A0 W A R7 R6 R5 R4 R3 R2 R1 R0 A I2C SDA SLAVE (ISL29038) SDA DRIVEN BY MASTER I2C CLK 1 2 3 4 5 6 7 A 8 9 A SDA DRIVEN BY MASTER 1 2 3 4 5 6 DEVICE ADDRESS STOP START 7 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 ISL29038 A A D7 D6 D5 D4 D3 D2 D1 D0 7 8 9 1 2 3 4 5 6 7 8 9 FIGURE 5. I2C DRIVER TIMING DIAGRAM FOR MASTER AND SLAVE CONNECTED TO COMMON BUS 6 FN7851.0 October 12, 2012 ISL29038 100 100 90 90 80 FULL SCALE RANGE (%) FULL SCALE RANGE (%) Typical Performance Curves 250mA 70 125mA 60 50 62.5mA 40 30 31.25mA 80 70 50 40 30 20 10 10 0 40 60 20 18% GREY CARD PROXIMITY DISTANCE (mm) CIE 1924 PHOTOPIC CURVE 60 20 0 ALS RESPONSE (BLUE) RANGE: 2k Lux 0 300 80 FIGURE 6. PROXIMITY SENSITIVITY (Note 12) 400 500 600 700 800 WAVELENGTH (nm) 900 1000 1100 FIGURE 7. ALS SENSITIVITY (Note 13) 100 15 NORMALIZED SENSITIVITY (%) VALUE CHANGE (% FSR) 90 10 50% 5 10% 0 0 8k 16k 80 70 60 50 40 30 20 10 24k 32k 40k 0 -90 -60 -30 FIGURE 8. PROXIMITY AMBIENT LIGHT REJECTION (Note 14) 0 30 60 90 ANGLE (°) AMBIENT LIGHT LEVEL (LUX) FIGURE 9. ALS ANGULAR SENSITIVITY (Note 15) NOTES: 12. Figure 6 shows ISL29038 Proximity distance sweeps with different IRDR LED current settings using an 18% Grey card reflector. 13. Figure 7 shows ISL29038 Ambient Light Sensor Spectral response when compared to a theoretical CIE 1924 Photopic curve. The ‘Blue’ line shows the ISL29038 response and the ‘Red’ line depicts the CIE 1924 Photopic curve. 14. Figure 8 shows the ISL29038 Proximity Ambient Light Rejection using a Norwood Solar Emulator. At 40k lux ambient light level, the Proximity Washout Count (Reg 0x0D[7:1]) is 127 indicating a saturation in Proximity Signal processing path. The Proximity Washout bit 0x0D[0] is active at approximately 90% of the maximum level. At 10% initial PROX count (due to optical leakage from IR LED to the ISL29038), the PROX data error is under 2%. At 50% initial PROX count (severe optical leakage), the PROX data error is about 7%. 15. Figure 9 shows the Ambient Light Sensor Angular Sensitivity of the ISL29038 using a white LED light source. 7 FN7851.0 October 12, 2012 ISL29038 ISL29038 Register Set TABLE 1. ISL29038 CONFIGURATION AND CONTROL REGISTERS ADDRESS (HEX) 0x00 REGISTER NAME Device ID POWER-ON DEFAULT b11000xxx REGISTER ACCESS RO BIT FIELDS [7:0] [7:3] 0x01 Config0 0x00 RW RW RW RW 0x02 Config1 0x00 0x04 Config2 INTConfig 0x00 0x10 8 FUNCTION Device Identification [11000] ISL29038 Device ID [2:0] Reserved [7:0] Proximity Configuration [7:6] Reserved [5] [4:2] [1:0] RW [7:0] RW [7] PROX_EN Proximity Enable/Disable [1] Enable [0] Disable PROX_SLP Proximity Sleep Time Select [000] 400ms [001] 100ms [010] 50ms [011] 25ms [100] 12.5ms [101] 6.25ms [110] 3.125ms [111] 0ms IRDR_DRV IR LED Current [00] 31.25mA [01] 62.5mA [10] 125mA [11] 250mA Proximity/ALS Configuration INT_ALG Interrupt Algorithm [0] Window Comparator [1] Hysteresis Window RW [6:3] PROX_OFFSET Proximity Offset Compensation RW [2] ALS_EN Ambient Light Sensing Enable/Disable [1] Enable [0] Disable RW 0x03 FUNCTION NAME/VALUE [1:0] ALS_RANGE Ambient Light Sensor Range Select [00] 125 Lux [01] 250 Lux [10] 2000 Lux [11] 4000 Lux ALS_IR_COMP Ambient Light Sensor IR Compensation RW [7:0] RW [7:5] RW [4:0] ALSIRComp ALS Infra Red Compensation (Unsigned Binary) RW [7:0] INTConfig Interrupt Configuration, Status & Control Reserved FN7851.0 October 12, 2012 ISL29038 TABLE 1. ISL29038 CONFIGURATION AND CONTROL REGISTERS (Continued) ADDRESS (HEX) REGISTER NAME POWER-ON DEFAULT REGISTER ACCESS RO RW RO RO RW RW BIT FIELDS [7] [6:5] [4] [3] [2:1] [0] FUNCTION NAME/VALUE PROX_INT_FLG FUNCTION Proximity Interrupt Flag [1] Proximity Interrupt Event [0] No Proximity Interrupt Event PROX_PRST Proximity Interrupt Reporting Persistency [00] INT after 1 Proximity Flag Event [01] INT after 2 Consecutive Proximity Flag Event [10] INT after 4 Consecutive Proximity Flag Event [11] INT after 8 Consecutive Proximity Flag Event PWR_FAIL Power Failure (Brown-out) Alarm [1] Brown-Out Detected [0] Normal Operation ALS_INT_FLG Ambient Light Sensor Interrupt Flag [1] ALS Interrupt Flag Event [0] No ALS Interrupt Flag Event ALS_INT_PRST ALS Interrupt Reporting Persistency [00] INT after 1 ALS Flag Event [01] INT after 2 Consecutive ALS Flag Event [10] INT after 4 Consecutive ALS Flag Event [11] INT after 8 Consecutive ALS Flag Event INT_CFG Interrupt Output (Pin) Configuration [1] Interrupt if ALS and PROX Event [0] Interrupt if ALS or PROX Event 0x05 PROX_INT_TL 0x00 RW [7:0] PROX_INT_TL Proximity Interrupt LOW threshold 0x06 PROX_INT_TH 0xFF RW [7:0] PROX_INT_TH Proximity Interrupt HIGH threshold 0x07 ALS_INT_TL 0x00 RW [7:0] ALS_INT_TL1 ALS Interrupt LOW threshold bit[11:4] 0x08 ALS_INT_TLH 0x0F RW [7:0] [7:4] ALS_INT_TL0 ALS Interrupt LOW threshold bit[3:0] [3:0] ALS_INT_TH1 ALS Interrupt HIGH threshold bit[11:8] [7:0] ALS_INT_TH0 ALS Interrupt HIGH threshold bit[7:0] 0x09 ALS_INT_TH 0xFF RW ALS Interrupt LOW/HIGH threshold bits 0x0A PROX_DATA RO [7:0] PROX_DATA Proximity Data (Unsigned Binary) 0x0B ALS_DATA_HB RO [7:0] ALS_DATA_HB ALS Data HIGH Byte [7:4] Set to 0000 [3:0] ALS Data Bit[11:8] 0x0C ALS_DATA_LB RO [7:0] ALS_DATA_LB ALS Data Bit[7:0] 0x0D PROX_AMBIR RO [7:0] PROX_AMBIR Proximity Mode Ambient IR Measurement [7:1] RO 0x0E Config3 0x00 9 [0] [7:0] Proximity Mode Ambient IR Component PROX_WASH Proximity Washout Status [1] Proximity Washout Detected [0] Normal Proximity Operation SoftReset Software Reset 0x38 Initiate Soft Reset 0x00 Normal operation FN7851.0 October 12, 2012 ISL29038 Registers 0x01, 0x02 are used to configure the primary proximity and ALS parameters. Register 0x03 is used for optimizing IR compensation in ALS measurements. A procedure to optimize IR compensation is described in “ALS IR Compensation” on page 11. Register 0x04 is the Interrupt Configuration and Status Register, and is used primarily to indicate interrupt events from proximity and ALS measurements. A PWR_FAIL bit to indicate a ‘Brown-Out’ event is available and is set in case of a power supply interruption. A ‘Brown-Out’ event does not generate a hardware interrupt. The host micro-controller must clear this bit by writing a ‘0’ to Reg 0x04[4]. Register 0x04 is also used to configure ALS & Proximity interrupt persistency and the operation of the INT pin. The ALS runs continuously with new data available every 90ms. The proximity sensor runs continuously with a time between conversions controlled by PROX_SLP (Reg 0x01[6:4]). Ambient Light Sensing The ISL29038 is set for ambient light sensing when Register bit ALS_EN = 1. Four measurement ranges from 125 Lux to 4000 Lux are available. The ALS measurement range is configured via Reg 0x02[1:0]. Proximity Sensing When proximity sensing is enabled (PROX_EN = 1), the external IR LED is driven for 100µs by the built-in IR LED driver through the IRDR pin. Registers 0x05 and 0x06 are used to set the proximity ‘LOW’ and ‘HIGH’ threshold for proximity interrupt event generation. Registers 0x07, 0x08 and 0x09 are used to set the ALS ‘LOW’ and ‘HIGH’ threshold. Two 12-bit numbers span three address locations as shown in Table 1. Data registers 0x0A holds result of proximity conversion. The proximity result should be validated by ‘Washout’ bit in Reg 0x0D[0]. Registers 0x0B and 0x0C hold result of an ALS measurement. The ALS data is 12 bits wide. Least Significant Byte of the ALS data is available at address 0x0C and Most Significant Byte (MSB) of ALS data is available at address 0x0B. The MSB is right justified, i.e., the upper nibble is always zero and lower nibble contains four data bits. Register 0x0D[7:1] contains ambient IR measurement in proximity measurement phase. This measurement is for detecting ambient Washout condition, which is indicated by Reg 0x0D[0] being ‘HIGH’. Proximity ‘Washout’ is described in “Proximity Ambient Washout Detection” on page 11. A software reset can be initiated by writing 0x38 to Reg 0x0E. ISL29038 Operation Photodiodes and ADCs The ISL29038 contains two photodiode arrays, which convert photons (light) into current. The ALS photodiodes are designed to mimic the human eye’s wavelength response curve to visible light. The ALS photodiodes’ current output is digitized by a 12-bit ADC. The ALS ADC output is accessed by reading from Reg 0x0B and 0x0C when the ADC conversion is completed. The ALS ADC converter uses a charge-balancing architecture. Charge-balancing is best suited for converting small current signals in the presence of periodic AC noise. ISL29038 targets an integration time of 90ms, which can vary ±15% from nominal. The ALS integration time is intended to minimize 60Hz flicker. The proximity sensor uses an 8-bit ADC, which operates in a similar fashion. The IRDR pin drives (pulses) an infrared LED, the emitted IR reflects off an object back into the ISL29038, and the photo diodes convert the reflected IR to a current signal in 0.5ms. The ADC subtracts the IR reading before and after the LED is driven to remove ambient IR contribution. 10 ALS CONVERSION TIME = 90ms (FIXED) SEVERAL µs BETWEEN CONVERSIONS ALS ACTIVE 90ms PROX SENSOR ACTIVE 90ms 90ms 90ms 90ms TIME 0.50ms FOR PROX CONVERSION TIME IRDR (CURRENT DRIVER) SERIES OF CURRENT PULSES TOTALING 0.09ms TIME SLEEP TIME (PROX_SLP) FIGURE 10. TIMING DIAGRAM FOR PROX/ALS EVENTS - NOT TO SCALE The IR LED current depends on PROX_DRV (Reg 0x01[1:0]). Drive current settings are as shown in Table 1. IR LED drive is in high impedance state when not active. When the IR from the LED reaches an object and gets reflected back to the ISL29038, the reflected IR light is converted into a current. This current is converted to digital data using an 8-bit ADC. The proximity measurement takes 0.5ms for one conversion including the 90μs LED drive time. The period between proximity measurements is determined by PROX_SLP (sleep time) in Reg 0x01[4:2]. Average LED driving current consumption is given by Equation 1. I lRDR ;PEAK × 90μs I lRDR ;AVE = ---------------------------------------------------T SLEEP (EQ. 1) A typical IRDR scheme is 250mA pulses every 400ms, averaging about 56μA DC. Total Current Consumption Total current consumption is the sum of IDD and IIRDR. The IRDR pin sinks current and the average IRDR current is calculated using Equation 1. IDD depends on voltage and the mode-of-operation. For simplicity, Equation 1 ignores proximity ADC conversion time since it is much smaller than the sleep time. FN7851.0 October 12, 2012 ISL29038 ALS IR Compensation Proximity Ambient Washout Detection The ISL29038 is designed for operation under dark glass cover. Glass or plastic covers can significantly attenuate visible light and pass the Infrared light without much attenuation. Consequently, the ISL29038 under a glass cover experiences an IR rich environment. Optical proximity sensor can saturate when illuminated with excessive ambient light. The ISL29038 provides a warning flag when the proximity measurement may be erroneous due to excessive ambient light. The PROX_WASH register (Reg 0x0D[0]) reports this condition. The on-chip ALS passive optical filter on the ISL29038 is designed to block most of the IR incident on the ALS photo diodes. In addition, the ISL29038 provides a programmable active IR compensation that subtracts residual IR still reaching the sensor. Interrupts Events The ALS_IR_COMP register (Reg 0x03[4:0]) allows fine tuning of the residual infrared component from the ALS output. The recommended procedure for determining ALS IR compensation is as follows: • Illuminate the ISL29038 based product with a light source without IR, such as a white LED. Record the ALS measurement and the Lux level. • Illuminate the device with an IR LED and the White LED. Take an ALS measurement and Lux level measurement. • Adjust the ALS_IR_COMP register (Reg 0x03, bits 4:0) to compensate for the IR contribution. • Repeat steps above until the IR light source contribution to the ALS measurement is under 10 percent assuming no change in Lux level due to IR light source. Proximity Offset Systems built with a protective glass cover over the ISL29038 can provide light ‘leakage’ or ‘crosstalk’ from the IR LED by reflection from the glass saturating the proximity sensor measurement system (Figure 11). Saturation can occur when the reflection from the glass with no object in the proximity detection space exceeds the full scale of the measurement system. The ISL29038 proximity system provides a user programmable proximity offset correction to compensate for this reflection. The ISL29038 interrupts are designed to minimize host micro-controller overhead of continuous polling. ISL29038 can generate interrupts on the results of an ALS measurement or proximity measurement. The ALS interrupt event ALS_FLAG (Reg 0x04[3]) is governed by Reg 0x07 through 0x09. Two-12 bit high and low threshold values are written to these registers. The ISL29038 will set the ALS interrupt flag if the ADC conversion count in Registers 0x0B and 0x0C are outside the programmed thresholds. The ALS_FLAG is cleared by writing a ‘0’ to Reg 0x04[3]. A proximity interrupt event (PROX_FLAG) is governed by the high and low thresholds in Reg 0x05 and 0x06 (PROX_LT and PROX_HT) and is indicated by Reg 0x04[7]. PROX_FLAG is set when the measured proximity data is more than the higher threshold. The proximity interrupt flag is cleared when the proximity data is lower than the low proximity threshold or by writing a ‘0’ to Reg 0x04[7]. The Proximity interrupt generation can be selected between ‘out-of-window’ threshold and hysteresis schemes. When the PROX_INT_ALG register (Reg 0x02, Bit 7) is set to 0, proximity uses a window comparator scheme; when set to 1, proximity uses a hysteresis scheme. In hysteresis mode, the interrupt event is generated if the proximity ADC count is higher than the PROX_HT threshold and the interrupt event is cleared when the proximity ADC count is less than the PROX_LT threshold. The interrupt event flag can also be cleared by writing a ‘0’ to Reg 0x04[7]. INTERRUPT PERSISTENCE To minimize interrupt events due to ‘transient’ conditions, an interrupt persistency option is available for both ALS and proximity measurements. Persistency requires ‘X-consecutive’ interrupt flags before the INT pin is driven low. Both ALS and PROX have their own independent interrupt persistency options. ALS_PRST and PROX_PRST configuration are controlled from Reg 0x04. GLASS COVER Power-Up and ‘Brown-Out’ Reset SENSOR LED PCB FIGURE 11. PROXIMITY SET-UP HIGHLIGHTING CROSSTALK REFLECTED FROM COVER GLASS The PROX_IR_COMP register (Reg 0x02[6:3]) applies a corrective offset to the received signal prior to ADC conversion, which allows the signal to be brought within the usable range of the proximity measurement system. 11 The ISL29038 has an enhanced power-on-reset system. A ‘Brown-Out’ detector flag in Reg 0x04[4] informs the system that the device has powered-up properly. This flag should be reset as part of the initialization sequence. A ‘Brown-Out’ condition is defined as an operating condition when the power supply voltage is not within the specified limits. During the brown-out period at power-up, the I2C interface and the IR LED driver are inactive. Following brown-out, the I2C interface is re-initialized and the configuration registers are set to power-up default values. After power-up and during device initialization, host should examine that the PWR_FAIL flag (Reg FN7851.0 October 12, 2012 ISL29038 0x04[4]) is set and then clear the flag by writing ‘0’ to Reg 0x04[4]. Following power-up, a ‘Brown-Out’ condition, if detected, is reported by PWR_FAIL flag by Reg 0x04[4]. Device configuration registers are not set to their power-up default after ‘Brown-Out’. PWR_FAIL flag should be periodically monitored to detect post power-up power supply interruption. Power-Down Setting ALS_EN (Reg 0x02[2]) and PROX_EN (Reg 0x01[5]) to ‘0’ puts the ISL29038 into a power-down state with power supply current dropping to less than 1µA. All configuration registers are maintained in power-down mode. Soft Reset A software reset to ISL29038 can be initiated by writing 0x38 to Reg 0x0E. Following reset, all configuration registers are set to their default power-up state. After soft reset, the ISL29038 defaults to the power-down configuration. ALS Data Count Read Out A 2 byte I2C read from ALS_DATA_HB outputs MSB 1st data on SDA. This data is LSB justified with a zero fill for unused bits. Note that the MSB byte address precedes the LSB byte address. The ALS count is 256*(ALS_DATA_HB) + ALS_DATA_LB. Proximity Detection of Various Objects Proximity sensing relies on the amount of IR reflected back from objects. A perfect black object would absorb all incident light and reflect no photons. The ISL29038 is sensitive enough to detect black ESD foam, which reflects only 1% of IR. Blonde hair typically reflects more than brown hair and skin tissue is more reflective than human hair. IR penetrates into the skin and is reflected from within. As a result, the proximity count generally peaks at contact and monotonically decreases as skin moves away. The reflective characteristics of skin are very different from that of a inanimate object such as paper. Typical Application Circuit A typical application circuit for the ISL29038 is shown in Figure 12. The ISL29038’s I2C address is internally hard wired as ‘1000100x’, with x representing the R/W bit. The device can be connected to a system’s I2C bus together with other I2C compliant devices. It is important to ensure that there is no address conflict with other I2C devices on the bus. The SCL, SDA and INT pins on ISL29038 are open drain and require pull-up resistors for proper system operation. Values of the pull-up resistors is system dependent and can range from 2.2k to 10k depending upon the number of I2C devices on the bus. The proximity sensing system can be powered using a dual power supply or using a single power supply. In dual supply configuration, the IR LED and the ISL29038 are powered from separate power supplies. The VDD IRLED can range from 2.25V to 5.0V and the VDD_ANALOG can range from 2.25V to 3.63V. In dual supply configuration, resistor R2 should not be installed. In single supply configuration, the IR LED and the ISL29038 are powered from the same power source. The VDD_IRLED can range from 2.25V to 3.63V and the VDD_Analog is derived from VDD_IRLED using resistor R2. In either power supply configuration, a 1µF decoupling capacitor should be installed close to the AVDD pin, and another 1µF decoupling capacitor should be placed close to the IR LED anode. VDD_PULLUP VDD_IRLED R2 100 VDD_ANALOG C2 1µF C1 1µF D1 IRLED SCL, SDA AND INT PULLUPs U1 1 8 GNDIR IRDR 2 7 AVDD INT 6 3 SDA AGND 4 5 SCL RExt SMBus MASTER INT SDA SCL ISL29038 R1 499k R1: 499k 1% RESISTOR R2: 100Ω 5% RESISTOR C1, C2: 1µF CERAMIC 10V CAPACITOR D1: OSRAM SFH4650 INFRARED LED FIGURE 12. TYPICAL APPLICATIONS CIRCUIT 12 FN7851.0 October 12, 2012 ISL29038 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. A standard reflow soldering profile with a +260°C maximum is recommended. Additional information regarding soldering ISL29038 is included in Intersil Technical Brief TB477. Suggested PCB Footprint Refer to TB477,“Surface Mount Assembly Guidelines for Optical Dual FlatPack No Lead (ODFN) Package” before starting ODFN product board mounting. Additional information regarding soldering is also included in Intersil Technical Brief TB477. PCB Layout Considerations The ISL29038 is relatively insensitive to PCB layout. Adherence to the following guidelines will ensure first pass success and best performance. Route the I2C/SMBus SCL, SDA and the INT traces away from sources of switching noise. A 499k 1% tolerance resistor must be connected from the REXT pin to AGND. This node also needs to be isolated from any switching noise. ISL29038 pins IRGND and AGND should connect to a low impedance ground with low resistance and low inductance traces. Ferrite beads and inductors should be avoided in the ground path. If necessary, due to RF consideration, the effects of DCR (DC resistance) should be evaluated on ALS and Proximity system performance. A 1µF ceramic decoupling capacitor should be placed as close to the AVDD pin as possible. The ISL29038 drives the IR LED with 0.09ms current pulses. To supply this pulsed current, a 1 to 10µF bulk decoupling capacitor (C1) must be connected from the IR LED anode to the GNDIR pin to minimize instantaneous resistive voltage drop. The connection from IR LED cathode to the IRDR pin should be short and with minimal inductance. Similarly, connection from the IR LED to VDD must be made with a low impedance trace. For most applications, a single power supply may be used to power the IR LED and the ISL29038. Use of resistor R2 and capacitor C2 (Figure 12) to help filter out the power supply noise generated from IR LED switching, is recommended for best ISL29038 performance when using a single power supply. For dual supply operation, resistor R2 should not be installed. 2.10 1 8 2 7 3 6 2.00 ALS SENSOR OFFSET 0.03mm ALS SENSOR AREA 0.66mm x 0.24mm PROX SENSOR OFFSET 0.42mm 4 5 PROX SENSOR AREA 0.57mm x 0.16mm 0.57 FIGURE 13. 8 LD ODFN SENSOR LOCATION OUTLINE - DIMENSIONS IN mm 13 FN7851.0 October 12, 2012 ISL29038 Revision History The revision history provided is for informational purposes only and is believed to be accurate, but not warranted. Please go to web to make sure you have the latest revision. DATE October 12, 2012 REVISION CHANGE FN7851.0 Initial Release. Products Intersil Corporation is a leader in the design and manufacture of high-performance analog semiconductors. The Company's products address some of the industry's fastest growing markets, such as, flat panel displays, cell phones, handheld products, and notebooks. Intersil's product families address power management and analog signal processing functions. Go to www.intersil.com/products for a complete list of Intersil product families. For a complete listing of Applications, Related Documentation and Related Parts, please see the respective product information page. Also, please check the product information page to ensure that you have the most updated datasheet: ISL29038 To report errors or suggestions for this datasheet, please go to: www.intersil.com/askourstaff FITs are available from our website at: http://rel.intersil.com/reports/sear For additional products, see www.intersil.com/en/products.html Intersil products are manufactured, assembled and tested utilizing ISO9000 quality systems as noted in the quality certifications found at www.intersil.com/en/support/qualandreliability.html 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 FN7851.0 October 12, 2012 ISL29038 Package Outline Drawing L8.2.1x2.0 8 LEAD OPTICAL DUAL FLAT NO-LEAD PLASTIC PACKAGE (ODFN) Rev 3, 1/11 2.10 A 6 PIN 1 INDEX AREA 0.15 B 0.25 6 PIN 1 INDEX AREA 0.50 1.50 2.00 1.50 0.20±0.05 4 (2X) 0.10 M C A B 0.10 8X 0 . 35 ± 0 . 05 TOP VIEW 0.75 BOTTOM VIEW SEE DETAIL "X" 2.50 0.10 C 2.10 0.70±0.05 C BASE PLANE SEATING PLANE 0.08 C SIDE VIEW (6x0.50) (1.50) (8x0.20) C (8x0.20) 5 0 . 00 MIN. 0 . 05 MAX. (8x0.55) DETAIL "X" (0.75) TYPICAL RECOMMENDED LAND PATTERN 0 . 2 REF NOTES: 1. Dimensions are in millimeters. Dimensions in ( ) for Reference Only. 2. Dimensioning and tolerancing conform to ASME Y14.5m-1994. 3. Unless otherwise specified, tolerance : Decimal ± 0.05 4. Dimension 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 FN7851.0 October 12, 2012