Integrated Digital Light Sensor with Interrupt ISL29023 Features The ISL29023 is an integrated ambient and infrared light to digital converter with I2C (SMBus Compatible) Interface. Its advanced self-calibrated photodiode array emulates human eye response with excellent IR rejection. The on-chip ADC is capable of rejecting 50Hz and 60Hz flicker caused by artificial light sources. The lux range select feature allows users to program the lux range for optimized counts/lux. * Resolution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16-bits ADC * Integrated Noise Reduction . . . . . . . . . . . . . . . . . . . . 50/60Hz * Light Sensor Close to Human Eye Response * Excellent Light Sensor IR and UV Rejection * Range Selection via I2C - Range1 = 0.015 to 1,000 Lux - Range2 = 0.06 to 4,000 Lux - Range3 = 0.24 to 16,000 Lux - Range4 = 0.96 to 64,000 Lux * Shutdown Modes . . . . . . . . . . . . . . . . . .Software & Automatic * Supply Current (Max) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85A For ambient light sensing, an internal 16-bit ADC has been designed based upon the charge-balancing technique. The ADC conversion time is nominally 90ms and is user adjustable from 11s to 90ms, depending on oscillator frequency and ADC resolution. In normal operation, typical current consumption is 70A. In order to further minimize power consumption, two power-down modes have been provided. If polling is chosen over continuous measurement of light, the auto-power-down function shuts down the whole chip after each ADC conversion for the measurement. The other power-down mode is controlled by software via the I2C interface. The power consumption can be reduced to less than 0.3A when powered down. * Shutdown Current (Max) . . . . . . . . . . . . . . . . . . . . . . . . . .0.3A * Control Interface . . . . . . . . . . . . . . . I2C and SMB Compatible * I2C Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . 1.7V to 3.63V * Sensor Power Supply . . . . . . . . . . . . . . . . . . . . . 2.25V to 3.63V * Operating Temperature Range. . . . . . . . . . . . -40C to +85C * Small Form Factor Package . . . . . . . .6 Ld 2.0x2.1x0.7 ODFN The ISL29023 supports a software and hardware interrupt that remains asserted until the host clears it through I2C interface. Function of ADC conversion continues without stopping after interrupt is asserted. Applications * Mobile Devices: Smart Phone, PDA, GPS * Computing Devices: Notebook PC, Webpad Designed to operate on supplies from 2.25V to 3.63V with an I2C supply from 1.7V to 3.63V, the ISL29023 is specified for operation over the -40C to +85C ambient temperature range. * Consumer devices: LCD-TV, Digital Picture Frame, Digital Camera * Industrial and Medical Light Sensing 1.2 HUMAN EYE 1.0 VBUS VDD R R 0.1F R 1 VDD MCU SDA 6 SDA SCL 5 SCL GPIO 4 INT REXT 3 500k NORMALIZED RESPONSE 0.8 10F 0.6 0.4 IR SENSING 0.2 0 VSS 2 AMBIENT LIGHT SENSING -0.2 300 400 500 600 700 800 900 1000 1100 WAVELENGTH (nm) FIGURE 1. ISL29023 TYPICAL APPLICATION DIAGRAM July 17, 2012 FN6691.1 1 FIGURE 2. NORMALIZED SPECTRAL RESPONSE FOR AMBIENT LIGHT SENSING AND IR SENSING 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. 2009, 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. ISL29023 Block Diagram VDD REXT 1 3 IREF fOSC COMMAND REGISTER I2C/SMB PHOTODIODE ARRAY LIGHT DATA PROCESS 5 6 SCL SDA DATA CMD Register REGISTER INTEGRATING ADC INTERRUPT 2 4 INT GND Pin Configuration Pin Descriptions ISL29023 (6 LD ODFN) TOP VIEW 1 VDD 2 GND 3 REXT PAD PIN NUMBER PIN NAME DESCRIPTION 1 VDD Positive supply; connect this pin to a 2.25V to 3.63V supply SDA 6 2 GND Ground pin SCL 5 3 REXT INT 4 External resistor pin for ADC reference; connect this pin to ground through a (nominal) 499k resistor. 4 INT Interrupt pin; low for interrupt alarming. INT pin is open drain. INT remains asserted until the interrupt flag status bit is reset. 5 SCL I2C serial clock. This line can be pulled from 1.7V to above VDD, 3.63V max. 6 SDA I2C serial data. This line can be pulled from 1.7V to above VDD, 3.63V max. PAD Exposed pad connected to ground or electrically isolated *EXPOSED PAD CAN BE CONNECTED TO GND OR ELECTRICALLY ISOLATED Ordering Information PART NUMBER (Notes 1, 2, 3) TEMP RANGE (C) ISL29023IROZ-T7S2378 ISL29023IROZ-EVALZ -40 to +85 PACKAGE TAPE & REEL (Pb-free) 6 Ld ODFN PKG. DWG. # L6.2x2.1 Evaluation Board (Pb-free) NOTES: 1. Please 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), please see device information page for ISL29023. For more information on MSL please see tech brief TB477. 2 FN6691.1 July 17, 2012 ISL29023 Absolute Maximum Ratings Thermal Information VDD to GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +4.0V I2C Bus (SCL, SDA) and INT Pin Voltage. . . . . . . . . . . . . . . . . . -0.2V to 4.0V I2C Bus (SCL, SDA) and INT Pin Current. . . . . . . . . . . . . . . . . . . . . . . <10mA REXT Pin Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.2V to VDD+0.5V Thermal Resistance (Typical) . . . . . . . . . . . . . . . . . . . . . . . . . . . JA (C/W) 6 Ld ODFN Package (Notes 4, 4) . . . . . . . . . . . . . . . . . . . . . . . . . 90 Maximum Junction Temperature (TJMAX). . . . . . . . . . . . . . . . . . . . . . . +90C Storage Temperature Range. . . . . . . . . . . . . . . . . . . . . . . .-40C to +100C Operating Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .-40C to +85C 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. NOTES: 4. JA 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. Electrical Specifications PARAMETER VDD = 3V, TA = +25C, REXT = 499k 1% tolerance, 16-bit ADC operation, unless otherwise specified. DESCRIPTION CONDITION VDD Power Supply Range IDD Supply Current IDD1 Supply Current when Powered Down MIN (Note 7) MAX (Note 7) UNIT 3.63 V 70 85 A 0.01 0.3 A TYP 2.25 I2C VI2C Supply Voltage Range for fOSC Internal Oscillator Frequency tint ADC Integration/Conversion Time FI2C I2C Clock Rate Range Software disabled or auto power-down Interface 1.7 675 16-bit ADC data 3.63 V 825 kHz 90 ms 1 to 400 kHz DATA_0 Count Output When Dark DATA_F Full Scale ADC Code DDATA DATA Count Output Variation Over Three Light Ambient light sensing Sources: Fluorescent, Incandescent and Sunlight DATA_1 Light Count Output With LSB of 0.015 lux/count E = 300 lux, Fluorescent light (Note 5), ALS Range 1 (1k lux) DATA_2 Light Count Output With LSB of 0.06 lux/count E = 300 lux, Fluorescent light (Note 5), ALS Range 2 (4k lux) 5000 Counts DATA_3 Light Count Output With LSB of 0.24 lux/count E = 300 lux, Fluorescent light (Note 5), ALS Range 3 (16k lux) 1250 Counts DATA_4 Light Count Output With LSB of 0.96 lux/count E = 300 lux, Fluorescent light (Note 5), ALS Range 4 (64k lux) 312 Counts Infrared Count Output E = 210 lux, Sunlight (Note 6), IR sensing, Range 1 DATA_IR1 E = 0 lux, Range 1 (1k lux) 750 1 Counts Counts 10 15000 15000 20000 20000 DATA_IR2 Infrared Count Output E = 210 lux, Sunlight (Note 6), IR sensing, Range 2 5000 DATA_IR3 Infrared Count Output E = 210 lux, Sunlight (Note 6), IR sensing, Range 3 1250 DATA_IR4 Infrared Count Output E = 210 lux, Sunlight (Note 6), IR sensing, Range 4 VREF 5 65535 % 25000 Counts 25000 312 Voltage of REXT Pin 0.52 V VIL SCL and SDA Input Low Voltage VIH SCL and SDA Input High Voltage 0.55 ISDA SDA Current Sinking Capability 4 5 mA IINT INT Current Sinking Capability 4 5 mA 1.25 V V NOTES: 5. 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. 6. 850nm IR 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. 7. Compliance to datasheet limits is assured by one or more methods: production test, characterization and/or design. 3 FN6691.1 July 17, 2012 ISL29023 Typical Performance Curves INCANDESCENT FLUORESCENT 400 500 600 700 800 900 WAVELENGTH (nm) 1000 1100 RADIATION PATTERN 10 10 0 20 20 30 40 50 50 0.8 0.6 0.4 60 60 70 70 80 80 90 90 1.0 0.2 0.4 0.6 0.8 RELATIVE SENSITIVITY 0 FIGURE 4. NORMALIZED SPECTRAL RESPONSE FOR AMBIENT LIGHT SENSING AND IR SENSING 1000 600 HALOGEN 500 32768 400 FLUORESCENT 300 200 1000 LUX x DATA Ecal = 216 100 0 0 100 200 300 400 500 600 700 800 900 1000 LUX METER READING (LUX) 0 FIGURE 6. SENSITIVITY TO THREE LIGHT SOURCES 1.10 NORMALIZED OUTPUT CODE 10 OUTPUT CODE (COUNTS) 65535 ALS SENSING 900 RANGE 1 (1k Lux) INCANDESCENT 800 16-BIT ADC NO COVER GLASS 700 FIGURE 5. RADIATION PATTERN 8 6 4 2 0 -60 IR SENSING 0.2 AMBIENT LIGHT SENSING -0.2 300 400 500 600 700 800 900 1000 1100 WAVELENGTH (nm) FIGURE 3. NORMALIZED SPECTRAL RESPONSE OF LIGHT SOURCES LUMINOSITY 30 ANGLE 40 1.0 ADC OUTPUT (COUNT) 300 HUMAN EYE NORMALIZED RESPONSE SUN HALOGEN CALCULATED ALS READING (LUX) NORMALIZED LIGHT INTENSITY 1.2 -20 20 60 1.05 300 Lux FLUORESCENT LIGHT ALS SENSING RANGE 1 (1k Lux) 1.00 0.95 0.90 -60 100 -20 60 100 FIGURE 8. OUTPUT CODE vs TEMPERATURE FIGURE 7. OUTPUT CODE FOR 0 LUX vs TEMPERATURE 90 SUPPLY CURRENT (A) 20 TEMPERATURE (C) TEMPERATURE (C) 85 ALS SENSING 10,000 Lux 80 75 70 65 60 -40 -20 0 20 40 60 80 TEMPERATURE (C) 100 120 FIGURE 9. SUPPLY CURRENT vs TEMPERATURE IN ALS SENSING 4 FN6691.1 July 17, 2012 ISL29023 Principles of Operation Photodiodes and ADC The ISL29023 contains two photodiode arrays, which convert light into current. The spectral response for ambient light sensing and IR sensing is shown in Figure 4 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-toDigital 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. The built-in ADC offers user flexibility in integration time or conversion time. There are two timing modes: Internal Timing Mode and External Timing Mode. In Internal Timing Mode, integration time is determined by an internal oscillator (fOSC), and the n-bit (n = 4, 8, 12, 16) counter inside the ADC. In External Timing Mode, integration time is determined by the time between two consecutive I2C External Timing Mode commands. 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 (Range 1) in the ambient light sensing. Low-Power Operation The ISL29023 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 ISL29023 receives an I2C command to do a one-time measurement from an I2C master, it will start ADC conversion with light 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 ISL29023 will continuously do ADC conversion with light 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 and IR Sensing There are four operational modes in ISL29023: Programmable ALS once with auto power-down, programmable IR sensing once with auto power-down, programmable continuous ALS sensing and programmable continuous IR sensing. These four modes can be programmed in series to fulfill the application needs. The detailed program configuration is listed in "Command-I Register (Address: 0x00)" on page 8. When the part is programmed for ambient light sensing, the ambient light with wavelength within the "Ambient Light Sensing" spectral response curve in Figure 4 is converted into current. With ADC, the current is converted to an unsigned n-bit (up to 16 bits) digital output. 5 When the part is programmed for infrared (IR) sensing, the IR light with wavelength within the "IR Sensing" spectral response curve in Figure 4 is converted into current. With ADC, the current is converted to an unsigned n-bit (up to 16-bits) digital output. Interrupt Function The active low interrupt pin is an open drain pull-down configuration. The interrupt pin serves as an alarm or monitoring function to determine whether the ambient light level exceeds the upper threshold or goes below the lower threshold. It should be noted that the function of ADC conversion continues without stopping after interrupt is asserted. If the user needs to read the ADC count that triggers the interrupt, the reading should be done before the data registers are refreshed by the following conversions. The user can also configure the persistency of the interrupt pin. 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. Serial Interface The ISL29023 supports the Inter-Integrated Circuit (I2C) bus data transmission protocol. The I2C bus is a two wire serial bidirectional interface consisting of SCL (clock) and SDA (data). Both the wires are connected to the device supply via pull-up resistors. The I2C protocol defines any device that sends data onto the bus as a transmitter and the receiving device as the receiver. The device controlling the transfer is a master and the device being controlled is the slave. The transmitting device pulls down the SDA line to transmit a "0" and releases it to transmit a "1". The master always initiates the data transfer, only when the bus is not busy, and provides the clock for both transmit and receive operations. The ISL29023 operates as a slave device in all applications. The serial communication over the I2C interface is conducted by sending the most significant bit (MSB) of each byte of data first. Start Condition During data transfer, the SDA line must remain stable while the SCL line is HIGH. All I2C interface operations must begin with a START condition, which is a HIGH to LOW transition of SDA while SCL is HIGH (refer to Figure 12). The ISL29023 continuously monitors the SDA and SCL lines for the START condition and does not respond to any command until this condition is met (refer to Figure 12). A START condition is ignored during the power-up sequence. Stop Condition All I2C interface operations must be terminated by a STOP condition, which is a LOW to HIGH transition of SDA while SCL is HIGH (refer to Figure 12). A STOP condition at the end of a read/write operation places the device in its standby mode. If a stop is issued in the middle of a Data byte, or before 1 full Data byte + ACK is sent, then the serial communication of ISL29023 resets itself without performing the read/write. The contents of the array are not affected. FN6691.1 July 17, 2012 ISL29023 Acknowledge Write Operation An acknowledge (ACK) is a software convention used to indicate a successful data transfer. The transmitting device releases the SDA bus after transmitting 8-bits. During the ninth clock cycle, the receiver pulls the SDA line LOW to acknowledge the reception of the eight bits of data (refer to Figure 12). The ISL29023 responds with an ACK after recognition of a START condition followed by a valid Identification Byte, and once again, after successful receipt of an Address Byte. The ISL29023 also responds with an ACK after receiving a Data byte of a write operation. The master must respond with an ACK after receiving a Data byte of a read operation Device Addressing Following a START condition, the master must output a Device Address byte. The 7 MSBs of the Device Address byte are known as the device identifier. The device identifier bits of ISL29023 are internally hard-wired as "1000100". The LSB of the Device Address byte is defined as read or write (R/W) bit. When this R/W bit is a "1", a read operation is selected and when "0", a write operation is selected (refer to Figure 10). The master generates a START condition followed by Device Address byte 1000100x (x as R/W) and the ISL29023 compares it with the internal device identifier. Upon a correct comparison, the device outputs an acknowledge (LOW) on the SDA line (refer to Figure 12). BYTE WRITE In a byte write operation, ISL29023 requires the Device Address byte, Register Address byte, and the Data byte. The master starts the communication with a START condition. Upon receipt of the Device Address byte, Register Address byte, and the Data byte, the ISL29023 responds with an acknowledge (ACK). Following the ISL29023 data acknowledge response, the master terminates the transfer by generating a STOP condition. ISL29023 then begins an internal write cycle of the data to the volatile memory. During the internal write cycle, the device inputs are disabled and the SDA line is in a high impedance state, so the device will not respond to any requests from the master (refer to Figure 11). SIGNAL FROM MASTER DEVICE S T DEVICE ADDRESS A BYTE R T ADDRESS BYTE S T O P DATA BYTE 1 0 0 0 1 0 0 0 SIGNAL AT SDA A C K SIGNALS FROM SLAVE DEVICE A C K A C K FIGURE 11. BYTE WRITE SEQUENCE BURST WRITE 1 0 0 0 1 0 0 R/W DEVICE ADDRESS BYTE A7 A6 A5 A4 A3 A2 A1 A0 REGISTER ADDRESS BYTE D7 D6 D5 D4 D3 D2 D1 D0 DATA BYTE FIGURE 10. DEVICE ADDDRESS, REGISTER ADDRESS, & DATA BYTE The ISL29023 has a burst write operation, which allows the master to write multiple consecutive bytes from a specific address location. It is initiated in the same manner as the byte write operation, but instead of terminating the write cycle after the first Data byte is transferred, the master can write to the whole register array. After the receipt of each byte, the ISL29023 responds with an acknowledge, and the address is internally incremented by one. The address pointer remains at the last address byte written. When the counter reaches the end of the register address list, it "rolls over" and goes back to the first Register Address. 8th CLk SCL FROM MASTER 9th CLk HIGH IMPEDANCE SDA FROM TRANSMITTER SDA FROM RECEIVER START DATA STABLE DATA CHANGE DATA STABLE ACK STOP FIGURE 12. START, DATA STABLE, ACKNOWLEDGE, AND STOP CONDITION 6 FN6691.1 July 17, 2012 ISL29023 SIGNAL FROM MASTER DEVICE S T A DEVICE ADDRESS WRITE R T SIGNAL AT SDA 1 0 0 0 1 0 0 0 ADDRESS BYTE DATA BYTE S T O P 1 0 0 0 1 0 0 1 A C K SIGNALS FROM SLAVE DEVICE S T A DEVICE ADDRESS READ R T A C K A C K FIGURE 13. BYTE ADDRESS READ SEQUENCE Read Operation ISL29023 has two basic read operations: Byte Read and Burst Read. BYTE READ Byte read operations allow the master to access any register location in the ISL29023. The Byte read operation is a two step process. The master issues the START condition and the Device Address byte with the R/W bit set to "0", receives an acknowledge, then issues the Register Address byte. After acknowledging receipt of the register address byte, the master immediately issues another START condition and the Device Address byte with the R/W bit set to "1". This is followed by an acknowledge from the device and then by the 8-bit data word. The master terminates the read operation by not responding with an acknowledge and then issuing a stop condition. Refer to Figure 13. BURST READ The master terminates the read operation by not responding with an acknowledge but issuing a STOP condition (refer to Figure 14). For more information about the I2C standard, please consult the PhillipsTM I2C specification documents. Power On Reset The Power-On Reset (POR) circuitry protects the internal logic against powering up in the incorrect state. The ISL29023 will power up into Standby mode after VDD exceeds the POR trigger level and will power down into Reset mode when VDD drops below the POR trigger level. This bi-directional POR feature protects the device against `brown-out' failure following a temporary loss of power. The POR is an important feature because it prevents the ISL29023 from starting to operate with insufficient voltage, prior to stabilization of the internal bandgap. The ISL29023 prevents communication to its registers and greatly reduces the likelihood of data corruption on power-up. Burst read operation is identical to the Byte Read operation. After the first Data byte is transmitted, the master now responds with an acknowledge, indicating it requires additional data. The device continues to output data for each acknowledge received. SIGNAL FROM MASTER DEVICE S T A DEVICE ADDRESS WRITE R T SIGNAL AT SDA 1 0 0 0 1 0 0 0 ADDRESS BYTE DATA BYTE 2 DATA BYTE 1 S T O P DATA BYTE n 1 0 0 0 1 0 0 1 A C K SIGNALS FROM SLAVE DEVICE S T A DEVICE ADDRESS READ R T A C K A C K A C K A C K ("n" is any integer greater than 1) FIGURE 14. BURST READ SEQUENCE 7 FN6691.1 July 17, 2012 ISL29023 TABLE 1. REGISTER MAP Register Address Register Bits NAME DEC HEX B7 B6 B5 COMMAND-I 0 0x00 OP2 OP1 OP0 COMMAND-II 1 0x01 DATALSB 2 0x02 D7 D6 D5 DATAMSB 3 0x03 D15 D14 INT_LT_LSB 4 0x04 TL7 INT_LT_MSB 5 0x05 INT_HT_LSB 6 INT_HT_MSB 7 B2 B1 B0 HEX FLAG PRST1 PRST0 0x00 RES1 RES0 RANGE1 RANGE0 0x00 D4 D3 D2 D1 D0 0x00 D13 D12 D11 D10 D9 D8 0x00 TL6 TL5 TL4 TL3 TL2 TL1 TL0 0x00 TL15 TL14 TL13 TL12 TL11 TL10 TL9 TL8 0x00 0x06 TH7 TH6 TH5 TH4 TH3 TH2 TH1 TH0 0xFF 0x07 TH15 TH14 TH13 TH12 TH11 TH10 TH9 TH8 0xFF All the functionalities of the device are controlled by the registers. The ADC data can also be read. The following sections explain the details of each register bit. All RESERVED bits must be set to zero, unless otherwise specified. Decimal to Hexadecimal Conversion To convert decimal value to hexadecimal value, divide the decimal number by 16, and write the remainder on the side as the least significant digit. This process is continued by dividing the quotient by 16 and writing the remainder until the quotient is 0. When performing the division, the remainders, which will represent the hexadecimal equivalent of the decimal number, are written beginning at the least significant digit (right) and each new digit is written to the next more significant digit (the left) of the previous digit. Consider the number 175 decimal. TABLE 2. DECIMAL TO HEXADECIMAL DIVISION QUOTIENT REMINDER HEX NUMBER 175/16 10 = A 15 = F 0xAF Command-I Register (Address: 0x00) TABLE 3. COMMAND-I REGISTER ADDRESS COMMANDI 0x00 Register Bits B6 B5 B4 B3 OP2 OP1 OP0 0 B2 B1 B0 DFLT (Hex) 0 FLAG PRST1 PRST0 0x00 The Command-I register consists of control and status bits. In this register, there are two interrupt persist bits, one interrupt status bit, and three operation mode bits. The operation mode bits and the interrupt persist bits are independent of each other. The default register value is 0x00 at power on. 8 RESERVED INTERRUPT PERSIST BITS (B0 - B1) Following are detailed descriptions of the control registers related to the operation of the ISL29023 ambient light sensor device. These register are accessed by the I2C serial interface. For details on the I2C interface, refer to "Serial Interface" on page 5. NAME B3 RESERVED Register Description Reg. Addr (Hex) B7 B4 DEFAULT The interrupt persist bits provides control over when interrupts occur. There are four different selections for this feature. A value of N (where N is 1, 4, 8, and 16) results in an interrupt only if the value remains outside the threshold window for N consecutive integration cycles. For example, if N is equal to 16 and the ADC resolution is set to 16-bits then the integration time is 100ms. An interrupt is generated whenever the last conversion results in a value outside of the programmed threshold window. The interrupt is active-low and remains asserted until cleared by writing the COMMAND register with the CLEAR bit set. Table 4 lists the possible interrupt presist bits. TABLE 4. INTERRUPT PERSIST BITS B1 B0 NUMBER OF INTEGRATION CYCLES (n) 0 0 1 0 1 4 1 0 8 1 1 16 INTERRUPT FLAG BIT (B2) The interrupt flag bit is a status bit for light intensity detection. The bit is set to logic HIGH when the light intensity crosses the interrupt thresholds window (register address 0x04 - 0x07), and set to logic LOW when its within the interrupt thresholds window. Once the interrupt is triggered, the INT pin goes low and the interrupt status bit goes HIGH until the status bit is polled through the I2C read command. Both the INT pin and the interrupt status bit are automatically cleared at the end of the 8-bit Device Register byte (0x00) transfer. Table 5 shows interrupt flag states. TABLE 5. INTERRUPT FLAG BIT BIT 2 OPERATION 0 Interrupt is cleared or not triggered yet 1 Interrupt is triggered FN6691.1 July 17, 2012 ISL29023 OPERATION MODE BITS (B5 - B7) . ISL29023 has different operating modes. These modes are selected by setting B5 -B7 bits on register address 0x00. The device powers up on a disable mode. Table 6 lists the possible operating modes. TABLE 6. OPERATING MODES BITS B6 B5 0 0 0 Power-down the device (Default) 0 0 1 The IC measures ALS only once every integration cycle. This is the lowest operating mode. 1 OPERATION 0 B3 B2 NUMBER OF CLOCK CYCLES n-BIT ADC 0 0 216 0 1 212 = 4,096 1 0 28 = 256 8 1 24 4 1 B7 0 TABLE 9. ADC RESOLUTION DATA WIDTH = 65,536 16 12 = 16 Data Registers (Addresses: 0x02 & 0x03) TABLE 10. ADC REGISTER BITS IR once NAME Register Bits Reg. Addr (Hex) B7 B6 B5 B4 B3 B2 B1 B0 DFLT (Hex) D7 D6 D5 D4 D3 0 1 1 Reserved (DO NOT USE) 1 0 0 Reserved (DO NOT USE) DATALSB 0x02 D2 D1 D0 0x00 1 0 1 The IC measures ALS continuously DATAMSB 0x03 D15 D14 D13 D12 D11 D10 D9 D8 0x00 1 1 0 The IC measures IR continuous 1 1 1 Reserved (DO NOT USE) Command-II Register (Address: 0x01) TABLE 7. COMMAND-II REGISTER BITS Register Bits Reg. Addr (Hex) B7 B6 B5 B4 NAME COMMANDII 0x01 0 0 0 B3 B2 B1 B0 DFLT (Hex) The ISL29023 has two 8-bit read-only registers to hold the upper and lower byte of the ADC value. The upper byte is accessed at address 0x03 and the lower byte is accessed at address 0x02. 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 and 4-bit resolution, the data is from D0 to D3. The registers are refreshed after every conversion cycle. The default register value is 0x00 at power on. TABLE 11. ADC DATA REGISTERS 0 RES1 RES0 RANGE1 RANGE0 0x00 The Command-II register consists of ADC control bits. In this register, there are two range bits, and two ADAC resolution bits. The default register value is 0x00 at power on. FULL SCALE RANGE (B0 - B1) The Full Scale Range (FSR) has four different selectable ranges. The range determines the ADC resolution (4-bits, 8-bits, 12-bits, and 16-bits). Each range has a maximum allowable lux value. Higher range values offer better resolution and wider ALS lux value. Table 8 lists the possible values of FSR for the 499k REXT resistor. TABLE 8. RANGE REGISTER BITS B0 B1 k RANGE(k) FSR (LUX) @ ALS SENSING 0 0 1 Range1 1,000 0 1 2 Range2 4,000 1 0 3 Range3 16,000 1 1 4 Range4 64,000 FSR @ IR SENSING B2 and B3 determine the ADC's resolution and the number of clock cycles per conversion. 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 9 lists the possible ADC resolution. CONTENTS 0x02 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 0x03 D15 is MSB for 16-bit resolution; D11 is MSB for 12-bit resolution Lower Interrupt Threshold Registers (Address: 0x04 & 0x05) TABLE 12. INTERRUPT REGISTER BITS Reg. Addr (Hex) Register Bits DFLT B1 B0 (Hex) B7 B6 B5 B4 B3 B2 INT_LT_LSB 0x04 TL7 TL6 TL5 TL4 TL3 TL2 TL1 TL0 0x00 NAME ADC RESOLUTION (B3 - B2) 9 ADDRESS (hex) INT_LT_MSB 0x05 TL15 TL14 TL13 TL12 TL11 TL10 TL9 TL8 0x00 The lower interrupt threshold registers are used to set the lower trigger point for interrupt generation. If the ALS value crosses below or is equal to the lower threshold, an interrupt is asserted on the interrupt pin and the interrupt flag. Registers INT_LT_LSB (0x04) and INT_LT_MSB (0x05) provide the low and high bytes, respectively, of the lower interrupt threshold. The high and low bytes from each set of registers are combined to form a 16-bit threshold value. The interrupt threshold registers default to 0x00 upon power up. FN6691.1 July 17, 2012 ISL29023 Upper Interrupt Threshold Registers (Address: 0x06 & 0x07) TABLE 14. INTEGRATION TIME OF n-BIT ADC TABLE 13. INTERRUPT REGISTER BITS Reg. Addr (Hex) n = 16-BIT n = 12-BIT n = 8-BIT n = 4-BIT 499** 90ms 5.6ms 352s 22s **Recommended REXT resistor value Register Bits B1 DFLT B0 (Hex) B7 B6 B5 B4 B3 B2 INT_HT_LSB 0x06 TH7 TH6 TH5 TH4 TH3 TH2 TH1 TH0 0xFF NAME REXT (k) INT_HT_MSB 0x07 TH15 TH14 TH13 TH12 TH11 TH10 TH9 TH8 0xFF The upper interrupt threshold registers are used to set the upper trigger point for interrupt generation. If the ALS value crosses above or is equal to the upper threshold, an interrupt is asserted on the interrupt pin and the interrupt flag. Registers INT_HT_LSB (0x06) and INT_HT_MSB (0x07) provide the low and high bytes, respectively, of the upper interrupt threshold. The high and low bytes from each set of registers are combined to form a 16-bit threshold value. The interrupt threshold registers default to 0xFF on power up. External Scaling Resistor REXT for fOSC and Range The ISL29023 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 499k: 499k Range = ------------------ x Range ( k ) R EXT (EQ. 5) 499k f OSC = ------------------ x 725 kHz R EXT (EQ. 6) ADC Output in IR Sensing Applications Information The ISL29023's ADC output codes, DATA, are directly proportional to the IR intensity received in the IR sensing. Calculating Lux DATA IR = x E IR The ISL29023's ADC output codes, DATA, are directly proportional to lux in the ambient light sensing. (EQ. 1) E cal = x DATA Here, Ecal is the calculated lux reading. The constant is determined by the Full Scale Range and the ADC's maximum output counts. The constant is independent of the light sources (fluorescent, incandescent and sunlight) because 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). Range ( k ) = ---------------------------Count max (EQ. 2) Here, Range(k) is defined in Table 8. Countmax is the maximum output counts from the ADC. The transfer function used for n-bits ADC becomes: Range ( k ) E cal = --------------------------- x 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). Integration and Conversion Time The ADC resolution and fOSC determine the integration time, tint. R EXT n 1 t int = 2 x -------------- = 2 x ---------------------------------------------725kHz x 499k f OSC n (EQ. 7) Here, EIR is the received IR intensity. The constant changes with the spectrum of background IR noise, such as sunlight and incandescent light. The also changes with the ADC's range and resolution selections. Noise Rejection Electrical AC power worldwide is distributed at either 50Hz or 60Hz. Artificial light sources vary in intensity at the AC power frequencies. The undesired interference frequencies are infused on the electrical signals. This variation is one of the main sources of noise for the light sensors. Integrating type ADC's have excellent noise-rejection characteristics for periodic noise sources whose frequency is an integer multiple of the conversion rate. By setting the sensor's integration time to an integer multiple of periodic noise signal, the performance of an ambient light sensor can be improved greatly in the presence of noise. In order to reject the AC noise, the integration time of the sensor must to adjusted to match the AC noise cycle. 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. Suggested PCB Footprint It is important that users check the "Surface Mount Assembly Guidelines for Optical Dual Flat Pack No Lead (ODFN) Package" before starting ODFN product board mounting. http://www.intersil.com/data/tb/TB477.pdf (EQ. 4) where n is the number of bits of resolution and n = 4, 8, 12 or 16. Therefore, 2n is the number of clock cycles. n can be programmed at the command register 01(hex) bits 3 and 2. 10 FN6691.1 July 17, 2012 ISL29023 Board Mounting Considerations Temperature Coefficient For applications requiring the light measurement, the board mounting location should be reviewed. The device uses an Optical Dual Flat Pack No Lead (ODFN) package, which subjects the die to mild stresses when the printed circuit (PC) board is heated and cooled, which slightly changes the shape. Because of these die stresses, placing the device in areas subject to slight twisting can cause degradation of reference voltage accuracy. It is normally best to place the device near the edge of a board, or on the shortest side, because the axis of bending is most limited in that location. The limits stated for temperature coefficient (Tempco) are governed by the method of measurement. The overwhelming standard for specifying the temperature drift of a reference is to measure the reference voltage at two temperatures, take the total variation, (VHIGH - VLOW), and divide by the temperature extremes of measurement (THIGH - TLOW). The result is divided by the nominal reference voltage (at T = +25C) and multiplied by 106 to yield ppm/C. This is the "Box" method for specifying temperature coefficient. Layout Considerations The ISL29023 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, 1F and 0.1F, placed close to the device. REXT must be placed as closely to the pin as possible to eliminate the stray capacitance, which will greatly affect the performance of the sensor. Soldering Considerations Digital Inputs and Termination The ISL29023 digital inputs are guaranteed to CMOS levels. The internal register is updated on the rising edge of the clock. To minimize reflections, proper termination should be implemented. If the lines driving the clock and the digital inputs are 50 lines, then 50 termination resistors should be placed as close to the sensor inputs as possible, connected to the digital ground plane (if separate grounds are used). Typical Circuit A typical application for the ISL29023 is shown in Figure 1. The ISL29023's I2C address is internally hard-wired as 1000100. The device can be tied onto a system's I2C bus together with other I2C compliant devices. Convection heating is recommended for reflow soldering; directinfrared heating is not recommended. The plastic ODFN package does not require a custom reflow soldering profile, and is qualified to +260C. A standard reflow soldering profile with a +260C maximum is recommended. 1.7V TO 3.63V R1 R2 I2C MASTER R3 MICROCONTROLLER SDA SCL INT 2.25V TO 3.63V I2C SLAVE_0 1 2 C1 10F C2 0.1F 3 REXT 499k VDD SDA GND SCL REXT INT I2C SLAVE_1 I2C SLAVE_n 6 SDA SDA 5 SCL SCL 4 ISL29023 FIGURE 15. ISL29023 TYPICAL SYSTEM DIAGRAM 11 FN6691.1 July 17, 2012 SENSOR OFFSET ISL29023 1 6 2 5 0.40 0.54 4 3 0.37 FIGURE 16. 6-LD ODFN SENSOR LOCATION OUTLINE 12 FN6691.1 July 17, 2012 ISL29023 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 REVISION CHANGE May 14, 2012 FN6691.1 I2C section & Register description explained in more detail. March 3, 2009 FN6691.0 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 device information page on intersil.com: ISL29023 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/search.php For additional products, see www.intersil.com/product_tree Intersil products are manufactured, assembled and tested utilizing ISO9000 quality systems as noted in the quality certifications found 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 13 FN6691.1 July 17, 2012 ISL29023 Package Outline Drawing L6.2x2.1 6 LEAD OPTICAL DUAL FLAT NO-LEAD PLASTIC PACKAGE (ODFN) Rev 3, 5/11 2.10 A 6 PIN #1 INDEX AREA B 6 PIN 1 INDEX AREA 1 0.65 1.35 2.00 1.30 REF 4 6X 0.300.05 (4X) 0.10 0.10 M C A B 0.65 TOP VIEW 6x0.35 0.05 BOTTOM VIEW 2.50 PACKAGE OUTLINE 2.10 SEE DETAIL "X" 0.65 (4x0.65) 0.10 C MAX 0.75 C BASE PLANE SEATING PLANE 0.08 C SIDE VIEW (1.35) (6x0.30) C (6x0.20) 0 . 2 REF 5 0 . 00 MIN. 0 . 05 MAX. (6x0.55) TYPICAL RECOMMENDED LAND PATTERN DETAIL "X" 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 0.15mm and 0.30mm 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 identifier may be either a mold or mark feature. 14 FN6691.1 July 17, 2012