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1 ? fn6619.1 caution: these devices are sensitive to electrosta tic 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, 2010. all rights reserved. all other trademarks mentioned are the property of their respective owners. isl29018 digital ambient li ght sensor and proximity sensor with interrupt function the isl29018 is an integrated ambient and infrared light to digital converter with a built-in ir led driver and i 2 c interface (smbus compatible). this device provides not only ambient light sensing to allow robust backlight/display brightness control but also infrared sensin g 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 11s 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 lu x-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 pr oximity sensor employs a noise cancellation scheme to highly reject unwanted ir noise, the digital output of proximity se nsing decreases with distance. the driver output current is us er selectable up to 100ma to drive different types of ir emitters leds. six different modes of operat ion can be selected via the i 2 c 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 over all supply current less than 0.5a. the isl29018 supports both hardware and software interrupts that remain asserted until the host clears it through i 2 c interface for ambient light sensing and proximity detection. designed to operate on supplies from 2.25v to 3.63v, the isl29018 is specified for opera tion over the -40c to +85c ambient temperature range. it is packaged in a clear, pb-free 8 ld odfn package. 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 i 2 c) - 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 ?90 a max operating current ? software shutdown and automatic shutdown -0.5 a max shutdown current easy to use ?i 2 c (smbus compatible) output ? no complex algorithms needed ? temperature compensated ? small form factor - 8 ld 3.0mmx3.0mmx0.7mm odfn package additional features ?i 2 c and smbus compatible ? 1.7v to 3.63v supply for i 2 c 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 data sheet february 11, 2010
2 fn6619.1 february 11, 2010 pinout isl29018 (8 ld odfn top view) ordering information part number (note) temp. range (c) package (pb-free) pkg. dwg. # ISL29018IROZ-T7* -40 to +85 8 ld odfn l8.3x3f isl29018iroz-evalz evaluation board *please refer to tb347 for detai ls on reel specifications. note: these intersil pb-free plastic packaged pr oducts employ special pb-free material sets; molding compounds/die attach materi als 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. 1 2 3 8 7 6 vddd vdda gnd irdr int sda 4 5 rext scl exposed pad can be connected to gnd or electrically isolated pin descriptions pin number pin name description 1 vddd positive digital supply: 2.25v to 3.63v. 2 vdda positive analog supply: 2.25v 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. 499k with 1% tolerance resistor is recommended. 5scli 2 c serial clock line the i 2 c bus lines can be pulled from 1.7v to above v dd , 3.63v max. 6sdai 2 c serial data line 7int interrupt pin; lo for interrupt/alarming. the int pin is an open drain. 8 irdr 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 i 2 c. exposed pad connected to ground or electrical ly isolated. isl29018
3 fn6619.1 february 11, 2010 block diagram vdda rext gnd sda scl ir photodiode light data 4 3 6 2 fosc iref 5 irdr isl29018 array photodiode process als and ir array integration adc 8 vddd 1 int 7 command register data register i 2 c ir driver interrupt isl29018
4 fn6619.1 february 11, 2010 absolute maxi mum ratings (t a = +25c) thermal information v sup (vddd,vdda) supply voltage between v dd and gnd . . . . . .4v v dda supply voltage between v dda and gnd . . . . . v ddd 0.5v i 2 c bus (scl, sda) and int pin voltage . . . . . . . . . . . . -0.2v to 4v i 2 c bus (scl, sda) and int pin current . . . . . . . . . . . . . . . <10ma irdr pin voltage . . . . . . . . . . . . . . . . . . . . . . . . -0.2v to v dd + 0.5v r ext pin voltage . . . . . . . . . . . . . . . . . . . . . . . . -0.2v to v dd + 0.5v esd rating human body model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2kv thermal resistance (typical, note 1) ja (c/w) 8 ld odfn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 maximum die temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . +90c storage temperature . . . . . . . . . . . . . . . . . . . . . . . .-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 fo r extended periods of time. exposure to such conditions may adv ersely impact product reliability and result in failures not covered by warranty. note: 1. ja is measured in free air with the component mounted on a high ef fective thermal conductivity te st board with ?direct attach? fe atures. see tech brief tb379. important note: all parameters having min/max specifications are guaranteed. typical values are for information purposes only. u nless otherwise noted, all tests are at the specified temperature and are pulsed tests, therefore: t j = t c = t a electrical specifications v sup(v ddd ,v dda ) = 3v, t a = +25c, r ext = 499k 1% tolerance, 16-bit adc operation, unless otherwise specified. parameter description condition min typ max unit v sup power supply range for v ddd , v dda (note 2) 2.25 3.63 v sr_v dd input power-up slew rate vdd rising edge between 0.4v and 2.25v 0.5 v/ms i sup(off) supply current when powered down software disabled or auto power-down 0.1 0.5 a i sup(on) supply current of ambient light and ir sensing 70 90 a v i 2 c supply voltage range for i 2 c interface 1.7 3.63 v f osc internal oscillator frequency 675 750 825 khz t int adc integration/conversion time 16-bit adc data 90 ms f i 2 c i 2 c clock rate range 1 to 400 khz data_0 count output when dark e = 0 lux 1 5 counts data_fs full scale adc code 65535 counts data data count output variation over three light sources: fluorescent, incandescent and sunlight ambient light sensing 10 % 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) 15000 20000 25000 counts data_2 light count output with lsb of 0.06 lux/count e = 300 lux, fluorescent light (note 3), ambient light sensing, range 2 (4k lux) 5000 counts data_3 light count output with lsb of 0.024 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 15000 20000 25000 counts data_ir2 infrared count output e = 210 lux, sunlight (note 4), ir sensing, range 2 5000 counts data_ir3 infrared count output e = 210 lux, sunlight (note 4), ir sensing, range 3 1250 counts data_ir4 infrared count output e = 210 lux, sunlight (note 4), ir sensing, range 4 312 counts v ref voltage of r ext pin 0.52 v v il scl and sda input low voltage 0.55 v v ih scl and sda input high voltage 1.25 v isl29018
5 fn6619.1 february 11, 2010 principles of operation photodiodes and adc the isl29018 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 i 2 c 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 (f osc ), 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 i 2 c 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. for very bright conditions, the adc can be configured at its highest range (range 4) in the proximity sensing. low-power operation the isl29018 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 isl29018 receives an i 2 c command to do a one-time measurement from an i 2 c 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 isl29018 will continuously do adc conversi on with light or proximity sensing if it receives an i 2 c command of continuous measurement. it will continuous ly update the data registers with the latest conversion data. it will go to the power-down mode after it receives the i 2 c command of power-down. ambient light, ir and proximity sensing there are six operational mode s in isl29018: programmable als once with auto power-down, programmable ir sensing once with auto power-down, prog rammable proximity sensing once with auto power-down; pr ogrammable continuous als sensing, programmable c ontinuous ir sensing and programmable continuous prox imity sensing. these six modes can be programmed in seri es to fulfill the application i sda, i int sda and int current sinking capability 4 5 ma i irdr1 irdr source current is<1:0> = 0 (note 5) 15 at irdr pin 100 ma i irdr2 irdr source current is<1:0> = 1 (note 5) 44 50 58 ma i irdr3 irdr source current is<1:0> = 2 (note 5) 25 ma i irdr4 irdr source current is<1:0> = 3 (note 5) 12.5 ma v irled voltage head room of irdr pin v dd - 0.6 v tr rise time for irdr source current r load = 15 at irdr pin, 20% to 80% 35 ns tf fall time for irdr source current r load = 15 at irdr pin, 80% to 20% 10 ns f irled1 ir led modulation frequency freq = 0 (note 5) dc khz f irled2 ir led modulation frequency freq = 1 (note 5) 360 khz i sup (irled1) supply current of proximity sensing is<1:0> = 0, freq = 0 (note 5) 101 ma i sup (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 sensing with object far away to provide no reflection ir and proximity sensing with range 2 and scheme 0; 15 @ irdr pin, is<1:0> = 0, freq = 0; e = 210 lux, sunlight. 1.0 % notes: 2. v sup is the common voltage to v ddd and v dda. 3. 550nm green led is used in production test. the 550nm led irr adiance 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 again st an illuminance level of 210 lux sunlight at sea level. 5. see ?register set? on page 7. electrical specifications v sup(v ddd ,v dda ) = 3v, t a = +25c, r ext = 499k 1% tolerance, 16-bit adc operation, unless otherwise specified. (continued) parameter description condition min typ max unit isl29018
6 fn6619.1 february 11, 2010 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 cu rve in 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 fo r infrared (ir) sensing, the ir light with wavelength within th e ?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 ampl itude 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. th e output reading is inversely proportional to the square of the distance between the sensor and the object. interrupt function the active low interrupt pin is an open drain pull-down configuration. there is also an interrupt bit in the i 2 c 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 of the interrupt. this reduces th e 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. i 2 c interface there are eight 8-bit registers available inside the isl29018. 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 digita l output, or t he number of clock cycles in the previous integration period. t he four 8-bit interrupt registers hold 16-bit interrupt high and low thresholds. the isl29018?s i 2 c interface slave address is internally hard-wired as 1000100. when 1000100x with x as r or w is sent after the start condition, th is 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 i 2 c 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 i 2 c 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 i 2 c transaction ends with the master asserting a stop condition (sda rising while scl remains high). for more information about the i 2 c standard, please consult the philips ? i 2 c specification documents. figure 1. i 2 c read timing diagram sample start w a a a6 a5 a4 a3 a2 a1 a0 w a r7 r6 r5 r4 r3 r2 r1 r0 a a6 a5 a4 a3 a2 a1 a0 w a a a ad7d6d5d4d3d2d1d0 1357 1357 123 45 6 9 2 4 6 stop start sda driven by master device address sda driven by isl29018 data byte0 register address out device address i 2 c data sda driven by master sda driven by master 2468 924689 78 1 3 5 789 i 2 c sda i 2 c sda i 2 c clk in isl29018
7 fn6619.1 february 11, 2010 register set there are eight registers that are available in the isl29018. table 1 summarizes their functions. 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. 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 high. both interrupt pin and the status bit are automatically cleared at the end of command register i transfer. 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. figure 2. i 2 c write timing diagram sample start w a a a6 a5 a4 a3 a2 a1 a0 w a r7 r6 r5 r4 r3 r2 r1 r0 a b7 b6 b5 b4 b3 b2 b1 b0 a a 12615948 stop sda driven by master functions register address device address sda driven by master sda driven by master i 2 c data i 2 c sda in i 2 c sda out i 2 c clk in aa 345 7 89 234 678 12 3 5 67 9 a table 1. register set addr reg name bit 7 6 5 4 3 2 1 0 default 00h command i op2 op1 op0 0 0 flag prst1 prst0 00h 01h command ii scheme freq is1 is0 res1 res0 range1 range0 00h 02h data lsb d7 d6 d5 d4 d3 d2 d1 d0 00h 03h data msb 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 08h test 0 0 0 0 0 0 0 0 00h table 2. operation mode bits 7 to 5 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 proximity continuous table 3. interrupt flag bit 2 operation 0 interrupt is cleared or not triggered yet 1 interrupt is triggered table 4. interrupt persist bits 1 to 0 number of integration cycles 00 1 01 4 10 8 11 16 isl29018
8 fn6619.1 february 11, 2010 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 detect ion. logic 0 of this bit, scheme 0, makes full n (4, 8, 12, 16) bits (unsigned) proximity detection. the ra nge of scheme 0 proximity count is from 0 to 2 n . logic 1 of this bit, scheme 1, makes n-1 (3, 7, 11, 15) bits (2?s complementary) proximity_less_ambient detec tion. 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. 2. modulation frequency: bits 6. this bit sets the ir led driver?s modulation frequency. 3. amplitude of ir driver curr ent: bits 5 and 4. this device provides current source to dr ive an external ir led. the drive capability can be programmed through bits 5 and 4. for example, the device sour ces 12.5ma out of the irdr pin if bits 5 and 4 are 0. 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-t o-digital (a/d) converter samples the photodiode current signal for a measurement. . 5. range: bits 1 and 0. the full scale range (fsr) can be adjusted via i 2 c using bits 1 and 0. table 9 lists the possible values of fsr for the 499k r ext resistor. 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. 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, t he interrupt threshold lo is 00 hex for both lsb and msb. 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, t he interrupt threshold hi is ff hex for both lsb and msb. test register (08 hex) the part functions in normal operation mode when register 8 is set to 0x00. calculating lux the isl29018?s adc output codes, data, are directly proportional to lux in the ambient light sensing as shown in equation 1. here, e cal 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 on the light sources (fluorescent, incandescent and sunlight) because of the light sources? ir component is removed during the light signal proces s. the constant can also be table 5. proximity sensing scheme bit 7 operation 0 sensing ir from led and ambient 1 sensing ir from led with ambient ir rejection table 6. modulation frequency bits 6 modulation frequency (khz) 0dc 1 360 table 7. current source capability at irdr pin bits 5 to 4 irdr pin source current 00 12.5ma ir led driver 01 25ma ir led driver 10 50ma ir led driver 11 100ma ir led driver table 8. resolution/width bits 3 to 2 number of clock cycles n-bit adc 00 2 16 = 65,536 16 01 2 12 = 4,096 12 10 2 8 = 256 8 11 2 4 = 16 4 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 table 10. data registers address (hex) 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 e cal data = (eq. 1) isl29018
9 fn6619.1 february 11, 2010 viewed as the sensitivity: th e smallest lux measurement the device can measure as shown in equation 2. here, range(k) is defined in table 9. count max is the maximum output counts from the adc. the transfer function us ed for n-bit adc becomes equation 3: here, n = 4, 8, 12 or 16. this is the number of adc bits programmed in the command register. 2 n 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 f osc determines the integration time, t int as shown in equation 4. where n is the number of bits of resolution and n = 4, 8, 12 or 16. 2 n , therefore, is the number of clock cycles. n can be programmed at the command register 01(hex) bits 3 and 2. external scaling resistor r ext for f osc and range the isl29018 uses an external resistor r ext to fix its internal oscillator frequency, f osc and the light sensing range, range. f osc and range are inversely proportional to r ext . for user simplicity, the proportionality constant is referenced to 499k as shown in equations 5 and 6: noise rejection in general, integrating type adc?s have excellent noise-rejection characteristi cs 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...k i ) 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 isl29018?s adc output codes, data, are directly proportional to the ir intensit y received in the ir sensing. here, e ir is the received ir intensity. the constant changes with the spectrum of background ir noise like sunlight and incandescent light. the also changes with the adc?s range and resolution selections. adc output in proximity sensing in the proximity sensing, th e 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 isl29018. here, and e ir have the same meanings as in equation 7. the constant depends on the spectrum of the used ir led and the adc?s range and resolution selections. e led is the ir intensity which is emitted from the ir led and reflected by a specific objector to the isl29018. e led depends on the current to the ir led and the surface of the object. e led decreases with the square of the distance between the object and the sensor. if background ir noise is small, e ir can be neglected, and the adc output directly decreases with the distance. if there is significant background ir noise, isl29018 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 isl29018 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 det ects three different sensing objects: 92% brightness paper, 18% gray card and esd black foam. figure 10 shows isl29018 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. isl29018 proximity sensing re lies on the amount of ir reflected back from the objects to be detected. clearly, it can table 11. integration time of n-bit adc r ext (k ) n = 16-bit (ms) n = 12-bit (ms) n = 8-bit (s) n = 4-bit (s) 250 45 2.812 175.5 10.8 499** 90 5.63 351 21.6 **recommended r ext resistor value () count max ---------------------------- = (eq. 2) (eq. 3) e cal range k () 2 n --------------------------- data = t int 2 n 1 f osc ------------- - 2 n r ext 725khz 499k ---------------------------------------------- == (eq. 4) (eq. 5) range 499k r ext ------------------ range k () = (eq. 6) f osc 499k r ext ------------------ 725 khz = data ir e ir = (eq. 7) data prox e ir e led + = (eq. 8) isl29018
10 fn6619.1 february 11, 2010 not detect an optically black object that reflects no light. however, isl29018 is sensitive enough to detect a black esd foam, which reflects slightly less than 1% of ir, as shown in figure 9. for biological objects, blonde hair reflects more than brunette hair, as expected and shown in 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 pr oximity count peaks at contact and monotonically decreases as skin moves away. this characteristic is very different from that of a plain paper reflector. 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 thres holds are loaded to interrupt registers 04, 05, 06 and 07 hex fo r proper interrupt detection. also, the interrupt persist counter will be reset to 0 when the mode of operation is changed. v dd power-up and power supply considerations upon power-up, please ensure a vdd slew rate of 0.5v/ms or greater. after power-up, or if the user?s power supply temporarily deviates from our sp ecification (2.25v to 3.63v), intersil recommends the user write 0x00 to two registers: 0x08, 0x00 (in that order), wait ~1ms or more and then rewrite all registers to the desired values. led modulation for proximity detection isl29018 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, t he proximity detection is twice as sensitive but consumes 2 times more current. the sensitivity of led 50ma, dc 50m a is identical to that of 100ma, 360khz modulation. please note that the isl29018 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 am bient 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 ope ration cycle that includes als, ir sensing and proximity sensing th ree different serial phases, the detection occurs once ev ery 30ms, the average current consumption including external ir led drive current can be calculated from equation 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: 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 layout considerations the isl29018 is relatively insensitive to layout. like other i 2 c 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 i 2 c traces as far as possible from all sources of noise. use two power-supply decoupling capacitor 0.1f, placed close to the device. typical circuit a typical application for the isl29018 is shown in figure 4. the isl29018?s i 2 c address is internally hardwired as 1000100. the device can be tied onto a system?s i 2 c bus together with other i 2 c 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 +260c. a standard reflow soldering profile with a +260c maximum is recommended. 0.05ma 0.05ma 1ma (50ma ? 50%)) ? 0.4ms +++ () [] /30ms = 0.35ma (eq. 9) 0.05ma 0.05ma 1ma (50ma ? 50%)) ? 7 ms +++ () [] /100ms = 1.83ma (eq. 10) isl29018
11 fn6619.1 february 11, 2010 figure 3. current consumption for each integration phase and detection cycle als ir proximity ir led 0.4ms 0.4ms 0.4ms 50a 50a 50ma 1ma 360 khz 1a 30ms vddd 1 gnd 3 rext 4 sda int 7 irdr 8 isl29018 r1 10k r2 10k rext 499k 2.25v to 3.63v microcontroller int sda slave_0 slave_1 i 2 c slave_n i 2 c master scl sda scl sda 1.7v to 3.63v 6 r3 10k scl 2 vdda 5 c1 0.1f figure 4. isl29018 typical circuit scl isl29018
12 fn6619.1 february 11, 2010 typical performance curves v sup (v ddd , v dda ) = 3v, r ext = 499k figure 5. spectrum of four light sources figure 6. spectral response for ambient light sensing and proximity sensing figure 7. radiation pattern figure 8. sensitivity to three light sources figure 9. adc output vs distance with different objects in proximity sensing figure 10. adc output vs distance with different led current amplitudes in proximity sensing 0 0.2 0.4 0.6 0.8 1.0 1.2 300 400 500 600 700 800 900 1000 1100 wavelength (nm) normalized light intensity sun incandescent halogen fluorescent -0.2 0 0.2 0.4 0.6 0.8 1.0 1.2 300 400 500 600 700 800 900 1000 1100 wavelength (nm) normalized response human eye response ambient light sensing ir and proximity sensing radiation pattern luminosity angle relative sensitivity 90 80 70 60 50 40 30 20 10 0 10 20 30 40 50 60 70 80 90 0.2 0.4 0.6 0.8 1.0 0 100 200 300 400 500 600 700 800 900 1000 0 100 200 300 400 500 600 700 800 900 1000 lux meter reading (lux) calculated als reading (lux) incandescent halogen fluorescent v dd = 3v range = 1000 lux 16-bit adc adc output (count) 0 32768 65535 1000 lux e cal = 2 16 x data 1 10 100 1000 10000 0 20406080100 distance (mm) data prox -data ir 92% brightness paper 18% gray card esd black foam 0 500 1000 1500 2000 2500 3000 3500 4000 4500 0 102030405060708090 distance (mm) data prox -data ir (count) i irled = 100ma i irled = 50ma i irled = 25ma i irled = 12.5ma isl29018
13 fn6619.1 february 11, 2010 figure 11. proximity de tections of various biological objects figure 12. output code for 0 lux vs temperature figure 13. output code vs temperature figure 14. output current vs temperature in proximity sensing figure 15. supply current vs temperature in als sensing typical performance curves v sup (v ddd , v dda ) = 3v, r ext = 499k (continued) 0 50 100 150 200 250 300 350 0 10 2030405060 distance (mm) data prox - data ir (count) 12-bit adc range 3 fled = 328khz iled = 12.5ma 4mm center-to-center for isl29018 and sfh4650, isolated by barrier and behind a 65% 18% gray blond hair brunette hair pig's skin ir transmitting glass 130 cts = 500 cts x 65% x 65% = 211 cts output code (counts) temperature (c) 0 2 4 6 8 10 -60 -20 20 60 100 als sensing 0 lux output code ratio (from +30c) temperature (c) 0.90 0.95 1.00 1.05 1.10 -60 -20 20 60 100 300 lux fluorescent light als sensing 100.0 100.5 101.0 101.5 102.0 102.5 103.0 103.5 104.0 104.5 105.0 -40 -20 0 20 40 60 80 100 120 temperature (c) irdr output current (ma) proximity sensing is<1:0> = 0 60 65 70 75 80 85 90 -40 -20 0 20 40 60 80 100 120 temperature (c) supply current (a) als sensing 10,000 lux isl29018
14 all intersil u.s. products are manufactured, asse mbled and tested utilizing iso9000 quality systems. intersil corporation?s quality certifications ca n be viewed at www.intersil.com/design/quality intersil products are sold by description only. intersil corpor ation reserves the right to make changes in circuit design, soft ware and/or specifications at any time without notice. accordingly, the reader is cautioned to verify that data sheets are current before placing orders. information furnishe d 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 paten ts 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 subsidiari es. for information regarding intersil corporation and its products, see www.intersil.com fn6619.1 february 11, 2010 sensor offset 8 1 6 5 4 3 2 7 0.54 0.37 3.00 0.40 3.00 figure 16. 8 ld odfn sensor location outline isl29018
15 fn6619.1 february 11, 2010 isl29018 package outline drawing l8.3x3f 8 lead optical dual flat no-lead plastic package rev 0, 01/07 located within the zone indicated. the pin #1 indentifier may be unless otherwise specified, tolerance : decimal ???? tiebar shown (if present) is a non-functional feature. the configuration of the pin #1 identifier is optional, but must be between 0.25mm and 0.35mm from the terminal tip. dimension b applies to the metallized terminal and is measured dimensions in ( ) for reference only. dimensioning and tolerancing conform to amse y14.5m-1994. 6. either a mold or mark feature. 3. 5. 4. 2. dimensions are in millimeters. 1. notes: bottom view detail "x" side view typical recommended land pattern top view 1 2 3 4 8 7 6 5 (2x) 0.10 index area pin 1 a b pin #1 index area 8x 0 . 40 ????? b 0.10 ma c c seating plane base plane 0.08 0.10 see detail "x" c c 0 . 00 min. 0 . 05 max. 0 . 2 ref c 5 6 6 3.00 3.00 (1.40) (1.95) 0.65 (2.29) (6x0.65) (2.80 typ) (1.40) (2.29) (8x0.60) 0.70???? 0.30???? (8x0.30)

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