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1 ISL29028 caution: these devices are sensitive to electrostatic discharge; follow proper ic handling procedures. 1-888-intersil or 1-888-468-3774 | intersil (and design) is a registered trademark of intersil americas inc. copyright ? intersil americas in c. 2010. all rights reserved. i 2 c bus is a registered trademark owned by nxp semiconductors netherlands, b.v. all other trademarks mentioned are the property of their respective owners. low power ambient light and proximity sensor with intelligent interrupt and sleep modes ISL29028 the ISL29028 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 uses two independent adcs for concurrently measuring ambient light and proximity in parallel. the flexible interrupt scheme is designed for minimal microcontroller utilization. for ambient light sensor (als) data conversions, an adc converts photodiode current (with a light sensitivity range up to 2000 lux) in 100ms per sample. the adc rejects 50hz/60hz flicker noise caused by artificial light sources. for proximity sensor (prox) data conversions, the built-in driver turns on an external infrared led and the proximity sensor adc converts the reflected ir intensity to digital. this adc rejects ambient ir noise (such as sunlight) and has a 540 s conversion time. the ISL29028 provides low power operation of als and proximity sensing with a typical 138 a normal operation current (110 a for sensors and internal circuitry, ~28 a for external led) with 220ma current pulses for a net 100 s, repeating every 800ms (or under). the ISL29028 uses both a hardware pin and software bits to indicate an interrupt event has occurred. an als interrupt is defined as a measurement which is outside a set window. a proximity interrupt is defined as a measurement over a threshold limit. the user may also require that both als/prox interrupts occur at once, up to 16 times in a row before activating the interrupt pin. the ISL29028 is designed to operate from 2.25v to 3.63v over the -40c to +85c ambient temperature range. it is packaged in a clear, lead-free 8 lead odfn package. pin configuration ISL29028 8 ld odfn (2.0 x 2.1 x 0.7 mm ) top view features ? works under all light sources including sunlight ? dual adcs measure als/prox concurrently ? intelligent interrupt scheme simplifies c code ambient light sensing ? simple output code directly proportional to lux ? 50hz/60hz flicker noise and ir rejection ? light sensor close to human eye response ? selectable 125/2000 lux range proximity sensing ? proximity sensor with broad ir spectrum - can use 850nm and 950nm external ir leds ?ir led driver with i 2 c programmable sink currents - net 100 s pulse with 110ma or 220ma amplitudes - periodic sleep time up to 800ms between pulses ? ambient ir noise cancellation (including sunlight) intelligent and flexible interrupts ? independent als/prox interrupt thresholds ? adjustable interrupt persistency - 1/4/8/16 consecutive triggers required before interrupt ultra low power ?138 a dc typical supply current for als/prox sensing -110 a for sensors and internal circuitry -28 a typical current for external ir led (assuming 220ma for 100 s every 800ms) ?<1.0 a supply current when powered down easy to use ? set registers; wait for interrupt ?i 2 c (smbus compatible) output ? temperature compensated ? tiny odfn8 2.0x2.1x0.7 (mm) package additional features ? 1.7v to 3.63v supply for i 2 c interface ? 2.25v to 3.63v sensor power supply ? pb-free (rohs compliant) ?i 2 c address selection pin applications* (see page 15) ? display and keypad dimming adjustment and proximity sensing for: - mobile devices: smar t phone, pda, gps - computing devices: laptop pc, netbook - consumer devices: lcd-tv, digital picture frame, digital camera ? industrial and medical light and proximity sensing 1 2 3 8 7 6 addr0 vdd gnd irdr int sda 4 5 rext scl thermal pad *thermal pad can be connected to gnd or electrically isolated november 4, 2011 fn6780.2
2 fn6780.2 november 4, 2011 block diagram ordering information part number (notes 1, 2) temp. range (c) package tape and reel (pb-free) pkg. dwg. # ISL29028iroz-t7 -40 to +85 8 ld odfn l8.2.1x2.0 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 terminat ion finish, which is rohs compliant and compatible with both snpb and pb-free soldering operations. intersil pb-free produc ts are msl classified at pb -free peak reflow temperatur es that meet or exceed the pb-free requirements of ipc/jedec j std-020. 3. for moisture sensitivity level (msl), please see device in formation page for ISL29028 . for more information on msl please see techbrief tb363 . pin descriptions pin number pin name description 0 t.pad thermal pad (connect to gnd or float) 1 addr0 i 2 c address pin - pull high or low (do not float) 2 vdd positive supply: 2.25v to 3.63v 3gndground 4 rext external resistor (499k ; 1%) connects this pin to ground 5scli 2 c clock line the i 2 c bus lines can be pulled from 1.7v to above v dd , 3.63v max 6sdai 2 c data line 7int interrupt pin; logic output (o pen-drain) for interrupt 8 irdr ir led driver pin - current fl ows into ISL29028 from led cathode vdd rext gnd scl ir photodiode light data 4 3 5 2 fosc iref irdr array als photodiode process als and ir array dual channel adcs 8 int 7 command register data register i 2 c ir driver interrupt sda 6 addr0 1 ISL29028
3 fn6780.2 november 4, 2011 absolute maximum ratings (t a = +25c) thermal information v dd supply voltage between v dd and gnd . . . . . . . . . .4.0v i 2 c bus pin voltage (scl, sda) . . . . . . . . . . . -0.5v to 4.0v i 2 c bus pin current (scl, sda) . . . . . . . . . . . . . . . . <10ma r ext pin voltage . . . . . . . . . . . . . . . . -0.5v to vdd + 0.5v irdr pin voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . .5.5v addr0 pin voltage . . . . . . . . . . . . . . . -0.5v to vdd + 0.5v int pin voltage . . . . . . . . . . . . . . . . . . . . . . -0.5v to 4.0v int pin current . . . . . . . . . . . . . . . . . . . . . . . . . . .<10ma esd rating human body model (note 5) . . . . . . . . . . . . . . . . . . . 2kv thermal resistance (typical, note 4) ja (c/w) 8 ld odfn. . . . . . . . . . . . . . . . . . . . . . . . . 88 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 for extended periods of time. exposure to such conditions may adv ersely 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. 5. esd on all pins is 2kv exce pt for irdr, which is 1.5kv. important note: all parameters having min/ma x specifications are guaranteed. typical va lues are for informat ion 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 dd = 3.0v, t a = +25c, r ext = 499k 1% tolerance. parameter description condition min typ max unit v dd power supply range 2.25 3.0 3.63 v sr_v dd input power-up slew rate v dd rising edge between 0.4v and 2.25v 0.5 v/ms i dd_off supply current when powered down al s_en = 0; prox_en = 0 0.1 0.8 a i dd_norm supply current for als+prox in sleep time als_en = 1; prox_en = 1 110 125 a i dd_prx_slp supply current for prox in sleep time als_en = 0; prox_en = 1 80 a i dd_als supply current for als als_e n = 1; prox_en = 0 96 a f osc internal oscill ator frequency 5.25 mhz t intgr_als 12-bit als integration/co nversion time 88 100 112 ms t intgr_prox 8-bit prox integration/conversion time 0.54 ms data als_0 als result when dark e ambient = 0 lux, 2k range 1 counts data als_f full scale als adc code e ambient > selected range maximum lux (note 9) 4095 counts data data count output variation over three light sources: fluorescent, incandescent and sunlight ambient light sensing 10 % data als_1 light count output with lsb of 0.0326 lux/count e = 53 lux, fluorescent (notes 6, 9), als_range = 0 1638 counts data als_2 light count output with lsb of 0.522 lux/count e = 320 lux, fluorescent (note 6), als_range = 1 460 614 768 counts data prox_0 prox measurement w/o object in path 1 counts data prox_f full scale prox adc code 255 counts data prox_1 prox measurement result (note 7) 36 46 56 counts t r rise time for irdr sink current r load = 15 at irdr pin, 20% to 80% 500 ns t f fall time for irdr sink current r load = 15 at irdr pin, 80% to 20% 500 ns i irdr_0 irdr sink current prox_dr = 0; v irdr = 0.5v 95 110 125 ma i irdr_1 irdr sink current prox_dr = 1; v irdr = 0.5v 220 ma ISL29028
4 fn6780.2 november 4, 2011 i irdr_leak irdr leakage current prox_en = 0; v dd = 3.63v (note 8) 0.001 1 a v irdr acceptable voltage range on irdr pin register bit prox_dr = 0 0.5 4.3 v t pulse net i irdr on time per prox reading 100 s v ref voltage of r ext pin 0.51 v f i 2 c i 2 c clock rate range 400 khz v i 2 c supply voltage range for i 2 c interface 1.7 3.63 v v il scl and sda input low voltage 0.55 v v ih scl and sda input high voltage 1.25 v i sda sda current sinking capability v ol = 0.4v 3 5 ma i int int current sinking capability v ol = 0.4v 3 5 ma psrr irdr ( i irdr )/( v irdr ) prox_dr = 0; v irdr = 0.5v to 4.3v 4 ma/v notes: 6. an led is used in production test. the led irradiance is calibrated to produce the same data count against a fluorescent ligh t source of the same lux level. 7. an 850nm infrared led is used to test prox /ir sensitivity in an internal test mode. 8. ability to guarantee i irdr leakage of ~1na is limited by test hardware. 9. for als applications under light-distorti ng glass, please see the section titled als range 1 considerations. electrical specifications v dd = 3.0v, t a = +25c, r ext = 499k 1% tolerance. (continued) parameter description condition min typ max unit i2c electrical specifications for scl and sda unless otherwise noted, v dd = 3v, t a = +25c, r ext = 499k 1% tolerance (note 10). parameter description condition min typ max unit v i 2 c supply voltage range for i 2 c interface 1.7 3.63 v f scl scl clock frequency 400 khz v il scl and sda input low voltage 0.55 v v ih scl and sda input high voltage 1.25 v v hys hysteresis of schmit t trigger input 0.05v dd v v ol low-level output voltage (open-drain) at 4ma sink current 0.4 v i i input leakage for each sda, scl pin -10 10 a t sp pulse width of spikes that must be suppressed by the input filter 50 ns t aa scl falling edge to sda output data valid 900 ns c i capacitance for each sda and scl pin 10 pf t hd:sta hold time (repeated) start condition aft er this period, th e first clock pulse is generated 600 ns t low low period of the scl clock measured at the 30% of vdd crossing 1300 ns t high high period of the scl clock 600 ns t su:sta set-up time for a repeated start condition 600 ns t hd:dat data hold time 30 ns t su:dat data set-up time 100 ns t r rise time of both sda and sc l signals (note 11) 20 + 0.1xc b ns ISL29028
5 fn6780.2 november 4, 2011 t f fall time of both sda and scl signals (note 11) 20 + 0.1xc b ns t su:sto set-up time for stop condition 600 ns t buf bus free time between a stop and start condition 1300 ns c b capacitive load for each bus line 400 pf r pull-up sda and scl system bus pull-up resi stor maximum is determined by t r and t f 1k t vd;dat data valid time 0.9 s t vd:ack data valid acknowledge time 0.9 s v nl noise margin at the low level 0.1vdd v v nh noise margin at the high level 0.2vdd v notes: 10. all parameters in i 2 c electrical specifications table are guaranteed by desi gn and simulation. 11. c b is the capacitance of the bus in pf. i2c electrical specifications for scl and sda unless otherwise noted, v dd = 3v, t a = +25c, r ext = 499k 1% tolerance (note 10). (continued) parameter description condition min typ max unit figure 1. i 2 c timing diagram ISL29028
6 fn6780.2 november 4, 2011 register map there are ten 8-bit registers accessible via i 2 c. registers 0x1 and 0x2 define the operation mode of the device. registers 0x3 through 0x7 store the various als/ir/prox th resholds which trigger interrupt events. registers 0x8 through 0xa store the results of als/ir/prox adc conversions. register descriptions table 1. ISL29028 registers and register bits addr reg name bit 7654321 0default 0x00 (n/a) (reserved) (n/a) 0x01 configure prox en prox_slp[2:0] pro x_dr als_en als_range alsir_mode 0x00 0x02 interrupt prox_flag prox_prst[1:0] (write 0) als_flag als_prst[1:0] int_ctrl 0x00 0x03 prox_lt prox_lt[7:0] 0x00 0x04 prox_ht prox_ht[7:0] 0xff 0x05 alsir_th1 alsir_lt[7:0] 0x00 0x06 alsir_th2 alsir_ht[3:0] alsir_lt[11:8] 0xf0 0x07 alsir_th3 alsir_ht[11:4] 0xff 0x08 prox_data prox_data[7:0] 0x00 0x09 alsir_dt1 alsir_data[7:0] 0x00 0x0a alsir_dt2 (unused) alsir_data[11:8] 0x00 0x0e test1 (write as 0x00) 0x00 0x0f test2 (write as 0x00) 0x00 table 2. register 0x00 (reserved) bit # access default name function/operation 7:0 ro (n/a) (n/a) reserved - no need to read or write table 3. register 0x01 (configure) - prox/als configuration bit # access default name function/operation 7rw0x00 prox_en (prox enable) when = 0, proximity sensing is disabled when = 1, continuous proximity sensing is enabled. prox data will be ready 0.54ms after this bit is set high 6:4 rw 0x00 prox_slp (prox sleep) for bits 6:4 = (see the following) 111; sleep time between prox ir led pulses is 0.0ms (run continuously) 110; sleep time between prox ir led pulses is 12.5ms 101; sleep time between prox ir led pulses is 50ms 100; sleep time between prox ir led pulses is 75ms 011; sleep time between prox ir led pulses is 100ms 010; sleep time between prox ir led pulses is 200ms 001; sleep time between prox ir led pulses is 400ms 000; sleep time between prox ir led pulses is 800ms 3rw0x00 prox_dr (prox drive) when = 0, irdr behaves as a pulsed 110ma current sink when = 1, irdr behaves as a pulsed 220ma current sink 2rw0x00 als_en (als enable) when = 0, als/ir sensing is disabled when = 1, continuous als/ir sensing is enabled with new data ready every 100ms 1rw0x00 als_range (als range) when = 0, als is in low-lux range when = 1, als is in high-lux range 0rw0x00 alsir_mode (alsir mode) when = 0, als/ir data register contains visible als sensing data when = 1, als/ir data register contains ir spectrum sensing data ISL29028
7 fn6780.2 november 4, 2011 table 4. register 0x02 (interrupt) - prox/als interrupt control bit # access default bit name function/operation 7flag0x00 prox_flag (prox flag) when = 0, no prox interrupt event has occurred since power-on or last ?clear? when = 1, a prox interrupt event occurred. clearable by writing ?0? 6:5 rw 0x00 prox_prst (prox persist) for bits 6:5 = (see the following) 00; set prox_flag if 1 conversion result trips the threshold value 01; set prox_flag if 4 conversion results trip the threshold value 10; set prox_flag if 8 conversion results trip the threshold value 11; set prox_flag if 16 conversion results trip the threshold value 4rw0x00 unused (write 0) unused register bit - write 0 3flag0x00 als_flag (als flag) when = 0, no als interrupt event has oc curred since power-on or last ?clear? when = 1, an als inte rrupt event occurred. clearable by writing ?0? 2:1 rw 0x00 als_prst (als persist) for bits 2:1 = (see the following) 00; set als_flag if 1 conversion is outside the set window 01; set als_flag if 4 conversions are outside the set window 10; set als_flag if 8 conversions are outside the set window 11; set als_flag if 16 conversions are outside the set window 0rw0x00 int_ctrl (interrupt control) when = 0, set int pin low if prox_flag or als_flag high (logical or) when = 1, set int pin low if prox_flag and als_flag high (logical and) table 5. register 0x03 (prox_lt) - interrupt low threshold for proximity sensor bit # access default bit name function/operation 7:0 rw 0x00 prox_lt (prox threshold) 8-bit interrupt low threshold for proximity sensing table 6. register 0x04 (prox_ht) - interru pt high threshold for proximity sensor bit # access default bit name function/operation 7:0 rw 0xff prox_ht (prox threshold) 8-bit interrupt high thresh old for proximity sensing table 7. register 0x05 (alsir_th1) - interrupt low threshold for als/ir bit # access default bit name function/operation 7:0 rw 0x00 alsir_lt[7:0] (als/ir low thr.) lower 8 bits (of 12 bits) for als/ir low interrupt threshold table 8. register 0x06 (alsir_th2) - interrupt low/high thresholds for als/ir bit # access default bit name function/operation 7:4 rw 0x0f alsir_ht[3:0] (als/ir high thr.) lower 4 bits (of 12 bits) for al s/ir high interrupt threshold 3:0 rw 0x00 alsir_lt[11:8] (als/ir low thr.) upper 4 bits (of 12 bits) for als/ir low interrupt threshold table 9. register 0x07 (alsir_th3) - interrupt high threshold for als/ir bit # access default bit name function/operation 7:0 rw 0xff alsir_ht[11:4] (als/ir high thr.) upper 8 bits (of 12 bits) for al s/ir high interrupt threshold ISL29028
8 fn6780.2 november 4, 2011 principles of operation i 2 c interface the ISL29028?s i 2 c interface slave address is internally hardwired as 0b100010, where ?0b? signifies binary notation and x represents the logic level on pin addr0. figure 2 shows a sample one-byte read. 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. every i 2 c transaction begins with the master asserting a start condition (sda falling wh ile scl remains high). the first transmitted byte is in itiated by the master and includes 7 address bits and a r/w bit. the slave is responsible for pulling sda lo w during the ack bit after every transmitted byte. each 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. photodiodes and adcs the ISL29028 contains two photodiode arrays which convert photons (light) into current. the als photodiodes are constructed to mimic the human eye?s wavelength response curve to visible light (see figure 6). the als photodiodes? current output is digitized by a 12-bit adc in 100ms. these 12 bits can be accessed by reading from i 2 c registers 0x9 and 0xa when the adc conversion is completed. the als converter is a charge-balancing integrating 12-bit adc. charge-balancing is best for converting small current signals in the presence of periodic ac noise. integrating over 100ms high ly rejects both 50hz and 60hz light flicker by picking the lowest integer number of cycles for both 50hz/60hz frequencies. table 10. register 0x08 (prox_data) - proximity sensor data bit # access default bit name function/operation 7:0 ro 0x00 prox_data (proximity data) results of 8-bit proximity sensor adc conversion table 11. register 0x09 (alsir_dt1) - als/ir sensor data (lower 8 bits) bit # access default bit name function/operation 7:0 ro 0x00 alsir_data (als/ir data) lower 8 bits (of 12 bits) from resu lt of als/ir sensor conversion table 12. register 0x0a (alsir_dt2) - als/ir sensor data (upper 4 bits) bit # access default bit name function/operation 7:4 ro 0x00 ( unused ) unused bits. 3:0 ro 0x00 alsir_data (als/ir data) upper 4 bits (of 12 bits) from resu lt of als/ir sensor conversion table 13. register 0x0e (test1) - test mode bit # access default bit name function/operation 7:0 rw 0x00 (write as 0x00) test mode register. when 0x00, in normal operation. table 14. register 0x0f (test2) - test mode 2 bit # access default bit name function/operation 7:0 rw 0x00 (write as 0x00) test mode register. when 0x00, in normal operation. figure 2. i 2 c driver timing diagram for master and slave connected to common bus 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 a d7 d6d5d4 d3d2 d1d0 1357 1357 123456 9246 stop start sda driven by master device address sda driven by ISL29028 data byte0 register address slave device address i 2 c data sda driven by master sda driven by master 2468 924689 78135789 i 2 c sda i 2 c sda i 2 c clk master (ISL29028) ISL29028
9 fn6780.2 november 4, 2011 the proximity sensor is an 8-bit adc which operates in a similar fashion. when proximity sensing is enabled, the irdr pin will drive a user-supplied infrared led, the emitted ir reflects off an object (i.e., a human head) back into the ISL29028, and a sensor converts the reflected ir wave to a current signal in 0.54ms. the adc subtracts the ir reading before and af ter the led is driven (to remove ambient ir such as sunlight), and converts this value to a digital count stored in register 0x8. the ISL29028 is designed to run two conversions concurrently: a proximity conversion and an als (or ir) conversion. please note that because of the conversion times, the user must let the adcs perform one full conversion first before reading from i 2 c registers prox_data (wait 0.54ms) or alsir_dt1/2 (wait 100ms). the timing between als and pr ox conversions is arbitrary (as shown in figure 3). the als runs continuously with new data available every 100ms. the proximity sensor runs continuously with a time between conversions decided by prox_slp (register 1 bits [6:4]). ambient light and ir sensing the ISL29028 is set for ambient light sensing when register bit alsir_mode = 0 and alr_en = 1. the light-wavelength response of the als appears as shown in figure 6. als measuring mode (as opposed to ir measuring mode) is set by default. when the part is programmed for infrared (ir) sensing (alsir_mode = 1; als_en = 1), infrared light is converted into a current and digitized by the same als adc. the result of an ir conversion is strongly related to the amount of ir energy incident on our sensor, but is unitless and is referred to in digital counts. proximity sensing when proximity sensing is enabled (prox_en = 1), the external ir led is driven for 0.1ms by the built-in ir led driver through the irdr pin. the amplitude of the ir led current depends on register 1 bit 3: prox_dr. if this bit is low, the load will see a fixed 110ma current pulse. if this bit is high, the load on irdr will see a fixed 220ma current pulse as seen in figure 4. when the ir from the led reaches an object and gets reflected back into the isl29 028, the reflected ir light is converted into current as per the ir spectral response shown in figure 7. one en tire proximity measurement takes 0.54ms for one conversion (which includes 0.1ms spent driving the led), and the period between proximity measurements is decided by prox_slp (sleep time) in register 1 bits 6:4. average led driving current consumption is given by equation 1. a typical irdr scheme is 220ma amplitude pulses every 800ms, which yields 28 a dc. total current consumption total current consumption is the sum of i dd and i irdr . the irdr pin sinks current (as shown in figure 4) and the average irdr current can be calculated using equation 1 above. i dd depends on voltage and the mode-of-operation as seen in figure 11. als active 100ms 100ms 100ms prox sensor active irdr (current driver) als conversion time = 100ms (fixed) 0.54ms for prox conversion series of current pulses totaling 0.1ms sleep time (prox_slp) 100ms 100ms several s between conversions time time time figure 3. timing diagram for prox/als events - not to scale figure 4. current drive mode options pin 8 - irdr 220ma (prox_dr = 1) (irdr is hi-z when not driving) 110ma (prox_dr = 0) i lrdr ave ; i lrdr peak ; 100 s t sleep ------------------------------------------------------- - = (eq. 1) ISL29028
10 fn6780.2 november 4, 2011 interrupt function the ISL29028 has an inte lligent interrupt scheme designed to shift some logic processing away from intensive microcontroller i 2 c polling routines (which consume power) and towards a more independent light sensor which can instruct a system to ?wake up? or ?go to sleep?. an als interrupt event (als_flag) is governed by registers 5 through 7. the user writes a high and low threshold value to these regi sters and the ISL29028 will issue an als interrupt flag if the actual count stored in registers 0x9 and 0xa are outside the user?s programmed window. the user must write 0 to clear the als_flag. a proximity interrupt event (prox_flag) is governed by the high and low thresholds in registers 3 and 4 (prox_lt and prox_ht). prox_flag is set when the measured proximity data is more than the higher threshold x-times-in-a-row (x is set by user; see next paragraph). the proximity interrupt flag is cleared when the prox data is lower than the low proximity threshold x-times-in-a-row, or when the user writes ?0? to prox_flag. interrupt persistency is another useful option available for both als and proximity measurements. persistency requires x-in-a-row interrupt flags before the int pin is driven low. both als and prox have their own independent interrupt persistency options. see als_prst and prox_prst bits in register 2. the final interrupt option is the ability to and or or the two interrupt flags using register 2 bit 0 (int_ctrl). if the user wants both als/prox interrupts to happen at the same time before changing the state of the interrupt pin, set this bit high. if the user wants the interrupt pin to change state when either the als or the proximity interrupt flag goes high, leave this bit to its default of 0. als range 1 considerations when measuring als counts higher than 1800 on range 1 (alsir_mode = 0, als_range = 0, als_data > 1800), switch to range 2 (change the als_range bit from ?0? to ?1?) and remeasure als counts. this recommendation pertains only to applications where the light incident upon the sensor is ir-heavy and is distorted by tinted glass that increases the ratio of infrared to visible light. for more information, see the separate als range 1 considerations document. v dd power-up and power supply considerations upon power-up, please ensure a v dd slew rate of 0.5v/ms or greater. after power-up, or if the user?s power supply temporarily deviates from our specification (2.25v to 3.63v), intersil recommends the user write the following: write 0x00 to register 0x01, write 0x29 to register 0x0f, write 0x00 to register 0x0e, and write 0x00 to register 0x0f. the user should then wait ~1ms or more and then rewrite all registers to the desired values. if the user prefers a hardware reset method instead of writing to test registers: set v dd = 0v for 1 second or more, power back up at the required slew rate, and write registers to the desired values. power-down to put the ISL29028 into a po wer-down state, the user can set both prox_en and als_en bits to 0 in register 1. or more simply, set all of register 1 to 0x00. calculating lux the ISL29028?s adc output codes are directly proportional to lux when in als mode (see alsir_mode bit). in equation 2, e calc is the calculated lux reading and out represents the adc code. the constant to plug in is determined by the range bi t als_range (register 0x1 bit 1) and is independent of the light source type. table 15 shows two different scale factors: one for the low range (als_range = 0) and the other for the high range (als_range = 1). noise rejection charge balancing adc?s have excellent noise-rejection characteristics for periodic noise sources whose frequency is an integer multiple of the conversion rate. for instance, a 60hz ac unwanted signal?s sum from 0ms to k*16.66ms (k = 1,2...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. since wall sockets may output at 60hz or 50hz, our integration time is 100ms: the lowest common integer number of cycles for both frequencies. proximity detection of various objects proximity sensing relies on the amount of ir reflected back from objects. a perf ectly black object would absorb all light and reflect no photons. the ISL29028 is sensitive enough to detect black esd foam which reflects only 1% of ir. for biological objects, blonde hair reflects more than brown hair and customers may notice that skin tissue is much more reflective than hair. ir penetrates into the skin and is reflected or scattered back from within. as a result, the proximity count peaks at contact and monotonically decreases as skin moves away. the reflective characteristics of skin are very different from that of paper. table 15. als sensitivity at different ranges als_range range (lux/count) 0 0.0326 1 0.522 e calc range out adc = (eq. 2) ISL29028
11 fn6780.2 november 4, 2011 typical circuit a typical application for the ISL29028 is shown in figure 5. the ISL29028?s i 2 c address is internally hardwired as 0b100010, with x representing the logic state of input i 2 c address pin addr0. 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 qua lified to +260c. a standard reflow soldering profile with a +260c maximum is recommended. ( http://www.intersil.com/data/tb/tb477.pdf ) suggested pcb footprint it is important that 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 ISL29028 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. a 0.1f an d 1f power supply decoupling capacitors need to be placed close to the device. addr0 1 gnd 3 rext 4 sda int 7 irdr 8 ISL29028 r1 10k r2 10k rext 499k v dd microcontroller int sda slave_0 slave_1 i 2 c slave_n i 2 c master scl sda scl sda v i2c_pull-up 6 r3 10k scl 2 vdd 5 c2 0.1f figure 5. ISL29028 typical circuit scl c1 1f v ir-led ISL29028
12 fn6780.2 november 4, 2011 typical performance curves v dd = 3.0v, r ext = 499k figure 6. spectrum of four light sources normalized by luminous intensity (lux) figure 7. ISL29028 sensitivity to different wavelengths figure 8. angular sensitivity figure 9. als linearity over 3 light sources (2000 lux range) figure 10. prox counts vs distance with 10cm x 10cm reflector (using ISL29028 evaluation board) figure 11. v dd vs i dd for various modes of operation 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 350 550 750 950 wavelength (nm) normalized intensity fluorescent sun incand. halogen 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 300 400 500 600 700 800 900 1000 1100 wavelength (nm) normalized response als human eye ir/prox 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 -90 -60 -30 0 30 60 90 angular offset () normalized sensitivity 0 500 1000 1500 2000 2500 0 1000 2000 3000 4000 5000 als code (12-bit) halogen fluorescent incandescent lux meter reading (lx) 0 50 100 150 200 250 300 0 20 40 60 80 100 120 140 160 180 200 distance (mm) prox counts (8-bit) white copy paper 220ma mode 18% grey card 110ma mode 40 60 80 100 120 140 160 2.25 2.40 2.55 2.85 3.00 3.15 3.45 input v dd (v) measured i dd (a) als+prox (during prox sleep) als-only 3.60 3.30 2.70 prox (during prox sleep) ISL29028
13 fn6780.2 november 4, 2011 figure 12. irdr pulse amplitude vs v irdr figure 13. stability of als count over temp (at 300 lux) figure 14. stability of als coun t over-temperature (at 0.00 lux) typical performance curves v dd = 3.0v, r ext = 499k (continued) 100 120 140 160 180 200 220 240 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 220ma-mode (prox_dr = 1) 110ma-mode (prox_dr = 0) v irdr (v) i irdr (a) -50 -40 -30 -20 -10 0 10 20 30 40 50 -40 -15 10 35 60 85 als count change from +25c measurement (%) temperature (c) 0 1 2 3 4 5 6 7 8 9 -40 10 60 temperature (c) als code (12-bit) 10 ISL29028
14 fn6780.2 november 4, 2011 figure 15. 8 ld odfn sensor loca tion outline - dimensions in mm 2.00 sensor offset 0.43 0.50 2.10 1 2 3 4 8 7 6 5 0.42 ISL29028
15 intersil products are manufactured, assembled and tested utilizing iso9000 qu ality 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, soft ware and/or specifications at any time without notice. accordingly, th e reader is cautioned to verify that data sheets are current before placing orders. information furnished by intersil is believed to be accura te and reliable. however, no re sponsibility is assumed by inte rsil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which ma y result from its use. no licen se is granted by implication o r otherwise under any patent or patent rights of intersil or its subsidiaries. for information regarding intersil corporation and its products, see www.intersil.com fn6780.2 november 4, 2011 for additional products, see www.intersil.com/product_tree products intersil corporation is a leader in the design and manuf acture 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 documentat ion and related parts, please see the respective device information page on intersil.com: ISL29028 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 revision history the revision history provided is for informat ional purposes only and is believed to be accurate, but not warranted. please go t o web to make sure you have the latest rev. date revision change 11/11/10 fn6780.2 updates to test methodology, addition of "als range 1 considerations" paragraph, updates to "power-up" sequence, test register clarification 3/2/10 fn6780.1 typo fixes and sensitivity updates 3/2/10 fn6780.0 initial release. ISL29028
16 fn6780.2 november 4, 2011 ISL29028 package outline drawing l8.2.1x2.0 8 lead optical dual flat no-lead plastic package (odfn) rev 1, 12/09 located within the zone indicated. the pin #1 identifier may be unless otherwise specified, tolerance : decimal 0.05 tiebar shown (if present) is a non-functional feature. the configuration of the pin #1 id entifier 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 asme y14.5m-1994. 6. either a mold or mark feature. 3. 5. 4. 2. dimensions are in millimeters. 1. notes: detail "x" side view typical recommended land pattern top view (2x) 0.10 index area pin 1 a b 8x 0 . 35 0 . 05 b 0.10 a c c seating plane base plane 0.08 0.10 see detail "x" c c 6 0.200.05 1.50 0.50 0.75 1.50 m 0 . 00 min. 0 . 05 max. 0 . 2 ref c 5 0.700.05 2.10 2.00 (6x0.50) (8x0.20) (8x0.55) (0.75) (1.50) 2.10 2.50 (8x0.20) index area pin 1 6 bottom view

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