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_______________________________________________________________ maxim integrated products 1 for pricing, delivery, and ordering information, please contact maxim direct at 1-888-629-4642, or visit maxims website at www.maxim-ic.com. MAX44000 ambient and infrared proximity sensor general description the MAX44000 combines a wide-dynamic range ambient light sensor with an integrated infrared proximity sensor. the ic is a perfect solution for touch-screen portable devices. the ic can consume as low as 11a (time averaged) in ambient light sensing plus proximity sensing, including external ir led current. the on-chip ambient sensor has the ability to make wide dynamic range 0.03 lux to 65,535 lux measurements. an on-chip ir proximity detector is matched with an inte - grated ir led driver. all readings are available on an i 2 c communication bus. a programmable interrupt pin minimizes the need to poll the device for data, freeing up microcontroller resources, reducing system software overhead, and ultimately, reducing power consumption. the ic is designed to drive an external ir led and can operate from a v dd of 1.7v to 3.6v. it consumes just 5a operating current when only the ambient light sensor is enabled and 7a when the proximity receiver and driver are enabled. applications smartphones accessories industrial sensors presence detection features s tiny, 2mm x 2mm x 0.6mm utdfn-opto package s v dd = 1.7v to 3.6v s low-power operation 5a in ambient mode 7a in ambient plus proximity mode 70a in ambient plus proximity mode, including 100ma led current s excellent light source matching programmable green and ir channel gains s integrated single-pulse ir led driver 10ma to 110ma programmable range internal ambient cancellation s -40 n c to +105 n c temperature range 19-5859; rev 0; 10/11 typical application circuit appears at end of data sheet. simplified block diagram + denotes a lead(pb)-free/rohs-compliant package. *ep = exposed pad. ordering information 14-/8-bit ir led drv vis + ir (als) ir (als) ir (prx) v led v dd i 2 c 14-bit als pga ambient cancellation als pga sda scl int v dd MAX44000 gnd microcontroller gnd prx pga part temp range pin-package MAX44000gdt+ -40 n c to +105 n c 6 otdfn-ep* www.datasheet.co.kr datasheet pdf - http://www..net/
2 ______________________________________________________________________________________ MAX44000 ambient and infrared proximity sensor stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. these are stress rating s only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specificatio ns is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. all pins to gnd .................................................... -0.3v to +4.0v output short-circuit current duration ....................... continuous continuous input current into any terminal ................... q 20ma continuous power dissipation (t a = +70 n c) 6-pin otdfn (derate 11.9mw/ n c above +70 n c) ............ 953mw operating temperature range ........................ -40 n c to +105 n c soldering temperature (reflow) ...................................... +260 n c electrical characteristics ( v dd = 1.8v, t min C t max = -40 c to +105 c, t a = +25 c, unless otherwise noted.) (note 2) absolute maximum ratings parameter symbol conditions min typ max units ambient light receiver characteristics maximum ambient light sensitivity fluorescent light (note 3) 0.03 lux/lsb ambient light saturation level 65,535 lux gain error green led 538nm response, t a = +25 n c (note 3) 15 % light source matching fluorescent/incandescent light 10 % infrared transmittance 850nm vs. 538nm, t a = +25 n c 0.5 % ultraviolet transmittance 363nm vs. 538nm, t a = +25 n c 2 % dark current level 100ms conversion time, 0 lux, t a = +25 n c 0 count adc conversion time 14-bit resolution, has 50hz/60hz rejection 100 ms 12-bit resolution 25 10-bit resolution 6.25 8-bit resolution 1.56 adc conversion time accuracy t a = -40 n c to +105 n c 6 % t a = +25 n c 0.7 infrared proximity receiver characteristics maximum proximity detection sensitivity 850nm ir led, 60w/cm 2 1.5 m w/cm2/ lsb sunlight rejection offset no reflector 0 to 100k lux 0 counts sunlight rejection gain error with reflector 0 to 100k lux 0.1 counts/ klux www.datasheet.co.kr datasheet pdf - http://www..net/
_______________________________________________________________________________________ 3 MAX44000 ambient and infrared proximity sensor electrical characteristics (continued) ( v dd = 1.8v, t min C t max = -40 c to +105 c, t a = +25 c, unless otherwise noted.) (note 2) parameter symbol conditions min typ max units ir led transmitter minimum ir led drive current sink 10 ma maximum ir led drive current sink 110 ma current control step 10 ma current control accuracy i out = 110ma, v drv = 1.5v 12 % i out = 50ma, v drv = 1.5v 10 i out = 10ma, v drv = 1.5v 12 drv leakage current i out = 0ma, v drv = 3.6v 0.1 f a voltage compliance of drv pin i drv = 110ma, d i out = 10%; v drv = 3.6v 0.5 v i drv = 100ma, d i out = 2%, v drv = 3.6v 0.6 internal transmit pulse width 100 f s power supply power-supply voltage v dd 1.7 3.6 v quiescent current (ambient mode) is 5 10 f a software shutdown current i shdn t a = +25 n c 0.1 0.3 f a t a = -40 n c to +105 n c 0.6 quiescent current proximity during ir led pulsed operation 375 600 f a quiescent current (als + proximity, time average) with proximity and als sensing on 6.8 f a power-up time t on 100 ms digital characteristics (sda, scl, int ) output low voltage (sda, int) v ol i sink = 6ma 0.06 0.4 v int leakage current 0.01 1000 na sda, scl input current 0.01 1000 na i 2 c input low voltage v il_i2c sda, scl 0.4 v i 2 c input high voltage v ih_i2c sda, scl 1.6 v input capacitance 3 pf www.datasheet.co.kr datasheet pdf - http://www..net/
4 ______________________________________________________________________________________ MAX44000 ambient and infrared proximity sensor note 2: all devices are 100% production tested at t a = +25 n c . temperature limits are guaranteed by design. note 3: guaranteed by design. green 538nm led chosen for production so that the ic responds to 100 lux flourescent light with 100 lux. electrical characteristics (continued) ( v dd = 1.8v, t min C t max = -40 c to +105 c, t a = +25 c, unless otherwise noted.) (note 2) typical operating characteristics (v dd = 1.8v, t min C t max = -40 c to +85 c, unless otherwise noted. all devices are 100% production tested at t a = +25c . temperature limits are guaranteed by design.) spectrum response MAX44000 toc01 wave length (nm) normalized output 970 870 770 670 570 470 370 20 40 60 80 100 120 0 270 1070 green channel red channel cie curve adc count vs. distance vs. led drive current MAX44000 toc02a distance (mm) adc count 120 100 80 60 40 20 50 100 150 200 250 300 0 0 140 i out = 110ma i out = 50ma i out = 20ma adc count vs. distance vs. object MAX44000 toc02b adc count 90 80 70 60 50 40 30 20 10 0 100 distance (mm) 50 100 150 200 250 300 0 grey card white card parameter symbol conditions min typ max units i 2 c timing characteristics serial-clock frequency f scl 400 khz bus free time between stop and start t buf 1.3 f s hold time (repeated) start condition t hd,sta 0.6 f s low period of the scl clock t low 1.3 f s high period of the scl clock t high 0.6 f s setup time for a repeated start t su.sta 0.6 f s data hold time t hd,dat 0 0.9 f s data setup time t su,dat 100 ns sda transmitting fall time t f i sink p 6ma, t r and t f between 0.3 x v dd and 0.7 x v dd 100 ns setup time for stop condition t su,sto 0.6 f s pulse width of suppressed spike t sp 0 50 ns www.datasheet.co.kr datasheet pdf - http://www..net/
_______________________________________________________________________________________ 5 MAX44000 ambient and infrared proximity sensor typical operating characteristics (continued) (v dd = 1.8v, t min C t max = -40 c to +85 c, unless otherwise noted. all devices are 100% production tested at t a = +25c . temperature limits are guaranteed by design.) light sensitivity vs. lux level MAX44000 toc03 reference meter reading (lux) adc count 900 800 600 700 200 300 400 500 100 200 400 600 800 1000 1200 1400 1600 fluorescent incandescent 1800 0 0 1000 alstim[1:0] = 00 alspga[1:0] = 10 sunlight rejection MAX44000 toc03b sunlight (lux) adc count 70k 60k 50k 40k 30k 20k 10k 50 100 150 0 0 80k no reflector prxtim, prxpga : 0x02 = 1111 xxxx led current: 0x03 = xxxx 1110 for 100ma with no reflector, prox count stayed at 0 at all lux level with a black glass as reflector and lux level changed from 50 to 75000 lux prox counts dropped by 7% at mid-adc range prox count dropped by 35% at quarter adc range black glass reflector radiation pattern MAX44000 toc04 luminosity angle () relative sensitivity (% from 0) 40 60 80 30 10 20 -60 -50 -40 -30 -20 -10 0 -80 -70 10 20 30 40 50 60 70 80 90 100 0 -90 50 70 90 rotated with axis between pin 1/2/3 and 4/5/6 supply current vs. supply voltage vs. temperature MAX44000 toc05 supply voltage (v) supply current (a) 3.5 3.3 2.9 3.1 2.1 2.3 2.5 2.7 1.9 1 2 3 4 5 6 7 8 9 10 0 1.7 3.7 t a = -40c t a = +25c t a = +85c t a = +105c standard ambient mode darkroom condition output error vs. temperature MAX44000 toc06 temperature (c) counts (units) 85 60 35 10 -15 1 2 3 4 5 6 7 8 9 10 11 0 -40 110 standard ambient mode darkroom condition v dd = 1.7 v to 3.6 v www.datasheet.co.kr datasheet pdf - http://www..net/
6 ______________________________________________________________________________________ MAX44000 ambient and infrared proximity sensor typical operating characteristics (continued) (v dd = 1.8v, t min C t max = -40 c to +85 c, unless otherwise noted. all devices are 100% production tested at t a = +25c . temperature limits are guaranteed by design.) lux 10k 1000 100 10 1 100k supply current vs. lux MAX44000 toc07 30 0 supply current (a) 5 10 15 20 25 standard ambient mode supply current vs. time MAX44000 toc08 100s/div i drv 50ma/div i dd 200a/div ambient + proximity mode output low voltage vs. sink current sink current (ma) output low voltage (v) 20 10 51 5 20 40 60 80 100 120 140 160 180 0 MAX44000 toc09 the data was taken on the interrupt pin ir led current vs. output drive voltage, i drv vs. v drv MAX44000 toc10 v drv (v) i drv (ma) 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 20 40 60 80 100 120 0 1.0 110ma i drv setting 50ma i drv setting 10ma i drv setting total current consumption including ir led current vs. ir led current level MAX44000 toc11 ir led level (ma) total current (ua) 100 80 60 40 20 10 20 30 40 50 60 70 0 120 i total = i dd + i ir_led ambient + proximity mode 100ms integration time i total i dd www.datasheet.co.kr datasheet pdf - http://www..net/
_______________________________________________________________________________________ 7 MAX44000 ambient and infrared proximity sensor pin description pin configuration detailed description the MAX44000 combines a wide-dynamic range ambi - ent light sensor with an integrated infrared proximity sensor. the die is placed inside an optically transparent (utdfn-opto) package. a photodiode array inside the ic converts the light to a current, which is then pro - cessed by low-power circuitry into a digital value. the data is then stored in an output register that is read by an i 2 c interface. the ic contains three types of photodiodes: a green pho - todiode and two types of infrared photodiodes. ambient light sensing (als) is accomplished by subtracting the infrared als photodiode signal from the green als photodiode signals after applying respective gains. the infrared proximity photodiodes are optimized for better sensitivity for near infrared signals, specifically 850nm, and can be used for proximity sensor measurements. in the als mode, the als photodiodes are connected to two adcs. the user can choose to view either just the green als signal, or just the infrared als signal, or the difference of the green and infrared als photodiodes. in the proximity detect mode, the infrared proximity pho - todiodes are connected to the proximity receiver circuit and then to an 8-bit adc. three key features of the ics analog design are its low- power design, single-pulse proximity receive operation, and interrupt pin operation. v dd sda 6 1 gnd scl 5 2 drv *ep = exposed pad, connect to gnd. ep* 4 3 top view MAX44000 int + pin name function 1 v dd power supply 2 gnd ground 3 drv ir led current driver 4 int interrupt. active-low output. 5 scl i 2 c clock 6 sda i 2 c data ep exposed pad. ep is internally connected to gnd. ep must be connected to gnd. www.datasheet.co.kr datasheet pdf - http://www..net/
8 ______________________________________________________________________________________ MAX44000 ambient and infrared proximity sensor figure 1. spectral response compared to ideal photopic curve figure 2. green channel and ir channel response at identical gains on a typical MAX44000 the ic operates from a v dd of 1.7v to 3.6v and con - sumes just 5 f a current in als mode and 7 f a time-aver - aged in proximity mode. the on-chip ir proximity detec - tor dc ambient rejection circuitry is synchronized with pulsing of an integrated ir led transmitter to improve noise immunity from external fluctuating ir sources. this scheme also reduces ir led power consumption compared to alternate methods and eliminates red-glow problems with the use of 850nm ir leds; power con - sumption is reduced to 11 f a (time averaged), includ - ing the current consumption of an external ir led. an on-chip programmable interrupt function eliminates the need to continually poll the device for data, resulting in a significant power saving. ambient light sensing the ambient light sensors are designed to detect bright - ness in the same way as human eyes do. to achieve this, the light sensor needs to have a spectral sensitivity that is identical to the photopic curve of the human eye (see figure 1). small deviations from the photopic curve can affect perceived brightness by ambient light sensors to be wildly different. however, there are practical difficul - ties in trying to reproduce the ideal photopic curve in a small cost-efficient package. the ic instead uses two different types of photodiodes (a green and an infrared) that have different spectral sensitivitieseach of which is amplified and subtracted on-chip with suitable gain coefficients so that the most extreme light sources (fluo - rescent and incandescent) are well matched to a com - mercial illuminance lux meter. the photopic curve represents a typical human eyes sensitivity to wavelength. as can be seen in figure 1 and figure 2, its peak sensitivity is at 555nm (green). the human eye is insensitive to infrared (> 700nm) and ultraviolet (< 400nm) radiation. variation between light sources can extend beyond the visible spectral range. for example, fluorescent and incandescent light sources with similar visible brightness (lux) can have substantially different ir radiation content (since the human eye is blind to it). since this infrared radiation can be picked up by silicon photodiodes, dif - ferences in light spectra can affect brightness measure - ment of light sensors. for example, light sources with high ir content, such as an incandescent bulb or sun - light, would suggest a much brighter environment than our eyes would perceive them to be. other light sources such as fluorescent and led-based systems have very little infrared content. the ic incorporates on-chip com - pensation techniques to minimize these effects and still output an accurate lux response in a variety of lighting conditions. on-chip user-programmable green channel and ir chan - nel gain trim registers allow the light sensor response to be tailored to the application, such as when the light sen - sor is placed under dark or colored glass. wavelength (nm) normalized response 970 870 770 670 570 470 370 20 40 60 80 100 120 0 270 1070 standard als (green-red) wavelength (nm) normalized output 970 870 770 670 570 470 370 20 40 60 80 100 120 0 270 1070 green channel red channel cie curve www.datasheet.co.kr datasheet pdf - http://www..net/
_______________________________________________________________________________________ 9 MAX44000 ambient and infrared proximity sensor register description proximity light sensing the proximity sensing uses an external, pulsed infrared led source to emit controlled amounts of infrared radia - tion. when an external object reflects back some of this infrared radiation back to the ic, it is detected by the integrated light detector. the amount of reflected light detected is then used to determine the objects proximity to the sensor. it is important to take account for the fact that different objects at the same distance from the sensor can reflect different amounts of infrared radiation depending on their texture and color. the ic includes on-chip ambient cancellation circuitry in the receive path of the infrared proximity sensor. this scheme allows the part to operate in the presence of large amounts of dc ir radiation. due to the use of a single-pulse technique in pulsing the external infrared led, the chip is also immune to fixed-frequency external infrared radiation such as from remote controls, elec - tronic ballasts, etc., leading to more reliable infrared proximity sensor operation. led driver the ic features a led driver that delivers a pulsed cur - rent at the output. the pulse amplitude is programmable through the i 2 c interface from 0 to 110ma in steps of 10ma. a low-voltage compliance of drv pin allows ir leds to be powered from lower voltage rails, possibly even a 1.8v rail. high-current drive accuracy improves performance by eliminating part-to-part variation. register b7 b6 b5 b4 b3 b2 b1 b0 register address power-on reset state r/w status interrupt status pwron prxints alsints 0x00 0x04 r configuration main configuration trim mode[2:0] prxinte alsinte 0x01 0x24 r/w receive configuration 1 1 1 1 alstim[1:0] alspga[1:0] 0x02 0x00 r/w transmit configuration drv[3:0] 0x03 0x00 r/w adc data adc high byte (als ) ofl alsdata[13:8] 0x04 0x00 r adc low byte (als ) alsdata[7:0] 0x05 0x00 r adc byte (prox) prxdata[7:0] 0x16 0x00 r threshold set als upper threshold (high byte ) upthr[13:8] 0x06 0x00 r/w als upper threshold (low byte) upthr[7:0] 0x07 0x00 r/w als lower threshold (high byte) lothr[13:8] 0x08 0x00 r/w als lower threshold (low byte) lothr[7:0] 0x09 0x00 r/w www.datasheet.co.kr datasheet pdf - http://www..net/
10 _____________________________________________________________________________________ MAX44000 ambient and infrared proximity sensor register description (continued) the individual register bits are explained below. default power-up bit states are highlighted in bold. interrupt status register (0x00) the pwron bit in the interrupt status register 0x00, if set, indicates that a power-on-reset (por) condition has occurred, and any user-programmed thresholds cannot be valid anymore. the alsints bit in the interrupt status reg - ister 0x00 indicates that an ambient light interrupt condition has occurred. the prxints bit in the interrupt status reg - ister 0x00 indicates that a proximity receive interrupt condition has occurred. if any of these bits is set to 1, the int pin is pulled low and asserted. note: on rev-1 of the device, the pwron bit does not pull the int pin low, even if set to 1. reading the interrupt status register clears the pwron, alsints, and prxints bits, if set, and deasserts the int pin. int is pulled high by the off-chip pullup resistor. the alsints and prxints bits are disabled and set to 0 if the respective interrupt enable bits in main configuration register 0x01 are set to 0. ambient interrupt status (alsints) register b7 b6 b5 b4 b3 b2 b1 b0 register address power-on reset state r/w threshold persist timer prxpst[1:0] alspst[1:0] 0x0a 0x00 r/w prox threshold indicator above 0x0b 0x00 r/w prox threshold prxthr[7:0] 0x0c 0x00 r/w digital gain trim of green channel trim_gain_green[6:0] trim_ green_ ir[0] 0x0f 0x80 r/w digital gain trim of infrared channel trim_gain_ir[8:1] 0x10 0x80 r/w register b7 b6 b5 b4 b3 b2 b1 b0 register address power-on reset state r/w interrupt status pwron prxints alsints 0x00 0x04 r bit 0 operation 0 no interrupt trigger event has occurred. 1 the ambient light intensity has traversed outside the designated window limits defined by threshold registers for greater than persist timer count alspst[1:0], or an overflow condition in the ambient light readings has occurred. this bit also causes the int pin to be pulled low. once set, the only way to clear this bit is to read this register or to set the alsinte bit in register 0x01 to 0. www.datasheet.co.kr datasheet pdf - http://www..net/
______________________________________________________________________________________ 11 MAX44000 ambient and infrared proximity sensor proximity interrupt status (prxints) power-on reset status (pwron) main configuration register (0x01) this register is used to set the operating mode of the ic (als and/or proximity) and enable interrupt operation of the device. trim mode[2:0] the 3-bit mode[2:0] defines eight operating modes for the ic, as shown below. bit 1 operation 0 no interrupt trigger event has occurred. 1 the ir proximity receive intensity has exceeded the threshold limit for greater than persist timer count prxpst[1:0]. this bit also causes the int pin to be pulled low. once set, the only way to clear this bit is to read this register or to set prxinte bit to 0. bit 2 operation 0 no interrupt trigger event has occurred. 1 the part went through a power-up event, either because the part was turned on or because there was a power- supply voltage glitch. all interrupt threshold settings in the registers have been reset to a default state and should be examined. a 1 on this bit also causes the int pin to be pulled low. note: int is not pulled low on rev-1 of the ic. once this bit is set, the only way to clear this bit is to read this register. register b7 b6 b5 b4 b3 b2 b1 b0 register address power-on reset state r/w main configuration trim mode[2:0] prxinte alsinte 0x01 0x24 r/w bit 5 operation 0 use bytes written to trim_gain_green[7:0] and trim_gain_ir[7:0] registers to set the fine-trim gain of the green and ir gain channels. 1 use factory-programmed gains for green and ir channels. ignore bytes written to trim_gain_green[7:0] and trim_gain_ir[7:0] registers. mode[2:0] operating mode operation 000 shutdown analog circuits are shut down, but the digital register retains values. 001 als g-ir standard als mode stores the difference between green and infrared channel readings. proximity channel operation and updates are disabled. 010 als g als green channel only. proximity channel operation and updates are disabled. 011 als ir infrared channel only. proximity channel operation and updates are disabled. 100 als/prox als and prox are interleaved continuously. 101 prox only prox only continuously. als channel operation and updates are disabled. 110 reserved do not use. 111 reserved do not use. www.datasheet.co.kr datasheet pdf - http://www..net/
12 _____________________________________________________________________________________ MAX44000 ambient and infrared proximity sensor proximity interrupt enable (prxinte) ambient interrupt enable (alsinte) receive configuration register (0x02) this register sets the adc integration time and front-end photodiode circuitry sensitivity (gain) for the als channel. the adc integration time also controls the bit resolution of measurements. adc conversions are made of msb first (the ic needs longer conversion times for higher resolution measurements). use of lower pga gains helps expand the full-scale range of the adc at the expense of per-lsb sensitivity. bit 1 operation 0 the prxints bit remains unasserted, and proximity channel readings are not compared with interrupt thresholds. 1 detection of a proximity interrupt event triggers a hardware interrupt (int pin is pulled low) and sets the prxints bit (register 0x00, b1). proximity channel readings are compared with proximity interrupt threshold settings and proximity persist timer. bit 0 operation 0 the alsints bit remains unasserted, and als channel readings are not compared with interrupt thresholds. 1 detection of an ambient light interrupt event triggers a hardware interrupt (int pin is pulled low) and sets the alsints bit (register 0x00, b0). als channel readings are compared with als interrupt threshold settings and als persist timer. register b7 b6 b5 b4 b3 b2 b1 b0 register address power-on reset state r/w receive configuration 1 1 1 1 alstim[1:0] alspga[1:0] 0x02 0x00 r/w www.datasheet.co.kr datasheet pdf - http://www..net/
______________________________________________________________________________________ 13 MAX44000 ambient and infrared proximity sensor ambient adc conversion time (alstim) the 2-bit alstim[1:0] sets the integration time for als adc conversion, as shown in table 1. table 1. ambient adc conversion time ambient light measurement gain (alspga) the 2-bit alspga[1:0] sets the gain of the ambient light sensing measurement according to table 2. table 2. ambient light measurement gain transmit configuration register (0x03) this register controls the driver current setting and is used when the proximity channel is enabled. led drive current setting (drv) the 4 bits of drv set the led drive current according to table 3. table 3. led drive current settings alstim[1:0] integration time (ms) full-scale adc counts bit resolution relative lsb size 00 100 16,384 14 1x 01 25 4096 12 4x 10 6.25 1024 10 16x 11 1.5625 256 8 64x alspga[1:0] lux/lsb relative lsb size 00 0.03125 1x 01 0.125 4x 10 0.5 16x 11 4 128x register b7 b6 b5 b4 b3 b2 b1 b0 register address power-on reset state r/w transmit configuration drv[3:0] 0x03 0x00 r/w drv[3:0] led current (ma) drv[3:0] led current (ma) 0000 led driver disabled 1000 40 0001 10 1001 50 0010 20 1010 60 0011 30 1011 70 0100 40 1100 80 0101 50 1101 90 0110 60 1110 100 0111 70 1111 110 www.datasheet.co.kr datasheet pdf - http://www..net/
14 _____________________________________________________________________________________ MAX44000 ambient and infrared proximity sensor the 2 bytes here (alsdata[13:0]) hold the results of the als signal conversion. the resolution and bit length of the result is controlled by the value of alstim[1:0] and alspga[1:0] bits. the result is always right justified in the two registers, and the unused high bits are zero. ofl indicates an overflow condition on the als channel. if this occurs, set the als range (alspga[1:0]) to a higher range. if the ofl bit is set to 1 (there is an overflow condition), and the alsinte bit is set to 1 (enabled), then the alsints bit is set to 1 and the int pin is pulled low. the data in this register could be the green channel, infrared channel, or als readings (green channel, infrared chan - nel readings), depending on the mode selected by the user. internal update of these two registers is disabled during i 2 c read operations to ensure proper data handoff between the adc and the i 2 c registers. update of the i 2 c registers is resumed once the master sends a stop (p) command. therefore, when reading the 2 bytes of this register, the master should not send a stop command between the 2-byte reads. instead, a repeated start (sr) command should be used. the exact read sequence using the repeated start command is shown in the i 2 c serial interface section. als data register (0x04, 0x05) prox data registers (0x15, 0x16) the byte here (prxdata[7:0]) hold the results of the proximity receive signal conversion. internal update of the register is disabled during i 2 c read operations to ensure proper data handoff between the adc and the i 2 c registers. update of the i 2 c registers is resumed once the master sends a stop command. register b7 b6 b5 b4 b3 b2 b1 b0 register address power-on reset state r/w adc high byte (als) ofl alsdata[13:8] 0x04 0x00 r adc low byte (als) alsdata[7:0] 0x05 0x00 r register b7 b6 b5 b4 b3 b2 b1 b0 register address power-on reset state r/w adc byte (prox) prxdata[7:0] 0x16 0x00 r www.datasheet.co.kr datasheet pdf - http://www..net/
______________________________________________________________________________________ 15 MAX44000 ambient and infrared proximity sensor als interrupt threshold registers (0x06C0x09) als/prox threshold persist timer register (0x0a) the MAX44000 incorporates a persist function that allows the users to set the number of consecutive triggers before interrupt. prxpst[1:0] and alspst[1:0] set one of four persist values that control how readily the interrupt logic reacts to a detected event. this feature is added to reduce false or nuisance interrupts. when alspst[1:0] is set to 00, and the alsinte bit is set to 1, the first time an als interrupt event is detected, the alsinte interrupt bit is set and the int pin goes low. if alspst[1:0] is set to 01, then four consecutive interrupt events must be detected on four consecutive measurement cycles. similarly, if alspst[1:0] is set to 10, or 11, then 8 or 16 consecutive interrupts must be detected. if there is an intervening measurement cycle where no interrupt is detected, then the count is reset to zero. the proximity interrupt function is managed in the same way with prxpst[1:0]. the als upper threshold and als lower threshold (upthr[13:0] and lothr[13:0]) set the window limits that are used to trigger an als interrupt. it is important to set these values according to the selected bit resolution/integration time chosen for the als measurement based on the alstim[1:0] and alspga[1:0] settings. the upper 2 bits are always ignored. if the inte bit is set, and the lux level is greater or lower than the respective thresholds for a period greater than that defined by the alspst persist time, the ints bit in the status register is set and the int pin is pulled low. register b7 b6 b5 b4 b3 b2 b1 b0 register address power-on reset state r/w threshold persist timer prxpst[1:0] alspst[1:0] 0x0a 0x00 r/w prxpst[1:0] or alspst[1:0] no. of consecutive triggers before interrupt 00 1 01 2 10 4 11 16 register b7 b6 b5 b4 b3 b2 b1 b0 register address power-on reset state r/w als upper threshold (high byte) upthr[13:8] 0x06 0x00 r/w als upper threshold (low byte) upthr[7:0] 0x07 0x00 r/w als lower threshold (high byte) lothr[13:8] 0x08 0x00 r/w als lower threshold (low byte) lothr[7:0] 0x09 0x00 r/w www.datasheet.co.kr datasheet pdf - http://www..net/
16 _____________________________________________________________________________________ MAX44000 ambient and infrared proximity sensor proximity threshold registers (0x0b, 0x0c) the value set by prxthr[7:0] in combination with the above bit controls the operation of the proximity interrupt func - tion. if the above bit is set to 1, the proximity interrupt has been enabled (prxinte = 1), and the result of a proximity measurement is greater than the value stored in prxthr[7:0], then a proximity interrupt event is recorded. the inter - rupt bit is set subject to count conditions set by prxpst[1:0]. similarly, if the above bit is set to 0, then an interrupt event is recorded if the result of a proximity measurement is less than value stored in prxthr[7:0]. digital gain trim registers (0x0f, 0x10) note: values read from trim_gain_ registers are the complements of the written value. this is true for reading both the factory- programmed values and the customer-programmed values. trim_gain_green[6:0] is used to modify the gain of the green channel. trim_gain_ir[8:0] is used to modify the gain of the ir channel. to tell the part to use the values written to this register, set the trim bit to 0 in the main configuration register after writing new values to these registers. register b7 b6 b5 b4 b3 b2 b1 b0 register address power-on reset state r/w prox threshold indicator above 0x0b 0x00 r/w prox threshold prxthr[7:0] 0x0c 0x00 r/w register b7 b6 b5 b4 b3 b2 b1 b0 register address power-on reset state r/w digital gain trim of green channel trim_gain_green[6:0] trim_ gain_ ir[0] 0x0f 0x80 r/tw digital gain trim of infrared channel trim_gain_ir[8:1] 0x10 0x80 r/tw www.datasheet.co.kr datasheet pdf - http://www..net/
______________________________________________________________________________________ 17 MAX44000 ambient and infrared proximity sensor applications information ambient sensing applications typical applications involve placing the ic behind a glass with a small semitransparent window placed above it. use the photodiode sensitive area as shown in figure 3 to properly position the window above the part. the part comes equipped with internal gain trim regis - ters for the green and ir als photodiodes. by suitably choosing the gains for these channels, accurate ambient light readings can be generated in all lighting conditions irrespective of the type of glass the part is used under. this is especially useful for black-glass applications, where for cosmetic reasons, the part is placed behind a black film to hide its presence, and this film has the peculiar property of attenuating most ambient light, but passing through infrared radiation. in standard als mode, the green channel and infrared channel readings are internally subtracted. since one is observing only the difference in two separate adc mea - surements, wrong readings can be obtained if one of the channels becomes saturated, while the other channel continues to rise. since both the green photodiode also picks up a lot of the infrared signal, this saturation can occur much before the maximum expected full-scale range in certain lighting conditions. for example, under incandescent light, there is a lot more infrared optical power than in the visible spectral range. in these situa - tions, the green channel can saturate much earlier than 511 lux in the most sensitive range. to assist the user in detecting these conditions, an ofl bit is provided that alerts the user of an overrange condition. this bit also triggers an als interrupt if it has been enabled. proximity sensing applications the ic integrates a novel proximity sensor interface circuit with a robust built-in ambient ir cancellation scheme. the internal dc ir rejection circuit eliminates problems of adc saturation in the presence of strong ambient infrared radiation, such as bright sunlight. further, the proximity sensor uses a single-pulse scheme for the ir transmitter that eliminates red-glow problems seen in competing solutions to drive 850nm ir leds, while also reducing average ir led power consumption to less than 0.1% of the ir led peak current. interrupt operation ambient interrupt is enabled by setting bit 0 of register 0x01 to 1 and proximity interrupt is enabled by setting bit 1 of register 0x01 to 1 (see table 1 and table 2). the interrupt pin, int , is an open-drain output and pulls low when an interrupt condition occurs (e.g., when ambient lux readings exceed threshold limits for a period greater than that set by the time register). the interrupt status bit is cleared automatically if register 0x00 is read or if the interrupts are disabled. a pwron interrupt bit is set to alert the master of a chip reset operation in case of a power-supply glitch that can happen on smartphones that place the light sensor on a flex with a small connector. it is best to utilize the interrupt pin on the ic to alert the master to come and read measurements from the ic. this eliminates the need for the microcontroller (i 2 c master) to continually poll the device for information. due to the use of pullup resistors on the i 2 c bus, minimizing i 2 c bus activity can reduce power consumption substantially. in addition, this frees up the microcontroller resources to service other background processes to improve device performance. the wide variety of smarts available on the chip, such as the ability to set the threshold levels and to count persist timer limits, allow the part to operate in an autonomous mode most of the time. figure 3. photodiode location MAX44000 top view 2mm 2mm 0.753mm 1.226mm 0.39mm 0.492mm drv 3 1 v cc 2 5s cl 6 sda gnd photo- diode 4 int www.datasheet.co.kr datasheet pdf - http://www..net/
18 _____________________________________________________________________________________ MAX44000 ambient and infrared proximity sensor interrupt pin voltage compliance the interrupt pin can withstand external voltages up to 4v when in high-impedance mode per the absolute maximum ratings of the ic. however, when the voltage on the int pin is higher than the v dd of the part (such as when external pullup voltage is greater than v dd of part), there is a small leakage current of 25a sink into int . this additional current drawn through the int pin should also be accounted for in power-sensitive applications. typical operating sequence the typical operating sequence for the master to com - municate to the ic is shown below: 1) read the interrupt status register (0x00) to confirm only the pwron bit is set. this also clears a hard - ware interrupt. note: for rev-1 devices, a pwron interrupt does not trigger a hardware interrupt. 2) set the threshold and threshold persist timer registers for ambient and proximity sensor mea - surements (registers 0x06C0x0c). note: for rev-1 devices, leave the threshold persist timer register (register 0x0a) set to 0. 3) write f0 to the receive configuration register (register 0x02) to set the als sensor in the high - est gain setting and als adcs in 14-bit modes of operation. 4) set the ir led current to a suitable level by writing to the transmit configuration register (0x03). 5) write 0x13 to main configuration register (register 0x01) to set the part in als + proximity mode, and to enable als and proximity interrupts. 6) set the new green channel gains and infrared channel gains, if necessary, to customize als operation for application conditions. ensure the trim bit is set to 0 when not using default factory- trim settings. 7) wait for interrupt. 8) read the interrupt status register (0x00) to confirm the ic to be the source of interrupt, and to check for the type of interrupt. if set, this should clear the hardware interrupt on the part. 9) if an als interrupt has occurred, read the adc high byte (als) and adc low byte (als) registers (registers 0x04, 0x05) to confirm if data is valid (i.e., ofl = 0), and take appropriate action (e.g., sets new backlight strength). set new als thresholds, if necessary. 10) if a prox interrupt has occurred, read the prox adc registers (register 0x15) and take appropriate action (typically, turn off or turn on touch screen and backlight). set new proximity thresholds, if necessary. 11) return to step 7. i 2 c serial interface the ic features an i 2 c/smbus-compatible, 2-wire serial interface consisting of a serial-data line (sda) and a serial-clock line (scl). sda and scl facilitate commu - nication between the ic and the master at clock rates up to 400khz. figure 4 shows the 2-wire interface tim - ing diagram. the master generates scl and initiates data transfer on the bus. a master device writes data to the ic by transmitting the proper slave address fol - lowed by the register address and then the data word. each transmit sequence is framed by a start (s) or repeated start condition and a stop condition. each word transmitted to the ic is 8 bits long and is followed by an acknowledge clock pulse. a master reading data from the ic transmits the proper slave address followed by a series of nine scl pulses. the ic transmits data on sda in sync with the master-generated scl pulses. the master acknowledges receipt of each byte of data. each read sequence is framed by a start or repeated start condition, a not acknowledge, and a stop condi - tion. sda operates as both an input and an open-drain output. a pullup resistor, typically greater than 500 i , is required on the sda bus. scl operates as only an input. a pullup resistor, typically greater than 500 i , is required on scl if there are multiple masters on the bus, or if the master in a single-master system has an open-drain scl output. series resistors in line with sda and scl are optional. series resistors protect the digital inputs of the ic from high-voltage spikes on the bus lines, and mini - mize crosstalk and undershoot of the bus signal. table 4. slave address slave address for writing slave address for reading 1001 0100 1001 0101 www.datasheet.co.kr datasheet pdf - http://www..net/
______________________________________________________________________________________ 19 MAX44000 ambient and infrared proximity sensor bit transfer one data bit is transferred during each scl cycle. the data on sda must remain stable during the high period of the scl pulse. changes in sda while scl is high are control signals. see the start and stop conditions sec - tion. sda and scl idle high when the i 2 c bus is not busy. start and stop conditions sda and scl idle high when the bus is not in use. a master initiates communication by issuing a start con - dition. a start condition is a high-to-low transition on sda with scl high. a stop condition is a low-to-high transition on sda while scl is high (figure 5). a start condition from the master signals the beginning of a transmission to the ic. the master terminates transmis - sion, and frees the bus by issuing a stop condition. the bus remains active if a repeated start condition is generated instead of a stop condition. early stop conditions the ic recognizes a stop condition at any point during data transmission except if the stop condition occurs in the same high pulse as a start condition. for proper operation, do not send a stop condition during the same scl high pulse as the start condition. acknowledge the acknowledge bit (ack) is a clocked 9th bit that the ic uses to handshake receipt of each byte of data when in write mode (figure 6). the ic pulls down sda dur - ing the entire master-generated ninth clock pulse if the previous byte is successfully received. monitoring ack allows for detection of unsuccessful data transfers. an unsuccessful data transfer occurs if a receiving device is busy or if a system fault has occurred. in the event of an unsuccessful data transfer, the bus master can retry communication. the master pulls down sda during the ninth clock cycle to acknowledge receipt of data when the ic is in read mode. an acknowledge is sent by the master after each read byte to allow data transfer to continue. a not acknowledge is sent when the master reads the final byte of data from the ic, followed by a stop condition. figure 4. 2-wire interface timing diagram figure 5. start, stop, and repeated start conditions figure 6. acknowledge scl sda start condition stop condition repeated start condition start condition t hd,sta t su,sta t hd,sta t sp t buf t su,sto t low t su,dat t hd,dat t high t r t f scl sda ss rp 1 scl start condition sda 28 9 clock pulse for acknowledgment acknowledge not acknowledge www.datasheet.co.kr datasheet pdf - http://www..net/
20 _____________________________________________________________________________________ MAX44000 ambient and infrared proximity sensor write data format a write to the ic includes transmission of a start condi - tion, the slave address with the r/ w bit set to 0, 1 byte of data to configure the internal register address pointer, one or more bytes of data, and a stop condition. figure 7 illustrates the proper frame format for writing 1 byte of data to the ic. the slave address with the r/ w bit set to 0 indicates that the master intends to write data to the ic. the ic acknowledges receipt of the address byte during the master-generated ninth scl pulse. the second byte transmitted from the master configures the ics internal register address pointer. the pointer tells the ic where to write the next byte of data. an acknowledge pulse is sent by the ic upon receipt of the address pointer data. the third byte sent to the ic contains the data that is written to the chosen register. an acknowledge pulse from the ic signals receipt of the data byte. figure 8 illus - trates how to write to multiple registers with one frame. the master signals the end of transmission by issuing a stop condition. read data format send the slave address with the r/ w bit set to 1 to initi - ate a read operation. the ic acknowledges receipt of its slave address by pulling sda low during the ninth scl clock pulse. a start command followed by a read command resets the address pointer to register 0x00. the first byte transmitted from the ic is the contents of register 0x00. transmitted data is valid on the rising edge of the master-generated serial clock (scl). the address pointer autoincrements after each read data byte. this autoincrement feature allows all registers to be read sequentially within one continuous frame. a stop condi - tion can be issued after any number of read data bytes. if a stop condition is issued followed by another read operation, the first data byte to be read is from register 0x00 and subsequent reads autoincrement the address pointer until the next stop condition. the address pointer can be preset to a specific register before a read command is issued. the master presets the address pointer by first sending the ics slave address with the r/ w bit set to 0 followed by the register address. a repeated start condition is then sent, followed by the slave address with the r/ w bit set to 1. the ic trans - mits the contents of the specified register. the address pointer autoincrements after transmitting the first byte. attempting to read from register addresses higher than 0xff results in repeated reads of 0xff. note that 0xf6 to 0xff are reserved registers. the master acknowl - edges receipt of each read byte during the acknowledge clock pulse. the master must acknowledge all correctly received bytes except the last byte. the final byte must be followed by a not acknowledge from the master and then a stop condition. figure 8 illustrates the frame format for reading 1 byte from the ic. figure 9 illustrates the frame format for reading two registers consecutively without a stop condition in between reads. figure 7. writing 1 byte of data to the ic a 0 slave address register address data byte acknowledge from MAX44000 r/w 1 byte acknowledge from MAX44000 acknowledge from MAX44000 b1 b0 b3 b2 b5 b4 b7 b6 s a a p www.datasheet.co.kr datasheet pdf - http://www..net/
______________________________________________________________________________________ 21 MAX44000 ambient and infrared proximity sensor figure 8. reading 1 indexed byte of data from the ic figure 9. reading two registers consecutively without a stop condition between reads acknowledge from MAX44000 1 byte acknowledge from MAX44000 not acknowledge from master a a p a 0 acknowledge from MAX44000 r/w sa r/w repeated start sr 1 slave address register address slave address data byte acknowledge from MAX44000 1 byte acknowledge from MAX44000 not acknowledge from master a a sr not acknowledge from master a 0 acknowledge from MAX44000 r/w sa r/w repeated start sr 1 slave address register address 1 slave address data byte 1 acknowledge from MAX44000 1 byte acknowledge from MAX44000 a a ap 0 acknowledge from MAX44000 r/w a s r/w repeated start sr 1 slave address register address 2 slave address data byte 2 www.datasheet.co.kr datasheet pdf - http://www..net/
22 _____________________________________________________________________________________ MAX44000 ambient and infrared proximity sensor typical applications circuit sda scl c (i 2 c master) i 2 c slave_1 sda scl i 2 c slave_1 sda 1.7v to 3.6v 10ki 10ki 10ki scl sda scl int v dd gnd drv int 1.7v to 3.6v 1f v led = 1.7v to 3.6v ir led MAX44000 www.datasheet.co.kr datasheet pdf - http://www..net/
______________________________________________________________________________________ 23 MAX44000 ambient and infrared proximity sensor package information for the latest package outline information and land patterns (footprints), go to www.maxim-ic.com/packages . note that a +, #, or - in the package code indicates rohs status only. package drawings may show a different suffix character, but the drawing pertains to the package regardless of rohs status. package type package code outline no. land pattern no. 6 otdfn-ep d622n+2 21-0490 90-0344 www.datasheet.co.kr datasheet pdf - http://www..net/
maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a maxim product. no circuit patent licenses are implied. maxim reserves the right to change the circuitry and specifications without notice at any time. 24 maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 ? 2011 maxim integrated products maxim is a registered trademark of maxim integrated products, inc. MAX44000 ambient and infrared proximity sensor revision history revision number revision date description pages changed 0 10/11 initial release www.datasheet.co.kr datasheet pdf - http://www..net/

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