View MAX30105_9059635.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

general description the MAX30105 is an integrated particle-sensing module. it includes internal leds, photodetectors, optical elements, and low-noise electronics with ambient light rejection. the MAX30105 provides a complete system solution to ease the design-in process of smoke detection applications including fire alarms. due to its extremely small size, the MAX30105 can also be used as a smoke detect ion sen - sor for mobile and wearable devices. the MAX30105 operates on a single 1.8v power supply and a separate 5.0v power supply for the internal leds. it communicates through a standard i 2 c-compatible inter - face. the module can be shut down through software with zero standby current, allowing the power rails to remain powered at all times. applications fire alarms smoke detectors for building automation smoke detectors for mobile devices smoke detectors for wearable devices benefts and features high sensitivity optical reflective solution for detection of wide variety of particle sizes tiny 5.6mm x 3.3mm x 1.55mm 14-pin optical module ? integrated cover glass for optimal, robust performance ultra-low power operation ? programmable sample rate and led current for power savings ? ultra-low shutdown current (0.7a, typ) robust motion artifact resilience ? high snr -40c to +85c operating temperature range capable of operating at high ambient levels excellent ambient rejection capability ordering information appears at end of data sheet. 19-8531; rev 1; 7/16 photo diode led drivers red/ir/green led packaging smoke/steam particles electrical optical ambient light 18-bit current adc ambient light cancellation digital noise cancellation data fifo host (ap) i 2 c driver hardware framework applications acrylic (cover glass) MAX30105 system diagram MAX30105 high-sensitivity optical sensor for smoke detection applications
v dd to gnd ......................................................... -0.3v to +2.2v gnd to pgnd ...................................................... -0.3v to +0.3v x_drv, v led+ to pgnd ...................................... -0.3v to +6.0v all other pins to gnd .......................................... -0.3v to +6.0v output short-circuit current duration ....................... continuous continuous input current into any terminal .................... 20ma continuous power dissipation (t a = +70c) oesip (derate 5.5mw/c above +70c) .................... 440mw operating temperature range .......................... -40c to +85c junction temperature ........................................................ +90c soldering temperature (reflow) ...................................... +260c storage temperature range ............................ -40c to +105c oesip junction-to-ambient thermal resistance ( ja ) ........ 180c/w junction-to-case thermal resistance ( jc ) ................. 150c/w (note 1) (v dd = 1.8v, v led+ = 5.0v, t a = -40c to +85c, unless otherwise noted. typical values are at t a = 25c.) (note 2) parameter symbol conditions min typ max units power supply power-supply voltage v dd guaranteed by red and ir count tolerance 1.7 1.8 2.0 v led supply voltage v led+ guaranteed by psrr of led driver (r_led+ and ir_led+ only) 3.1 3.3 5.25 v supply current i dd particle-sensing mode, pw = 215s, 50sps 600 1100 a ir only mode, pw = 215s, 50sps 600 1100 supply current in shutdown i shdn t a = +25c, mode = 0x80 0.7 2.5 a optical sensor characteristics adc resolution 18 bits red adc count (note 3) redc red_pa = 0x0c, led_pw = 0x01, spo2_sr = 0x05, adc_rge = 0x00, t a = +25c 65536 counts ir adc count (note 3) irc ir_pa = 0x0c, led_pw = 0x01, spo2_sr = 0x05 adc_rge = 0x00, t a = +25c 65536 counts green adc count (note 3) grnc grn_pa = 0x24, led_pw = 0x11, spo2_sr = 0x05 adc_rge = 0x00, t a = +25c 65536 counts snr ir led snr ir white card loop-back, led_pw = 0x11, adc_rge = 0x10, t a = 25c 89 300 db snr red led snr red white card loop-back, led_pw = 0x11, adc_rge = 0x10, t a = 25c 88.9 300 db snr green led snr green white card loop-back, led_pw = 0x11, adc_rge = 0x01, t a = 25c 80.4 db maxim integrated 2 note 1: package thermal resistances were obtained using the method described in jedec specification jesd51-7, using a four-layer board. for detailed information on package thermal considerations, refer to www.maximintegrated.com/thermal-tutorial . absolute maximum ratings package thermal characteristics electrical characteristics www.maximintegrated.com MAX30105 high-sensitivity optical sensor for smoke detection applications
(v dd = 1.8v, v led+ = 5.0v, t a = -40c to +85c, unless otherwise noted. typical values are at t a = 25c.) (note 2) parameter symbol conditions min typ max units dark current count led_dcc red_pa = ir_pa = 0x00, led_pw = 0x03, spo2_sr = 0x01 adc_rge = 0x02 30 128 counts 0.01 0.05 % of fs dc ambient light rejection (note 4) alr adc counts with fnger on sensor under direct sunlight (100k lux), adc_rge = 0x3, led_pw = 0x03, spo2_sr = 0x01 red led 2 counts ir led 2 counts adc countpsrr (v dd ) psrrv dd 1.7v < v dd < 2.0v, led_pw = 0x00, spo2_sr = 0x05 t a = +25c 0.25 1 % of fs frequency = dc to 100khz, 100mv p-p 10 lsb adc countpsrr (led driver outputs) psrr led 3.6v < v led+ , < 5.0v, t a = +25c 0.05 1 % of fs frequency = dc to 100khz, 100mv p-p 10 lsb adc clock frequency clk 10.2 10.48 10.8 mhz adc integration time (note 4) int led_pw = 0x00 69 s led_pw = 0x01 118 led_pw = 0x02 215 led_pw = 0x03 411 slot timing (timing between sequential channel samples; e.g., red pulse rising edge to ir pulse rising edge) int led_pw = 0x00 427 s led_pw = 0x01 525 led_pw = 0x02 720 led_pw = 0x03 1107 cover glass characteristics (note 4) hydrolytic resistance class per din iso 719 hgb 1 ir led characteristics (note 4) led peak wavelength p i led = 20ma, t a = +25c 870 880 900 nm full width at half max ? i led = 20ma, t a = +25c 30 nm forward voltage v f i led = 20ma, t a = +25c 1.4 v radiant power p o i led = 20ma, t a = +25c 6.5 mw red led characteristics (note 4) led peak wavelength p i led = 20ma, t a = +25c 650 660 670 nm full width at half max ? i led = 20ma, t a = +25c 20 nm forward voltage v f i led = 20ma, t a = +25c 2.1 v maxim integrated 3 electrical characteristics (continued) www.maximintegrated.com MAX30105 high-sensitivity optical sensor for smoke detection applications
(v dd = 1.8v, v led+ = 5.0v, t a = -40c to +85c, unless otherwise noted. typical values are at t a = 25c.) (note 2) radiant power p o i led = 20ma, t a = +25c 9.8 mw parameter symbol conditions min typ max units green led characteristics (note 4) led peak wavelength p i led = 50ma, t a = +25c 530 537 545 nm full width at half max ? i led = 50ma, t a = +25c 35 nm forward voltage v f i led = 50ma, t a = +25c 33 v radiant power p o i led = 50ma, t a = +25c 17.2 mw photodetector characteristics (note 4) spectral range of sensitivity > 30% qe qe: quantum effciency 640 980 nm radiant sensitive area a 1.36 mm 2 dimensions of radiant sensitive area l x w 1.38 x 0.98 mm x mm internal die temperature sensor temperature adc acquisition time t t t a = +25c 29 ms temperature sensor accuracy t a t a = +25c 1 c temperature sensor minimum range t min -40 c temperature sensor maximum range t max 85 c digital inputs (scl, sda) input logic-low voltage v il 0.3 x v dd v input logic-high voltage v ih 0.7 x v dd v input hysteresis v hys 0.5 x v dd v input leakage current i in 0.1 1 a input capacitance c in 10 pf digital outputs (sda, int) output low voltage v ol i sink = 3ma 0.4 v i 2 c timing characteristics i 2 c write address ae hex i 2 c read address af hex scl clock frequency f scl lower limit not tested 0 400 khz bus free time between stop and start condition t buf 1.3 s maxim integrated 4 electrical characteristics (continued) www.maximintegrated.com MAX30105 high-sensitivity optical sensor for smoke detection applications
(v dd = 1.8v, v led+ = 5.0v, t a = -40c to +85c, unless otherwise noted. typical values are at t a = 25c.) (note 2) note 2: all devices are 100% production tested at t a = +25c. specifications over temperature limits are guaranteed by maxim integrateds bench or proprietary automated test equipment (ate) characterization. note 3: specifications are guaranteed by maxim integrateds bench characterization and by 100% production test using proprietary ate setup and conditions. note 4: for design guidance only. not production tested. note 5: these specifications are guaranteed by design, characterization, or i 2 c protocol. figure 1. i 2 c-compatible interface timing diagram parameter symbol conditions min typ max units hold time (repeated) start condition t hd,sta 0.6 s scl pulse-width low t low 1.3 s scl pulse-width high t high 0.6 s setup time for a repeated start condition t su,sta 0.6 s data hold time t hd;dat 0 0.9 s data setup time t su;dat 100 ns setup time for stop condition t su;sto 0.6 s pulse width of suppressed spike t sp 50 ns bus capacitance c b 400 pf sda and scl receiving rise time t r (note 5) 20 300 ns sda and scl receiving fall time t rf (note 5) 20 x v dd /5.5 300 ns sda transmitting fall time t of 20 x v dd /5.5 250 ns sda scl t hd,sta start condition t r t f t low t su,dat t hd,dat t su,sta t hd,sta repeated start condition t sp t su,sto t buf stop condition start condition t high maxim integrated 5 electrical characteristics (continued) www.maximintegrated.com MAX30105 high-sensitivity optical sensor for smoke detection applications
(v dd = 1.8v, v led+ = 5.0v, t a = +25c, unless otherwise noted.) 0 10 20 30 40 50 60 0 1 2 3 4 5 ir led current (ma) v led voltage (v) ir led supply headroom toc02 i led = 50ma i led = 20ma 0 10 20 30 40 50 60 0 1 2 3 4 5 green led current (ma) v led voltage (v) green led supply headroom toc03 i led = 50ma i led = 20ma v led = v x_drv 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 0 0.5 1 1.5 2 2.5 supply current (ma) supply voltage (v) v dd supply current vs . supply voltage toc04 shutdown mode 0 5000 10000 15000 20000 25000 30000 35000 40000 45000 50000 0 5 10 15 20 counts (sum) distance (mm) dc counts vs. distance for white high impact styrene card toc05 green ir mode = spo2 and hr adc res = 18 bits adc sr = 100 sps adc full scale = 16384na dc counts vs. distance for white high impact styrene card red mode = led adc res = 18 bits adc sr = 100 sps adc full scale = 16384na 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 -50 0 50 100 150 v dd shutdown current (a) temperature ( c) v dd shutdown current vs. temperature toc06 v dd 2.2v 2.0v 1.8v 1.7v 0 10 20 30 40 50 60 0 1 2 3 4 5 red led current (ma) v led voltage (v) red led supply headroom toc01 i led = 50ma i led = 20ma -20 0 20 40 60 80 100 120 500 600 700 800 normalized power (%) wavelength (nm) red led spectra at t a = +30 c toc08 0.06 0.07 0.08 0.09 0.10 0.11 0.12 0.13 0.14 -50 0 50 100 150 v led shutdown current (a) temperature ( c) v led shutdown current vs. temperature v led = 4.75v toc07 v led = 5.25v 0 20 40 60 80 100 120 700 800 900 1000 normalized power (%) wavelength (nm) ir led spectra at t a = +30 c toc09 maxim integrated 6 typical operating characteristics www.maximintegrated.com MAX30105 high-sensitivity optical sensor for smoke detection applications
(v dd = 1.8v, v led+ = 5.0v, t a = +25c, unless otherwise noted.) 645 650 655 660 665 670 675 -50 0 50 100 150 peak wa vele ngth (nm) tem pe rat ur e ( c) red led pe ak wa ve length vs . t empe ra t ur e toc11 le d curr en t: 10 ma 20 ma 30 ma 50 ma mode = f lex le d a dc r es = 18 bi ts a dc sr = 400 sp s a dc fu ll sc ale = 2048n a 860 870 880 890 900 910 -50 0 50 100 150 pea k wa ve length (nm) temperature (c) ir led peak wavelength vs. temperature toc12 led cur rent 10ma 20ma 30 m a 50 m a 0 10 20 30 40 50 60 1.80 1.90 2.00 2.10 2.20 2.30 forwa rd curr ent (ma) forwa rd voltage (v) red led forw ard vo lt age vs . forw ar d curr ent at t a = +25c toc13 mode = f lex le d a dc r es = 18 bi ts a dc sr = 100 sp s a dc fu ll sc ale = 2048n a 0 10 20 30 40 50 60 70 1.25 1.30 1.35 1.40 1.45 forwa rd curr ent (ma) forwa rd voltage (v) ir led forw ard vo lt age vs . forw ar d curr ent at t a = +25c toc14 mode = f lex le d a dc r es = 18 bi ts a dc sr = 100 sp s a dc fu ll sc ale = 2048n a 0 10 20 30 40 50 60 2.7 2.8 2.9 3 3.1 forward current (ma) forward voltage (v) green led forward voltage vs. forward current at 25 c toc15 mode = flex led adc res = 18 bits adc sr = 200 sps adc full scale = 2048na 0 25 50 75 100 125 150 0 25 50 75 100 125 150 175 200 225 r el ati ve intensity (%) i f (ma) relati ve intensity vs . g r ee n led forw ard curr ent toc16 -8 -4 0 4 8 12 16 0 50 100 150 200 dominant wa vele ngth shift (nm) i f (ma) domi nan t wa ve length shift vs . g r ee n led forw ard curr ent toc17 -70 -60 -50 -40 -30 -20 -10 0 10 100 1000 10000 100000 magnitude (db) frequency (hz) pw = 69 s pw = 118 s pw = 215 s pw = 411 s ambient reject ion vs. ambient freque nc y toc18 -20 0 20 40 60 80 100 120 400 450 500 550 600 650 700 normalized power (%) wavelength (nm) green led spectra at 30 c toc10 maxim integrated 7 typical operating characteristics (continued) www.maximintegrated.com MAX30105 high-sensitivity optical sensor for smoke detection applications
(v dd = 1.8v, v led+ = 5.0v, t a = +25c, unless otherwise noted.) 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 400 500 600 700 800 900 1000 1100 quantum e ff icie nc y wa vele ngth (nm) photod io de q uan tum e ff icie nc y vs . wa ve length toc19 maxim integrated 8 typical operating characteristics (continued) www.maximintegrated.com MAX30105 high-sensitivity optical sensor for smoke detection applications
pin name function 1, 8, 14 n.c. no connection. connect to pcb pad for mechanical stability. 2 scl i 2 c clock input 3 sda i 2 c clock data, bidirectional (open-drain) 4 pgnd power ground of the led driver blocks 5 r_drv red led driver 6 ir_drv ir led driver 7 g_drv green led driver 9 v led+ led power supply (anode connection). use a bypass capacitor to pgnd for best performance. 10 v led+ 11 v dd analog power supply input. use a bypass capacitor to gnd for best performance. 12 gnd analog ground 13 int active-low interrupt (open-drain). connect to an external voltage with a pullup resistor. n.c. 1 scl 2 sda 3 pgnd 4 r_drv 5 ir_drv 6 g_drv 7 14 n.c. 13 int 12 gnd 11 v dd 10 v led+ 9 v led+ 8 n.c. sensor leds MAX30105 pin description pin confguration maxim integrated 9 www.maximintegrated.com MAX30105 high-sensitivity optical sensor for smoke detection applications
detailed description the MAX30105 is a complete particle detection sensor system solution module. the MAX30105 maintains a very small solution size without sacrificing optical/electrical performance. minimal external hardware components are required for integration into a smoke detection system. the MAX30105 is fully adjustable through software registers, and the digital output data can be stored in a 32-deep fifo within the ic. the fifo allows the MAX30105 to be connected to a microcontroller or processor on a shared bus, where the data is not being read continuously from the MAX30105s registers. particle-sensing subsystem the particle-sensing subsystem contains ambient light cancellation (alc), a continuous-time sigma-delta adc, and proprietary discrete time filter. the alc has an internal track/hold circuit to cancel ambient light and increase the effective dynamic range. the particle-sensing adc has a programmable full-scale range from 2a to 16a. the alc can cancel up to 200a of ambient current. the internal adc is a continuous time oversampling sigma-delta converter with 18-bit resolution. the adc sampling rate is 10.24mhz. the adc output data rate can be programmed from 50sps (samples per second) to 3200sps. temperature sensor the MAX30105 has an on-chip temperature sensor for calibrating the temperature dependence of the particle- sensing subsystem. the temperature sensor has an inherent resolution 0.0625c. led driver the MAX30105 integrates red, green, and ir led drivers to modulate led pulses for particle-sensing measurements. the led current can be programmed from 0 to 50ma with proper supply voltage. the led pulse width can be programmed from 69s to 411s to allow the algorithm to optimize particle-sensing accuracy and power consumption based on use cases. proximity function when the particle-sensing function is initiated (by writing the mode register), the ir led is activated in proximity mode with a drive current set by the pilot_pa register. when an object is detected by exceeding the ir adc count threshold (set in the prox_int_thresh regis - ter), the part transitions automatically to the normal parti- cle-sensing mode. to reenter proximity mode, the mode register must be rewritten (even if the value is the same). the proximity function can be disabled by resetting prox_int_en to 0. in this case, the particle-sensing mode begins immediately. 880nm 660nm adc ambient light cancellation analog adc die temp oscillator digital filter digital data register led drivers i 2 c communication int sda scl v dd v led+ ir_drv r_drv gnd pgnd red ir visible+ir MAX30105 green 527nm g_drv maxim integrated 10 functional diagram www.maximintegrated.com MAX30105 high-sensitivity optical sensor for smoke detection applications
register maps and descriptions register b7 b6 b5 b4 b3 b2 b1 b0 reg addr por state r/w status interrupt status 1 a_full data_ rdy alc_ ovf prox_ int pwr_ rdy 0x00 0x00 r interrupt status 2 die_temp _rdy 0x01 0x00 r interrupt enable 1 a_full_ en data_ rdy_en alc_ ovf_en prox_ int_en 0x02 0x00 r/w interrupt enable 2 die_temp _rdy_en 0x03 0x00 r/w fifo fifo write pointer fifo_wr_ptr[4:0] 0x04 0x00 r/w overfow counter ovf_counter[4:0] 0x05 0x00 r/w fifo read pointer fifo_rd_ptr[4:0] 0x06 0x00 r/w fifo data register fifo_data[7:0] 0x07 0x00 r/w configuration fifo confguration smp_ave[2:0] fifo_ roll over_en fifo_a_full[3:0] 0x08 0x00 r/w mode confguration shdn reset mode[2:0] 0x09 0x00 r/w spo 2 confguration 0 (reserved) adc_rge [1:0] sr[2:0] led_pw[1:0] 0x0a 0x00 r/w reserved 0x0b 0x00 r/w led pulse amplitude led1_pa[7:0] 0x0c 0x00 r/w led2_pa[7:0] 0x0d 0x00 r/w led3_pa[7:0] 0x0e 0x00 r/w reserved 0x0f 0x00 r/w proximity mode led pulse amplitude pilot_pa[7:0] 0x10 0x00 r/w multi-led mode control registers slot2[2:0] slot1[2:0] 0x11 0x00 r/w slot4[2:0] slot3[2:0] 0x12 0x00 r/w maxim integrated 11 www.maximintegrated.com MAX30105 high-sensitivity optical sensor for smoke detection applications
* xx denotes a 2-digit hexadecimal number (00 to ff) for part revision identification. contact maxim integrated for the revision id number assigned for your product. register maps and descriptions (continued) register b7 b6 b5 b4 b3 b2 b1 b0 reg addr por state r/w reserved 0x13C 0x17 0xff r/w reserved 0x18- 0x1e 0x00 r die temperature die temp integer tint[7:0] 0x1f 0x00 r die temp fraction tfrac[3:0] 0x20 0x00 r die temperature confg temp _en 0x21 0x00 r reserved 0x22C 0x2f 0x00 r/w proximity function proximity interrupt threshold prox_int_thresh[7:0] 0x30 0x00 r/w part id revision id rev_id[7:0] 0xfe 0xxx* r part id part_id[7] 0xff 0x15 r maxim integrated 12 www.maximintegrated.com MAX30105 high-sensitivity optical sensor for smoke detection applications
whenever an interrupt is triggered, the MAX30105 pulls the active-low interrupt pin into its low state until the interrupt is cleared. a_full: fifo almost full flag in par t icle-sensing mode, this interrupt triggers when the fifo write pointer has a certain number of free spaces remaining. the trigger number can be set by the fifo_a_full[3:0] register. the interrupt is cleared by reading the interrupt status 1 register (0x00). data_rdy: new fifo data ready in par t icle-sensing mode, this interrupt triggers when there is a new sample in the data fifo. the interrupt is cleared by reading the interrupt status 1 register (0x00), or by reading the fifo_data register. alc_ovf: ambient light cancellation overfow this interrupt triggers when the ambient light cancellation function of the particle-sensing photodiode has reached its maximum limit, and therefore, ambient light is affecting the output of the adc. the interrupt is cleared by reading the interrupt status 1 register (0x00). prox_int: proximity threshold triggered the proximity interrupt is triggered when the proximity threshold is reached, and particle-sensing mode has begun. this lets the host processor know to begin running the particle-sensing algorithm and collect data. the interrupt is cleared by reading the interrupt status 1 register (0x00). pwr_rdy: power ready flag on power-up or after a brownout condition, when the supply voltage v dd transitions from below the undervoltage-lockout (uvlo) voltage to above the uvlo voltage, a power-ready interrupt is triggered to signal that the module is powered-up and ready to collect data. die_temp_rdy: internal temperature ready flag when an internal die temperature conversion is finished, this interrupt is triggered so the processor can read the temperature data registers. the interrupt is cleared by reading either the interrupt status 2 register (0x01) or the tfrac register (0x20). interrupt status (0x00C0x01) register b7 b6 b5 b4 b3 b2 b1 b0 reg addr por state r/w interrupt status 1 a_full data_ rdy alc_ovf prox_ int pwr_ rdy 0x00 0x00 r interrupt status 2 die_ temp_rdy 0x01 0x00 r maxim integrated 13 www.maximintegrated.com MAX30105 high-sensitivity optical sensor for smoke detection applications
the interrupts are cleared whenever the interrupt status register is read, or when the register that triggered the interrupt is read. for example, if the particle-sensing sensor triggers an interrupt due to finishing a conversion, reading either the fifo data register or the interrupt register clears the interrupt pin (which returns to its normal high state). this also clears all the bits in the interrupt status register to zero. interrupt enable (0x02C0x03) each source of hardware interrupt, with the exception of power ready, can be disabled in a software register within the MAX30105 ic. the power-ready interrupt cannot be disabled because the digital state of the module is reset upon a brownout condition (low power supply voltage), and the default condition is that all the interrupts are disabled. also, it is important for the system to know that a brownout condition has occurred, and the data within the module is reset as a result. the unused bits should always be set to zero for normal operation. fifo (0x04C0x07) fifo write pointer the fifo write pointer points to the location where the MAX30105 writes the next sample. this pointer advances for each sample pushed on to the fifo. it can also be changed through the i 2 c interface when mode[2:0] is 010, 011, or 111. fifo overfow counter when the fifo is full, samples are not pushed on to the fifo, samples are lost. ovf_counter counts the number of samples lost. it saturates at 0xf. when a complete sample is popped (i.e., removal of old fifo data and shifting the samples down) from the fifo (when the read pointer advances), ovf_counter is reset to zero. fifo read pointer the fifo read pointer points to the location from where the processor gets the next sample from the fifo through the i 2 c interface. this advances each time a sample is popped from the fifo. the processor can also write to this pointer after reading the samples to allow rereading samples from the fifo if there is a data communication error. register b7 b6 b5 b4 b3 b2 b1 b0 reg addr por state r/w interrupt enable 1 a_ full_ en data_ rdy_en alc_ ovf_en prox_ int_en 0x02 0x00 r/w interrupt enable 2 die_temp_ rdy_en 0x03 0x00 r/w register b7 b6 b5 b4 b3 b2 b1 b0 reg addr por state r/w fifo write pointer fifo_wr_ptr[4:0] 0x04 0x00 r/w over flow counter ovf_counter[4:0] 0x05 0x00 r/w fifo read pointer fifo_rd_ptr[4:0] 0x06 0x00 r/w fifo data register fifo_data[7:0] 0x07 0x00 r/w maxim integrated 14 www.maximintegrated.com MAX30105 high-sensitivity optical sensor for smoke detection applications
fifo data register the circular fifo depth is 32 and can hold up to 32 samples of data. the sample size depends on the number of led channels configured as active. as each channel signal is stored as a 3-byte data signal, the fifo width can be 3 bytes, 6 bytes, 9 bytes, or 12 bytes in size. the fifo_data register in the i 2 c register map points to the next sample to be read from the fifo. fifo_rd_ptr points to this sample. reading the fifo_data register does not automatically increment the i 2 c register address. burst reading this register reads the same address over and over. each sample is 3 bytes of data per channel (i.e., 3 bytes for red, 3 bytes for ir, etc.). the fifo registers (0x04C0x07) can all be written and read, but in practice only the fifo_rd_ptr register should be written to in operation. the others are automatically incremented or filled with data by the MAX30105. when starting a new particle-sensing conversion, it is recommended to first clear the fifo_wr_ptr, ovf_counter, and fifo_rd_ptr registers to all zeroes (0x00) to ensure the fifo is empty and in a known state. when reading the MAX30105 registers in one burst-read i2c transaction, the register address pointer typically increments so that the next byte of data sent is from the next register, etc. the exception to this is the fifo data register, register 0x07. when reading this register, the address pointer does not increment, but the fifo_rd_ptr does. so the next byte of data sent represents the next byte of data available in the fifo. entering and exiting the proximity mode (when prox_int_en = 1) clears the fifo by setting the write and read pointers equal to each other. reading from the fifo normally, reading registers from the i 2 c interface autoincrements the register address pointer, so that all the registers can be read in a burst read without an i 2 c start event. in the MAX30105, this holds true for all registers except for the fifo_data register (register 0x07). reading the fifo_data register does not automatically increment the register address. burst reading this register reads data from the same address over and over. each sample comprises multiple bytes of data, so multiple bytes should be read from this register (in the same transaction) to get one full sample. the other exception is 0xff. reading more bytes after the 0xff register does not advance the address pointer back to 0x00, and the data read is not meaningful. fifo data structure the data fifo consists of a 32-sample memory bank that can store green, ir, and red adc data. since each sample consists of three channels of data, there are 9 bytes of data for each sample, and therefore 288 total bytes of data can be stored in the fifo. the fifo data is left-justified as shown in table 1 ; in other words, the msb bit is always in the bit 17 data position regardless of adc resolution setting. see table 2 for a visual presentation of the fifo data structure. table 1. fifo data is left-justified adc resolution fifo_data[17] fifo_data[16] fifo_data[12] fifo_data[11] fifo_data[10] fifo_data[9] fifo_data[8] fifo_data[7] fifo_data[6] fifo_data[5] fifo_data[4] fifo_data[3] fifo_data[2] fifo_data[1] fifo_data[0] 18-bit 17-bit 16-bit 15-bit maxim integrated 15 www.maximintegrated.com MAX30105 high-sensitivity optical sensor for smoke detection applications
fifo data contains 3 bytes per channel the fifo data is left-justified, meaning that the msb is always in the same location regardless of the adc resolution setting. fifo data[18] C [23] are not used. table 2 shows the structure of each triplet of bytes (containing the 18-bit adc data output of each channel). each data sample in particle-sensing mode comprises two data triplets (3 bytes each), to read one sample, requires an i 2 c read command for each byte. thus, to read one sample in particle-sensing mode requires 6 i 2 c byte reads. to read one sample with three led channels requires 9 i 2 c byte reads. the fifo read pointer is automatically incremented after the first byte of each sample is read. write/read pointers write/read pointers are used to control the flow of data in the fifo. the write pointer increments every time a new sample is added to the fifo. the read pointer is incremented every time a sample is read from the fifo. to reread a sample from the fifo, decrement its value by one and read the data register again. the fifo write/read pointers should be cleared (back to 0x00) upon entering particle-sensing mode, so that there is no old data represented in the fifo. the pointers are automatically cleared if v dd is power-cycled or v dd drops below its uvlo voltage. table 2. fifo data (3 bytes per channel) figure 2a and 2b. graphical representation of the fifo data register. the left shows three leds in multi-led mode, and the right shows ir and red only in particle-sensing mode. byte 1 fifo_ data[17] fifo_ data[16] byte 2 fifo_ data[15] fifo_ data[14] fifo_ data[13] fifo_ data[12] fifo_ data[11] fifo_ data[10] fifo_ data[9] fifo_ data[8] byte 3 fifo_ data[7] fifo_ data[6] fifo_ data[5] fifo_ data[4] fifo_ data[3] fifo_ data[2] fifo_ data[1] fifo_ data[0] sample 2: led channel 1 (byte 1-3) sample 2: led channel 2 (byte 1-3) newer samples 2(a) sample 2: led channel 3 (byte 1-3) sample 1: led channel 3 ( byte 1-3) sample 1: led channel 1 (byte 1-3) sample 1: led channel 2 (byte 1-3) 2(b) older samples sample 2: red channel (byte 1-3) sample 2: ir channel (byte 1-3) newer samples 2(a) sample 1: ir channel ( byte 1-3) sample 1: red channel ( byte 1-3) older samples maxim integrated 16 www.maximintegrated.com MAX30105 high-sensitivity optical sensor for smoke detection applications
pseudo-code example of reading data from fifo first transaction: get the fifo_wr_ptr: start; send device address + write mode send address of fifo_wr_ptr; repeated_start; send device address + read mode read fifo_wr_ptr; stop; the central processor evaluates the number of samples to be read from the fifo: num_available_samples = fifo_wr_ptr C fifo_rd_ptr (note: pointer wrap around should be taken into account) num_samples_to_read = < less than or equal to num_available_samples > second transaction: read num_samples_to_read samples from the fifo: start; send device address + write mode send address of fifo_data; repeated_start; send device address + read mode for (i = 0; i < num_samples_to_read; i++) { read fifo_data; save led1[23:16]; read fifo_data; save led1[15:8]; read fifo_data; save led1[7:0]; read fifo_data; save led2[23:16]; read fifo_data; save led2[15:8]; read fifo_data; save led2[7:0]; read fifo_data; save led3[23:16]; read fifo_data; save led3[15:8]; read fifo_data; save led3[7:0]; read fifo_data; } stop; maxim integrated 17 www.maximintegrated.com MAX30105 high-sensitivity optical sensor for smoke detection applications
start; send device address + write mode send address of fifo_rd_ptr; write fifo_rd_ptr; stop; third transaction: write to fifo_rd_ptr register. if the second transaction was successful, fifo_rd_ptr points to the next sample in the fifo, and this third transaction is not necessary. otherwise, the processor updates the fifo_rd_ptr appropriately, so that the samples are reread. fifo confguration (0x08) bits 7:5: sample averaging (smp_ave) to reduce the amount of data throughput, adjacent samples (in each individual channel) can be averaged and decimated on the chip by setting this register. bit 4: fifo rolls on full (fifo_rollover_en) this bit controls the behavior of the fifo when the fifo becomes completely filled with data. if fifo_rollover_en is set (1), the fifo address rolls over to zero and the fifo continues to fill with new data. if the bit is not set (0), then the fifo is not updated until fifo_data is read or the write/read pointer positions are changed. bits 3:0: fifo almost full value (fifo_a_full) this register sets the trigger for the fifo_a_full interrupt. for example, if set to 0x0f, the interrupt triggers when there are 15 empty space left (17 data samples), and so on. table 3. sample averaging register b7 b6 b5 b4 b3 b2 b1 b0 reg addr por state r/w fifo confguration smp_ave[2:0] fifo_rol lover_en fifo_a_full[3:0] 0x08 0x00 r/w smp_ave[2:0] no. of samples averaged per fifo sample 000 1 (no averaging) 001 2 010 4 011 8 100 16 101 32 110 32 111 32 fifo_a_full[3:0] no. of samples in the fifo 0x0h 32 0x1h 31 0x2h 30 0x3h 29 0xfh 17 maxim integrated 18 www.maximintegrated.com MAX30105 high-sensitivity optical sensor for smoke detection applications
mode confguration (0x09) bits 6:5: particle-sensing adc range control this register sets the particle-sensing sensor adcs full-scale range as shown in table 5 . bit 7: shutdown control (shdn) the part can be put into a power-save mode by setting this bit to one. while in power-save mode, all registers retain their values, and write/read operations function as normal. all interrupts are cleared to zero in this mode. bit 6: reset control (reset) when the reset bit is set to one, all configuration, threshold, and data registers are reset to their power-on-state through a power-on reset. the reset bit is cleared automatically back to zero after the reset sequence is completed. note: setting the reset bit does not trigger a pwr_rdy interrupt event. bits 2:0: mode control these bits set the operating state of the MAX30105. changing modes does not change any other setting, nor does it erase any previously stored data inside the data registers. particle-sensing confguration (0x0a) table 4. mode control table 5. particle-sensing adc range control (18-bit resolution) register b7 b6 b5 b4 b3 b2 b1 b0 reg addr por state r/w mode confguration shdn reset mode[2:0] 0x09 0x00 r/w register b7 b6 b5 b4 b3 b2 b1 b0 reg addr por state r/w spo 2 confguration adc_rge<1:0> sr[2:0] led_pw[2:0] 0x0a 0x00 r/w mode[2:0] mode active led channels 000 do not use 001 do not use 010 particle-sensing mode using 1 led red only 011 particle-sensing mode using 2 leds red and ir 100C110 do not use 111 multi-led mode green, red, and/or ir adc_rge[1:0] lsb size (pa) full scale (na) 00 7.81 2048 01 15.63 4096 02 31.25 8192 03 62.5 16384 maxim integrated 19 www.maximintegrated.com MAX30105 high-sensitivity optical sensor for smoke detection applications
bits 4:2: particle-sensing sample rate control (using 2 leds) these bits define the effective sampling rate with one sample consisting of one ir pulse/conversion and one red pulse/conversion. the sample rate and pulse width are related in that the sample rate sets an upper bound on the pulse width time. if the user selects a sample rate that is too high for the selected led_pw setting, the highest possible sample rate is programmed instead into the register. bits 1:0: led pulse width control and adc resolution these bits set the led pulse width (the ir, red, and green have the same pulse width), and therefore, indirectly sets the integration time of the adc in each sample. the adc resolution is directly related to the integration time. table 6. particle-sensing sample rate control table 7. led pulse width control sr[2:0] samples per second 000 50 001 100 010 200 011 400 100 800 101 1000 110 1600 111 3200 led_pw[1:0] pulse width (s) adc resolution (bits) 00 69 (68.95) 15 01 118 (117.78) 16 10 215 (215.44) 17 11 411 (410.75) 18 see table 11 and table 12 for pulse width vs. sample rate information. maxim integrated 20 www.maximintegrated.com MAX30105 high-sensitivity optical sensor for smoke detection applications
led pulse amplitude (0x0cC0x10) these bits set the current level of each led as shown in table 8 . table 8. led current control * actual measured led current for each part can vary significantly due to the trimming methodology. register b7 b6 b5 b4 b3 b2 b1 b0 reg addr por state r/w led pulse amplitude led1_pa[7:0] 0x0c 0x00 r/w led2_pa[7:0] 0x0d 0x00 r/w led pulse amplitude led3_pa[7:0] 0x0e 0x00 r/w reserved 0x0f 0x00 r/w proximity mode led pulse amplitude pilot_pa[7:0] 0x10 0x00 r/w ledx_pa [7:0] typical led current (ma)* 0x00h 0.0 0x01h 0.2 0x02h 0.4 0x0fh 3.1 0x1fh 6.4 0x3fh 12.5 0x7fh 25.4 0xffh 50.0 maxim integrated 21 www.maximintegrated.com MAX30105 high-sensitivity optical sensor for smoke detection applications
the purpose of pilot_pa[7:0] is to set the led power during the proximity mode, as well as in multi-led mode. multi-led mode control registers (0x11C0x12) in multi-led mode, each sample is split into up to four time slots, slot1 through slot4. these control registers determine which led is active in each time slot, making for a very flexible configuration. each slot generates a 3-byte output into the fifo. one sample comprises all active slots, for example if slot1 and slot2 are non-zero, then one sample is 2 x 3 = 6 bytes. if slot1 through slot3 are all non-zero, then one sample is 3 x 3 = 9 bytes. the slots should be enabled in order (i.e., slot1 should not be disabled if slot2 or slot3 are enabled). table 9. multi-led mode control registers register b7 b6 b5 b4 b3 b2 b1 b0 reg addr por state r/w multi-led mode control registers slot2[2:0] slot1[2:0] 0x11 0x00 r/w slot4[2:0] slot3[2:0] 0x12 0x00 r/w slotx[2:0] setting which led is active led pulse amplitude setting 000 none (time slot is disabled) n/a (off) 001 led1 (red) led1_pa[7:0] 010 led2 (ir) led2_pa[7:0] 011 led3 (green) led3_pa[7:0] 100 none n/a (off) 101 led1 (red) pilot_pa[7:0] 110 led2 (ir) pilot_pa[7:0] 111 led3 (green) pilot_pa[7:0] maxim integrated 22 www.maximintegrated.com MAX30105 high-sensitivity optical sensor for smoke detection applications
temperature data (0x1fC0x21) temperature integer the on-board temperature adc output is split into two registers, one to store the integer temperature and one to store the fraction. both should be read when reading the temperature data, and the equation below shows how to add the two registers together: t measured = t integer + t fraction this register stores the integer temperature data in 2s complement format, where each bit corresponds to 1c. temperature fraction this register stores the fractional temperature data in increments of 0.0625c. if this fractional temperature is paired with a negative integer, it still adds as a positive fractional value (e.g., -128c + 0.5c = -127.5c). temperature enable (temp_en) this is a self-clearing bit which, when set, initiates a single temperature reading from the temperature sensor. this bit clears automatically back to zero at the conclusion of the temperature reading when the bit is set to one in particle- sensing mode. table 10. temperature integer register b7 b6 b5 b4 b3 b2 b1 b0 reg addr por state r/w temp_integer tint[7] 0x1f 0x00 r/w temp_fraction tfrac[3:0] 0x20 0x00 r/w die temperature confg temp_en 0x21 0x00 r register value (hex) temperature (c) 0x00 0 0x00 +1 ... ... 0x7e +126 0x7f +127 0x80 -128 0x81 -127 ... ... 0xfe -2 0xff -1 maxim integrated 23 www.maximintegrated.com MAX30105 high-sensitivity optical sensor for smoke detection applications
proximity mode interrupt threshold (0x30) this register sets the ir adc count that will trigger the beginning of particle-sensing mode. the threshold is defined as the 8 msbs of the adc count. for example, if prox_int_thresh[7:0] = 0x01, then an adc value of 1023 (decimal) or higher triggers the prox interrupt. if prox_int_thresh[7:0] = 0xff, then only a saturated adc triggers the interrupt. applications information sampling rate and performance the maximum sample rate for the adc depends on the selected pulse width, which in turn, determines the adc resolution. for instance, if the pulse width is set to 69s then the adc resolution is 15 bits, and all sample rates are selectable. however, if the pulse width is set to 411s, then the samples rates are limited. the allowed sample rates for both particle-sensing modes are summarized in table 11 and table 12 . power considerations the led waveforms and their implication for power supply design are discussed in this section. the leds in the MAX30105 are pulsed with a low duty cycle for power savings, and the pulsed currents can cause ripples in the v led+ power supply. to ensure these pulses do not translate into optical noise at the led outputs, the power supply must be designed to handle these. ensure that the resistance and inductance from the power supply (battery, dc/dc converter, or ldo) to the pin is much smaller than 1, and that there is at least 1f of power supply bypass capacitance to a good ground plane. the capacitance should be located as close as physically possible to the ic. table 11. particle-sensing mode using 2 leds (allowed settings) table 12. particle-sensing mode using 1 leds (allowed settings) register b7 b6 b5 b4 b3 b2 b1 b0 reg addr por state r/w proximity interrupt threshold prox_int_thresh[7:0] 0x30 0x00 r/w samples per second pulse width (s) samples per second pulse width (s) 69 118 215 411 69 118 215 411 50 o o o o 50 o o o o 100 o o o o 100 o o o o 200 o o o o 200 o o o o 400 o o o o 400 o o o o 800 o o o 800 o o o o 1000 o o 1000 o o o o 1600 o 1600 o o o 3200 3200 o resolution (bits) 15 16 17 18 resolution (bits) 15 16 17 18 maxim integrated 24 www.maximintegrated.com MAX30105 high-sensitivity optical sensor for smoke detection applications
particle-sensing temperature compensation the MAX30105 has an accurate on-board temperature sensor that digitizes the ics internal temperature upon command from the i 2 c master. table 13 shows the correlation of red led wavelength versus the temperature of the led. since the led die heats up with a very short thermal time constant (tens of microseconds), the led wavelength should be calculated according to the current level of the led and the temperature of the ic. use table 13 to estimate the temperature. red led current settings vs. led temperature rise add estimated temperature rise to the module tempera - ture reading to estimate the led temperature and output wavelength. the led temperature estimate is valid even with very short pulse widths, due to the fast thermal time constant of the led. interrupt pin functionality the active-low interrupt pin pulls low when an interrupt is triggered. the pin is open-drain, which means it normally requires a pullup resistor or current source to an external voltage supply (up to +5v from gnd). the interrupt pin is not designed to sink large currents, so the pullup resistor value should be large, such as 4.7k. table 13. red led current settings vs. led temperature rise red led current setting red led duty cycle (% of led pulse width to sample time) estimated temperature rise (add to temp sensor measurement) (c) 0001 (0.2ma) 8 0.1 1111 (50ma) 8 2 0001 (0.2ma) 16 0.3 1111 (50ma) 16 4 0001 (0.2ma) 32 0.6 1111 (50ma) 32 8 maxim integrated 25 www.maximintegrated.com MAX30105 high-sensitivity optical sensor for smoke detection applications
timing for measurements and data collection slot timing in multi-led modes the MAX30105 can support up to three led channels of sequential processing (red, ir, and green). in multi- led modes, a time slot or period exists between active sequential channels. table 14 below displays the the four possible channel slot times associated with each pulse width setting. figure 3 shows an example of channel slot timing for a particle-sensing mode application with a 1khz sample rate. table 14. slot timing red led 660nm red on 69s red off 931s ir on 69s ir off 931s 358s infrared led 880nm figure 3. channel slot timing for the multi-led mode with a 1khz sample rate pulse-width setting ( s) channel slot timing (timing period between pulses) ( s) channel-channel timing (rising edge-to-rising edge) ( s) 69 358 427 118 407 525 215 505 720 411 696 1107 maxim integrated 26 www.maximintegrated.com MAX30105 high-sensitivity optical sensor for smoke detection applications
timing in particle-sensing mode using 2 leds the internal fifo stores up to 32 samples, so that the system processor does not need to read the data after every sample ( figure 4). figure 4. timing for data acquisition and communication when in particle-sensing mode using 2 leds table 15. events sequence for figure 4 in particle-sensing mode using 2 leds event description comments 1 enter into particle-sensing mode. initiate a temperature measurement. i 2 c write command sets mode[2:0] = 0x03. at the same time, set the temp_en bit to initiate a single temperature measurement. mask the data_rdy interrupt. 2 temperature measurement complete, interrupt generated temp_rdy interrupt triggers, alerting the central processor to read the data. 3 temp data is read, interrupt cleared 4 fifo is almost full, interrupt generated interrupt is generated when the fifo almost full threshold is reached. 5 fifo data is read, interrupt cleared 6 next sample is stored new sample is stored at the new read pointer location. effectively, it is now the frst sample in the fifo. int i 2 c bus led outputs ~ ~ ~ sample #1 sample #2 sample #3 sample # 16 sample # 17 1 4 5 6 temp sensor temperature sample 2 3 29 ms 15 ms to 300 ms ir red ir red ir red ir red ir red ir red ir red maxim integrated 27 www.maximintegrated.com MAX30105 high-sensitivity optical sensor for smoke detection applications
timing in particle-sensing mode using 1 led the internal fifo stores up to 32 samples, so that the system processor does not need to read the data after every sample (figure 5). figure 5. timing for data acquisition and communication when in particle-sensing mode using 1 led table 16. events sequence for figure 5 in particle-sensing mode using 1 led event description comments 1 enter particle-sensing mode i 2 c write command sets mode[2:0] = 0x02. mask the data_rdy interrupt. 2 fifo is almost full, interrupt generated interrupt is generated when the fifo has only one empty space left. 3 fifo data is read, interrupt cleared 4 next sample is stored new sample is stored at the new read pointer location. effectively, it is now the frst sample in the fifo. int i 2 c bus led outputs ir ~ ~ ~ sample #1 sample #2 sample #3 sample # 30 sample # 31 1 2 3 4 15 ms to 300 ms ir ir ir ir ir ir maxim integrated 28 www.maximintegrated.com MAX30105 high-sensitivity optical sensor for smoke detection applications
power sequencing and requirements power-up sequencing figure 6 shows the recommended power-up sequence for the MAX30105. it is recommended to power the v dd supply first, before the led power supplies (v led+ ). the interrupt and i 2 c pins can be pulled up to an external voltage even when the power supplies are not powered up. after the power is established, an interrupt occurs to alert the system that the MAX30105 is ready for operation. reading the i 2 c interrupt register clears the interrupt, as shown in figure 6. power-down sequencing the MAX30105 is designed to be tolerant of any power supply sequencing on power-down. i 2 c interface the MAX30105 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 communication between the MAX30105 and the master at clock rates up to 400khz. figure 1 shows the 2-wire interface timing diagram. the master generates scl and initiates data transfer on the bus. the master device writes data to the MAX30105 by transmitting the proper slave address followed by data. each transmit sequence is framed by a start (s) or repeated start (sr) condition and a stop (p) condition. each word transmitted to the MAX30105 is 8 bits long and is followed by an acknowledge clock pulse. a master read - ing data from the MAX30105 transmits the proper slave address followed by a series of nine scl pulses. the MAX30105 transmits data on sda in sync with the master-generated scl pulses. the master acknowl - edges receipt of each byte of data. each read sequence is framed by a start (s) or repeated start (sr) condition, a not acknowledge, and a stop (p) condition. sda operates as both an input and an open-drain output. a pullup resistor, typically greater than 500, is required on sda. scl operates only as an input. a pullup resistor, typically greater than 500, is required on scl if there are multiple masters on the bus, or if the single master has an open-drain scl output. series resistors in line with sda and scl are optional. series resistors protect the digital inputs of the MAX30105 from high voltage spikes on the bus lines and minimize crosstalk and undershoot of the bus signals. 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 section. start and stop conditions sda and scl idle high when the bus is not in use. a mas - ter initiates communication by issuing a start condition. 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 7 ). a start condition from the master signals the beginning of a transmission to the MAX30105. the master terminates transmission, and frees the bus, by issuing a stop condition. the bus remains active if a repeated start condition is gener - ated instead of a stop condition. early stop conditions the MAX30105 recognizes a stop condition at any point during data transmission except if the stop condition occurs in the same scl high pulse as a start condi - tion. for proper operation, do not send a stop condition during the same scl high pulse as the start condition. slave address a bus master initiates communication with a slave device by issuing a start condition followed by the 7-bit slave id. when idle, the MAX30105 waits for a start condition followed by its slave id. the serial interface compares each slave id bit by bit, allowing the interface to power down and disconnect from scl immediately if an incor - rect slave id is detected. after recognizing a start condition followed by the correct slave id, the MAX30105 is programmed to accept or send data. the lsb of the slave id word is the read/write (r/ w ) bit. r/w indicates whether the master is writing to or reading data from the MAX30105 (r/ w = 0 selects a write condition, r/ w = 1 selects a read condition). after receiving the proper slave figure 6. power-up sequence of the power supply rails v led + v dd int sda , scl high (i/ o pullup ) high (i/ o pullup ) pwr _ rdy interrupt read to clear interrupt maxim integrated 29 www.maximintegrated.com MAX30105 high-sensitivity optical sensor for smoke detection applications
id, the MAX30105 issues an ack by pulling sda low for one clock cycle. the MAX30105 slave id consists of seven fixed bits, b7Cb1 (set to 0b1010111). the most significant slave id bit (b7) is transmitted first, followed by the remaining bits. table 17 shows the possible slave ids of the device. acknowledge the acknowledge bit (ack) is a clocked 9th bit that the MAX30105 uses to handshake receipt of each byte of data when in write mode ( figure 8 ). the MAX30105 pulls down sda during the entire master-generated 9 th 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 retries communication. the master pulls down sda during the 9th clock cycle to acknowledge receipt of data when the MAX30105 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 MAX30105, followed by a stop condition. write data format for the write operation, send the slave id as the first byte followed by the register address byte and then one or more data bytes. terminate the data transfer with a stop condition. the write operation is shown in figure 9. the internal register address pointer increments auto - matically, so writing additional data bytes fill the data registers in order. figure 7. start, stop, and repeated start conditions figure 9. writing one data byte to the MAX30105 figure 8. acknowledge table 17. slave id description b7 b6 b5 b4 b3 b2 b1 b0 write address read address 1 0 1 0 1 1 1 rw 0xae 0xaf s sr p scl1 sda1 scl1 sda1 start condition 1 2 8 9 clock pulse for acknowledgment not acknowledge acknowledge s 1 0 1 0 1 1 1 r/w = 0 ack a7 a6 a5 a4 a3 a2 slave id a1 a0 ack p s = start condition p = stop condition ack = acknowledge by the receiver register address d7 d6 d5 d4 d3 d2 d1 d0 ack data byte internal address pointer auto-increment (for writing multiple bytes maxim integrated 30 www.maximintegrated.com MAX30105 high-sensitivity optical sensor for smoke detection applications
read data format for the read operation, two i 2 c operations must be per - formed. first, the slave id byte is sent followed by the i 2 c register that you wish to read. then a repeat start (sr) condition is sent, followed by the read slave id. the MAX30105 then begins sending data beginning with the register selected in the first operation. the read pointer increments automatically, so the MAX30105 continues sending data from additional registers in sequential order until a stop (p) condition is received. the exception to this is the fifo_data register, at which the read pointer no longer increments when reading additional bytes. to read the next register after fifo_data, an i 2 c write command is necessary to change the location of the read pointer. figure 10 and figure 11 show the process of reading one byte or multiple bytes of data. an initial write operation is required to send the read register address. data is sent from registers in sequential order, starting from the register selected in the initial i 2 c write operation. if the fifo_data register is read, the read pointer will not automatically increment, and subsequent bytes of data will contain the contents of the fifo. figure 10. reading one byte of data from MAX30105 figure 11. reading multiple bytes of data from the MAX30105 s 1 0 1 0 1 1 1 r/w = 0 ack a7 a6 a5 a4 a3 a2 a1 a0 ack 1 0 1 0 1 1 1 ack d7 d6 d5 d4 d3 d2 d1 d0 nack data byte p s = start condition sr = repeated start condition p = stop condition ack = acknowledge by the receiver nack = not acknowledge slave id register address sr slave id r/w = 1 s 1 0 1 0 1 1 1 r/w = 0 ack a7 a6 a5 a4 a3 a2 a1 a0 ack 1 0 1 0 1 1 1 ack d7 d6 d5 d4 d3 d2 d1 d0 am data 1 s = start condition sr = repeated start condition p = stop condition ack = acknowledge by the receiver am = acknowledge by the master nack = not acknowledge slave id register address sr slave id r/w = 1 d7 d6 d5 d4 d3 d2 d1 am d7 d6 d5 d4 d3 d2 d1 d0 nack data n p data n-1 d0 maxim integrated 31 www.maximintegrated.com MAX30105 high-sensitivity optical sensor for smoke detection applications
along with maxims sensor, customers need smart algo - rithms to detect the particles of interest. maxim is partner - ing with valor inc. to develop state-of-the-art algorithms for smoke detection applications using the MAX30105. contact valor for licensing information at www.valorfire - safety.com/licensing/ . external partner +denotes lead(pb)-free/rohs-compliant package. t = tape and reel. part temp range pin-package MAX30105efd+t -40c to +85c 14 oesip (0.8mm pin pitch) 880nm 660nm adc ambient light cancellation analog adc die temp oscillator digital filter digital data register led drivers i 2 c communication int sda scl v dd v led+ ir_drv r_drv gnd pgnd red ir visible+ir 1k? v ddio host processor 4.7f +1.8v 20ma 10f +5.0v 200ma max (no connect) MAX30105 green 527nm g_drv maxim integrated 32 typical application circuit ordering information www.maximintegrated.com MAX30105 high-sensitivity optical sensor for smoke detection applications
package type package code outline no. land pattern no. 14 oesip f143a5mk+1 21-1048 90-0602 maxim integrated 33 package information for the latest package outline information and land patterns (footprints), go to www.maximintegrated.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. www.maximintegrated.com MAX30105 high-sensitivity optical sensor for smoke detection applications
maxim integrated tm maxim integrated 34 package information (continued) for the latest package outline information and land patterns (footprints), go to www.maximintegrated.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. www.maximintegrated.com MAX30105 high-sensitivity optical sensor for smoke detection applications
revision number revision date description pages changed 0 5/16 initial release 1 7/16 updated title, general description, benefts and features , applications , system diagram , electrical characteristics global conditions, led supply voltage parameter, adc countpsrr (led driver outputs) parameter conditions, typical operating characteristics global conditions, pin confguration , detailed description , temperature sensor , proximity function , register maps and descriptions , interrupt status (0x00C0x01) , interrupt enable (0x02C0x03) , fifo data register, bits 3:0, fifo almost full value (fifo_a_full) mode confguration (0x09) , table 4, particle-sensing confguration (0x0a) , table 5, bits 4:2: particle-sensing sample rate control (using 2 leds) , table 6, table 8, sampling rate and performance , power considerations , table 11, table 12, particle-sensing temperature compensation , red led current settings vs. led temperature rise , figure 3 caption, timing in particle-sensing mode using 2 leds , figure 4 caption, table 15, timing in particle-sensing mode using 1 led , figure 5 caption, table 16, power-up sequencing , early stop conditions , slave address, acknowledge , write data format, read data format , external partner 1C35 ? 2016 maxim integrated products, inc. 35 revision history maxim integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a maxim integrated product. no circuit patent licenses are implied. maxim integrated reserves the right to change the circuitry and specifcations without notice at any time. the parametric values (min and max limits) shown in the electrical characteristics table are guaranteed. other parametric values quoted in this data sheet are provided for guidance. maxim integrated and the maxim integrated logo are trademarks of maxim integrated products, inc. MAX30105 high-sensitivity optical sensor for smoke detection applications for pricing, delivery, and ordering information, please contact maxim direct at 1-888-629-4642, or visit maxim integrateds website at www.maximintegrated.com.

▲Up To Search▲

Price & Availability of MAX30105

	To Download MAX30105 Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .