MAX30102 Datasheet by Maxim Integrated

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MAX30102 High-Sensitivity Pulse Oximeter and DR‘VER maxim Integrated ,,
General Description
The MAX30102 is an integrated pulse oximetry and
heart-rate monitor module. It includes internal LEDs,
photodetectors, optical elements, and low-noise electronics
with ambient light rejection. The MAX30102 provides a
complete system solution to ease the design-in process
for mobile and wearable devices.
The MAX30102 operates on a single 1.8V power supply
and a separate 3.3V power supply for the internal LEDs.
Communication is through a standard I2C-compatible
interface. The module can be shut down through software
with zero standby current, allowing the power rails to
remain powered at all times.
Applications
Wearable Devices
Fitness Assistant Devices
Smartphones
Tablets
Benefits and Features
Heart-Rate Monitor and Pulse Oximeter Sensor in
LED Reflective Solution
Tiny 5.6mm x 3.3mm x 1.55mm 14-Pin Optical Module
Integrated Cover Glass for Optimal, Robust
Performance
Ultra-Low Power Operation for Mobile Devices
Programmable Sample Rate and LED Current for
Power Savings
Low-Power Heart-Rate Monitor (< 1mW)
Ultra-Low Shutdown Current (0.7µA, typ)
Fast Data Output Capability
High Sample Rates
Robust Motion Artifact Resilience
High SNR
-40°C to +85°C Operating Temperature Range
Ordering Information appears at end of data sheet.
19-7740; Rev 1; 10/18
PHOTO
DIODE
LED DRIVERS RED/IR LED
PACKAGING
HUMAN
SUBJECT
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
COVER GLASS
MAX30102
MAX30102 High-Sensitivity Pulse Oximeter and
Heart-Rate Sensor for Wearable Health
System Diagram
Click here for production status of specific part numbers.
VDD to GND .........................................................-0.3V to +2.2V
GND to PGND ......................................................-0.3V to +0.3V
VLED+ 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
ESD, Human Body Model (HBM) ....................................... 2.5kV
Latchup Immunity ...........................................................±250mA
Continuous Power Dissipation (TA = +70°C)
OESIP (derate 5.5mW/°C above +70°C) ....................440mW
Operating Temperature Range .......................... -40°C to +85°C
Junction Temperature ........................................................ +90°C
Soldering Temperature (reflow) ...................................... +260°C
Storage Temperature Range ............................ -40°C to +105°C
(VDD = 1.8V, VLED+ = 5.0V, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C) (Note 1)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
POWER SUPPLY
Power-Supply Voltage VDD
Guaranteed by RED and IR count
tolerance 1.7 1.8 2.0 V
LED Supply Voltage
VLED+ to PGND VLED+ Guaranteed by PSRR of LED driver 3.1 3.3 5.0 V
Supply Current IDD
SpO2 and HR mode, PW = 215µs,
50sps 600 1200 µA
IR only mode, PW = 215µS, 50sps 600 1200
Supply Current in Shutdown ISHDN TA = +25°C, MODE = 0x80 0.7 10 µA
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MAX30102 High-Sensitivity Pulse Oximeter and
Heart-Rate Sensor for Wearable Health
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.
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only; functional operation of the device at these or any
other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device
reliability.
Absolute Maximum Ratings
Electrical Characteristics
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.
Package Information
PACKAGE TYPE: 14 OESIP
Package Code F143A5MK+1
Outline Number 21-1048
Land Pattern Number 90-0602
THERMAL RESISTANCE, FOUR-LAYER BOARD
Junction to Ambient (θJA) 180°C/W
Junction to Case (θJC) 150°C/W
(VDD = 1.8V, VLED+ = 5.0V, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C) (Note 1)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
PULSE OXIMETRY/HEART-RATE SENSOR CHARACTERISTICS
ADC Resolution 18 bits
Red ADC Count
(Note 2) REDC
LED1_PA = 0x0C, LED_PW = 0x01,
SPO2_SR = 0x05,
ADC_RGE = 0x00
65536 Counts
IR ADC Count
(Note 2) IRC
LED2_PA = 0x0C, LED_PW = 0x01,
SPO2_SR = 0x05
ADC_RGE = 0x00
65536 Counts
Dark Current Count LED_DCC
LED1_PA = LED2_PA = 0x00,
LED_PW = 0x03, SPO2_SR = 0x01
ADC_RGE = 0x02
30 128 Counts
0.01 0.05 % of
FS
DC Ambient Light Rejection ALR
ADC counts with finger 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 Count—PSRR (VDD) PSRRVDD
1.7V < VDD < 2.0V,
LED_PW = 0x01, SPO2_SR = 0x05 0.25 1 % of
FS
Frequency = DC to 100kHz, 100mVP-P
10 LSB
ADC Count—PSRR
(LED Driver Outputs) PSRRLED
3.1V < VLED+, < 5.0V, LED1_PA =
LED2_PA = 0x0C, LED_PW = 0x01,
SPO2_SR = 0x05
0.05 1 % of
FS
Frequency = DC to 100kHz, 100mVP-P
10 LSB
ADC Clock Frequency CLK 10.32 10.48 10.64 MHz
ADC Integration Time INT
LED_PW = 0x00 69
µs
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 427.1
µs
LED_PW = 0x01 524.7
LED_PW = 0x02 720.0
LED_PW = 0x03 1106.6
COVER GLASS CHARACTERISTICS (Note 3)
Hydrolytic Resistance Class Per DIN ISO 719 HGB 1
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MAX30102 High-Sensitivity Pulse Oximeter and
Heart-Rate Sensor for Wearable Health
Electrical Characteristics (continued)
(VDD = 1.8V, VLED+ = 5.0V, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C) (Note 1)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
IR LED CHARACTERISTICS (Note 3)
LED Peak Wavelength λPILED = 20mA, TA = +25°C 870 880 900 nm
Full Width at Half Max Δλ ILED = 20mA, TA = +25°C 30 nm
Forward Voltage VFILED = 20mA, TA = +25°C 1.4 V
Radiant Power POILED = 20mA, TA = +25°C 6.5 mW
RED LED CHARACTERISTICS (Note 3)
LED Peak Wavelength λPILED = 20mA, TA = +25°C 650 660 670 nm
Full Width at Half Max Δλ ILED = 20mA, TA = +25°C 20 nm
Forward Voltage VFILED = 20mA, TA = +25°C 2.1 V
Radiant Power POILED = 20mA, TA = +25°C 9.8 mW
PHOTODETECTOR CHARACTERISTICS (Note 3)
Spectral Range of Sensitivity
λ
(QE > 50%)
QE: Quantum Efficiency 600 900 nm
Radiant Sensitive Area A 1.36 mm2
Dimensions of Radiant Sensitive
Area L x W 1.38 x
0.98
mm x
mm
INTERNAL DIE TEMPERATURE SENSOR
Temperature ADC Acquisition
Time TTTA = +25°C 29 ms
Temperature Sensor Accuracy TATA = +25°C ±1 °C
Temperature Sensor Minimum
Range TMIN -40 °C
Temperature Sensor Maximum
Range TMAX 85 °C
DIGITAL INPUT CHARACTERISTICS: SCL, SDA
Input High Voltage VIH VDD = 2V 0.7 x
VDD
V
Input Low Voltage VIL VDD = 2V 0.3 x
VDD
V
Hysteresis Voltage VH0.2 V
Input Leakage Current IIN VIN = GND or VDD (STATIC) ±0.05 ±1 µA
DIGITAL OUTPUT CHARACTERISTICS: SDA, INT
Ouput Low Voltage VOL ISINK = 6mA 0.2 V
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MAX30102 High-Sensitivity Pulse Oximeter and
Heart-Rate Sensor for Wearable Health
Electrical Characteristics (continued)
(VDD = 1.8V, VLED+ = 5.0V, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C) (Note 1)
Note 1: All devices are 100% production tested at TA = +25°C. Specifications over temperature limits are guaranteed by Maxim
Integrated’s bench or proprietary automated test equipment (ATE) characterization.
Note 2: Specifications are guaranteed by Maxim Integrated’s bench characterization and by 100% production test using proprietary
ATE setup and conditions.
Note 3: Guaranteed by design and characterization. Not tested in final production.
Figure 1. I2C-Compatible Interface Timing Diagram
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
I2C TIMING CHARACTERISTICS (SDA, SDA, INT) (Note 3)
I2C Write Address AE Hex
I2C Read Address AF Hex
Serial Clock Frequency fSCL 0 400 kHz
Bus Free Time Between STOP
and START Conditions tBUF 1.3 µs
Hold Time (Repeated) START
Condition tHD;STA 0.6 µs
SCL Pulse-Width Low tLOW 1.3 µs
SCL Pulse-Width High tHIGH 0.6 µs
Setup Time for a Repeated
START Condition tSU;STA 0.6 µs
Data Hold Time tHD;DAT 0 900 ns
Data Setup Time tSU;DAT 100 ns
Setup Time for STOP Condition tSU;STO 0.6 µs
Pulse Width of Suppressed
Spike tSP 0 50 ns
Bus Capacitance CB400 pF
SDA and SCL Receiving Rise
Time tR20 + 0.1CB300 ns
SDA and SCL Receiving Fall
Time tRF 20 + 0.1CB300 ns
SDA Transmitting Fall Time tTF 300 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
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MAX30102 High-Sensitivity Pulse Oximeter and
Heart-Rate Sensor for Wearable Health
Electrical Characteristics (continued)
(VDD = 1.8V, VLED+ = 5.0V, TA = +25°C, RST, unless otherwise noted.)
0
10
20
30
40
50
60
012345
IR LED CURRENT (mA)
VLED VOLTAGE (V)
IR LED SUPPLY HEADROOM
toc02
ILED = 50mA
ILED = 20mA
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)
VDD SUPPLY CURRENT vs.
SUPPLY VOLTAGE toc03
SHUTDOWN
MODE
NORMAL
OPERATION
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
toc04
RED
IR
MODE = SPO2 and HR
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
-50 050 100 150
V
DD
SHUTDOWN CURRENT (uA)
TEMPERATURE (°C)
V
DD
SHUTDOWN CURRENT
vs. TEMPERATURE
toc05
VDD
2.2V
2.0V
1.8V
1.7V
0.06
0.07
0.08
0.09
0.10
0.11
0.12
0.13
0.14
-50 050 100 150
V
LED
SHUTDOWN CURRENT (µA)
TEMPERATURE (°C)
V
LED
SHUTDOWN CURRENT
vs. TEMPERATURE
VLED = 4.75V
toc06
VLED = 5.25V
0
10
20
30
40
50
60
012345
RED LED CURRENT (mA)
VLED VOLTAGE (V)
RED LED SUPPLY HEADROOM
toc01
ILED = 50mA
ILED = 20mA
-20
0
20
40
60
80
100
120
500 600 700 800
NORMALIZED POWER (%)
WAVELENGTH (nm)
RED LED SPECTRUM AT T
A
= +30°C
toc08
0
20
40
60
80
100
120
700 800 900 1000
NORMALIZED POWER (%)
WAVELENGTH (nm)
IR LED SPECTRUM AT T
A
= +30°C
toc09
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6
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MAX30102 High-Sensitivity Pulse Oximeter and
Heart-Rate Sensor for Wearable Health
Typical Operating Characteristics
mnwmocunnwm)
(VDD = 1.8V, VLED+ = 5.0V, TA = +25°C, RST, unless otherwise noted.)
860
870
880
890
900
910
-50 050 100 150
PEAK WAVELENGTH (nm)
TEMPERATURE (deg C)
IR LED PEAK WAVELENGTH
vs. TEMPERATURE
toc11
LED CURRENT
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
FORWARD VOLTAGE (V)
RED LED FORWARD VOLTAGE vs.
FORWARD CURRENT AT TA= +25°C
toc12
MODE = FLEX LED
ADC RES = 18 BITS
ADC SR = 100 SPS
ADC FULL SCALE = 2048nA
0
10
20
30
40
50
60
70
1.25 1.30 1.35 1.40 1.45
FORWARD CURRENT (mA)
FORWARD VOLTAGE (V)
IR LED FORWARD VOLTAGE vs.
FORWARD CURRENT AT TA= +25°Ctoc13
MODE = FLEX LED
ADC RES = 18 BITS
ADC SR = 100 SPS
ADC FULL SCALE = 2048nA
-70
-60
-50
-40
-30
-20
-10
0
10 100 1000 10000 100000
MAGNITUDE (dB)
FREQUENCY (Hz)
PW = 69µs
PW = 118µs
PW = 215µs
PW = 411µs
AMBIENT LIGHT CANCELLATION
PASSBAND CHARACTERISTICS toc14
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 EFFICIENCY
WAVELENGTH (nm)
PHOTODIODE QUANTUM EFFICIENCY
vs. WAVELENGTH
toc15
645
650
655
660
665
670
675
-50 050 100 150
PEAK WAVELENGTH (nm)
TEMPERATURE (°C)
RED LED PEAK WAVELENGTH
vs. TEMPERATURE
toc10
LED CURRENT:
10mA
20mA
30mA
50mA
MODE = FLEX LED
ADC RES = 18 BITS
ADC SR = 400 SPS
ADC FULL SCALE = 2048nA
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MAX30102 High-Sensitivity Pulse Oximeter and
Heart-Rate Sensor for Wearable Health
Typical Operating Characteristics (continued)
PIN NAME FUNCTION
1, 5, 6,
7, 8, 14 N.C. No Connection. Connect to PCB pad for mechanical stability.
2 SCL I2C Clock Input
3 SDA I2C Data, Bidirectional (Open-Drain)
4 PGND Power Ground of the LED Driver Blocks
9 VLED+ LED Power Supply (anode connection). Use a bypass capacitor to PGND for best
performance.
10 VLED+
11 VDD 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
N.C. 5
N.C. 6
N.C. 7
14 N.C.
13 INT
12 GND
11 V
DD
10 V
LED+
9V
LED+
8N.C.
SENSOR
LED
MAX30102
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MAX30102 High-Sensitivity Pulse Oximeter and
Heart-Rate Sensor for Wearable Health
Pin Description
Pin Configuration
‘2:
Detailed Description
The MAX30102 is a complete pulse oximetry and heart-rate
sensor system solution module designed for the demanding
requirements of wearable devices. The device maintains a
very small solution size without sacrificing optical or electrical
performance. Minimal external hardware components are
required for integration into a wearable system.
The MAX30102 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 MAX30102 to be
connected to a microcontroller or processor on a shared
bus, where the data is not being read continuously from
the MAX30102’s registers.
SpO2 Subsystem
The SpO2 subsystem of the MAX30102 contains ambient
light cancellation (ALC), a continuous-time sigma-delta
ADC, and a proprietary discrete time filter. The ALC has
an internal Track/Hold circuit to cancel ambient light and
increase the effective dynamic range. The SpO2 ADC has
programmable full-scale ranges from 2µA to 16µA. The
ALC can cancel up to 200µA 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 MAX30102 has an on-chip temperature sensor for
calibrating the temperature dependence of the SpO2 sub-
system. The temperature sensor has an inherent resolu-
tion of 0.0625°C.
The device output data is relatively insensitive to the
wavelength of the IR LED, where the Red LED’s wave-
length is critical to correct interpretation of the data. An
SpO2 algorithm used with the MAX30102 output signal
can compensate for the associated SpO2 error with ambient
temperature changes.
LED Driver
The MAX30102 integrates Red and IR LED drivers to
modulate LED pulses for SpO2 and HR measurements.
The LED current can be programmed from 0 to 50mA
with proper supply voltage. The LED pulse width can be
programmed from 69µs to 411µs to allow the algorithm to
optimize SpO2 and HR accuracy and power consumption
based on use cases.
880nm660nm
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+
N.C.N.C. GND PGND
RED IR
VISIBLE+IR
MAX30102
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MAX30102 High-Sensitivity Pulse Oximeter and
Heart-Rate Sensor for Wearable Health
Functional Diagram
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 PPG_
RDY
ALC_
OVF
PWR_
RDY 0x00 0X00 R
Interrupt
Status 2
DIE_TEMP
_RDY 0x01 0x00 R
Interrupt
Enable 1
A_FULL_
EN
PPG_
RDY_EN
ALC_
OVF_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
Overflow
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
Configuration SMP_AVE[2:0]
FIFO_
ROLL
OVER_EN
FIFO_A_FULL[3:0] 0x08 0x00 R/W
Mode
Configuration SHDN RESET MODE[2:0] 0x09 0x00 R/W
SpO2
Configuration
0
(Reserved)
SPO2_ADC_RGE
[1:0] SPO2_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
RESERVED 0x0E 0x00 R/W
RESERVED 0x0F 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
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MAX30102 High-Sensitivity Pulse Oximeter and
Heart-Rate Sensor for Wearable Health
*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 0x13–
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
Config
TEMP
_EN 0x21 0x00 R/W
RESERVED 0x22–
0x2F 0x00 R/W
PART ID
Revision ID REV_ID[7:0] 0xFE 0xXX* R
Part ID PART_ID[7] 0xFF 0x15 R
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MAX30102 High-Sensitivity Pulse Oximeter and
Heart-Rate Sensor for Wearable Health
Whenever an interrupt is triggered, the MAX30102 pulls the active-low interrupt pin into its low state until the interrupt is
cleared.
A_FULL: FIFO Almost Full Flag
In SpO2 and HR modes, 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).
PPG_RDY: New FIFO Data Ready
In SpO2 and HR modes, 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 Overflow
This interrupt triggers when the ambient light cancellation function of the SpO2/HR 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).
PWR_RDY: Power Ready Flag
On power-up or after a brownout condition, when the supply voltage VDD 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 (0x00–0x01)
REGISTER B7 B6 B5 B4 B3 B2 B1 B0 REG
ADDR
POR
STATE R/W
Interrupt
Status 1 A_FULL PPG_RDY ALC_OVF PWR_
RDY 0x00 0X00 R
Interrupt
Status 2
DIE_
TEMP_RDY 0x01 0x00 R
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MAX30102 High-Sensitivity Pulse Oximeter and
Heart-Rate Sensor for Wearable Health
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 SpO2 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 (0x02-0x03)
Each source of hardware interrupt, with the exception of power ready, can be disabled in a software register within the
MAX30102 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 (0x04–0x07)
FIFO Write Pointer
The FIFO Write Pointer points to the location where the MAX30102 writes the next sample. This pointer advances for
each sample pushed on to the FIFO. It can also be changed through the I2C interface when MODE[2:0] is 010, 011, or 111.
FIFO Overflow 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 0x1F. 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
I2C 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
PPG_
RDY_EN
ALC_
OVF_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
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MAX30102 High-Sensitivity Pulse Oximeter and
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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 (a.k.a. channels) configured as active. As each channel signal is stored as a 3-byte data signal, the FIFO width
can be 3 bytes or 6 bytes in size.
The FIFO_DATA register in the I2C register map points to the next sample to be read from the FIFO. FIFO_RD_PTR
points to this sample. Reading FIFO_DATA register, does not automatically increment the I2C 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 (0x04–0x07) 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 MAX30102. When starting a new
SpO2 or heart rate 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 MAX30102 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.
Reading from the FIFO
Normally, reading registers from the I2C interface autoincrements the register address pointer, so that all the registers
can be read in a burst read without an I2C start event. In the MAX30102, 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 IR and Red ADC data. Since each sample consists
of two channels of data, there are 6 bytes of data for each sample, and therefore 192 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
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MAX30102 High-Sensitivity Pulse Oximeter and
Heart-Rate Sensor for Wearable Health
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] – [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 SpO2 mode comprises two data triplets (3 bytes each), To read one sample, requires an I2C read
command for each byte. Thus, to read one sample in SpO2 mode, requires 6 I2C 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 SpO2 mode or HR mode, so that there is
no old data represented in the FIFO. The pointers are automatically cleared if VDD is power-cycled or VDD drops below
its UVLO voltage.
Figure 2. Graphical Representation of the FIFO Data Register. It shows IR and Red in SpO2 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: 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
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MAX30102 High-Sensitivity Pulse Oximeter and
Heart-Rate Sensor for Wearable Health
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 – 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;
}
STOP;
START;
Send device address + write mode
Send address of FIFO_RD_PTR;
Write FIFO_RD_PTR;
STOP;
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MAX30102 High-Sensitivity Pulse Oximeter and
Heart-Rate Sensor for Wearable Health
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 Configuration (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 number of data samples (3 bytes/sample) remaining in the FIFO when the interrupt is issued. For
example, if this field is set to 0x0, the interrupt is issued when there is 0 data samples remaining in the FIFO (all 32
FIFO words have unread data). Furthermore, if this field is set to 0xF, the interrupt is issued when 15 data samples are
remaining in the FIFO (17 FIFO data samples have unread data).
Table 3. Sample Averaging
REGISTER B7 B6 B5 B4 B3 B2 B1 B0 REG
ADDR
POR
STATE R/W
FIFO
Configuration 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] EMPTY DATA SAMPLES IN FIFO WHEN
INTERRUPT IS ISSUED
UNREAD DATA SAMPLES IN FIFO WHEN
INTERRUPT IS ISSUED
0x0h 0 32
0x1h 1 31
0x2h 2 30
0x3h 3 29
… …
0xFh 15 17
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MAX30102 High-Sensitivity Pulse Oximeter and
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Mode Configuration (0x09)
Bits 6:5: SpO2 ADC Range Control
This register sets the SpO2 sensor ADC’s 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 MAX30102. Changing modes does not change any other setting, nor does it
erase any previously stored data inside the data registers.
SpO2 Configuration (0x0A)
Table 4. Mode Control
Table 5. SpO2 ADC Range Control (18-Bit Resolution)
REGISTER B7 B6 B5 B4 B3 B2 B1 B0 REG
ADDR
POR
STATE R/W
Mode
Configuration SHDN RESET MODE[2:0] 0x09 0x00 R/W
REGISTER B7 B6 B5 B4 B3 B2 B1 B0 REG
ADDR
POR
STATE R/W
SpO2
Configuration SPO2_ADC_RGE[1:0] SPO2_SR[2:0] LED_PW[1:0] 0x0A 0x00 R/W
MODE[2:0] MODE ACTIVE LED CHANNELS
000 Do not use
001 Do not use
010 Heart Rate mode Red only
011 SpO2 mode Red and IR
100–110 Do not use
111 Multi-LED mode Red and IR
SPO2_ADC_RGE[1:0] LSB SIZE (pA) FULL SCALE (nA)
00 7.81 2048
01 15.63 4096
10 31.25 8192
11 62.5 16384
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MAX30102 High-Sensitivity Pulse Oximeter and
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Bits 4:2: SpO2 Sample Rate Control
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 and Red 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. SpO2 Sample Rate Control
Table 7. LED Pulse Width Control
SPO2_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 (µs) 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.
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MAX30102 High-Sensitivity Pulse Oximeter and
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LED Pulse Amplitude (0x0C–0x0D)
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 widely 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
LEDx_PA [7:0], RED_PA[7:0], or IR_PA[7:0] TYPICAL LED CURRENT (mA)*
0x00h 0.0
0x01h 0.2
0x02h 0.4
… …
0x0Fh 3.0
… …
0x1Fh 6.2
… …
0x3Fh 12.6
… …
0x7Fh 25.4
… …
0xFFh 51.0
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MAX30102 High-Sensitivity Pulse Oximeter and
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H
Multi-LED Mode Control Registers (0x11–0x12)
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.
The slots should be enabled in order (i.e., SLOT1 should not be disabled if SLOT2 is 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 None N/A (Off)
100 None N/A (Off)
101 Reserved Reserved
110 Reserved Reserved
111 Reserved Reserved
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MAX30102 High-Sensitivity Pulse Oximeter and
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Temperature Data (0x1F–0x21)
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:
TMEASURED = TINTEGER + TFRACTION
This register stores the integer temperature data in 2’s complement format, where each bit corresponds to 1°C.
Temperature Fraction
This register stores the fractional temperature data in increments of 0.0625°C. If this fractional temperature is paired with
a negative integer, it still adds as a positive fractional value (e.g., -128°C + 0.5°C = -127.5°C).
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.
Table 10. Temperature Integer
REGISTER B7 B6 B5 B4 B3 B2 B1 B0 REG
ADDR
POR
STATE R/W
Die Temp Integer TINT[7] 0x1F 0x00 R
Die Temp Fraction TFRAC[3:0] 0x20 0x00 R
Die Temperature
Config TEMP_EN 0x21 0x00 R/W
REGISTER VALUE (hex) TEMPERATURE (°C)
0x00 0
0x01 +1
... ...
0x7E +126
0x7F +127
0x80 -128
0x81 -127
... ...
0xFE -2
0xFF -1
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MAX30102 High-Sensitivity Pulse Oximeter and
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Applications Information
Sample 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 69µs
then the ADC resolution is 15 bits, and all sample rates are
selectable. However, if the pulse width is set to 411µs, then
the samples rates are limited. The allowed sample rates for
both SpO2 and HR Modes are summarized in the Table 11
and Table 12.
Power Considerations
The LED waveforms and their implication for power sup-
ply design are discussed in this section.
The LEDs in the MAX30102 are pulsed with a low duty cycle
for power savings, and the pulsed currents can cause rip-
ples in the VLED+ 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
1Ω, and that there is at least 1µF 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. SpO2 Mode (Allowed Settings) Table 12. HR Mode (Allowed Settings)
SAMPLES
PER
SECOND
PULSE WIDTH (µs)
SAMPLES
PER
SECOND
PULSE WIDTH (µs)
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
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MAX30102 High-Sensitivity Pulse Oximeter and
Heart-Rate Sensor for Wearable Health
In the Heart Rate mode, only the Red LED is used to
capture optical data and determine the user’s heart rate
and/or photoplethysmogram (PPG).
SpO2 Temperature Compensation
The MAX30102 has an accurate on-board temperature
sensor that digitizes the IC’s internal temperature upon
command from the I2C master. The temperature has an
effect on the wavelength of the red and IR LEDs. While
the device output data is relatively insensitive to the wave-
length of the IR LED, the red LED’s wavelength is critical
to correct interpretation of the data.
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 the temperature rise to the module temperature
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 4.7kΩ.
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)
00000001 (0.2mA) 8 0.1
11111010 (50mA) 8 2
00000001 (0.2mA) 16 0.3
11111010 (50mA) 16 4
00000001 (0.2mA) 32 0.6
11111010 (50mA) 32 8
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MAX30102 High-Sensitivity Pulse Oximeter and
Heart-Rate Sensor for Wearable Health
Timing for Measurements and Data
Collection
Slot Timing in Multi-LED Modes
The MAX30102 can support two LED channels of sequential
processing (Red and IR). Table 14 below displays the four
possible channel slot times associated with each pulse width
setting. Figure 3 shows an example of channel slot timing for
a SpO2 mode application with a 1kHz sample rate.
Table 14. Slot Timing
RED LED
660nm
Red On
69μs
Red Off
931μs
IR On
69μs
IR Off
931μs
358μs
INFRARED LED
880nm
Figure 3. Channel Slot Timing for the SpO2 Mode with a 1kHz Sample Rate
PULSE-WIDTH SETTING (µs) CHANNEL SLOT TIMING (TIMING
PERIOD BETWEEN PULSES) (µs)
CHANNEL-CHANNEL TIMING
(RISING EDGE-TO-RISING EDGE)
(µs)
69 358 427
118 407 525
215 505 720
411 696 1107
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MAX30102 High-Sensitivity Pulse Oximeter and
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—l\H\H|\—(\H\H\HH
Timing in SpO2 Mode
The internal FIFO stores up to 32 samples, so that the
system processor does not need to read the data after
every sample. The temperature does not need to be
sampled very often–once a second or every few seconds
should be sufficient.
Figure 4. Timing for Data Acquisition and Communication When in SpO2 Mode
Table 15. Events Sequence for Figure 4 in SpO2 Mode
EVENT DESCRIPTION COMMENTS
1Enter into SpO2 Mode. Initiate a
Temperature measurement.
I2C Write Command sets MODE[2:0] = 0x03 and A_FULL_EN. Then to
enable and initiate a single temperature measurement, set TEMP_EN
and DIE_TEMP_RDY_EN.
2Temperature Measurement Complete,
Interrupt Generated
DIE_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 first sample in the FIFO.
INT
I2C BUS
LED
OUTPUTS ~
~
~
SAMPLE #1 SAMPLE #2 SAMPLE #3 SAMPLE #16
SAMPLE #17
1 4 5 6
TEMP
SENSOR TEMPERATURE SAMPLE
2 3
29ms
15ms TO 300ms
IRRED IRRED IRRED IRRED IR
RED IRRED IRRED
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MAX30102 High-Sensitivity Pulse Oximeter and
Heart-Rate Sensor for Wearable Health
D D D 8 C D
Timing in HR Mode
The internal FIFO stores up to 32 samples, so that the system
processor does not need to read the data after every sample.
In HR mode (Figure 5), unlike in SpO2 mode, temperature
information is not necessary to interpret the data. The user
can select either the red LED or the infrared LED channel for
heart rate measurements.
Figure 5. Timing for Data Acquisition and Communication When in HR Mode
Table 16. Events Sequence for Figure 5 in HR Mode
EVENT DESCRIPTION COMMENTS
1 Enter into Mode I2C Write Command sets MODE[2:0] = 0x02. Mask the A_FULL_EN
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 first sample in the FIFO.
INT
I2C Bus
LED
OUTPUTS IR ~
~
~
SAMPLE #1 SAMPLE #2 SAMPLE #3 SAMPLE #30 SAMPLE #31
1 2 3 4
15ms TO 300ms
IR IR IR IR IR IR
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MAX30102 High-Sensitivity Pulse Oximeter and
Heart-Rate Sensor for Wearable Health
Power Sequencing and Requirements
Power-Up Sequencing
Figure 6. shows the recommended power-up sequence
for the MAX30102.
It is recommended to power the VDD supply first, before
the LED power supplies (VLED+). The interrupt and I2C
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 MAX30102 is ready for operation.
Reading the I2C interrupt register clears the interrupt, as
shown in Figure 6.
Power-Down Sequencing
The MAX30102 is designed to be tolerant of any power
supply sequencing on power-down.
I2C Interface
The MAX30102 features an I2C/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 MAX30102 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 MAX30102 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 MAX30102 is 8 bits long and is followed by
an acknowledge clock pulse. A master reading data from the
MAX30102 transmits the proper slave address followed by a
series of nine SCL pulses.
The MAX30102 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 500Ω, is required
on SDA. SCL operates only as an input. A pullup resistor,
typically greater than 500Ω, 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 MAX30102 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 master
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 device.
The master terminates transmission, 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 MAX30102 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.
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 MAX30102 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 incorrect slave ID
is detected. After recognizing a START condition followed
by the correct slave ID, the MAX30102 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 MAX30102 (R/W = 0
selects a write condition, R/W = 1 selects a read condition).
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
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28
MAX30102 High-Sensitivity Pulse Oximeter and
Heart-Rate Sensor for Wearable Health
After receiving the proper slave ID, the MAX30102 issues
an ACK by pulling SDA low for one clock cycle.
The MAX30102 slave ID consists of seven fixed bits,
B7–B1 (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
MAX30102 uses to handshake receipt each byte of data
when in write mode (Figure 8). The MAX30102 pulls down
SDA during the entire master-generated 9th 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 MAX30102 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 MAX30102,
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. The register address pointer increments
automatically after each byte of data received, so for
example the entire register bank can be written by at one
time. Terminate the data transfer with a STOP condition.
The write operation is shown in Figure 9.
The internal register address pointer increments automatically,
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 MAX30102
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 R/W0xAE 0xAF
S Sr P
SCL1
SDA1
SCL1
SDA1
START
CONDITION
1 2 8 9
CLOCK PULSE FOR
ACKNOWLEDGMENT
NOT ACKNOWLEDGE
ACKNOWLEDGE
S1010 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
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29
MAX30102 High-Sensitivity Pulse Oximeter and
Heart-Rate Sensor for Wearable Health
Read Data Format
For the read operation, two I2C operations must be
performed. First, the slave ID byte is sent followed by
the I2C register that you wish to read. Then a REPEAT
START (Sr) condition is sent, followed by the read slave
ID. The MAX30102 then begins sending data beginning
with the register selected in the first operation. The read
pointer increments automatically, so the device 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 I2C write
command is necessary to change the location of the read
pointer.
Figure 10 and Figure 11 show the process of reading one
byte and 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 I2C 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 MAX30102
Figure 11. Reading Multiple Bytes of Data from the MAX30102
S1010111R/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
S10101
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
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30
MAX30102 High-Sensitivity Pulse Oximeter and
Heart-Rate Sensor for Wearable Health
+Denotes lead(Pb)-free/RoHS-compliant package.
T = Tape and reel.
PART TEMP RANGE PIN-PACKAGE
MAX30102EFD+T -40°C to +85°C 14-Lead OESIP
(0.8mm Pin Pitch)
880nm660nm
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
N.C.N.C. GND PGND
RED IR
VISIBLE+IR
1kΩ V
DDIO
HOST
PROCESSOR
(NOT CONNECTED)
MAX30102
+3.3V
200mA MAX
V
LED+
10µF 0.1µF 4.7µF
+1.8V
20mA
0.1µF
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31
MAX30102 High-Sensitivity Pulse Oximeter and
Heart-Rate Sensor for Wearable Health
Typical Application Circuit
Ordering Information
REVISION
NUMBER
REVISION
DATE DESCRIPTION PAGES
CHANGED
0 9/15 Initial release
1 10/18
Updated the General Description, Applications, Absolute Maximum Ratings, Electrical
Characteristics, Pin Description, Timing in SpO2 Mode, Power-Up Sequencing
sections; updated the System Diagram, Pin Configuration, and Functional Diagram;
updated the Register Map, Interrupt Status (0x00–0x01), Interrupt Enable (0x02–
0x03), FIFO (0x04–0x07), LED Pulse Amplitude (0x0C–0x0D), Table 8, Multi-LED
Mode Control Registers (0x11–0x12), Table 9, Temperature Data (0x1F–0x21), Table
13, Table 15, Table 16; replaced the Typical Application Circuit; removed the Proximity
Function section and the Proximity Mode Interrupt Threshold (0x30) register
1–5, 8–14, 18
20–24, 26–28, 31
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 specifications 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. © 2018 Maxim Integrated Products, Inc.
32
MAX30102 High-Sensitivity Pulse Oximeter and
Heart-Rate Sensor for Wearable Health
Revision History
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