Click here for production status of specific part numbers. MAX30101 High-Sensitivity Pulse Oximeter and Heart-Rate Sensor for Wearable Health General Description The MAX30101 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 MAX30101 provides a complete system solution to ease the design-in process for mobile and wearable devices. The MAX30101 operates on a single 1.
MAX30101 High-Sensitivity Pulse Oximeter and Heart-Rate Sensor for Wearable Health Absolute Maximum Ratings 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........................
MAX30101 High-Sensitivity Pulse Oximeter and Heart-Rate Sensor for Wearable Health Electrical Characteristics (continued) (VDD = 1.8V, VLED+ = 5.0V, TA = +25°C, min/max are from TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = 25°C.
MAX30101 High-Sensitivity Pulse Oximeter and Heart-Rate Sensor for Wearable Health Electrical Characteristics (continued) (VDD = 1.8V, VLED+ = 5.0V, TA = +25°C, min/max are from TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = 25°C.
MAX30101 High-Sensitivity Pulse Oximeter and Heart-Rate Sensor for Wearable Health Electrical Characteristics (continued) (VDD = 1.8V, VLED+ = 5.0V, TA = +25°C, min/max are from TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = 25°C.
MAX30101 High-Sensitivity Pulse Oximeter and Heart-Rate Sensor for Wearable Health Typical Operating Characteristics (VDD = 1.8V, VLED+ = 5.0V, TA = +25°C, RST, unless otherwise noted.) RED LED SUPPLY HEADROOM 60 ILED = 50mA 50 IR LED CURRENT (mA) RED LED CURRENT (mA) IR LED SUPPLY HEADROOM toc01 60 40 30 ILED = 20mA 20 10 ILED = 50mA 50 40 30 ILED = 20mA 20 10 0 0 1 2 3 4 0 5 0 1 2 VLED VOLTAGE (V) toc03 VLED = VX_DRV ILED = 50mA 50 30 ILED = 20mA 0.7 0.6 0.5 0.4 0.
MAX30101 High-Sensitivity Pulse Oximeter and Heart-Rate Sensor for Wearable Health Typical Operating Characteristics (continued) (VDD = 1.8V, VLED+ = 5.0V, TA = +25°C, RST, unless otherwise noted.) GREEN LED SPECTRA AT 30°C 120 RED LED PEAK WAVELENGTH vs.
MAX30101 High-Sensitivity Pulse Oximeter and Heart-Rate Sensor for Wearable Health Typical Operating Characteristics (continued) (VDD = 1.8V, VLED+ = 5.0V, TA = +25°C, RST, unless otherwise noted.) RED LED FORWARD VOLTAGE vs. FORWARD CURRENT AT TA = +25°C toc13 MODE = FLEX LED ADC RES = 18 BITS ADC SR = 100 SPS ADC FULL SCALE = 2048nA 40 30 20 10 0 1.90 2.00 2.10 2.20 40 30 20 0 2.30 MODE = FLEX LED ADC RES = 18 BITS ADC SR = 100 SPS ADC FULL SCALE = 2048nA 1.25 1.30 RELATIVE INTENSITY vs.
MAX30101 High-Sensitivity Pulse Oximeter and Heart-Rate Sensor for Wearable Health Pin Configuration 14 N.C. N.C. 1 SCL 2 SDA 3 12 GND PGND 4 11 VDD N.C. 5 N.C. 6 N.C. 7 SENSOR MAX30101 13 INT 10 VLED+ LED 9 VLED+ 8 N.C. Pin Description PIN NAME 1, 5, 6, 7, 8, 14 N.C. No Connection. Connect to PCB pad for mechanical stability.
MAX30101 High-Sensitivity Pulse Oximeter and Heart-Rate Sensor for Wearable Health Functional Diagram VDD VLED+ RED IR AMBIENT LIGHT CANCELLATION GREEN ANALOG VISIBLE+IR ADC 660nm 880nm 527nm DIE TEMP N.C. N.C. DIGITAL FILTER SCL DATA REGISTER I 2C COMMUNICATION SDA INT ADC OSCILLATOR N.C.
MAX30101 High-Sensitivity Pulse Oximeter and Heart-Rate Sensor for Wearable Health Register Maps and Descriptions REGISTER B7 B6 B5 A_FULL PPG_ RDY ALC_ OVF B4 B3 B2 B1 B0 REG ADDR POR STATE R/W PWR_ RDY 0x00 0X00 R 0x01 0x00 R 0x02 0X00 R/W 0x03 0x00 R/W STATUS Interrupt Status 1 Interrupt Status 2 DIE_TEMP _RDY Interrupt Enable 1 A_FULL_ EN PPG_ ALC_ RDY_EN OVF_EN Interrupt Enable 2 DIE_TEMP _RDY_EN FIFO FIFO Write Pointer FIFO_WR_PTR[4:0] 0x04 0x00 R/W Overflow C
MAX30101 High-Sensitivity Pulse Oximeter and Heart-Rate Sensor for Wearable Health Register Maps and Descriptions (continued) REG ADDR POR STATE R/W RESERVED 0x13– 0x17 0xFF R/W RESERVED 0x180x1E 0x00 R 0x1F 0x00 R 0x20 0x00 R 0x21 0x00 R/W 0x22– 0x2F 0x00 R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DIE TEMPERATURE Die Temp Integer TINT[7:0] Die Temp Fraction TFRAC[3:0] Die Temperature Config TEMP _EN RESERVED PART ID Revision ID REV_ID[7:0] 0xFE 0xXX* R Part ID PART_I
MAX30101 High-Sensitivity Pulse Oximeter and Heart-Rate Sensor for Wearable Health Interrupt Status (0x00–0x01) REGISTER Interrupt Status 1 B7 B6 B5 B4 B3 B2 B1 A_FULL PPG_RDY ALC_OVF Interrupt Status 2 DIE_ TEMP_RDY B0 REG ADDR POR STATE R/W PWR_ RDY 0x00 0X00 R 0x01 0x00 R Whenever an interrupt is triggered, the MAX30101 pulls the active-low interrupt pin into its low state until the interrupt is cleared.
MAX30101 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.
MAX30101 High-Sensitivity Pulse Oximeter and Heart-Rate Sensor for Wearable Health 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, 6 bytes, 9 bytes, or 12 bytes in size. The FIFO_DATA register in the I2C register map points to the next sample to be read from the FIFO.
MAX30101 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).
MAX30101 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
MAX30101 High-Sensitivity Pulse Oximeter and Heart-Rate Sensor for Wearable Health 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.
MAX30101 High-Sensitivity Pulse Oximeter and Heart-Rate Sensor for Wearable Health Mode Configuration (0x09) REGISTER B7 B6 Mode Configuration SHDN RESET B5 B4 B3 B2 B1 B0 MODE[2:0] REG ADDR POR STATE R/W 0x09 0x00 R/W 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.
MAX30101 High-Sensitivity Pulse Oximeter and Heart-Rate Sensor for Wearable Health 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.
MAX30101 High-Sensitivity Pulse Oximeter and Heart-Rate Sensor for Wearable Health LED Pulse Amplitude (0x0C–0x0F) REGISTER B7 B6 LED Pulse Amplitude B5 REG ADDR POR STATE R/W LED1_PA[7:0] 0x0C 0x00 R/W LED2_PA[7:0] 0x0D 0x00 R/W LED3_PA[7:0] 0x0E 0x00 R/W LED4_PA[7:0] 0x0F 0x00 R/W B4 B3 B2 B1 B0 These bits set the current level of each LED as shown in Table 8. Table 8. LED Current Control LEDx_PA [7:0] TYPICAL LED CURRENT (mA)* 0x00h 0.0 0x01h 0.2 0x02h 0.
MAX30101 High-Sensitivity Pulse Oximeter and Heart-Rate Sensor for Wearable Health Multi-LED Mode Control Registers (0x11–0x12) REGISTER B7 Multi-LED Mode Control Registers B6 B5 B4 B3 B2 B1 B0 REG ADDR POR STATE R/W SLOT2[2:0] SLOT1[2:0] 0x11 0x00 R/W SLOT4[2:0] SLOT3[2:0] 0x12 0x00 R/W In multi-LED mode, each sample is split into up to four time slots, SLOT1 through SLOT4.
MAX30101 High-Sensitivity Pulse Oximeter and Heart-Rate Sensor for Wearable Health Temperature Data (0x1F–0x21) REGISTER B7 B6 B5 Temp_Integer B4 B3 B2 B1 B0 TINT[7] Temp_Fraction TFRAC[3:0] Die Temperature Config TEMP_EN REG ADDR POR STATE R/W 0x1F 0x00 R/W 0x20 0x00 R/W 0x21 0x00 R/W 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.
MAX30101 High-Sensitivity Pulse Oximeter and Heart-Rate Sensor for Wearable Health 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 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.
MAX30101 High-Sensitivity Pulse Oximeter and Heart-Rate Sensor for Wearable Health SpO2 Temperature Compensation Red LED Current Settings vs. LED Temperature Rise The MAX30101 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.
MAX30101 High-Sensitivity Pulse Oximeter and Heart-Rate Sensor for Wearable Health Timing for Measurements and Data Collection setting. Figure 3 shows an example of channel slot timing for a SpO2 mode application with a 1kHz sample rate. Slot Timing in Multi-LED Modes The MAX30101 can support up to three LED channels of sequential processing (Red, IR, and Green). In multiLED modes, a time slot or period exists between active sequential channels.
MAX30101 High-Sensitivity Pulse Oximeter and Heart-Rate Sensor for Wearable Health Timing in SpO2 Mode data. In this case, the temperature does not need to be sampled very often – once a second or every few seconds should be sufficient. The internal FIFO stores up to 32 samples, so that the system processor does not need to read the data after every sample.
MAX30101 High-Sensitivity Pulse Oximeter and Heart-Rate Sensor for Wearable Health Timing in HR Mode mode, temperature information is not necessary to interpret the data. The user can select either the Red, IR, or Green LED channel for heart rate. The internal FIFO stores up to 32 samples, so that the system processor does not need to read the data after every sample.
MAX30101 High-Sensitivity Pulse Oximeter and Heart-Rate Sensor for Wearable Health Power Sequencing and Requirements Power-Up Sequencing VDD Figure 6 shows the recommended power-up sequence for the MAX30101. 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.
MAX30101 High-Sensitivity Pulse Oximeter and Heart-Rate Sensor for Wearable Health ID, the MAX30101 issues an ACK by pulling SDA low for one clock cycle. The MAX30101 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. during the 9th clock cycle to acknowledge receipt of data when the MAX30101 is in read mode.
MAX30101 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 MAX30101 then begins sending data beginning with the register selected in the first operation.
MAX30101 High-Sensitivity Pulse Oximeter and Heart-Rate Sensor for Wearable Health Typical Application Circuit +1.8V 20mA +5.0V 200mA MAX 4.7µF 10µF VLED+ RED IR VDD AMBIENT LIGHT CANCELLATION GREEN 1kΩ ANALOG VISIBLE+IR ADC 660nm 880nm 527nm DIE TEMP DIGITAL DIGITAL FILTER VDDIO SCL DATA REGISTER I2C COMMUNICATION SDA INT HOST PROCESSOR ADC OSCILLATOR LED DRIVERS MAX30101 N.C. N.C. PGND GND N.C.
MAX30101 High-Sensitivity Pulse Oximeter and Heart-Rate Sensor for Wearable Health Revision History REVISION NUMBER REVISION DATE 0 3/16 Initial release 1 6/18 Changed register descriptions, updated tables 8,9,13,15,16, removed Proximity function, updated FIFO_A_FULL description table 10–15, 18, 21–25, 27, 28 9/18 Updated the Applications, Absolute Maximum Ratings, Electrical Characteristics, Pin Description, and Power-Up Sequencing sections; updated the System Diagram, Pin Configuration, Functi
