MAX30102 High-Sensitivity Pulse Oximeter and Heart-Rate Sensor for Wearable Health Functional Diagram VLED+ VDD AMBIENT LIGHT RED IR CANCELLATION ANALOG DIGITAL SCL VISIBLE+IR SDA ADC DIGITAL I2C FILTER DATA REGISTER COMMUNICATION INT 660nm 880nm DIE TEMP ADC OSCILLATOR LED DRIVERS MAX30102 N.C. N.C. GND PGND Detailed Description sampling rate is 10.24MHz. The ADC output data rate The MAX30102 is a complete pulse oximetry and heart-rate can be programmed from 50sps (samples per second) to sensor system solution module designed for the demanding 3200sps. requirements of wearable devices. The device maintains a Temperature Sensor very small solution size without sacrificing optical or electrical performance. Minimal external hardware components are The MAX30102 has an on-chip temperature sensor for required for integration into a wearable system. calibrating the temperature dependence of the SpO2 sub- system. The temperature sensor has an inherent resolu- The MAX30102 is fully adjustable through software registers, tion of 0.0625°C. and the digital output data can be stored in a 32-deep FIFO within the IC. The FIFO allows the MAX30102 to be The device output data is relatively insensitive to the connected to a microcontroller or processor on a shared wavelength of the IR LED, where the Red LED’s wave- bus, where the data is not being read continuously from length is critical to correct interpretation of the data. An the MAX30102’s registers. SpO2 algorithm used with the MAX30102 output signal can compensate for the associated SpO2 error with ambient SpO2 Subsystem temperature changes. The SpO2 subsystem of the MAX30102 contains ambient LED Driver light cancellation (ALC), a continuous-time sigma-delta ADC, and a proprietary discrete time filter. The ALC has The MAX30102 integrates Red and IR LED drivers to an internal Track/Hold circuit to cancel ambient light and modulate LED pulses for SpO2 and HR measurements. increase the effective dynamic range. The SpO The LED current can be programmed from 0 to 50mA 2 ADC has programmable full-scale ranges from 2µA to 16µA. The with proper supply voltage. The LED pulse width can be ALC can cancel up to 200µA of ambient current. programmed from 69µs to 411µs to allow the algorithm to The internal ADC is a continuous time oversampling optimize SpO2 and HR accuracy and power consumption sigma-delta converter with 18-bit resolution. The ADC based on use cases. www.maximintegrated.com Maxim Integrated │ 9