Optimized Pulse-Oximeter and Heart Rate AFE for Wearable Health

The MAX30112 is a complete optical pulse oximetry and heart rate detection integrated analog front-end. The MAX30112 has a high-resolution, optical readout signal-processing channel with built-in ambient light cancellation, as well as high-current LED driver DACs, to form a complete optical readout signal chain. With external LED(s) and photo diode(s), the MAX30112 offers the lowest power, highest performance heart rate detection solution for wrist applications.

The MAX30112 operates on a 1.8V main supply voltage, with a separate 3.1V to 5.25V LED driver power supply. The device supports a standard I2C compatible interface, as well as shutdown modes through the software with near-zero standby current, allowing the power rails to remain powered at all times.

Applications

* Fitness Wearable Devices * In-Ear Wearable Devices * SpO2 Monitoring Devices * Wrist-Worn Wearable Devices

* Reflective or Transmissive Heart Rate, Heart Rate Variability, or SpO2 Monitoring

* Transmit Section

* Two 8-bit LED Current DACs

* Four Current Ranges 50mA, 100mA, 150mA, 200mA

* Low Noise Current Sources for High Peak Transmit to Receive Dynamic Range

* Low 160mV Dropout to Support Direct Drive From Rechargeable Li Battery

* High Output Impedance and High Supply Rejection to Support Unregulated Supply or Direct Drive From Boost Switcher Supply

* Receive Section

* 19-bit Optical ADC Path to Support the Lowest Perfusions Situations

* Low 25pA-RMS Input Referred Noise to Minimize LED Power Under Most Conditions

* High Ambient Light Input Range of 200μA and to Support Extraction of HRM Signal in the Most Adverse Lighting Conditions

* Built-in Front And Back End Ambient Light Cancellation, Improving Rejection and Eliminating System Complexity of Dealing with Ambient Light

* Short Exposure Pulse Widths of 52μs, 104μs, 206μs, 417μs for Efficient Uses of LED Light

* Multiple Sample Rate Options from 20sps to 3.2ksps

* Ultra-Low-Power Operation for Mobile and Body-Wearable Device

* Dynamic Power Down Modes to 100sps for Low-Power Consumption

* Full AFE Power Consumption of Less Than 25μA (typ) at 25sps

* Large 32 Sample FIFO to Support Batch Processing in the Microcontroller

* Variety of System Monitors Mappable to Interrupts to Off-Load System Monitoring Functions From the Microcontroller

* Low Shutdown Current = 1.4μA (typ)

* I2C interface

* Supports a Single 1.8V Supply with Separate 3.1V to 5.25V LED Supply

* Miniature 2.8mm x 2.0mm, 6x4, 0.4mm Ball Pitch WLP Package

* -40°C to +85°C Operating Temperature Range