Best-in-Class Optical Pulse Oximeter and Heart-Rate Sensor AFE for Wearable Health

The MAX86174A/MAX86174B are ultra-low-power optical data acquisition systems with both transmit and receive channels. On the transmitter side, the MAX86174A/MAX86174B have four LED driver output pins. Each pin is programmable from two, high-current, 8-bit LED drivers. On the receiver side, the MAX86174A consists of two optical readout channels that can operate simultaneously while the MAX86174B has a single optical readout channel. The devices have low-noise, charge-integrating analog front-end, 20-bit ADC, and best-in-class ambient-light cancellation (ALC) circuits.

Due to the low power consumption, compact size, ease and flexibility of use, the MAX86174A/MAX86174B are ideal for a wide variety of optical sensing applications such as pulse oximetry and heart-rate detection.

The MAX86174A/MAX86174B operate on a 1.8V main supply voltage and a 2.7V to 5.5V LED driver supply voltage. The devices support both I2C- and SPI-compatible interfaces in a fully autonomous way. The devices have a large 256-word built-in FIFO. The MAX86174A/MAX86174B are available in a compact 16-WLP package.

Applications

* Body Hydration * Clinical Accuracy * Heart-Rate Variability * Maximum Oxygen Consumption (VO2 max) * Muscle and Tissue Oxygen Saturation (SmO2 and StO2) * Optical Heart Rate * Optimized Performance to Detect * Oxygen Saturation (SpO2) * Suitable for Wrist, Finger, Ear, and Other Locations * Wearable Devices for Fitness, Wellness and Medical Applications

* Complete Optical Data Acquisition System

* Ultra-Low-Power Operation for Body Wearable Devices

* Low-Power-Operation, Optical Readout Channel < 11µA (typ) at 25fps

* Exposure Integration Period Ranging from 14.6µs to 117.1µs

* Low Shutdown Current < 1µA (typ)

* Excellent Top-End Dynamic Range > 93dB in White Card Loop-Back Test (Nyquist Sample-to-Sample Variance)

* Extended Dynamic Range up to 111dB (Averaging and Off-Chip Filtering) to Enable SpO2 on Wrist/Chest for Low Perfusion Cases

* Support Frame Rates from 1fps to 2048fps

* High-Resolution 20-Bit Charge-Integrating ADCs

* Support Both Burst Averaging and Decimation Averaging Modes

* On-Chip 12Hz Low-Pass Filter for Improved SNR and Reduced Power for Continuous Heart-Rate Measurement

* Supports Two PD Inputs for Multi-Parameter Measurements

* Supports Four LED Driver Output Pins Generated from Two 8-Bit LED Current Drivers

* Low Dark-Current Noise of < 50pARMS (Sample-to-Sample Variance in 117.1µs Integration Time)

* Excellent Ambient Range and Rejection Capability

* 200µA Ambient Photodiode Current

* > 70dB Ambient Rejection at 120Hz (Burst Average > 2)

* Miniature 1.67mm x 1.78mm, 0.4mm Ball Pitch, 4 x 4 WLP Package

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