Low-Noise AFE for Pulse Oximeter and Heart Rate Monitor

The MAX86170B is an ultra-low-power optical data acquisition system with both transmit and receive channels. On the transmitter side, the MAX86170B has four LED driver output pins, programmable from three high-current, 8-bit LED drivers. On the receiver side, MAX86170B has a low-noise charge integrating front-end that includes a 20-bit ADC and best-in-class ambient light cancellation (ALC) circuit, producing the highest performing integrated optical data acquisition system on the market today.

Due to its low power consumption, compact size, ease- and flexibility-of-use, the MAX86170B is ideal for a wide variety of optical sensing applications such as pulse oximetry and heart rate detection.

The MAX86170B operates on a 1.8V main supply voltage and a 3.1V to 5.5V LED driver supply voltage. The device supports both I2C- and SPI-compatible interfaces in a fully autonomous way. The device has a large 256-word built-in FIFO. The MAX86170B is available in a compact WLP package 2.78mm x 1.71mm with 6 x 4, 0.4mm ball pitch.

APPLICATIONS

* Wearable Devices for Fitness, Wellness, and Medical Applications

* Clinical Accuracy

* Suitable for Wrist, Finger, Ear, and Other Locations

* Optimized Performance to Detect:

* Optical Heart Rate

* Heart-Rate Variability

* Oxygen Saturation (SpO2)

* Body Hydration

* Muscle and Tissue Oxygen Saturation (SmO2 and StO2)

* Maximum Oxygen Consumption (VO2 max)

* Complete Single-Channel Optical Data Acquisition System

* Ultra Low-Power Operation for Wearable Devices

* Low-Power Operation, Optical Readout Channel < 11micro;A at 25fps

* Exposure Integration Period Ranging from 14.6µs to 117.1µs

* Low Shutdown Current < 1µA * Excellent Top-End Dynamic Range > 91dB in White Card Loop-Back Test (Nyquist Sample-to-Sample Variance)

* Extended Dynamic Range up to 110dB (Averaging and Off-Chip Filtering)

* Supports Frame Rates from 1fps to 2.9kfps

* High Resolution 20-Bit Charge Integrating ADC

* Supports Two PD Inputs for Multiparameter Measurements

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

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

* Excellent Ambient Range and Rejection Capability

* 200µA Ambient Photodetector Current

* > 70dB Ambient Rejection at 120Hz * Miniature 2.78mm x 1.71mm 6 x 4, 0.4mm Ball Pitch WLP Package

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