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

The MAX86140/MAX86141 are ultra-low-power, completely integrated, optical data acquisition systems. On the transmitter side, the MAX86140/MAX86141 have three programmable high-current LED drivers that can be configured to drive up to six LEDs using an external 3x2:1 mux. With two MAX86140/MAX86141 devices working in master-slave mode, the LED drivers can drive up to twelve LEDs using an external 3x2:1 mux. On the receiver side, MAX86140 consists of a single optical readout channel, while the MAX86141 has two optical readout channels that can operate simultaneously. The devices have low-noise signal conditioning analog front-end (AFE) including 19-bit ADC, an industry-lead ambient light cancellation (ALC) circuit, and a picket fence detect and replace function. Due to the low power consumption, compact size, ease of use, and industry-lead ambient light rejection capability of MAX86140/MAX86141, the devices are ideal for a wide variety of optical-sensing applications, such as pulse oximetry and heart rate detection.

The MAX86140/MAX86141 operate on a 1.8V main supply voltage and a 3.1V to 5.5V LED driver supply voltage. Both devices support a standard SPI compatible interface and fully autonomous operation. Each device has a large 128-word built-in FIFO. The MAX86140/MAX86141 is available in compact wafer-level package (WLP) (2.048 x 1.848mm) with 0.4mm ball pitch.

Applications

* Muscle Oxygen Saturation (SmO2 and StO2)

* Optical Heart Rate

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

* Optimized Performance for High Quality PPG Signal to Detect

* Oxygen Saturation (SpO2)

* Wearable Devices for Fitness, Wellness, and Medical Applications

* Complete Single-Channel, Optical Data Acquisition System

* Optimized Architecture for Transmissive and Reflective Heart Rate or SpO2 Monitoring

* Low Dark Current Noise of < 50pA RMS (Sample to Sample Variance)

* Lower Effective Dark Current Noise Achievable Through Multiple Sample Modes and On-Chip Averaging

* High-Resolution, 19-bit Charge Integrating ADC

* Three Low-Noise, 8-Bit LED Current DACs

* Excellent Dynamic Range >89dB in White Card Loop-Back Test (Sample-to-Sample Variance)

* Dynamic Range Extendable to >104dB for SpO2 and >110dB for HRM with Multiple Sample Modes and On-Chip Averaging

* Excellent Ambient Range and Rejection Capability

* > 100µA Ambient Photodetector Current

* > 70dB Ambient Rejection at 120Hz

* Ultra-Low-Power Operation for Body Wearable Devices

* Low-Power Operation, Optical Readout Channel <10µA Typical at 25sps

* Short Exposure Integration Period of 14.8µs, 29.4µs, 58.7µs, 117.3µs

* Low Shutdown Current = 0.6µA (typ)

* Rejection of Fast Ambient Transients

* Miniature 2.048 x 1.848mm, 5 x 4 0.4mm Ball Pitch WLP

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