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

Description

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The MAX86140/MAX86141 are ultra-low-power, com- pletely 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 func- tion. 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.

Introducing the MAX-HEALTH-BAND Heart Rate and Activity Monitor

Wristband Health Monitoring Demo with MAX86141

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Key Features

• 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

Applications/Uses

• - Muscle Oxygen Saturation (SmO₂ and StO₂)
• - Optical Heart Rate
• - Oxygen Saturation
• Optimized for Wrist, Finger, Ear, and Other Locations
• Optimized Performance for High Quality PPG Signal to Detect
• Wearable Devices for Fitness, Wellness, and Medical Applications