Single-Supply Integrated Optical Module for HR and SpO₂ Measurement

Description

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The MAXM86161 is an ultra-low-power, completely integrated, optical data-acquisition system. On the transmitter side, the MAXM86161 has three programmable high-current LED drivers. On the receiver side, MAXM86161 consists of a high efficiency PIN photo-diode and an optical readout channel. The optical readout has a 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 algorithm. Due to the low power consumption, compact size, easy, flexible-to-use, and industry lead ambient light rejection capability of the MAXM86161, the device is ideal for a wide variety of optical sensing applications such as heart rate detection and pulse oximetry.

The MAXM86161 operates on a 3.0V to 5.5V V_LED single supply voltage. It supports a standard compatible interface and fully autonomous operation. Each device has a large 128-word built-in FIFO. The MAXM86161 is available in compact 2.9mm x 4.3mm x 1.4mm, 14-pin OLGA package.

Key Features

• Complete Single-Channel Optical Data Acquisition System
• Built-In Algorithm Further Enhances Rejection of Fast Ambient Transients
• Optimized Architecture for Reflective Heart Rate and 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)
• Excellent Ambient Range and Rejection Capability
  • > 100μA Ambient Photodetector Current
  • > 70dB Ambient Rejection at 120Hz
• Ultra-Low-Power Operation for 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 = 1.6μA (typ)
• Miniature 2.9mm x 4.3mm x 1.4mm, 14-pin OLGA Package
• -40°C to +85°C Operating Temperature Range

Applications/Uses

• Optimized for In-Ear Applications
• Miniature Package for Mobile Applications
• Optimized Performance to Detect:
• Continuous Monitoring for HRV
• Optical Heart Rate
• Oxygen Saturation (SpO₂)