Analog Devices Inc. MAXM86161A Single-Supply Integrated Optical Module
Analog Devices MAXM86161A Single-Supply Integrated Optical Modules are ultra‑low‑power, fully integrated optical data‑acquisition modules. The ADI MAXM86161A features three programmable high‑current LED drivers on the transmitter side and a high‑efficiency PIN photodiode paired with an optical readout channel on the receiver side. The optical readout includes a low‑noise analog front end (AFE) with a 19‑bit analog-to-digital converter (ADC), an industry‑leading ambient light cancellation (ALC) circuit, and a picket‑fence detection and replacement algorithm. Thanks to the low power requirements, compact form factor, ease of use, and excellent ambient‑light rejection, the MAXM86161A modules are well-suited for a broad range of optical sensing applications, including heart‑rate monitoring and pulse oximetry.
These ADI modules operate from a single VLED supply of 3.0V to 5.5V and support a standard digital interface along with fully autonomous operation. It also includes a 128‑word built‑in FIFO. The MAXM86161A is offered in a compact 2.9mm × 4.3mm × 1.4mm, 14‑pin OLGA package.
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 <50pARMS dark current noise (sample-to-sample variance)
- Lower effective dark current noise is achievable through multiple sample modes and on-chip averaging
- High-resolution 19-bit charge integrating analog-to-digital converter (ADC)
- Three low-noise 8-Bit LED current digital-to-analog converters (DACs)
- Excellent >89dB dynamic range in white card loop-back test (sample-to-sample variance)
- Excellent ambient range and rejection capability
- 200μA ambient photodetector current
- >70dB ambient rejection at 120Hz
- Ultra-low-power operation for wearable devices
- Low <10μA typical power operation at 25sps, optical readout channel
- 14.8μs, 29.4μs, 58.7μs, and 117.3μs short exposure integration periods
- Low 1.6μA typical shutdown current
- Miniature 2.9mm x 4.3mm x 1.4mm, 14-pin OLGA package
- -40°C to +85°C operating temperature range
Applications
- Optimized performance to detect
- Optical heart rate
- Oxygen saturation (SpO2)
- Continuous monitoring for heart rate variability (HRV)
- Optimized for in-ear applications
- Mobile applications
Specifications
- 36mW maximum continuous power dissipation
- Power supply
- 3.0V to 5.5V LED supply voltage range
- 1.68V to 1.92V LDO output voltage range
- 400μA to 1300μA typical average LED supply current range
- 0.3μA to 11μA maximum LED supply current range in shutdown
- 1.195V to 1.220V VREF range
- Read-out channel
- 8sps to 4096sps PPG sample rate range
- ±2% sample rate error
- 200μA maximum DC ambient light rejection
- LED driver
- 8-bit LED current resolution
- 31mA to 124mA full-scale LED current range
- 160mV to 700mV minimum output voltage range
- IR LED characteristics
- 880nm typical centroid wavelength
- 1.9V maximum forward voltage
- 38mW minimum radiant power
- +115°C maximum junction temperature
- Red LED characteristics
- 660nm typical centroid wavelength
- 2.4V maximum forward voltage
- 11mW minimum radiant power
- +115°C maximum junction temperature
- Green LED characteristics
- 520nm to 535nm centroid wavelength range
- 2.8V to 3.4V forward voltage range
- 70mW minimum radiant power
- +150°C maximum junction temperature
- Photodiode
- 860nm typical wavelength of peak sensitivity
- 420nm to 1020nm typical spectral bandwidth range
- Digital I/O
- 0.3V to 1.4V input voltage range
- 400mV typical input hysteresis
- 1μA maximum input leakage current
- 10pF typical input capacitance
- I2C timing
- 0kHz to 400kHz serial clock frequency range
- 0ns to 900ns data hold time range
- 100ns minimum data setup time
- 400pF maximum bus capacitance
- 55.49°C/W junction-to-ambient thermal resistance
Simplified Block Diagram
Typical Application Circuit
