Analog Devices Inc. ADPD4000/1 Multimodal Sensor Front End can stimulate up to eight LEDs and measure the return signal on up to eight separate current inputs. Twelve available time slots can enable 12 separate measurements per sampling period. The data output and functional configuration utilize an I2C interface on the ADPD4001 or a serial port interface (SPI) on the ADPD4000. The control circuitry includes flexible LED signaling and synchronous detection. The devices use a 1.8V analog core and 1.8V/3.3V compatible digital input/output (I/O).
FEATURES
8 input channels with multiple operation modes to accommodate the following measurements: PPG, ECG, EDA, impedance, and temperature
Dual channel processing with simultaneous sampling
12 programmable time slots for synchronized sensor measurements
Flexible input multiplexing to support differential and single-ended sensor measurements
8 LED drivers, 4 of which can be driven simultaneously
On-chip digital filtering
Flexible sampling rate from 0.004Hz to 9kHz using internal oscillators
SNR of transmit and receive signal chain: 90dB
Ambient light rejection: 60dB up to 1kHz
400mA total LED drive current
Total system power dissipation: 50µW (combined LED and AFE power), continuous PPG measurement at 75dB SNR, 25Hz ODR, 100nA/mA CTR
SPI and I2C communications supported
256-byte FIFO
APPLICATIONS
Wearable health and fitness monitors: heart rate monitors (HRMs), heart rate variability (HRV), stress, blood pressure estimation, SpO2, hydration, body composition
Industrial monitoring: CO, CO2, smoke, and aerosol detection
Home patient monitoring
