1 Features

Integrated signal chains for Bio-Z, EDA, ECG, PPG
Synchronized ECG, PPG enables PTT-based BP
Bio-Z signal chain
- Multi-frequency Body impedance Analysis (BIA) with frequency programmable up to 250 kHz
- Low frequency excitation mode for EDA/GSR
- Complex (I,Q) Tetrapolar impedance measurement
- Sine-wave excitation with a 7-bit DAC
- Calibration scheme compensates for electrode impedance to achieve accurate Bio-Z
- State machine for Automatic Calibration
ECG signal chain:
- 1-lead ECG signal acquisition up to 2 kHz
- INA gain programmable from 2-21
- RLD output to set body bias through third electrode
- Input noise (0.5-150 Hz): 0.75 µVrms at 1 kHz
- ± 0.6 V differential DC offset and ± 0.3 V CM range
- HPF with 0.4 Hz corner, quick saturation recovery
- >1 GΩ input impedance, CMRR > 100 dB
- Integrated 300 Hz anti-aliasing low pass filter
- AC, DC lead-off detect: 1.6-nA to 100-nA
PPG signal chain
- Supports acquisition of up to 24 PPG signals
- Flexible allocation of 8 LED, 4 PD in each phase
- Supports PPG sensors at different data rates
- Optical loopback SNR of 100-dB, extendable to 110-dB with on-chip filtering
- Low Current for Continuous Operation with a Typical Value: 15-μA for an LED, 15-μA for the Receiver
PPG Transmitter
- 8-Bit Programmable LED Current with range adjustable from 25 mA to 250 mA
- Programmable LED On-Time per-phase
- Support of 8 LEDs in Common Anode
PPG Receiver
- Supports 4 PDs, 2 parallel receive paths
- Noise filtering with programmable bandwidth
- Trans-impedance Gain: 3.7 kΩ to 1 MΩ
- 8-bit Ambient Offset Subtraction DAC with range from16-256 µA
- 8-bit LED Offset Subtraction DAC with range from 32 to 64 µA
- Automatic ambient & LED DC cancellation
- Supports external clock and internal oscillator modes
- FIFO with 256-sample Depth
- SPI^TM, I²C interfaces: Selectable by pin
- Supplies: Rx:1.7-1.9V (LDO Bypass); 1.9 V to -3.6 V (LDO Enabled), Tx: 3 V to 5.5 V, IO:1.7-RX_SUP