1 Features

1• Supports signal acquisition of up to 24 phases

• Flexible allocation of 6 LED, 4 PD in each PPG

phase

• Synchronized PPG/ECG signal acquisition with

each phase configurable as PPG or ECG, and at

different data rates

• Synchronized PPG/ECG supports up to 1 kHz

data rate

• ECG-only mode supports up to 4 kHz data rate

• PPG signal chain:

– System SNR up to 108-dB at 16 μA PD current

– Low current for continuous operation on a

wearable device with a typical value: 15 μA for

an LED, 20 μA for the receiver

• PPG Transmitter:

– Supports common anode LED configuration

– 8-Bit programmable LED current with range

adjustable from 25 mA to 250 mA

– Mode to fire two LEDs in parallel with

independent per-phase current control

– Programmable LED on-time per-phase

– Simultaneous support of 6 LEDs for SpO2,

HRM, or multi-wavelength HRM

• PPG Receiver:

– Supports 4 time-multiplexed photodiode inputs

– 2 parallel receivers to sample two PD channels

simultaneously

– Individual ambient offset subtraction DAC at

each TIA Input with 8-bit per-phase control and

range adjustable up to 255-μA

– Individual LED offset subtraction DAC at each

TIA input with 5-bit per-phase control and

15.5-μA range

– Close to 100 dB ambient rejection up to 10 Hz

– Noise filtering with programmable bandwidth

– Transimpedance Gain: 3.7 kΩ to 1 MΩ

• ECG Signal Chain

– 1-lead ECG with RLD output for bias

– INA gain programmable from 1.6 – 13

– <1 μVrms input noise (in a 1-150 Hz

bandwidth) at 4-kHz sample rate

– Integrated 450 Hz Low Pass Filter

– AC, DC lead-off detect with 3.125-100 nA

current and programmable interrupt

• Supports external clock and internal oscillator

modes

• Option to acquire data synchronized with a system

master clock

• Automatic cancellation of DC from ambient, LED

• FIFO with 128-sample depth

• I2C interface

• 2.6-mm × 2.1-mm DSBGA, 0.4-mm pitch

• Supplies: Rx: 1.7 V-1.9 V (LDO bypass); 1.9 V-3.6

V (LDO enabled), Tx: 3 V-5.5 V, IO: 1.7-3.6 V

• Supports operation with 2 supplies - 1.8 V, 5 V

2 Applications

• ECG on a wearable device

• Synchronized PPG, ECG for PTT-based Blood

pressure

• Optical heart-rate monitoring (HRM) and Heartrate

variability (HRV) for wearables, hearables

• Pulse oximetry (SpO2) measurements

• Maximum oxygen consumption (VO2 Max)

3 Description

The AFE49I30 is an analog front-end for optical biosensing/

PPG and ECG measurement applications.

The device supports up to six switching light-emitting

diodes (LEDs) and up to four photodiodes. Up to 24

signal phases can be defined and the PPG or ECG

signals can be acquired from each phase in a

synchronized manner.