AFE4404YZPT Datasheet PDF - TI

●The AFE4404YZPT is an Analog Front-End for optical bio-sensing applications, such as heart-rate monitoring (HRM) and saturation of peripheral capillary oxygen (SpO2). The device supports three switching light-emitting diodes (LEDs) and a single photodiode. The current from the photodiode is converted into voltage by the transimpedance amplifier (TIA) and digitized using an analog-to-digital converter (ADC). The ADC code can be read out using an I²C interface. The AFE also has a fully integrated LED driver with a 6-bit current control. The device has a high dynamic range transmit and receive circuitry that helps with the sensing of very small signal levels.

● Transmitter - supports common anode LED configuration

● Transmitter - 100dB dynamic range

● Transmitter - 6-bit programmable LED current to 50mA (Extendable to 100 mA)

● Transmitter - Programmable LED on-time

● Transmitter - Simultaneous Support of 3 LEDs for Optimized SpO2, HRM or multi-wavelength HRM

● 24-bit Representation of the current input from a photodiode in twos complement format

● Receiver - Individual DC offset subtraction DAC at TIA input for each LED and ambient phase

● Receiver - Digital ambient subtraction at ADC output

● Receiver - 10 kR to 2 MR Programmable transimpedance gain

● Receiver - 100dB Dynamic range

● Receiver - Dynamic power-saving mode to reduce current to less than 200µA

● 10 to 1000SPS Pulse frequency

● Flexible pulse sequencing and timing control

● Flexible clock options - External 4 to 60MHz Input Clock, Internal 4MHz Oscillator