AFE4410 Ultra-Small Analog Front-End (AFE)

Texas Instruments AFE4410 Ultra-Small Analog Front-End (AFE) is for optical biosensing applications, such as heart-rate monitoring (HRM). The device supports up to four switching light-emitting diodes (LEDs) and up to three photodiodes. The current from the photodiode is converted into a voltage by the transimpedance amplifier (TIA) and digitized using an analog-to-digital converter (ADC). The ADC code is stored in a 128-sample first in, first-out block (FIFO) with programmable depth. The FIFO can be read out using either an I²C interface or a serial peripheral interface (SPI). The AFE also has a fully integrated LED driver with 8-bit current control. The AFE4410 has high dynamic range transmit-and-receive circuitry offering a dynamic range of up to 100dB that enables accurate heart-rate sensing. The AFE achieves extremely low current levels by operating an ultralow power (ULP) mode set by using the ENABLE_ULP register bit.

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