AFE4405YZR

AFE4405 Ultra-Small Integrated Analog Front-End

Texas Instruments AFE4405 Ultra-Small Integrated Analog Front-End (AFE) is designed for optical bio-sensing applications. These applications include heart-rate monitoring (HRM) and saturation of peripheral capillary oxygen (SpO₂). The device supports three switching light-emitting diodes (LEDs) and up to two 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 can be stored in a 240-sample first in, first out (FIFO) block with programmable depth. The FIFO depth can be partitioned to accommodate the phases that must be stored. The FIFO can be read out using either an I²C or an SPI interface. The AFE also has a fully-integrated LED driver with an 8-bit current control. The device has a high dynamic range transmit-and-receive circuitry that helps with the sensing of very small signal levels.