The AFE4405 is an analog front-end (AFE) 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
up to two photodiodes. 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 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 a 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.To request a full data sheet or other design resources:
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AFE4405
