Texas Instruments

AFE4404 Analog Front-End

Texas Instruments offers its ultra-small, integrated AFE for wearable optical heart rate monitoring and bio-sensing

Image of Texas Instruments' AFE4404 Analog Front-EndTexas Instruments' AFE4404 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 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.

Features
  • Receiver:
    • 24-bit representation of the current input from a photodiode in two's complement format
    • Individual DC offset subtraction DAC at TIA input for each LED and ambient phase
    • Digital ambient subtraction at ADC output
    • Programmable transimpedance gain: 10 kΩ to 2 MΩ
    • Dynamic range: 100 dB
    • Dynamic power-saving mode to reduce current to less than 200 µA
  • Transmitter:
    • Supports common anode LED configuration
    • Dynamic range: 100 dB
    • 6-bit programmable LED current to 50 mA (extendable to 100 mA)
    • Programmable LED on-time
    • Simultaneous support of 3 LEDs for optimized SpO2, HRM, or multi-wavelength HRM

AFE4404 Analog Front-End

ImageManufacturer Part NumberDescriptionAvailable QuantityPriceView Details
IC AFE 1 CHAN 24BIT 15DSBGAAFE4404YZPTIC AFE 1 CHAN 24BIT 15DSBGA414 - Immediate$5.34View Details

AFE4404 Analog Front-End Eval Module

ImageManufacturer Part NumberDescriptionAvailable QuantityPriceView Details
EVAL BOARD FOR AFE4404AFE4404EVMEVAL BOARD FOR AFE44046 - Immediate$206.25View Details
Published: 2015-10-09