AFE4405YZR

The AFE4405YZR is a highly versatile analog front-end designed specifically for optical bio-sensing applications, such as heart-rate monitoring and SpO2 measurement. With support for three switching LEDs and up to two photodiodes, this device offers flexibility and accuracy in tracking vital signs. The transimpedance amplifier converts current from the photodiode into voltage, which is then digitized by the ADC for further processing. The FIFO block allows for storage of ADC codes, with programmable depth to accommodate different phases of data collection

Key Features

• Transmitter:
  • Supports Common Anode LED Configuration
  • Dynamic Range: 100 dB
  • 8-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
• Receiver:
  • Supports 2 Time-Multiplexed Photodiode Inputs
  • 24-Bit Representation of the Current Input from the Photodiode in Twos Complement Format
  • Individual DC Offset Subtraction DAC
    (±15.75-µA Range) at TIA Input for Each LED, Ambient
  • Digital Ambient Subtraction at ADC Output
  • Transimpedance Gain: 10 kΩ to 2 MΩ
  • Dynamic Range: 100 dB
  • Dynamic Power-Saving Mode to Reduce Receiver Current to 200 µA
• Pulse Frequency: 5 SPS to 1000 SPS
• Flexible Pulse Sequencing and Timing Control
• Flexible Clock Options:
  • External Clocking:
    4-MHz to 60-MHz Input Clock
  • Internal Clocking: 4-MHz Oscillator
• FIFO with 240 Sample Depth:
  • Programmable Partitioning Across Phases
• I²C, SPI Interfaces: Selectable by Pin
• Operating Temperature Range: –20°C to +70°C
• 2.6-mm × 2.1-mm DSBGA, 0.4-mm Pitch
• Supplies: Rx: 2 V to 3.6 V, Tx: 3 V to 5.25 V,
  IO: 1.8 V to 3.6 V