AFE4404 Ultra-Small Integrated AFE for Wearable, Optical Heart-Rate Monitoring and Biosensing | TI.com

AFE4404 (ACTIVE)

Ultra-Small Integrated AFE for Wearable, Optical Heart-Rate Monitoring and Biosensing

Ultra-Small Integrated AFE for Wearable, Optical Heart-Rate Monitoring and Biosensing - AFE4404
 

Description

The 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

  • 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
  • Receiver:
    • 24-Bit Representation of the Current Input from a Photodiode in Twos 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
    • Average Current Less Than 200 µA for PPG Signal Acquisition
  • Pulse Frequency: 10 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
  • I2C Interface
  • Operating Temperature Range: –20°C to 70°C
  • 2.6-mm × 1.6-mm DSBGA Package, 0.5-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

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Parametrics Compare all products in Biosensing AFEs

 
# Input Channels
Resolution (Bits)
Interface
Number of LEDs
Features
Operating Temperature Range (C)
Package Group
Package Size: mm2:W x L (PKG)
Approx. Price (US$)
AFE4404 AFE4403 AFE4405 AFE4410 AFE4490 AFE4900
1     1     2     3     1     3    
24     22     24     24     22     24    
I2C     SPI     I2C
SPI    
SPI
I2C    
Serial SPI     SPI
I2C    
3     3     3     4     2     4    
Optical biosensing     Optical biosensing     Optical biosensing     Optical biosensing     Optical biosensing     Optical biosensing    
-20 to 70     -20 to 70     -20 to 70     -20 to 70     -40 to 85     -20 to 70    
DSBGA     DSBGA         VQFN      
See datasheet (DSBGA)     See datasheet (DSBGA)         40VQFN: 36 mm2: 6 x 6(VQFN)      
2.28 | 1ku     3.25 | 1ku     2.50 | 1ku     2.65 | 1ku     7.95 | 1ku     2.75 | 1ku