AFE4400 Integrated Analog Front End (AFE) for Heart-Rate Monitors and Low-Cost Pulse Oximeters |

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Integrated Analog Front End (AFE) for Heart-Rate Monitors and Low-Cost Pulse Oximeters


Recommended alternative parts

  • AFE4490  - The device has the SAME FUNCTIONALITY and PINOUT as the compared device but is NOT an exact equivalent.   AFE4490 is similar to the AFE4400 but has a higher performance spec


The AFE4400 is a fully-integrated analog front-end (AFE) ideally suited for pulse oximeter applications. The device consists of a low-noise receiver channel with an integrated analog-to-digital converter (ADC), an LED transmit section, and diagnostics for sensor and LED fault detection. The device is a very configurable timing controller. This flexibility enables the user to have complete control of the device timing characteristics. To ease clocking requirements and provide a low-jitter clock to the AFE4400, an oscillator is also integrated that functions from an external crystal. The device communicates to an external microcontroller or host processor using an SPI™ interface.

The device is a complete AFE solution packaged in a single, compact VQFN-40 package (6 mm × 6 mm) and is specified over the operating temperature range of 0°C to 70°C.


  • Fully-Integrated Analog Front-End for Pulse Oximeter Applications:
    • Flexible Pulse Sequencing and
      Timing Control
  • Transmit:
    • Integrated LED Driver
      (H-Bridge, Push, or Pull)
    • Dynamic Range: 95 dB
    • LED Current:
      • Programmable to 50 mA with 8-Bit Current Resolution
    • Low Power:
      • 100 µA + Average LED Current
    • Programmable LED On-Time
    • Independent LED2 and LED1 Current Reference
  • Receive Channel with High Dynamic Range:
    • 13 Noise-Free Bits
    • Low Power: < 670 µA at 3.3-V Supply
    • Integrated Digital Ambient Estimation and Subtraction
    • Flexible Receive Sample Time
    • Flexible Transimpedance Amplifier with Programmable LED Settings
  • Integrated Fault Diagnostics:
    • Photodiode and LED Open and
      Short Detection
    • Cable On and Off Detection
  • Supplies:
    • Rx = 2.0 V to 3.6 V
    • Tx = 3.0 V to 5.25 V
  • Package: Compact VQFN-40 (6 mm × 6 mm)
  • Specified Temperature Range: 0°C to 70°C


Compare all products in Biosensing AFEs Email Download to Excel
Part number Order Number of 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$)
AFE4400 Order now 1     22     SPI     2     Optical biosensing     0 to 70     VQFN | 40     40VQFN: 36 mm2: 6 x 6 (VQFN | 40)     2.95 | 1ku    
AFE4490 Order now 1     22     Serial SPI     2     Optical biosensing     -40 to 85     VQFN | 40     40VQFN: 36 mm2: 6 x 6 (VQFN | 40)     7.95 | 1ku