SPO2 analog front-end

The SPO2 analog front-end is a fully integrated analog solution for medical pulse oximeter applications.

It supports flexible pulse sequencing and timing control from 200Hz to 1KHz for individual LED and up to 3 LEDs at same time.

Key features:


  • Integrated LED driver (H-Bridge, push or pull)
  • 8 bit programmable LED current range from 25mA, 50mA, 75mA to 100mA
  • Independent LED3, LED2, LED1 current reference


  • Input-referred noise: 50 pA (RMS) (at 5 μA powerdown current)
  • 5 noise-free bits (at 5 μA powerdown current)
  • Analog ambient cancellation scheme with selectable 1 μA to 10 μA ambient current
  • I-V amplifier with seven separate LED2 and LED1 programmable feedback R and C settings
  • Reconfigurable 12/16/20 bit ADC depending on applications
SPO2 analog front-end block diagram
SPO2 analog front-end block diagram