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Texas Instruments AFE4490 Integrated Analog Front End

Texas Instruments AFE4490 Integrated Analog Front End is a fully-integrated AFE that is ideally suited for pulse-oximeter applications. This TI device consists of a low-noise receiver channel with a 22-bit analog-to-digital converter (ADC), an LED transmit section, and diagnostics for sensor and LED fault detection. AFE4490 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 AFE4490, 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.

Applications

  • Fully-Integrated Analog Front-End for Pulse Oximeter Applications
    • Flexible Pulse Sequencing and Timing Control
  • Transmit
    • Integrated LED Driver (H-Bridge or Push/Pull)
    • 110dB Dynamic Range Across Full Range (Enables Low Noise at Low LED Current)
    • LED Current: Programmable Ranges of 50mA, 75mA, 100mA, 150mA, and 200mA, Each with 8-Bit Current Resolution
    • Low Power: 100µA + Average LED Current
    • LED On-Time Programmability from (50µs + Settle Time) to 4ms
    • Independent LED2 and LED1 Current Reference
  • Receive Channel with High Dynamic Range
    • Input-Referred Noise
    • 50pARMS (at 5µA PD Current)
    • 13.5 Noise-Free Bits (at 5µA PD Current)
    • Analog Ambient Cancellation Scheme with Selectable 1µA to 10µA Ambient Current
    • Low Power: < 2.3mA at 3.0V Supply
  • Integrated Fault Diagnostics
    • Photodiode and LED Open and Short Detection
    • Cable On/Off Detection

Applications

  • Medical Pulse Oximeter Applications
  • Industrial Photometry Applications

Block Diagram

Block Diagram - Texas Instruments AFE4490 Integrated Analog Front End
게시일: 2013-07-16 | 갱신일: 2022-03-11