AFE4490 Integrated Analog Front End (AFE) for Pulse Oximeters | TI.com

AFE4490 (ACTIVE) Integrated Analog Front End (AFE) for Pulse Oximeters

 

Recommended alternative parts

  • AFE4400  - The device has the SAME FUNCTIONALITY and PINOUT as the compared device but is NOT an exact equivalent.   AFE4400 is similar to the AFE4490 but has a lower performance spec
  • AFE4403  - The device has SIMILAR FUNCTIONALITY but is not functionally equivalent to the compared device. 

Description

The AFE4490 is a fully-integrated analog front-end (AFE) that is ideally suited for pulse-oximeter applications. The 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. 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 device, 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 –40°C to 85°C.

Features

  • Fully-Integrated Analog Front-End for
    Pulse Oximeter Applications:
    • Flexible Pulse Sequencing and
      Timing Control
  • Transmit:
    • Integrated LED Driver (H-Bridge, Push, or Pull)
    • 110-dB Dynamic Range Across Full Range (Enables Low Noise at Low LED Current)
    • LED Current:
      • Programmable Ranges of 50 mA, 75 mA, 100 mA, 150 mA, and 200 mA,
        Each with 8-Bit Current Resolution
    • Low Power:
      • 100 µA + Average LED Current
    • LED On-Time Programmability from
      (50 µs + Settle Time) to 4 ms
    • Independent LED2, LED1 Current Reference
  • Receive Channel with High Dynamic Range:
    • Input-Referred Noise:
      50 pARMS (at 5-µA PD Current)
    • 13.5 Noise-Free Bits (at 5-µA PD Current)
    • Analog Ambient Cancellation Scheme with Selectable 1-µA to 10-µA Ambient Current
    • Low Power: < 2.3 mW at 3.0-V Supply
    • Rx Sample Time: 50 µs to 4 ms
    • I-V Amplifier with Seven Separate LED2 and LED1 Programmable Feedback R and C Settings
    • Integrated Digital Ambient Estimation and Subtraction
  • Integrated Fault Diagnostics:
    • Photodiode and LED Open and
      Short Detection
    • Cable On or Off Detection
  • Supplies:
    • Rx = 2.0 V to 3.6 V
    • Tx = 3.0 V or 5.25 V
  • Package: Compact VQFN-40 (6 mm × 6 mm)
  • Specified Temperature Range: –40°C to 85°C

Parametrics

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$)
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    
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    
AFE4403 Order now 1     22     SPI     3     Optical biosensing     -20 to 70     DSBGA | 36     See datasheet (DSBGA)     3.25 | 1ku    
AFE4404 Order now 1     24     I2C     3     Optical biosensing     -20 to 70     DSBGA | 15     See datasheet (DSBGA)     2.28 | 1ku    
AFE4405 Samples not available 2     24     I2C
SPI    
3     Optical biosensing     -20 to 70         2.50 | 1ku    
AFE4410 Samples not available 3     24     SPI
I2C    
4     Optical biosensing     -20 to 70         2.65 | 1ku    
AFE4900 Samples not available 3     24     SPI
I2C    
4     Optical biosensing     -20 to 70         2.75 | 1ku