SBAS689D June   2015  – December 2016 AFE4404

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Timing Requirements
    7. 7.7 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 TIA and Switched RC Filter
        1. 8.3.1.1 Operation with Two and Three LEDs
          1. 8.3.1.1.1 LED Current Setting
        2. 8.3.1.2 TIA Gain Settings
        3. 8.3.1.3 TIA Bandwidth Settings
      2. 8.3.2 Power Management
        1. 8.3.2.1 Transmitter Supply (TX_SUP)
        2. 8.3.2.2 Receiver Supply (RX_SUP)
        3. 8.3.2.3 I/O Supply (IO_SUP)
        4. 8.3.2.4 Boost Converters Selection
      3. 8.3.3 Offset Cancellation DAC
        1. 8.3.3.1 Offset Cancellation DAC Controls
      4. 8.3.4 Analog-to-Digital Converter (ADC)
      5. 8.3.5 I2C Interface
      6. 8.3.6 Timing Engine
        1. 8.3.6.1 Timer and PRF Controls
        2. 8.3.6.2 Timing Control Registers
        3. 8.3.6.3 Receiver Timing
        4. 8.3.6.4 Dynamic Power-Down Timing
        5. 8.3.6.5 Sample Register Values
    4. 8.4 Device Functional Modes
      1. 8.4.1 Power Modes
      2. 8.4.2 RESET Modes
      3. 8.4.3 Clocking Modes
      4. 8.4.4 PRF Programmability
      5. 8.4.5 Averaging Modes
      6. 8.4.6 Decimation Mode
        1. 8.4.6.1 Decimation Mode Power and Performance
    5. 8.5 Register Map
      1. 8.5.1  Register 0h (address = 0h) [reset = 0h]
      2. 8.5.2  Register 1h (address = 1h) [reset = 0h]
      3. 8.5.3  Register 2h (address = 2h) [reset = 0h]
      4. 8.5.4  Register 3h (address = 3h) [reset = 0h]
      5. 8.5.5  Register 4h (address = 4h) [reset = 0h]
      6. 8.5.6  Register 5h (address = 5h) [reset = 0h]
      7. 8.5.7  Register 6h (address = 6h) [reset = 0h]
      8. 8.5.8  Register 7h (address = 7h) [reset = 0h]
      9. 8.5.9  Register 8h (address = 8h) [reset = 0h]
      10. 8.5.10 Register 9h (address = 9h) [reset = 0h]
      11. 8.5.11 Register Ah (address = Ah) [reset = 0h]
      12. 8.5.12 Register Bh (address = Bh) [reset = 0h]
      13. 8.5.13 Register Ch (address = Ch) [reset = 0h]
      14. 8.5.14 Register Dh (address = Dh) [reset = 0h]
      15. 8.5.15 Register Eh (address = Eh) [reset = 0h]
      16. 8.5.16 Register Fh (address = Fh) [reset = 0h]
      17. 8.5.17 Register 10h (address = 10h) [reset = 0h]
      18. 8.5.18 Register 11h (address = 11h) [reset = 0h]
      19. 8.5.19 Register 12h (address = 12h) [reset = 0h]
      20. 8.5.20 Register 13h (address = 13h) [reset = 0h]
      21. 8.5.21 Register 14h (address = 14h) [reset = 0h]
      22. 8.5.22 Register 15h (address = 15h) [reset = 0h]
      23. 8.5.23 Register 16h (address = 16h) [reset = 0h]
      24. 8.5.24 Register 17h (address = 17h) [reset = 0h]
      25. 8.5.25 Register 18h (address = 18h) [reset = 0h]
      26. 8.5.26 Register 19h (address = 19h) [reset = 0h]
      27. 8.5.27 Register 1Ah (address = 1Ah) [reset = 0h]
      28. 8.5.28 Register 1Bh (address = 1Bh) [reset = 0h]
      29. 8.5.29 Register 1Ch (address = 1Ch) [reset = 0h]
      30. 8.5.30 Register 1Dh (address = 1Dh) [reset = 0h]
      31. 8.5.31 Register 1Eh (address = 1Eh) [reset = 0h]
      32. 8.5.32 Register 20h (address = 20h) [reset = 0h]
      33. 8.5.33 Register 21h (address = 21h) [reset = 0h]
      34. 8.5.34 Register 22h (address = 22h) [reset = 0h]
      35. 8.5.35 Register 23h (address = 23h) [reset = 0h]
      36. 8.5.36 Register 29h (address = 29h) [reset = 0h]
      37. 8.5.37 Register 2Ah (address = 2Ah) [reset = 0h]
      38. 8.5.38 Register 2Bh (address = 2Bh) [reset = 0h]
      39. 8.5.39 Register 2Ch (address = 2Ch) [reset = 0h]
      40. 8.5.40 Register 2Dh (address = 2Dh) [reset = 0h]
      41. 8.5.41 Register 2Eh (address = 2Eh) [reset = 0h]
      42. 8.5.42 Register 2Fh (address = 2Fh) [reset = 0h]
      43. 8.5.43 Register 31h (address = 31h) [reset = 0h]
      44. 8.5.44 Register 32h (address = 32h) [reset = 0h]
      45. 8.5.45 Register 33h (address = 33h) [reset = 0h]
      46. 8.5.46 Register 34h (address = 34h) [reset = 0h]
      47. 8.5.47 Register 35h (address = 35h) [reset = 0h]
      48. 8.5.48 Register 36h (address = 36h) [reset = 0h]
      49. 8.5.49 Register 37h (address = 37h) [reset = 0h]
      50. 8.5.50 Register 39h (address = 39h) [reset = 0h]
      51. 8.5.51 Register 3Ah (address = 3Ah) [reset = 0h]
      52. 8.5.52 Register 3Dh (address = 3Dh) [reset = 0h]
      53. 8.5.53 Register 3Fh (address = 3Fh) [reset = 0h]
      54. 8.5.54 Register 40h (address = 40h) [reset = 0h]
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 System-Level ESD Considerations
        2. 9.2.2.2 Reducing Sensitivity to Ambient Light Modulation
      3. 9.2.3 Application Curves
        1. 9.2.3.1 Choosing the Right AFE Settings
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Receiving Notification of Documentation Updates
    2. 12.2 Community Resources
    3. 12.3 Trademarks
    4. 12.4 Electrostatic Discharge Caution
    5. 12.5 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • YZP|15
Thermal pad, mechanical data (Package|Pins)
Orderable Information

1 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

2 Applications

  • Optical Heart-Rate Monitoring (HRM)
  • Heart-Rate Variability (HRV)
  • Pulse Oximetry (SpO2 Measurement)
  • VO2 Max
  • Calorie Expenditure

3 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.

Device Information(1)

PART NUMBER PACKAGE BODY SIZE (NOM)
AFE4404 DSBGA (15) 2.60 mm × 1.60 mm(2)
  1. For all available packages, see the orderable addendum at the end of the datasheet.
  2. Refers to dimensions D × E in Figure 99.

Simplified Block Diagram

AFE4404 frontpage_sbas689.gif