SBOSA28 august   2023 LOG200

ADVANCE INFORMATION  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Revision History
  6. 5 Pin Configuration and Functions
  7. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 High Speed, Logarithmic Current-to-Voltage Conversion
      2. 7.3.2 Voltage and Current References
      3. 7.3.3 Adaptive Photodiode Bias
      4. 7.3.4 Auxiliary Operational Amplifier
    4. 7.4 Device Functional Modes
  9. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Logarithmic Transfer Function
        1. 8.1.1.1 Logarithmic Conformity Error
    2. 8.2 Typical Application
      1. 8.2.1 Optical Current Sensing
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
        3. 8.2.1.3 Application Curves
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Device Support
      1. 9.1.1 Third-Party Products Disclaimer
    2. 9.2 Documentation Support
      1. 9.2.1 Related Documentation
    3. 9.3 Receiving Notification of Documentation Updates
    4. 9.4 Support Resources
    5. 9.5 Trademarks
    6. 9.6 Electrostatic Discharge Caution
    7. 9.7 Glossary
  11. 10Mechanical, Packaging, and Orderable Information

Package Options

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

8.2.1.3 Application Curves

The following figures show oscilloscope captures of the LOG200 output as the device responds to one-decade shifts in the input current. Rising and falling steps between 10 nA and 100 nA, and between 10 µA and 100 µA, were recorded. The oscilloscope was set to use the ac-coupled path.

For the current steps between 10 nA and 100 nA, a 10-mA laser diode bias was used. A rise time of approximately 268 ns and a fall time of approximately 626 ns were observed.

GUID-20230718-SS0I-XXSN-GP7T-DKW807TXRTZX-low.pngFigure 8-6 Oscilloscope Capture of a 10‑nA to 100‑nA Current Step
GUID-20230718-SS0I-9GSG-C8HP-FPKWKPZFJCQT-low.pngFigure 8-7 Oscilloscope Capture of a 100‑nA to 10‑nA Current Step

For the current steps between 10 µA and 100 µA, a 13‑mA laser diode bias was used. A rise time of approximately 45.60 ns and a fall time of approximately 55.60 ns were observed.

GUID-20230718-SS0I-QTRD-3GSX-27TP9DDNTLJH-low.pngFigure 8-8 Oscilloscope Capture of a 10‑µA to 100‑µA Current Step
GUID-20230718-SS0I-1QT2-4SX5-VRWZTHTVXFKR-low.pngFigure 8-9 Oscilloscope Capture of a 100‑µA to 10‑µA Current Step