SBOS993A December   2021  – December 2022 OPT4001

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Revision History
  6. 5 Description (continued)
  7. 6 Pin Configuration and Functions
  8. 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 Typical Characteristics
  9. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Spectral Matching to Human Eye
      2. 8.3.2 Automatic Full-Scale Range Setting
      3. 8.3.3 Output Register CRC and Counter
        1. 8.3.3.1 Output Sample Counter
        2. 8.3.3.2 Output CRC
      4. 8.3.4 Output Register FIFO
      5. 8.3.5 Threshold Detection
    4. 8.4 Device Functional Modes
      1. 8.4.1 Modes of Operation
      2. 8.4.2 Interrupt Modes of Operation
      3. 8.4.3 Light Range Selection
      4. 8.4.4 Selecting Conversion Time
      5. 8.4.5 Light Measurement in Lux
      6. 8.4.6 Light Resolution
    5. 8.5 Programming
      1. 8.5.1 I2C Bus Overview
        1. 8.5.1.1 Serial Bus Address
        2. 8.5.1.2 Serial Interface
      2. 8.5.2 Writing and Reading
        1. 8.5.2.1 High-Speed I2C Mode
        2. 8.5.2.2 Burst Read Mode
        3. 8.5.2.3 General-Call Reset Command
        4. 8.5.2.4 SMBus Alert Response
    6. 8.6 Register Maps
      1. 8.6.1 ALL Register Map
  10. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Electrical Interface
        1. 9.2.1.1 Design Requirements
          1. 9.2.1.1.1 Optical Interface
        2. 9.2.1.2 Detailed Design Procedure
          1. 9.2.1.2.1 Optomechanical Design (PicoStar Variant)
          2. 9.2.1.2.2 Optomechanical Design (SOT-5X3 Variant)
        3. 9.2.1.3 Application Curves (PicoStar Variant)
    3. 9.3 Do's and Don'ts
    4. 9.4 Power Supply Recommendations
    5. 9.5 Layout
      1. 9.5.1 Layout Guidelines
      2. 9.5.2 Layout Example
        1. 9.5.2.1 Soldering and Handling Recommendations (SOT-5X3 Variant)
        2. 9.5.2.2 Soldering and Handling Recommendations (PicoStar Variant)
          1. 9.5.2.2.1 Solder Paste
          2. 9.5.2.2.2 Package Placement
          3. 9.5.2.2.3 Reflow Profile
          4. 9.5.2.2.4 Special Flexible Printed-Circuit Board (FPCB) Recommendations
          5. 9.5.2.2.5 Rework Process
  11. 10Device and Documentation Support
    1. 10.1 Documentation Support
      1. 10.1.1 Related Documentation
    2. 10.2 Receiving Notification of Documentation Updates
    3. 10.3 Support Resources
    4. 10.4 Trademarks
    5. 10.5 Electrostatic Discharge Caution
    6. 10.6 Glossary
  12. 11Mechanical, Packaging, and Orderable Information
    1. 11.1 Tape and Reel Information
    2. 11.2 Package Option Addendum

Package Options

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

9.5.1 Layout Guidelines

Before understanding the layout requirement for OPT4001, understanding the placement on the PCB is critical.

OPT4001 Placement Side View of Packages Figure 9-9 Placement Side View of Packages

In case of the SOT-5X3 package variant the device, since the lighting sensitive area and the device pins are on opposite sides of each other, a conventional placement on the PCB makes sure of good light collection. In case of the PicoStar™ variant of the device, since the light sensitive area and the device pins are on the same side, special arrangement as shown in the figure is required to achieve good light collection. Typically a thin flexible PCB with a hole or a cutout centered around the optical area is required for wide angle light collection for the PicoStar™ variant. A regular PCB can be used but the amount of light collected and the field of view of light collection are not very good and generally not recommended. Cut out for the light collection can be of any shape with large enough opening to let ample light fall on the light sensitive area. Figure 9-12 and Figure 9-13 show examples of two such shapes which help maximize light collection. A circular cut out as much larger as the manufacturing allows is also acceptable but can restrict the field of view and reduce the light collection. Tools and documentation are available on TI product folder to estimate the field of view based on the hole size.

Placing the decoupling capacitor close to the device is highly recommended at the same time, note that optically reflective surfaces of components also affect the performance of the design. The three-dimensional geometry of all components and structures around the sensor must be taken into consideration to prevent unexpected results from secondary optical reflections. Placing capacitors and components at a distance of at least twice the height of the component is usually sufficient. The best optical layout is to place all close components on the opposite side of the PCB from the OPT4001. However, this approach is not be practical for the constraints of every design.

The device layout is also critical for good SMT assembly. Two types of land pattern pads can be used for this package: solder mask defined pads (SMD) and non-solder mask defined pads (NSMD). SMD pads have a solder mask opening that is smaller than the metal pads, whereas NSMD has a solder mask opening that is larger than the metal pad. Figure 9-10 illustrates these types of landing-pattern pads. SMD is preferred because SMD provides a more accurate soldering-pad dimension with the trace connections. For further discussion of SMT and PCB recommendations, see the Soldering and Handling Recommendations.

OPT4001 Soldermask Defined Pad (SMD) and Non-Soldermask Defined Pad (NSMD) Figure 9-10 Soldermask Defined Pad (SMD) and Non-Soldermask Defined Pad (NSMD)