SPRAA99C March   2008  – May 2021 AM3351 , AM3352 , AM3354 , AM3356 , AM3357 , AM3358 , AM3359 , AM4372 , AM4376 , AM4377 , AM4378 , AM4379 , OMAPL138B-EP , TMUX646

 

  1.   Trademarks
  2. 1Introduction
  3. 2PCB Design Considerations
    1. 2.1 Solder Land Areas
    2. 2.2 Conductor Width/Spacing
    3. 2.3 High-Density Routing Techniques
    4. 2.4 Via Density
    5. 2.5 Conventional PCB Design
    6. 2.6 Advanced Design Methods
  4. 3Reliability
    1. 3.1 Reliability Calculations
    2. 3.2 Package Characteristics
    3. 3.3 Thermal Modeling
  5. 4Surface-Mounting nFBGA Packages
    1. 4.1 Design for Manufacturability (DFM)
    2. 4.2 Solder Paste
    3. 4.3 Solder Ball Collapse
    4. 4.4 Reflow
    5. 4.5 Inspection
  6. 5Packing and Shipping
    1. 5.1 Tray Packing Method
    2. 5.2 Tape-and-Reel Packing Method
    3. 5.3 Tape Format
    4. 5.4 Device Insertion
    5. 5.5 Packaging Method
  7. 6Sockets
    1. 6.1 The Design Challenge
    2. 6.2 Contacting the Ball
    3. 6.3 Pinch Contact
    4. 6.4 Micro Tuning Fork Contact
    5. 6.5 Texas Instruments Sockets
  8. 7Summary
  9.   A Frequently Asked Questions
    1.     A.1 Package Questions
    2.     A.2 Assembly Questions
    3.     A.3 Small Body nFBGA Package Questions
  10.   B Package Data Sheets
  11.   C Thermal Modeling Results
  12.   Revision History

A.1 Package Questions

QDo the solder balls come off during shipping?
ANo, this has never been observed. The balls are inspected for coplanarity, diameter, and other physical properties prior to packing for shipment. Because solder is used during the ball-attachment process, uniformly high ball-attachment strengths are developed. Also, the ball-attachment strength is monitored frequently in the assembly process to prevent ball loss from vibration and other shipping forces.
QIs package repair possible? Are tools available?
AYes, some limited package repair is possible, and there are some semiautomatic M/C tools available. However, TI does not specify the reliability of repaired packages.
QWhat are the leads that appear on the package edge for? Are they connected to the inner pattern?
AThose leads are used for plating connections during the plating of Ni/Au on the copper trace during the fabrication of the substrate. Since they do have electrical connection with the inner pattern, they can be used for test probing and signal analysis. There is no reliability risk with them.
QIs burn-in testing possible? How about ball damage?
AThere are commercial sockets available for fine pitch package burn-in. For further information your local TI Field Sales representative can give you up-to-date information. The ball damage observed falls within specified tolerances, so the testing does not affect board mount.
QIs tape-and-reel shipping available?
AYes, tape-and-reel is an available method for shipping nFBGA packages.
QHow does the packaging cost compare to QFPs?
ACSPs are in many ways an ideal solution to cost reduction and miniaturization requirements. They offer enormous area reductions in comparison to QFPs and have increasing potential to do so without adding to system-level costs. In the best case, CSPs compete today on a cost-per-terminal basis with QFPs. For example, various CSPs from Texas Instruments are now available at cost parity within QFPs.