DFX Analysis (DFM, DFA AND DFT)

DFA

What is DFA?

The term "DFA" stands for "Design for Assembly". DFA analysis is a process that validates the Gerber released to the FAB house and the BOM released to the component engineering team to verify that the two are in sync.

In addition, these checks will allow user to confirm whether the Assembly house is capable enough to assemble the board with respect to our requirement.

Inputs required for DFA - ODB++ or Gerber files (Preferably ODB++) and Bill of Materials (BOM) BOM should have the following contents: Item #; Quantity; Reference Designators; Manufacturer part numbers; Manufacturer name.


Steps followed in DFA

1. Component analysis

Few of the checks in component analysis are listed below

  • ✔   Component height, pitch and rotation
  • ✔    Component spacing
  • ✔   Component to gold finger
  • ✔   Misplaced and multiple reference designators
  • ✔   Component under Component
  • ✔   Component placement outside keep in area
  • ✔   Component placement within keep out area

2. Footprint analysis

Few of the checks in Footprint analysis are listed below

  • ✔   Check for package contradiction
  • ✔   Check for Multiple MPN in BOM for same component
  • ✔   Check for the component present in BOM, not in CAD and in CAD, not in BOM

3. Pin to pad analysis

Few of the checks in pin to pad analysis are listed below

  • ✔   Toe vs. heel distance
  • ✔   Left vs. right distance
  • ✔   Hole missing for pins
  • ✔   Pin count mismatch
  • ✔   ET pin without PTH
  • ✔   Components with recommended land pattern

4. Pad-stack analysis

Few of the checks in pad-stack analysis are listed below

  • ✔   Toeprint to Toeprint distance
  • ✔   Via in SMD
  • ✔   Hole in SMD
  • ✔   Non uniform SMD pad size
  • ✔   Minimum SMD pad size

   5. FIDUCIAL ANALYSIS

Few of the checks in Fiducial analysis are listed below

  • ✔   Global fiducial summary
  • ✔   Local fiducial summary
  • ✔   Fiducial to copper distance
  • ✔   Fiducial to hole distance