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Digital Functional Test 🚧

This post was originally written in English.

References & Acknowledgements

  • The Fundamentals Of Digital Semiconductor Testing
  • Fundamentals of Testing Using ATE

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Drive and Compare Timing

  • D0 or Drive On: Start of cycle for each channel
  • D1 or Drive Data: Start of drive pulse for each channel
  • D2 or Drive Return: End of drive pulse for each channel
  • D3 or Drive Off: Time of I/O switch
  • R0 or Compare Start (On): Start of compare window for each channel (window strobe)
  • R1 or Compare End (Off): End of compare window for each channel (window strobe) or edge strobe

Troubleshooting of Digital Functional Debug

  1. Reduce test frequency.
  2. View the actual waveform, modify the position of comparison.
  3. Repeat pattern lines for more times in prevent of the influence of setup time.
  4. Use Shmoo method to analyze.
  5. Switching the order of test execution, in prevent of the interaction between tests.
  6. Pay attention to the Pin Electronic Driver Mode
  7. Vt, Hi-Z, Largeswing-VT1K or Smallswing-VT?
    • Hi-Z: the balance bridge will be used for driving, and VCOM will be used for current loads.
    • Vt: directly connect to Vt level through a 50Ω resistance. If the DUT output is running at a high speed, using the VT results in fewer reflections seen by the comparator.
  8. Check if TDR is calibrated.
  9. Defects with pattern itself.