Digital Functional Test 🚧
This post was originally written in English.
References & Acknowledgements
- The Fundamentals Of Digital Semiconductor Testing
- Fundamentals of Testing Using ATE
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
- Reduce test frequency.
- View the actual waveform, modify the position of comparison.
- Repeat pattern lines for more times in prevent of the influence of setup time.
- Use Shmoo method to analyze.
- Switching the order of test execution, in prevent of the interaction between tests.
- Pay attention to the Pin Electronic Driver Mode
- 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.
- Check if TDR is calibrated.
- Defects with pattern itself.