Design for testability (DFT) in PCB Design - Dashboard Guide

Dashboard Mode - Design for testability (DFT)

Business Question

How can we monitor and improve the test coverage and fault detection efficiency in our PCB designs using Design for Testability (DFT) metrics?

Sample Data: PCB Test Metrics

PCB_ID	Test_Points	Tested_Points	Faults_Detected	Total_Faults	Test_Time_Minutes
PCB001	100	95	5	6	30
PCB002	120	110	8	10	40
PCB003	90	85	4	5	25
PCB004	150	140	12	15	50
PCB005	80	75	3	4	20

Dashboard Components

• KPI Card: Average Test Coverage (%)
  Formula: Average Test Coverage = AVERAGE(Tested_Points / Test_Points * 100)
  Result: ((95/100)*100 + (110/120)*100 + (85/90)*100 + (140/150)*100 + (75/80)*100) / 5 = 93.44%
• KPI Card: Average Fault Detection Rate (%)
  Formula: Average Fault Detection Rate = AVERAGE(Faults_Detected / Total_Faults * 100)
  Result: ((5/6)*100 + (8/10)*100 + (4/5)*100 + (12/15)*100 + (3/4)*100) / 5 = 79.67%
• KPI Card: Average Test Time (Minutes)
  Formula: Average Test Time = AVERAGE(Test_Time_Minutes)
  Result: (30 + 40 + 25 + 50 + 20) / 5 = 33 minutes
• Bar Chart: Test Coverage per PCB
  X-axis: PCB_ID
  Y-axis: Test Coverage (%) = Tested_Points / Test_Points * 100
  Values:
  PCB001: 95%
  PCB002: 91.67%
  PCB003: 94.44%
  PCB004: 93.33%
  PCB005: 93.75%
• Bar Chart: Fault Detection Rate per PCB
  X-axis: PCB_ID
  Y-axis: Fault Detection Rate (%) = Faults_Detected / Total_Faults * 100
  Values:
  PCB001: 83.33%
  PCB002: 80%
  PCB003: 80%
  PCB004: 80%
  PCB005: 75%
• Table: Detailed PCB Test Data
  Columns: PCB_ID, Test_Points, Tested_Points, Faults_Detected, Total_Faults, Test_Time_Minutes

Dashboard Layout

+--------------------------------------------------+
| Average Test Coverage (%) | Average Fault Detection Rate (%) | Average Test Time (min) |
+--------------------------+--------------------------------+-------------------------+
|                      Bar Chart: Test Coverage per PCB                      |
+--------------------------------------------------------------------------+
|                    Bar Chart: Fault Detection Rate per PCB                |
+--------------------------------------------------------------------------+
|                            Table: Detailed PCB Test Data                  |
+--------------------------------------------------------------------------+

Interactivity

A filter slicer for PCB_ID allows selecting one or multiple PCBs. When a PCB_ID is selected:

• All KPI cards update to show averages only for the selected PCBs.
• Both bar charts update to display data only for the selected PCBs.
• The detailed table filters to show only the selected PCB rows.

This helps focus on specific PCB designs to analyze their testability performance.

Self Check

If you add a filter to select only PCB002 and PCB004, which components update and what are the new average test coverage and fault detection rate?

• All KPI cards update to averages for PCB002 and PCB004 only.
• Bar charts show only these two PCBs.
• Table shows only rows for PCB002 and PCB004.

Calculations:

• Test Coverage: ((110/120)*100 + (140/150)*100) / 2 = (91.67 + 93.33) / 2 = 92.5%
• Fault Detection Rate: ((8/10)*100 + (12/15)*100) / 2 = (80 + 80) / 2 = 80%

Key Result

Dashboard shows PCB test coverage, fault detection rates, and test times to monitor Design for Testability effectiveness.