IEEE P1149.8.1 Selective Toggle Fault Detection and Isolation Steve Butkovich – Cisco Systems, Inc . y ,
Goal of the Fault Evaluation Goal of the Fault Evaluation • Using the faults Using the faults portrayed in figure 6 expand on the “Table expand on the Table 1 — Potential defects for the circuit in for the circuit in Figure 6” chart
Detection Circuit Stolen from Low impedance input O ti Optimized for Open Pin Detection i d f O Pi D t ti All pins share a common input through the detection plate
Opens Detection p Open Pin 1 Reduced signal at sense Pin 2 Reduced signal at sense Pin 3 Reduced signal at sense Pin 4 Reduced signal at sense Pin 5 Reduced signal at sense Pin 6 Reduced signal at sense C (£F) 25.0 20.0 15.0 10.0 5.0 0.0 100 200 300 400 500 600 700 800 900 Open Pin Average Separation in microns 0.5 mm facing area
Single Ended Shorts Detection Power or Ground P G d Primary Detection Method EXTEST with Self Monitoring Capabilities Secondary Detection Method Capacitively coupled signal reduction Not clear that linearity constraint Not clear that linearity constraint Short Pin to GND/PWR would provide repeatable test Pin 1 Reduced Signal at Sense Pin 2 Reduced Signal at Sense Tertiary Detections Method S Smoke and Flames k d Fl
Single Ended Shorts Detection P Power or Ground G d Unpowered VTEP with induced shorts 100 100 90 80 70 60 VTEP No Short VTEP No Short 50 50 VTEP Short to GND 40 VTEP Short to Vdd 30 20 Short induced Short induced 10 on pin on pin 0 1 2 3 4 5 6 7 8 9 10111213141516171819202122232425
Differential Shorts Detection P Power or Ground G d Primary Detection Method EXTEST with independent Self M Monitoring Capabilities it i C biliti
Component Short, Open, Value p , p , Open Short Wrong Value R1 NOT FOUND Reduced Signal at Sense NOT FOUND R2 NOT FOUND Reduced Signal at Sense NOT FOUND C1 Reduced Signal at Sense NOT FOUND NOT FOUND C2 Reduced Signal at Sense NOT FOUND NOT FOUND C3 Reduced Signal at Sense NOT FOUND NOT FOUND
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