To reduce electrical stress during ICT operation, two major corrective actions were implemented. The first modification changed the drive patterns from

Original patterns:

00 / 01 / 10 / 11

Were replaced with:

00 / 0X / X0 / XX,

where “X” represents a “Don’t Care” state. In this updated approach, the logic-high condition was no longer actively driven by the tester (open-drain driver). Instead, the output was allowed to rise high through the existing pull-up resistors. This significantly reduced edge-rate aggressiveness which minimized overshoot generation during a low-to-high transition. The use of open-drain also resolves any contention with the pedestal voltage from the TCA9617 on B-side.

In addition to the software changes, hardware changes were made by adding 200Ω series resistors to SCLA, SDAA, SCLB, and SDAB on the ICT test platform. The resistors provided edge-rate reduction, reflection damping, and suppression of LC resonance created by the long ICT interconnect structure. The resistors also limit the current to and from the buffer.

Figure 2-4 New ICT Setup with Software and Hardware Changes Reduces Overshoot/Undershoot Behavior and Resolves B-side Pedestal Contention