The initial evaluation will characterize the performance of units shipped year to date and hopefully identify a work-around, screen, and temperature and operating profile. Wafer lots in inventory will also be evaluated for this anomaly. At this time we believe the anomaly affects QML A, V, and RHR product only. From the evaluation performed to date we have observed the following. As temperature increases the voltage threshold decreases.
Unprogrammed parts behave better than programmed parts either due to self-heating or ground bounce.
At -40 C, with the limited data taken to date, the threshold ranges from 4.7 to 4.9. The data presented in this memo is from a small sample size and could improve or get worse. As a result, the output buffers would enter a high impedance state. Additionally, the best way to get out of this state was by removing power from the chip, and performing another power-up sequence. As a result, the output buffers are placed in the high impedance state.