Has anyone run this part to its rated temperature of 150 Celsius? We are able to run up to and beyond this temperature, but if power is cycled the part will not start reliably. We have tried running with and without the PLL, with the internal oscillator, a crystal, a high temperature oscillator, and an oscillator outside of the oven, with brownout on and off, and with various circuits on the reset pin and at various frequencies. The part is only using two output compare modules, one UART, one ICD interface, and powering a couple of LED's. All of the other pins are floating. We have monitored the voltage on VCAP and it stays around 2.5 volts. The part recovers after cool down. We have also tried letting the part soak unpowered for long periods to make sure it is not self heating.
If there are any tricks to make it start or if you have had a similar experience, I would be grateful to hear.