We are currently using the MSC1210 die packaged in an MCM up to 150C. We time the processor using an external crystal oscillator at 3.6864MHz. In July 2009, we began having issues with the crystal starting at exactly half the expected frequency upon circuit power up. This failure didn't occur in every assembly, and would occur anywhere between 60-150C, though again, every tool had a different failure temperature. The crystal was of course the suspect, but several crystals were tested with no clear indication that the failure was only related to the crystal. Several crystals were sent back to the manufacturer, but no failure was identified with the crystals. Lengthy troubleshooting ensued with many different steps taken, but the root cause of this issue was never identified. We eventually opted to replace the crystal with a separate oscillator module so as not to depend on the crystal start up/driver.
Unfortunately, we don't have the space to insert this module on one of our PCBs, so we are again attempting to determine the root cause of this issue. I know that often processor manufacturers will have an ideal oscillator circuit for specific parts. I think I remember reading a TI technical document on proper oscillator circuit setup, though upon searching, I cannot find it. Is there a recommended crystal oscillator circuit for use with the MSC1210?
