Somewhat off topic I know and apologize in advance. However I am developing with 8051 devices and need some information on a packaging issue.

My 8051 based controller needs to be packaged to survive the high pressures at 3000-4000 meters sea depth (around 5000PSI). It interfaces to a motor and Hall sensors and a communications chip. Specifics are proprietary so please don't ask.

What (I think) I know:
- Deep sea electronics are typically packaged by covering with a potting compound to distribute the high pressures
- Electrolytics, crystals and other devices packaged in "cans" are susceptible to crushing and failure
- Dielectric fluid (silicone based) may be used to immerse the electronics to balance the internal compartment pressure with external pressure (presuming electronics packaged in some kind of enclosure)
- Hybrid design is sometimes used, combined with potting. This gets away from any problems with high pressures on IC packages.

What I'm looking for:
- Actual testimonials and experience with successful projects of similar nature or knowledge of same

What I'm not looking for:
- Opinions and "Have you tried...?"

I "haven't tried" anything yet - still in the research phase. Thanks in advance.

Steve C.