Performance of hybrid circuit components under deep ocean pressure

If hybrid circuitry is to be used in the deep ocean, unprotected from the high pressure encountered there, the performance of the various components that make up the circuitry must be known. To determine this performance, both thick-film and thin-film hybrid circuitry was pressure tested. The first series of tests (up to 15 000 psig) were on thick-film and thin-film resistors and ceramic chip capacitors. The components were fabricated and mounted by using ordinary hybrid techniques and were then enclosed in a standard hybrid package. Prior to being pressure tested, the package was filled with an inert liquid. The results of these tests indicated that at 15 000 psig (1) thin-film resistors are very stable, having a\Delta R(change in resistance) of -100 to -400 ppm, (2) thick-film resistors have\DeltaR's of up to 43%, (3) ceramic chip capacitors (both NPO and non-NPO), glass capacitors, and solid tantalum capacitors have\DeltaC's of less than\pm 5%, and (4) Zener diodes have\DeltaV's of less than 0.3%.