Patent ID: 7239211

Claim:
A temperature-compensated crystal oscillator comprising: a substrate having a circuit pattern disposed on a surface thereof and mounting electrodes disposed on a reverse side thereof and electrically connected to said circuit pattern; circuit components mounted on the surface of said substrate and electrically connected to said circuit pattern; and a surface-mount crystal unit having a crystal unit, and mounted on the surface of said substrate and electrically connected to said circuit pattern, the crystal unit being hermetically sealed in a casing independent of said substrate; said crystal unit having a cavity defined in a mounting surface thereof, at least one of said circuit components being housed in said cavity, the remaining circuit components being disposed outside of said cavity, and wherein the casing of the hermetically sealed crystal unit is not directly mounted on the substrate; wherein the remaining circuit components disposed outside of said cavity include two capacitors; and wherein the two capacitors are selected to optimize the temperature compensation characteristics of the temperature-compensated crystal oscillator.