Abstract: A circuit assembly has a heat sink assembly and a chip scale package assembly. The chip scale package assembly has an integrated circuit die coupled to a first printed wiring board. The heat sink assembly has an integrated circuit die coupled to a second printed wiring board. Preferably, the heat sink assembly and the chip scale package assembly are assembled separately then assembled together. The circuit pads on the first printed wiring board correspond with circuit pads on the second printed wiring board. The circuit pads may be coupled together by solder or adhesive bonding. The circuit pads on the first printed wiring board may have solder balls formed of high temperature solder that do not melt when the heat sink assembly is assembled with chip scale package assembly. The solder balls allow chip scale package assembly to maintain a predetermined distance from the circuit pads on the second printed wiring board.

Abstract: A chip-on-board electronic device includes an electronic device die affixed to a printed circuit board, and electrically interconnected thereto by wirebonds. The electronic device is protected by coating it with a layer of silicon oxynitride and, optionally, an overlying thin layer of a conformal coating such as parylene. Under some circumstances, a protective layer of an organic material may be used instead of the layer of silicon oxynitride. The chip-on-board electronic device may be protected with an overlying layer of the conformal coating.

Abstract: A circuit assembly has a heat sink assembly and a chip scale package assembly. The chip scale package assembly has an integrated circuit die coupled to a first printed wiring board. The heat sink assembly has an integrated circuit die coupled to a second printed wiring board. Preferably, the heat sink assembly and the chip scale package assembly are assembled separately then assembled together. The circuit pads on the first printed wiring board correspond with circuit pads on the second printed wiring board. The circuit pads may be coupled together by solder or adhesive bonding. The circuit pads on the first printed wiring board may have solder balls formed of high temperature solder that do not melt when the heat sink assembly is assembled with chip scale package assembly. The solder balls allow chip scale package assembly to maintain a predetermined distance from the circuit pads on the second printed wiring board.

Abstract: A reworkable circuit board assembly including a flip chip adapted for removal in the event of a failure and a method for fabricating the same is disclosed. The reworkable circuit board assembly includes a heat sink having a coefficient of thermal expansion substantially matched to the coefficient of thermal expansion of the flip chip. It also includes a deformable circuit board having a first side and a second side, wherein the first side is secured to a side of the heat sink in thermal communication therewith. The flip chip is bonded to the second side of the deformable circuit board without underfill or with weak bond strength underfill to facilitate removal of the flip chip in the event of a rework.

Abstract: A clutch/brake assembly for coupling and decoupling (and simultaneously braking the rotation of) a rotary implement to a drive shaft. The clutch portion of the assembly operates in one mode during low rotational speeds of the implement and at higher rotational speeds changes modes to become a centrifugal clutch. The clutch is also torque sensitive such that when the implement is subjected to high loads and low rotational speeds, the clutch is more tightly engaged to avoid clutch slippage. The brake portion of the assembly has some components common to the clutch assembly. The brake portion is self-energized and constructed to obtain braking assistance from centrifugal force such as at high rotational speeds of the implement and is torque sensitive so that at low rotational speeds and high braking force, the braking surfaces are maintained in tight engagement.

Abstract: An exhaust system for a motorcycle having at least two exhaust conduits connected to different cylinders of a multiple cylinder motorcycle engine. Each exhaust conduit includes a curved flow divider for directing a portion of the exhaust gases through a crossover pipe for passage through the other exhaust conduit.