| 摘要 |
A dual cavity semiconductor package (1) containing a high voltage (greater than 1500 volts) isolation amplifier includes a ceramic substrate with tungsten metalization thereon defining die bonding and wire bonding sites and interconnections in the two cavities (3,4) for input and output circuitry of the isolation amplifier, respectively. The metalization also defines a pair of precisely matched planar fringe capacitors (10,13) forming a high voltage small signal isolation barrier located between the two cavities. A layer of ceramic having apertures therein defining the two cavities is laminated over the substrate. The assembly is cofired at about 2,000 DEG Centigrade, causing ceramic to fill the gaps between the conductors of the fringe capacitors, providing very high voltage isolation therebetween. Separate tungsten sealing rings (71,72) are provided around the peripheries of the cavities on the top surface of the second layer. In another embodiment of the invention, a single large cavity has spaced separate regions for input and output circuitry of the isolation amplifier; a transformer has coils defined by printed conductors combined with wire loops. A further embodiment uses a multilayer capacitor for the isolation barrier. <IMAGE> |
