| 摘要 |
PURPOSE:To make it possible to obtain the high-frequency characteristics and low thermal resistance of the title amplifier by a method wherein a power transistor chip and a bipolar bare chip are mounted on an Al nitride substrate and a through hole is provided for a feed. CONSTITUTION:A circuit wiring conductor pattern 20 is formed on the upper surface of an Al nitride substrate 10 and chip components 30 to 33 are mounted, while the lower surface of the substrate 10 is used as a solid grounding surface 21. Moreover, the connection between the upper surface conductor pattern 20 and the lower surface conductor pattern 21 is performed through a through hole 22. Here, as the thermal expansion coefficient of the substrate 10 is near that of Si, the adhesion of the substrate 10 with the power transistor chip 32 and the bipolar bare chip 33 is easy, the chips 32 and 33 can be mounted in a small size and the dielectric constant and dielectric loss of the substrate 10 are low. Moreover, as the substrate 10 has a high thermal conductivity, the chip 32 is superior in heat dissipation. Thereby, a high-frequency video amplifier is superior in high-frequency characteristics and the thermal resistance of the amplifier can be made small. |
