Siemens Aktiengesellschaft

Knut Brenndoerfer

Jakob Huber

A SMD with an RF semiconductor chip (1) encapsulated in a plastic housing is provided. The device has at least one active RF component or an integrated RF circuit with terminal locations, these being contacted by bond wires (4) in the interior of the housing to interconnects of a system carrier (2, 3) that form the outer terminals, the semiconductor chip to be secured on the system carrier. The housing is cost-beneficial and has good RF properties even at extremely high frequencies, e.g., above 2.4 GHz. The system carrier (2, 3) is formed as a co-planar three-band stripline composed of at least one inner RF conductor (3) and outer conductors (7) proceeding at a lateral spacing therefrom which serve as ground terminal. The outer conductors (7) form a planar connection in the housing interior on which the semiconductor chip (1) is secured lying opposite the end of the inner RF conductor (3).

Low-impedance surface-mount device

A high-frequency transistor has a suitably doped and structured semiconductor chip (1) that is composed of a doped Si substrate and has base, collector and emitter contactings (2, 3, 4). The chip (1) is surrounded by a housing (8), the contacts being connected to the respective base, collector and emitter terminals (6, 7, 5) of the housing. With the housing the transistor has a high gain at frequencies above 1 GHz. The base, collector and emitter contacts (2, 3, 4) are provided at the upper side of the semiconductor chip (1). The semiconductor chip (1) has its underside arranged on the emitter terminal (5) of the housing (8) which is fashioned as HF ground. The emitter contact (4) is connected over a short distance to the emitter terminal (5) of the housing (8). The base and collector contacts (2, 3) are each respectively connected via at least one bond wire (9) to the respective base or collector terminals (6, 7).

Growing community of inventors

Ismaning, Germany

Knut Brenndoerfer