Varian Associates, Inc.

Lee B Max

Joseph H Johnson

The base-to-emitter bias voltage and current of a high frequency transistor, operating class AB or class A, is derived from a semiconductive bias device consisting of a semiconductive diode junction fed with current from a constant current source to derive a V.sub.BE voltage thereacross which is the bias source voltage. This source voltage is applied across the base-to-emitter junction of the RF transistor via the intermediary of a positive temperature coefficient silicon resistor. The diode and silicon resistor are packaged together for mounting on a heat sink common to the transistor, whereby the transistor is compensated for temperature dependent changes in V.sub.BE and h.sub.FE.

Temperature compensating transistor bias device

A semiconductor package for containing two individual devices such that they may be externally connected in a pushpull relationship. Two transistors, each having an input and output pad are formed on the same dielectric wafer, in a spaced relationship with each other and a ground plane so as to form two separate transmission line paths. The transistors are wired either in a grounded emitter or grounded base configuration. A shunt inductor is formed by a metallized strip or lead bond from the collector of one transistor to the collector of the other transistor. This inductor reduces the influence of the parasitic capacitance in the equivalent output circuit of the transistors. Since the collectors of both transistors are at the same DC level it is not necessary to include a DC blocking capacitor in series with the inductor. This increases the reliability and the reproducibility of the circuit because bonding wires necessary in prior devices to connect the blocking capacitor in series with the output inductance is not necessary. This packaging technique increases the output impedance, decreases the internal losses, and increases the bandwidth when wired as a push-pull circuit.

Package for push-pull semiconductor devices

A semiconductor package for containing two individual devices such that they may be externally connected in a push-pull relationship. Two transistors, each having an input and output pad are formed on the same dielectric wafer, in a spaced relationship with each other and a ground plane so as to form two separate transmission line paths. The transistors are wired either in a grounded emitter or grounded base configuration. A shunt inductor is formed by a metallized strip or lead bond from the collector of one transistor to the collector of the other transistor. This inductor reduces the influence of the parasitic capacitance in the equivalent output circuit of the transistors. Since the collectors of both transistors are at the same DC level it is not necessary to include a DC blocking capacitor in series with the inductor. This increases the reliability and the reproducibility of the circuit because bonding wires necessary in prior devices to connect the blocking capacitor in series with the output inductance is not necessary. This packaging technique increases the output impedance, decreases the internal losses, and increases the bandwidth when wired as a push-pull circuit.

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Sunnyvale, CA, United States of America

Lee B Max