The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 21, 2003
Filed:
Nov. 14, 2001
Cyushiro Kusano, Niiza, JP;
Eiichi Hase, Iruma, JP;
Hideyuki Ono, Kokubunji, JP;
Osamu Kagaya, Tokyo, JP;
Yasunari Umemoto, Sayama, JP;
Takahiro Fujita, Fussa, JP;
Kiichi Yamashita, Tsukui, JP;
Other;
Abstract
In a high frequency power amplifier module of a multi-stage structure in which a plurality of heterojunction bipolar transistors (npn-type HBTs) are cascade-connected, a protection circuit in which a plurality of pn junction diodes are connected in series is connected between the collector and emitter of each HBT. The p-side is connected to the collector side, and the n-side is connected to the emitter side. A protection circuit in which pn junction diodes of the number equal to or smaller than that of the pn junction diodes are connected in series is connected between the base and the emitter. The p-side is connected to the base side, and the n-side is connected to the emitter side. With the configuration, in the case where an overvoltage is applied across the collector and emitter due to a fluctuation in load on the antenna side, the collector terminal is clamped by an ON-state voltage of the protection circuits, so that the HBT can be prevented from being destroyed. Since the similar protection circuit is assembled between the base and emitter, even when the operator touches the module at the time of manufacturing the high frequency power amplifier module, the HBT can be prevented from being destroyed by the clamping effect of the protection circuit between the base and emitter and the protection circuit between the collector and emitter. Thus, an improved manufacturing yield of the high frequency power amplifier module and a wireless communication apparatus can be achieved, and destruction caused by fluctuation in load impedance of the wireless communication apparatus can be prevented.