Voltage-controlled oscillator using a surface elastic wave resonator

• US 5,025,229 A
• Filed: 05/24/1990
• Issued: 06/18/1991
• Est. Priority Date: 06/01/1989
• Status: Expired due to Term

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Takahashi, Masao, Hasegawa, Makoto, Takahashi, Kazuaki, Shimazu, Takayuki, Makimoto, Mitsuo
• Primary Examiner(s): GRIMM, SIEGFRIED H
• Application Number:
  US07/528,079
• Time in Patent Office: 390 Days
• Field of Search: 331/107 A, 331/117 R, 331/116 R, 331/75, 331/177 V
• US Class Current: 331/107.00A
• CPC Class Codes: H03B 2200/0008 Colpitts oscillator
• CPC Class Codes: H03B 2200/0026 relating to the pins of integrated circuits
• CPC Class Codes: H03B 2200/004 including a variable capacitance, e.g. a varicap, a varactor or a variable capacitance of a diode or transistor
• CPC Class Codes: H03B 5/32 being a piezoelectric resonator selection of piezoelectric material H10N30/00
• CPC Class Codes: H03B 5/326 the resonator being an acoustic wave device, e.g. SAW or BAW device
• CPC Class Codes: H03B 5/368 the means being voltage variable capacitance diodes

Abstract

A Colpitts oscillator has an integrated circuit. The integrated circuit includes a transistor having an equivalent large size, a bypass capacitor connected between a collector of the transistor and a ground, a first feedback capacitor connected between a base and an emitter of the transistor, a second feedback capacitor connected between the emitter of the transistor and the ground, and an emitter follower connected to the emitter of the transistor. In a package, a stray reactance and a bonding wire are designed so as to agree with an element value and a Q value which can be used as parts of a resonator. A surface elastic wave resonator disposed outside the integrated circuit is connected between the base of the transistor and the ground. The oscillator is voltage controlled by a variable capacitance diode connected in series with the resonator.

Claims

1. A Colpitts voltage-controlled oscillator comprising:

an integrated circuit including a transistor comprising a parallel combination of sub transistors, a bypass capacitor connected between a collector of the transistor and a ground, a first feedback capacitor connected between a base and an emitter of the transistor, a second feedback capacitor connected between the emitter of the transistor and the ground, and an emitter follower connected to the emitter of the transistor; and

a series combination of an inducer, a surface elastic wave resonator, and a variable capacitance diode, the series combination being disposed outside the integrated circuit and being connected between the base of the transistor and ground.

2. A Colpitts voltage-controlled oscillator comprising:

an integrated circuit including a transistor, a bypass capacitor connected between a collector of the transistor and a ground, a first feedback capacitor connected between a base and an emitter of the transistor, a second feedback capacitor connected between the emitter of the transistor and the ground, and an emitter follower connected to the emitter of the transistor; and

a series combination of an inductor, a surface elastic wave resonator, and a variable capacitance diode, the series combination being disposed outside the integrated circuit and being connected between the base of the transistor and ground,

said transistor having a diffusion size which equals three or more times that of a normal transistor for an amplifier.