Trimmable multi-terminal capacitor for a voltage controlled oscillator

• US 5,726,608 A
• Filed: 10/17/1995
• Issued: 03/10/1998
• Est. Priority Date: 10/17/1995
• Status: Expired due to Fees

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: .ANG.rlin, Michael
• Primary Examiner(s): Pascal, Robert
• Assistant Examiner(s): KINKEAD, ARNOLD M
• Application Number:
  US08/544,203
• Time in Patent Office: 875 Days
• Field of Search: 361/328, 361/329, 361/330, 331/117 R, 331/96, 331/107 DP, 331/117 D, 333/24 C, 333/235
• US Class Current: 331/117.00D
• CPC Class Codes: H01G 4/255 Means for correcting the capacitance value

Abstract

The invention provides a trimmable multi-terminal capacitor. The multi-terminal capacitor comprises a plurality of capacitors with each of the capacitors having a common terminal. The capacitors are formed on a layer of dielectric material having a common plate of conductive material disposed on its top surface, and a plurality of separate plates of conductive material disposed on its lower surface. The capacitance value of each of the capacitors is separately tunable to tight tolerances. The capacitor is particularly suited to be used in a voltage controlled oscillator (VCO) to couple a plurality of devices to a resonator.

Claims

1. A multi-terminal capacitor, comprising:

a dielectric layer having a first and a second surface, said surfaces being substantially parallel in relation to one another;

a common conductor on said first surface, said common conductor comprising a central terminal of said multi-terminal capacitor, and having a plurality of tabs being selectively removable to tune the capacitance value of said multi terminal capacitor; and

a plurality of separate conductors on said second surface, wherein said separate conductors and said common conductor are aligned to form a corresponding plurality of capacitors, and each of said separate conductors comprises an outside terminal of said multi-terminal capacitor, the selectively removable tabs removed to tune the capacitance values of the plurality of capacitors.

2. The multi-terminal capacitor of claim 1 in which said common conductor comprises a first terminal, and in which said plurality of separate conductors comprises a second and third conductor, said second and third conductors comprising a second and third terminal, respectively.

3. A voltage controlled oscillator circuit comprising:

a resonator having an output terminal; and

a multi-terminal capacitor comprising;

a dielectric layer having a first and a second surface, said surfaces being substantially parallel in relation to one another;

a common conductor on said first surface, said common conductor comprising a central terminal of said multi-terminal capacitor, said central terminal being connected to said output terminal of said resonator, and having a plurality of tabs being selectively removable to tune the capacitance value of said multi terminal capacitor; and

a plurality of separate conductors on said second surface, wherein said separate conductors and said common conductor are aligned to form a corresponding plurality of capacitors, and each of said separate conductors comprises an outside terminal of said multi-terminal capacitor, the selectively removable tabs removed to tune the capacitance values of the plurality of capacitors.

4. The voltage controlled oscillator of claim 3 in which said common conductor comprises a first terminal, and in which said plurality of separate conductors comprise a second and a third conductor and said second and third conductors comprise a second and third terminal, respectively.

5. A voltage controlled oscillator circuit comprising:

a resonator having an output terminal; and

a multi-terminal capacitor comprising;

a dielectric layer having a first and a second surface, said surfaces being substantially parallel in relation to one another;

a common conductor disposed on said first surface, portions of the common conductor being removable to tune the capacitance of the multi-terminal capacitor, said common conductor comprising a central connection terminal of said multi-terminal capacitor connected to said output terminal of said resonator; and

two separate conductors disposed on said second surface, wherein said two separate conductors and said common conductor are aligned to form two capacitors, and each of said separate conductors comprising an outside connection terminal of said multi-terminal capacitor.

6. The multi-terminal capacitor of claim 5 wherein the removable portions of the common conductor comprise a plurality of tabs, said tabs being selectively removable to tune the capacitance values of each of said two capacitors.