Stress tolerant differential colpitts voltage controlled oscillators
AssigneeMarvell International Ltd.
InventorsHimanshu Arora, Belal Helal, Chuan-Cheng Cheng
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Abstract
Some of the embodiments of the present disclosure provide an apparatus comprising a voltage controlled oscillator (VCO) having a first transistor, a first resistor operatively coupled between a first terminal of the first transistor and a first node, a first capacitor operatively coupled between a second terminal of the first transistor and the first node, and a second capacitor operatively coupled to the first node, wherein the first capacitor and the second capacitor forms a capacitive voltage divider. Other embodiments are also described and claimed.
Claims19
A voltage controlled oscillator (VCO) comprising:
- a first transistor;
- a first resistor having (i) a first terminal operatively coupled to a source terminal of the first transistor and (ii) a second terminal operatively coupled to a first node;
- a first capacitor having (i) a first terminal operatively coupled to a drain terminal of the first transistor and (ii) a second terminal operatively coupled to the first node;
- and
- a second capacitor having (i) a first terminal operatively coupled to the first node and (ii) a second terminal operatively coupled to a ground terminal,
- wherein the first capacitor and the second capacitor form a capacitive voltage divider, and
- wherein the first node defines a mid-point of the capacitive voltage divider.
A differential colpitts voltage controlled oscillator (VCO) comprising:
- a cross coupled transistor pair comprising a first transistor and a second transistor;
- a first capacitive voltage divider associated with the first transistor and comprising at least a first capacitor;
- a second capacitive voltage divider associated with the second transistor and comprising at least a second capacitor;
- a first resistor having (i) a first terminal operatively coupled to between a source terminal of the first transistor and (ii) a second terminal operatively coupled to a mid-point of the first capacitive voltage divider the first capacitor, wherein the first capacitor has (i) a first terminal is operatively coupled to between a drain terminal of the first transistor and (ii) a second terminal coupled to the second terminal of the first resistor;
- and
- a second resistor having (i) a first terminal operatively coupled to a source terminal of the second transistor and (ii) a second terminal operatively coupled to a mid-point of the second capacitive voltage divider.
A method of forming a differential colpitts voltage controlled oscillator, the method comprising:
- forming a cross coupled transistor pair that comprises a first transistor and a second transistor;
- forming a first capacitive voltage divider associated with the first transistor, the first capacitive voltage divider comprising at least a first capacitor;
- forming a second capacitive voltage divider associated with the second transistor, the second capacitive voltage divider comprising at least a second capacitor;
- degenerating a transconductance of the first transistor by operatively coupling (i) a first terminal of a first resistor to a source terminal of the first transistor and (ii) a second terminal of the first resistor to a mid-point of the first capacitive voltage divider, wherein the first capacitor has (i) a first terminal operatively coupled to a terminal of the first transistor and (ii) a second terminal coupled to the second terminal of the first resistor;
- and
- degenerating a transconductance of the second transistor by operatively coupling (i) a first terminal of a second resistor to a source terminal of the second transistor and (ii) a second terminal of the second resistor to a mid-point of the second capacitive voltage divider.
Dependencies are inferred from the claim text.