Operational amplifier
AssigneeMotorola, Inc.
InventorFuad H. Musa
Life of this patent
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Abstract
A family of operational amplifiers are described which utilize only MOSFET transistors as the active devices. These operational amplifiers exhibit an infinite input impedance and zero input offset and bias currents. The circuits are capable of operating over a wide range of DC supply voltages at extremely low DC current drain. An operational amplifier is shown which operates from a single positive DC supply voltage and which handles a wide range of input common mode voltage swings including some negative common mode voltages. Another operational amplifier is shown which operates from a combination of a single positive and a single negative supply voltage and which handles a wide range of positive and negative input common mode voltage swings.
Claims4
An operational amplifier comprising:
- A. a source of potential having at least a first and a second voltage level;
- B. a first and a second differential amplifier, each of said differential amplifiers including:
- C. differential input means for receiving two input signals to be compared, each of said differential input means comprising:
- 1. a first MOSFET input device having source, drain and gate electrodes;
- 2.
An operational amplifier comprising:
- A. a source of potential having at least a first and a second voltage level;
- B. a first and a second differential amplifier, each of said differential amplifiers including:
- C. differential input means for receiving two input signals to be compared, each of said differential input means comprising:
- 1. a first MOSFET input device having source, drain and gate electrodes;
- 2. a second MOSFET input device having source, drain and gate electrodes:
- 3. said source electrodes of said first and said second input devices being connected together and being coupled to a MOSFET constant current source means;
- 4.
Dependencies are inferred from the claim text.