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US 6,664,853 B1Granted
Wide-bandwidth differential signal amplifier
AssigneeApplied Micro Circuits Corporation
InventorsRunhua Sun, Thomas Clark Bryan, Zhixiang Jason Liu
Life of this patent
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Abstract
An impedance element connecting the outputs of two transistors of a wide-bandwidth amplifier forms a zero. The output of transistor is connected to a current source. The wide-bandwidth amplifier has a bandwidth greater than conventional amplifiers utilizing a single current source without an increase in power dissipation.
Claims17
An amplifier for producing an output signal at an amplifier output in response to an input signal received at an amplifier input, the amplifier comprising:
- a pair of transistors, each transistor of the pair having a control port, an input port and an output port, the control ports forming the amplifier input and the input ports forming the amplifier output;
- a pair of current sources, each current source of the pair of current sources connected to the output port of one of the transistors;
- a capacitor having its ends respectively directly connected to the output ports;
- and
- a resistor having its ends respectively directly connected to the output ports.
2 more elements
An amplifier for producing a differential output signal at an amplifier output in response to a differential input signal received at an amplifier input, the amplifier comprising:
- a first Complementary Metal Oxide Semiconductor Field Effect Transistor (CMOSFET) having a drain connected to a supply voltage through a first load resistor;
- a second Complementary Metal Oxide Semiconductor Field Effect Transistor (CMOSFET) having a drain connected to the supply voltage through a second load resistor;
- the amplifier input formed across a gate of the first CMOSFET and a gate of the second CMOSFET, the amplifier output formed across the drains of the first and second CMOSFETs;
- a first current source FET connected to a source of the first CMOSFET;
- a second current source FET connected to a source of the second CMOSFET;
- a compensation resistor having a first end directly connected to the source of the first CMOSFET and a second end directly connected to the source of the second CMOSFET;
- and
- a compensation capacitor having a first end directly connected to the source of the first CMOSFET and a second end directly connected to the source of the second CMOSFET.
5 more elements
A method for amplifying a differential input signal to form a differential output signal, the method comprising:
- receiving the differential input signal across gates of two field effect transistors (FETs), a drain of each FET connected to a supply voltage through a load resistor;
- directing current flow through the two load resistors in accordance with the input signal to form the output signal across the drains of the FETs;
- directing current flow from each source of each FET to a reference supply using two current sources each having an input connected to one of the FET sources;
- and
- directing current flow through a parallel combination of a compensation capacitor and a compensation resistor, the parallel combination having a first end directly connected to the input of one of the two current sources and a second end directly connected to the input of the other one of the two current sources, and between the inputs of the current sources in accordance with a frequency of the input signal.
2 more elements
An integrated circuit comprising:
- an amplifier for producing an output signal at an amplifier output in accordance with an input signal received at an amplifier input, the amplifier comprising:
- a pair of transistors, each transistor of the pair having a control port, an input port and an output port, the control ports forming the amplifier input and the input ports forming the amplifier output;
- a pair of current sources, each current source of the pair of current sources connected to the output port of one of the transistors;
- a capacitor having its ends respectively directly connected to the output ports;
- and
- a resistor having its ends respectively directly connected to the output ports.
3 more elements
An integrated circuit comprising:
- an amplifier for producing a differential output signal at an amplifier output in response to a differential input signal received at an amplifier input, the amplifier comprising:
- a first Complementary Metal Oxide Semiconductor Field Effect Transistor (CMOSFET) having a drain connected to a supply voltage through a first load resistor;
- a second Complementary Metal Oxide Semiconductor Field Effect Transistor (CMOSFET) having a drain connected to the supply voltage through a second load resistor;
- the amplifier input formed across a gate of the first CMOSFET and a gate of the second CMOSFET, the amplifier output formed across the drains of the first and second CMOSFETs;
- a first current source FET connected to a source of the first CMOSFET;
- a second current source FET connected to a source of the second CMOSFET;
- a compensation resistor having a first end directly connected to the source of the first CMOSFET and a second end directly connected to the source of the second CMOSFET;
- and
- a compensation capacitor having a first end directly connected to the source of the first CMOSFET and a second end directly connected to the source of the second CMOSFET.
6 more elements
Dependencies are inferred from the claim text.