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US 5,477,190 AGranted
Low voltage linear output buffer operational amplifier
AssigneeAdvanced Micro Devices, Inc.
InventorsGeoffrey G. Brehmer, Carlin D. Cabler
Life of this patent
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Abstract
This invention includes a linear, low noise, low voltage operational amplifier which drives variable resistive and capacitive output loads and includes a slave emitter follower buffer stage.
Claims24
A linear, low noise operational amplifier, comprising:
- a first gain stage, including a plurality of differential inputs and an output, wherein a plurality of current sourcing transistors in a cascode configuration are connected to said plurality of differential inputs;
- a second gain stage, including an input connected to said output of said first gain stage and including an output;
- an emitter follower slave stage, including a compensation capacitor, a first buffer transistor, a first current sinking transistor and an output, wherein the emitter of said first buffer transistor is connected to said output of said emitter follower slave stage output and said first current sinking transistor is connected to said output of said emitter follower slave stage and wherein said compensation capacitor connected between said output of said first gain stage and said output of said emitter follower slave stage;
- and
- an emitter follower output stage, including a second buffer transistor, a second current sinking transistor and an output, wherein the emitter of said second buffer transistor and said current sinking transistor are connected to said output of said emitter follower output stage.
2 more elements
A linear, low noise operational amplifier, comprising:
- a first gain stage, including a plurality of differential inputs, and an output, wherein a plurality of current sourcing transistors in a cascode configuration are connected to said plurality of differential inputs;
- a second gain stage, including an input connected to said output of said first gain stage, an output, and a transistor connected to said output of said first and said second gain stage;
- an emitter follower slave stage, including an input connected to said output of said second gain stage, and an output, wherein said emitter follower slave stage output is connected to a compensation capacitor, to a first buffer transistor, and to a first current sinking transistor;
- and
- an emitter follower output stage, which includes a second buffer transistor which is connected to the output of said second gain stage, an output, wherein said second buffer transistor and a second current sinking transistor are connected to said output of said emitter follower output stage.
2 more elements
An linear, low noise operational amplifier, comprising:
- a first gain stage, including a plurality of differential inputs, and an output, wherein a plurality of current sourcing transistors in a cascode configuration are connected to said plurality of differential inputs;
- a second gain stage, including an input connected to said output of said first gain stage, an output and a first plurality of current sinking transistors configured in a cascode configuration connected to said output of said second gain stage;
- an emitter follower slave stage, including an input connected to said output of said second gain stage, an output and a first buffer transistor, wherein the emitter of said first buffer transistor is connected to said output of said emitter follower slave stage, and wherein a second plurality of current sinking transistors is connected to said output of said emitter follower slave stage;
- and
- an emitter follower output stage, including a second buffer transistor connected to an input of said first buffer transistor, an output, wherein the emitter of said second buffer transistor is connected to said output of said emitter follower output stage, and wherein a third plurality of current sinking transistors in a cascode configuration is connected to said output of said emitter follower output stage.
2 more elements
A linear, low noise operational amplifier, comprising:
- a first gain stage, including a plurality of differential inputs and an output;
- a second gain stage, including an input connected to said output of said first gain stage and an output, wherein said second gain stage output is connected to a plurality of current sourcing transistors in a cascode configuration;
- an emitter follower slave stage, including a first buffer transistor connected to said output of said second gain stage and an output, wherein said output of said emitter follower slave stage is connected to a first plurality of current sinking transistors in a cascode configuration;
- and
- an emitter follower output stage, including a second buffer transistor which is connected to said output of said second gain stage and an output, wherein said output of said emitter follower output stage is connected to an emitter of said second buffer transistor and is connected to a second plurality current sinking cascode configuration of N-channel MOSFETs.
2 more elements
A linear, low noise operational amplifier, comprising:
- a first gain stage, including a plurality of differential inputs and an output;
- a second gain stage, including an input connected to said output of said first gain stage and an output, wherein said second gain stage output is connected to a second stage P-channel MOSFET and is connected to a first plurality of current sinking transistors in a cascode configuration;
- a source follower slave stage, including a first buffer transistor connected to said output of said second gain stage and an output, wherein said output of said source follower slave stage is connected to said first buffer transistor and to a second plurality of current sinking transistors in a cascode configuration;
- and
- a source follower output stage, including a second buffer transistor connected to said output of said second gain stage and an output, wherein said source follower output stage output is connected to said second buffer transistor and to a third plurality of current sinking transistors in a cascode configuration.
2 more elements
A linear, low noise operational amplifier, comprising:
- a first gain stage, including a plurality of differential inputs, a first plurality of current sinking transistors in a cascode configuration connected to said plurality of differential inputs, and an output;
- a second gain stage, including an input connected to said output of said first gain stage and an output, wherein said second gain stage output is connected to a second plurality of current sinking transistors in a cascode configuration;
- an emitter follower slave stage, including an input connected to said output of said second gain stage, a first buffer transistor connected to said output of said second gain stage and an output, wherein said output of said emitter follower slave stage is connected to a third plurality of current sinking transistors in a cascode configuration;
- and
- an emitter follower output stage, including a second buffer transistor connected to said output of said second gain stage and an output, wherein said emitter follower output stage output is connected to the emitter of said second buffer transistor and is connected to a fourth plurality of current sinking transistors in a cascode configuration.
2 more elements
Dependencies are inferred from the claim text.