Patent US4820998A successfully refreshed from Google Patents.
US4820998A
Expired / Lapsed
US
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Operational amplifier
Assignee: Siemens AG
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Filing: 1987-09-24
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Granted: 1989-04-11
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Expires: 2007-09-24
Abstract
Abstract An operational amplifier of the folded-cascode type with: push-pull output terminals; a differential-input transistors; a load impedance in the form of a cascode current source coupled to the differential-input, and a dynamic common-mode negative feedback. A current source transistor in the cascode current source is incorporated into the dynamic common-mode negative feedback.
Inventors
- 👤 Bernward Roessler
- 👤 Eberhard Wolter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 08:40
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/30; H03F3/3001; H03F3/45; H03F3/45071; H03F3/45076; H03F3/45179; H03F3/45183; H03F3/45192; H03F3/45479; H03F2203/00; H03F2203/45; H03F2203/45421
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
65 words
An operational amplifier of the folded-cascode type, comprising: push-pull output terminals; differential-input transistors; a load impedance in the form of a cascode current source coupled to said differential-input transistors; and a switched capacitor common-mode negative feedback circuit; wherein: a single transistor both operates as a current source transistor in said cascode current source and also is incorporated into said switched capacitor common-mode negative feedback circuit.
Claim 2
Dependent Claim
65 words
An operational amplifier of the folded-cascode type, comprising: push-pull output terminals; differential-input transistors; a load impedance in the form of a cascode current source coupled to said differential-input transistors; and a switched capacitor common-mode negative feedback circuit; wherein: a single transistor both operates as a current source transistor in said cascode current source and also is incorporated into said switched capacitor common-mode negative feedback circuit.
Claim 3
Dependent Claim
66 words
An operational amplifier of the folded-cascode type, comprising: push-pull output terminals; first differential-input transistors; a load impedance in the form of a cascode current source coupled to said differential-input transistors; offset compensation differential-input transistors, coupled in parallel with said first differential-input transistors; and a dynamic common-mode negative feedback; wherein: a current source transistor in said cascode current source is incorporated into said dynamic common-mode negative feedback.
Claim 4
Dependent Claim
66 words
An operational amplifier of the folded-cascode type, comprising: push-pull output terminals; first differential-input transistors; a load impedance in the form of a cascode current source coupled to said differential-input transistors; offset compensation differential-input transistors, coupled in parallel with said first differential-input transistors; and a dynamic common-mode negative feedback; wherein: a current source transistor in said cascode current source is incorporated into said dynamic common-mode negative feedback.
Claim 5
Dependent Claim
14 words
The operational amplifier of claim 2, wherein all of the transistors are field-effect transistors.
Claim 6
Dependent Claim
14 words
The operational amplifier of claim 1, wherein all of the transistors are field-effect transistors.
Claim 7
Dependent Claim
20 words
The operational amplifier of claim 1, further comprising offset compensation differential-input transistors, coupled in parallel with said first-mentioned differential-input transistors.
Claim 8
Dependent Claim
15 words
The operational amplifier of claim 5, wherein said offset compensation differential-input transistors are field-effect transistors.
References Cited (Backward Citations)
US4656437A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-04-10 | 1992-10-10 | 1993-04-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-04-10 | 1996-10-10 | 1997-04-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-04-10 | 2000-10-10 | 2001-04-11 | $7700.00 | Window Closed / Lapsed |