US4092619A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Mos voltage controlled lowpass filter
Assignee: Intel Corp
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Filing: 1976-12-27
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Granted: 1978-05-30
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Expires: 1996-12-27
Abstract
Abstract An MOS field-effect device which may be fabricated as part of an integrated circuit having the general characteristics of a lowpass filter. A source and drain region define a long channel (e.g. 500 microns or longer). The cutoff frequency of this lowpass filter which is in the audio range, is controllable by the potential applied to a gate member insulated from the channel.
Inventors
- 👤 John M. Huggins
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 10:23
CPC Classifications
H; H10; H10D; H10D62/00; H10D62/10; H10D62/17; H10D62/213; H10D62/221; H10D62/235; H03; H03H; H03H11/00; H03H11/02; H03H7/00; H03H7/01; H03H7/06; H10D30/00; H10D30/60; H10D30/637; H10D64/00; H10D64/20; H10D64/27; H10D64/311; H10D64/411; H10D64/511; H10D64/517; H10D64/518
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
135 words
An MOS field-effect device fabricated on a substrate of a first conductivity type for filtering an input signal, said device having the general characteristics of a lowpass filter with a controllable cutoff frequency, comprising: an elongated gate member insulated from said substrate, said gate member having a length of approximately 500 microns, or longer; a pair of spaced-apart regions in said substrate of a second conductivity type disposed at opposite ends of said gate member, said regions defining a channel in said substrate beneath said gate member, one of said regions coupled to receive said input signal; and, voltage supply means coupled to said gate member for defining said cutoff frequency of said device; whereby said device acts as a lowpass filter between said regions with the cutoff frequency determined by said voltage supply means.
Claim 2
Dependent Claim
135 words
An MOS field-effect device fabricated on a substrate of a first conductivity type for filtering an input signal, said device having the general characteristics of a lowpass filter with a controllable cutoff frequency, comprising: an elongated gate member insulated from said substrate, said gate member having a length of approximately 500 microns, or longer; a pair of spaced-apart regions in said substrate of a second conductivity type disposed at opposite ends of said gate member, said regions defining a channel in said substrate beneath said gate member, one of said regions coupled to receive said input signal; and, voltage supply means coupled to said gate member for defining said cutoff frequency of said device; whereby said device acts as a lowpass filter between said regions with the cutoff frequency determined by said voltage supply means.
Claim 3
Dependent Claim
12 words
The device defined by claim 1 wherein said channel is ion implanted.
Claim 4
Dependent Claim
25 words
The device defined by claim 1 wherein said device conducts between said regions when said gate member and said substrate are at the same potential.
Claim 5
Dependent Claim
20 words
The device defined by claim 1 wherein said substrate is a p-type substrate and wherein said regions are n-type regions.
Claim 6
Dependent Claim
24 words
The device defined by claim 4 wherein said device conducts between said regions when said substrate and said regions are at the same potential.
Claim 7
Dependent Claim
23 words
The device defined by claim 5 wherein said voltage supply means is a source of a constant positive potential, relative to said substrate.
Claim 8
Dependent Claim
19 words
The device defined by claim 6 wherein the width of said gate member is approximately eight microns, or greater.
Claim 9
Dependent Claim
20 words
The device defined by claim 1 wherein said voltage supply means provides a time variable voltage to said gate member.
Claim 10
Dependent Claim
86 words
An MOS lowpass filter fabricated on a p-type silicon substrate, comprising: a pair of spaced-apart n-type regions disposed in said substrate, said regions defining a channel of approximately 500 microns in length, or longer; a gate member insulated from said substrate and extending between said regions over said channel; voltage means for controlling the cutoff frequency of said filter, coupled to said gate member; whereby an input signal applied to one of said regions is filtered, and whereby the cutoff frequency of said filter is controllable.
Claim 11
Dependent Claim
86 words
An MOS lowpass filter fabricated on a p-type silicon substrate, comprising: a pair of spaced-apart n-type regions disposed in said substrate, said regions defining a channel of approximately 500 microns in length, or longer; a gate member insulated from said substrate and extending between said regions over said channel; voltage means for controlling the cutoff frequency of said filter, coupled to said gate member; whereby an input signal applied to one of said regions is filtered, and whereby the cutoff frequency of said filter is controllable.
Claim 12
Dependent Claim
13 words
The MOS filter defined by claim 9 wherein said channel is ion implanted.
Claim 13
Dependent Claim
24 words
The MOS filter defined by claim 10 wherein said voltage means applies a constant positive potential, relative to said substrate, to said gate member.
Claim 14
Dependent Claim
25 words
The MOS filter defined by claim 9 wherein said filter conducts between said regions when said gate member and substrate are at the same potential.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-05-29 | 1981-11-28 | 1982-05-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-05-29 | 1985-11-28 | 1986-05-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-05-29 | 1989-11-28 | 1990-05-30 | $7700.00 | Window Closed / Lapsed |