USRE35221E - Schottky enhanced CMOS output circuit - Google Patents
Schottky enhanced CMOS output circuit Download PDFInfo
- Publication number
- USRE35221E USRE35221E US08/061,628 US6162893A USRE35221E US RE35221 E USRE35221 E US RE35221E US 6162893 A US6162893 A US 6162893A US RE35221 E USRE35221 E US RE35221E
- Authority
- US
- United States
- Prior art keywords
- channel transistor
- output circuit
- schottky diode
- voltage potential
- iaddend
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10D—INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10D84/00—Integrated devices formed in or on semiconductor substrates that comprise only semiconducting layers, e.g. on Si wafers or on GaAs-on-Si wafers
- H10D84/80—Integrated devices formed in or on semiconductor substrates that comprise only semiconducting layers, e.g. on Si wafers or on GaAs-on-Si wafers characterised by the integration of at least one component covered by groups H10D12/00 or H10D30/00, e.g. integration of IGFETs
- H10D84/811—Combinations of field-effect devices and one or more diodes, capacitors or resistors
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K19/00—Logic circuits, i.e. having at least two inputs acting on one output; Inverting circuits
- H03K19/003—Modifications for increasing the reliability for protection
- H03K19/00315—Modifications for increasing the reliability for protection in field-effect transistor circuits
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K19/00—Logic circuits, i.e. having at least two inputs acting on one output; Inverting circuits
- H03K19/02—Logic circuits, i.e. having at least two inputs acting on one output; Inverting circuits using specified components
- H03K19/08—Logic circuits, i.e. having at least two inputs acting on one output; Inverting circuits using specified components using semiconductor devices
- H03K19/094—Logic circuits, i.e. having at least two inputs acting on one output; Inverting circuits using specified components using semiconductor devices using field-effect transistors
- H03K19/09425—Multistate logic
- H03K19/09429—Multistate logic one of the states being the high impedance or floating state
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K19/00—Logic circuits, i.e. having at least two inputs acting on one output; Inverting circuits
- H03K19/02—Logic circuits, i.e. having at least two inputs acting on one output; Inverting circuits using specified components
- H03K19/08—Logic circuits, i.e. having at least two inputs acting on one output; Inverting circuits using specified components using semiconductor devices
- H03K19/094—Logic circuits, i.e. having at least two inputs acting on one output; Inverting circuits using specified components using semiconductor devices using field-effect transistors
- H03K19/0944—Logic circuits, i.e. having at least two inputs acting on one output; Inverting circuits using specified components using semiconductor devices using field-effect transistors using MOSFET or insulated gate field-effect transistors, i.e. IGFET
- H03K19/0948—Logic circuits, i.e. having at least two inputs acting on one output; Inverting circuits using specified components using semiconductor devices using field-effect transistors using MOSFET or insulated gate field-effect transistors, i.e. IGFET using CMOS or complementary insulated gate field-effect transistors
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10D—INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10D84/00—Integrated devices formed in or on semiconductor substrates that comprise only semiconducting layers, e.g. on Si wafers or on GaAs-on-Si wafers
- H10D84/80—Integrated devices formed in or on semiconductor substrates that comprise only semiconducting layers, e.g. on Si wafers or on GaAs-on-Si wafers characterised by the integration of at least one component covered by groups H10D12/00 or H10D30/00, e.g. integration of IGFETs
- H10D84/82—Integrated devices formed in or on semiconductor substrates that comprise only semiconducting layers, e.g. on Si wafers or on GaAs-on-Si wafers characterised by the integration of at least one component covered by groups H10D12/00 or H10D30/00, e.g. integration of IGFETs of only field-effect components
- H10D84/83—Integrated devices formed in or on semiconductor substrates that comprise only semiconducting layers, e.g. on Si wafers or on GaAs-on-Si wafers characterised by the integration of at least one component covered by groups H10D12/00 or H10D30/00, e.g. integration of IGFETs of only field-effect components of only insulated-gate FETs [IGFET]
- H10D84/85—Complementary IGFETs, e.g. CMOS
Definitions
- This invention relates generally to semiconductor integrated circuits, and more particularly the invention relates to CMOS output circuit.
- the standard CMOS output circuit as used in interfacing one of a plurality of devices to a common bus has an input signal applied to both gates of the CMOS transistor pair, and an inverted output is taken at the common terminal of the two serially-connected transistors.
- the output circuit can assume a high impedance state (i.e., tri-state) by taking the gate of the P-channel transistor high and the gate of the N-channel transistor low.
- an output circuit can have a voltage applied to its output terminal which is greater in magnitude than the supply voltages for that output circuit. In this circumstance, the substrate/source-drain diodes of the transistors can forward bias thus loading the common bus and causing potential latchup problems.
- An object of the invention is a CMOS output circuit having an enhanced high impedance state.
- a future of the invention is a provision of Schottky diodes in series with the transistors of a CMOS output circuit to prevent forward bias of the substrate/source-drain diodes when the circuit is in a high impedance state.
- FIG. 1 is a schematic of a conventional CMOS output circuit.
- FIG. 2 is a schematic of a CMOS output circuit in accordance with one embodiment of the invention.
- FIG. 3 is a section view of a semiconductor circuit illustrating the CMOS output circuit of FIG. 2.
- FIG. 1 is a schematic of a conventional CMOS output circuit.
- a P-channel transistor 10 is serially connected with an N-channel transistor 12 between a positive voltage potential (V+) and ground.
- the input signals to the circuit (PEN and NEN) are applied to the gates of the transistors 10, 12, and the output of the circuit is taken at the common terminal of the two transistors.
- the CMOS output circuit can be employed to connect a device to a bus shared with other devices.
- the circuit can isolate the device from the bus through the application of a high voltage potential to the gate of the P-channel transistor 10 and a low voltage to the gate of the N-channel transistor 12. In this mode both transistors are turned off thus isolating the output terminal.
- various devices connected to a common bus can have different operating voltages. Thus, the voltage level on the bus can be beyond the voltage levels For the output circuit.
- the substrate/source-drain diodes of the transistor devices can forward bias and inject current into the substrate thereby causing latchup problems and undesirably loading the common bus.
- Schottky diodes 14 and 16 are serially connected with the transistors 10 and 12 as illustrated in the schematic of FIG. 2.
- the presence of the Schottky diode 14 prevents the drain-substrate diode of the P-channel transistor from forward biasing even though the output voltage exceeds V+.
- Schottky diode 16 prevents the substrate-drain diode of N-channel transistor 12 from forward biasing even though the output voltage is below ground potential. Because the Schottky diodes will not forward bias and inject current into the substrate, the circuit will be free from latchup problems.
- the Schottky diodes can be formed in a semiconductor device structure from a normal metal (e.g. aluminum) to N -well junction in a standard N-well CMOS process. Such a structure is illustrated in the cross-sectional view of a CMOS device of FIG. 3.
- the device is fabricated in a P-substrate 20 with the P-channel transistor 10 formed in an N-well 22 and the N-channel of transistor 12 formed directly in the P-substrate 20.
- Schottky diode 14 is formed by an aluminum contact directly contacting the N-well 22, while the Schottky diode 16 is formed by a metal contacting N-well 24.
- An N+diffusion 26 is provided in N-well 22 to facilitate contact to the well.
- N+diffusion 28 is formed in N-well 22 to facilitate the contact to the N-well.
- the source 32 of the N-channel transistor is connected to ground, while the drain 34 of the P-channel transistor 10 is connected to the output terminal and to Schottky diode 16.
- the Schottky diodes are readily fabricated using conventional processing technology and conventional cell structures as described above.
- the Schottky diode 14 must be placed between V+ and the transistor 10 because of the N-well configuration including the Schottky diode, the transistor, and the output connection.
- the diode could be placed between transistor 10 and the output terminal if the N-well could be isolated from the substrate.
- Schottky diode 16 could between transistor 12 and ground if the N-well could be isolated from the substrate.
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- Computing Systems (AREA)
- General Engineering & Computer Science (AREA)
- Mathematical Physics (AREA)
- Power Engineering (AREA)
- Metal-Oxide And Bipolar Metal-Oxide Semiconductor Integrated Circuits (AREA)
Abstract
Description
Claims (7)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US08/061,628 USRE35221E (en) | 1989-02-23 | 1993-05-13 | Schottky enhanced CMOS output circuit |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US07/314,378 US5015889A (en) | 1989-02-23 | 1989-02-23 | Schottky enhanced CMOS output circuit |
| US08/061,628 USRE35221E (en) | 1989-02-23 | 1993-05-13 | Schottky enhanced CMOS output circuit |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US07/314,378 Reissue US5015889A (en) | 1989-02-23 | 1989-02-23 | Schottky enhanced CMOS output circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| USRE35221E true USRE35221E (en) | 1996-04-30 |
Family
ID=23219719
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US07/314,378 Ceased US5015889A (en) | 1989-02-23 | 1989-02-23 | Schottky enhanced CMOS output circuit |
| US08/061,628 Expired - Lifetime USRE35221E (en) | 1989-02-23 | 1993-05-13 | Schottky enhanced CMOS output circuit |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US07/314,378 Ceased US5015889A (en) | 1989-02-23 | 1989-02-23 | Schottky enhanced CMOS output circuit |
Country Status (1)
| Country | Link |
|---|---|
| US (2) | US5015889A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6262460B1 (en) * | 2000-01-07 | 2001-07-17 | National Semiconductor Corporation | Long channel MOS transistor that utilizes a schottky diode to increase the threshold voltage of the transistor |
| US20050148126A1 (en) * | 2004-01-06 | 2005-07-07 | Yaowen Chang | Low voltage CMOS structure with dynamic threshold voltage |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5274284A (en) * | 1991-01-24 | 1993-12-28 | Texas Instruments Incorporated | Output buffer circuits with controlled Miller effect capacitance |
| US5149991A (en) * | 1991-06-06 | 1992-09-22 | National Semiconductor Corporation | Ground bounce blocking output buffer circuit |
| JPH05198755A (en) * | 1991-08-29 | 1993-08-06 | Mitsubishi Electric Corp | Semiconductor logic circuit |
| JP2707954B2 (en) * | 1993-09-01 | 1998-02-04 | 日本電気株式会社 | Code setting circuit |
| US5451889A (en) * | 1994-03-14 | 1995-09-19 | Motorola, Inc. | CMOS output driver which can tolerate an output voltage greater than the supply voltage without latchup or increased leakage current |
| ITTO20010530A1 (en) * | 2001-06-01 | 2002-12-01 | St Microelectronics Srl | OUTPUT BUFFER FOR A NON-VOLATILE MEMORY WITH SWITCHING NOISE REDUCTION ON THE OUTPUT SIGNAL AND NON-VOLATILE MEMORY INCLUDED |
| US6963214B2 (en) * | 2003-10-06 | 2005-11-08 | Taiwan Semiconductor Manufacturing Company, Ltd. | OBIRCH dual power circuit |
| JP2015015643A (en) * | 2013-07-05 | 2015-01-22 | ローム株式会社 | Signal transmission circuit |
Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4023122A (en) * | 1975-01-28 | 1977-05-10 | Nippon Electric Company, Ltd. | Signal generating circuit |
| JPS5864828A (en) * | 1981-10-14 | 1983-04-18 | Toshiba Corp | Cmos logical circuit device |
| US4578600A (en) * | 1982-01-26 | 1986-03-25 | Itt Industries, Inc. | CMOS buffer circuit |
| JPS62260426A (en) * | 1986-05-06 | 1987-11-12 | Nec Corp | Cmos output buffer circuit |
| US4740713A (en) * | 1985-01-26 | 1988-04-26 | Kabushiki Kaisha Toshiba | MOS semiconductor integrated circuit in which the production of hot carriers near the drain of a short n channel conductivity type MOS transistor is decreased |
| US4791321A (en) * | 1985-12-27 | 1988-12-13 | Kabushiki Kaisha Toshiba | CMOS output circuit device |
| US4801983A (en) * | 1985-08-30 | 1989-01-31 | Hitachi, Ltd. | Schottky diode formed on MOSFET drain |
| US4996449A (en) * | 1988-07-19 | 1991-02-26 | Kabushiki Kaisha Toshiba | Output circuit having high speed operation and low power dissipation |
| US5097153A (en) * | 1989-05-11 | 1992-03-17 | Texas Instruments Incorporated | TTL compatible BICMOS input circuit |
| US5233237A (en) * | 1991-12-06 | 1993-08-03 | National Semiconductor Corporation | Bicmos output buffer noise reduction circuit |
-
1989
- 1989-02-23 US US07/314,378 patent/US5015889A/en not_active Ceased
-
1993
- 1993-05-13 US US08/061,628 patent/USRE35221E/en not_active Expired - Lifetime
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4023122A (en) * | 1975-01-28 | 1977-05-10 | Nippon Electric Company, Ltd. | Signal generating circuit |
| JPS5864828A (en) * | 1981-10-14 | 1983-04-18 | Toshiba Corp | Cmos logical circuit device |
| US4578600A (en) * | 1982-01-26 | 1986-03-25 | Itt Industries, Inc. | CMOS buffer circuit |
| US4740713A (en) * | 1985-01-26 | 1988-04-26 | Kabushiki Kaisha Toshiba | MOS semiconductor integrated circuit in which the production of hot carriers near the drain of a short n channel conductivity type MOS transistor is decreased |
| US4801983A (en) * | 1985-08-30 | 1989-01-31 | Hitachi, Ltd. | Schottky diode formed on MOSFET drain |
| US4791321A (en) * | 1985-12-27 | 1988-12-13 | Kabushiki Kaisha Toshiba | CMOS output circuit device |
| JPS62260426A (en) * | 1986-05-06 | 1987-11-12 | Nec Corp | Cmos output buffer circuit |
| US4996449A (en) * | 1988-07-19 | 1991-02-26 | Kabushiki Kaisha Toshiba | Output circuit having high speed operation and low power dissipation |
| US5097153A (en) * | 1989-05-11 | 1992-03-17 | Texas Instruments Incorporated | TTL compatible BICMOS input circuit |
| US5233237A (en) * | 1991-12-06 | 1993-08-03 | National Semiconductor Corporation | Bicmos output buffer noise reduction circuit |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6262460B1 (en) * | 2000-01-07 | 2001-07-17 | National Semiconductor Corporation | Long channel MOS transistor that utilizes a schottky diode to increase the threshold voltage of the transistor |
| US20050148126A1 (en) * | 2004-01-06 | 2005-07-07 | Yaowen Chang | Low voltage CMOS structure with dynamic threshold voltage |
| US7141470B2 (en) * | 2004-01-06 | 2006-11-28 | Macronix International Co., Ltd. | Low voltage CMOS structure with dynamic threshold voltage |
Also Published As
| Publication number | Publication date |
|---|---|
| US5015889A (en) | 1991-05-14 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FPAY | Fee payment |
Year of fee payment: 8 |
|
| FPAY | Fee payment |
Year of fee payment: 12 |
|
| FEPP | Fee payment procedure |
Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY |
|
| AS | Assignment |
Owner name: ANALOG DEVICES INTERNATIONAL UNLIMITED COMPANY, IRELAND Free format text: CHANGE OF NAME;ASSIGNOR:LINEAR TECHNOLOGY LLC;REEL/FRAME:057423/0429 Effective date: 20181105 Owner name: LINEAR TECHNOLOGY LLC, CALIFORNIA Free format text: CHANGE OF NAME;ASSIGNOR:LINEAR TECHNOLOGY CORPORATION;REEL/FRAME:057421/0355 Effective date: 20170502 |