EP0260125A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Electrostatic discharge protection circuit
Assignee: BAE Systems PLC
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Filing: 1987-09-09
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Granted: —
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Expires: 2007-09-09
Abstract
Abstract An integrated circuit device including a substrate (2), power supply buses (V DD , V SS ), and a number of terminal pads (1) has an electrostatic discharge protection circuit associated with one of its terminal pads (1). The protection circuit comprises a diode (D1) directly connected between the pad (1) and one of the power supply buses (V DD , V SS ), a punchthrough transistor (TR1) directly connected to the other one of the power supply buses (V DD , V SS ) and a resistive path (R1) connecting the pad (1) to the remainder of the integrated circuit. Static charges applied to the pad (1) are transmitted to the one or the other power supply bus (V DD , V SS ) via the diode (D1) or the punchthrough transistor (TR1) rather than being transmitted to the remainder of the integrated circuit. In a preferred embodiment the diode (D1) and transistor (TR1) are formed by the substrate (2) in combination with diffusion regions of a different conductivity to the substrate (2) underlying the pad (1) and further diffusion regions (5, 8) formed along the sides of the pad (1).
Inventors
- 👤 Clive Roland C/O British Aerospace Plc Taylor
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 05:21
CPC Classifications
H; H10; H10D; H10D89/00; H10D89/60; H10D89/601
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
148 words
An integrated circuit device including a substrate (2), power supply buses (V DD , V SS ), and a number of terminal pads (1) and having an electrostatic discharge protection circuit associated with one of its terminal pads (1), the protection circuit comprising a diode (D1) directly connected between the pad (1) and one of the power supply buses (V DD , V SS , a punchthrough transistor (TR1) directly connected to the other one of the power supply buses (V DD , V SS ) and a resistive path (R1) connecting the pad (1) to the remainder of the integrated circuit so that static charges applied to the pad (1) are transmitted to the one or the other power supply bus (V DD , V SS ) via the diode (D1) or the punchthrough transistor (TR1) rather than being transmitted to the remainder of the integrated circuit.
Claim 2
Dependent Claim
148 words
An integrated circuit device including a substrate (2), power supply buses (V DD , V SS ), and a number of terminal pads (1) and having an electrostatic discharge protection circuit associated with one of its terminal pads (1), the protection circuit comprising a diode (D1) directly connected between the pad (1) and one of the power supply buses (V DD , V SS , a punchthrough transistor (TR1) directly connected to the other one of the power supply buses (V DD , V SS ) and a resistive path (R1) connecting the pad (1) to the remainder of the integrated circuit so that static charges applied to the pad (1) are transmitted to the one or the other power supply bus (V DD , V SS ) via the diode (D1) or the punchthrough transistor (TR1) rather than being transmitted to the remainder of the integrated circuit.
Claim 3
Dependent Claim
167 words
A device according to claim 1, in which the electrostatic discharge protection circuit for an integrated circuit device formed on a substrate (2) of one conductivity type comprises a first diffusion region (3) of the other conductivity type underlying the pad (1), a second diffusion region (8) of the one conductivity type adjacent one side of the pad (1) and connected to the one power supply bus (V DD ) so that the first (3) and second (8) diffusion regions form the diode (D1), a third diffusion region (5) of the other conductivity type spaced from the first region (3) and adjacent another side of the pad (1), the third region (5) being connected to the other power supply bus (V SS ) so that the substrate (2) and the first (3) and third (5) diffusion regions form the punchthrough transistor (TR1), and the resistive path (R1) is connected to the first region (3) of other conductivity type and leads to the remainder of the integrated circuit.
Claim 4
Dependent Claim
41 words
A device according to claim 2, in which the second diffusion region (8) is formed along two adjacent sides of the pad (1) and the third diffusion region (5) is formed along the other two adjacent sides of the pad (1).
Claim 5
Independent Claim
68 words
A device according to any one of the preceding claims, in which the protection circuit also includes a pair of diodes (D2, D3) connected in series in a reverse bias configuration between the one and other power supply buses (V DD , V SS ) with the node between the diodes (D2, D3) being connected to the end of the resistive path (R1) remote from the pad (1).
Claim 6
Dependent Claim
154 words
A device according to claim 4 when dependent upon claim 2 or 3, in which the protection circuit includes a fourth region (11) of the other conductivity type connected to the end of the resistive path (R1) and located adjacent the second diffusion region (8), a fifth diffusion region (15) of the one conductivity type which is also connected to the other power supply bus (V SS ) located adjacent the fourth region (11) to form with the fourth region (11) a first of the pair of diodes (D1, D2), a sixth diffusion region (13) of the one conductivity type which is connected in series with the fourth diffusion region (11) and a seventh diffusion region (18) of the other conductivity type which is connected to the one power supply bus (V DD ) and is arranged adjacent the sixth diffusion region (13) to form the second of the pair of diodes (D1, D2).
Claim 7
Dependent Claim
61 words
A device according to claim 5, in which the fourth (11) and fifth (14) diffusion regions are adjacent at least part of the second diffusion region (8) along one side of the pad (1) and the sixth (13) and seventh (18) diffusion regions are adjacent at least part of the third diffusion region (5) along another side of the pad (1).
Claim 8
Dependent Claim
29 words
A device according to claim 5 or 6, in which the sixth (13) and seventh (18) diffusion regions are located in a well (17) of the other conductivity type.
References Cited (Backward Citations)
No citation records indexed.
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