US5510947A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrostatic discharge protective device having a reduced current leakage
Assignee: STMicroelectronics SRL
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Filing: 1995-01-03
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Granted: 1996-04-23
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Expires: 2015-01-03
Abstract
Abstract In an anti-ESD protective structure, especially designed for pins destined to reach below ground and/or above supply voltages, includes a pair of Zener diodes or lateral NPN structures with a resistive connection between base and emitter, connected in opposition among each other between the pin to be protected and a grounded substrate of the integrated circuit. An amplifying effect on the leakage current which is drawn/injected through the pin by the protective structure caused by the triggering of an intrinsic parasitic transistor is effectively eliminated by connecting a biasing element, such as a forward biased junction, between the node of interconnection between the two Zener orlateral NPN structures and a node of the integrated circuit biased with a voltage sufficiently high as to ensure, under any condition, a reverse biasing of the base-emitter junction of the parasitic transistor.
Inventors
- 👤 Franco Pellegrini
- 👤 Marco Morelli
- 👤 Athos Canclini
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 18:04
CPC Classifications
H; H10; H10D; H10D89/00; H10D89/60
Claims Analysis
Total Claims: 32
Claim 1
Independent Claim
108 words
An integrated structure for protecting integrated components connected to a pin of an integrated circuit which may be hit by an electrostatic discharge, the structure comprising: a pair of discharging elements connected in series between the pin and ground, with the discharging elements opposing one another; and a biasing element connected between a node of interconnection between the discharging elements and a supply voltage node to provide a voltage at the node of interconnection greater than a maximum design voltage reached by the pin under normal conditions, said biasing element biasing said node of interconnection such that leakage current is limited during normal operation of the integrated circuit.
Claim 2
Dependent Claim
108 words
An integrated structure for protecting integrated components connected to a pin of an integrated circuit which may be hit by an electrostatic discharge, the structure comprising: a pair of discharging elements connected in series between the pin and ground, with the discharging elements opposing one another; and a biasing element connected between a node of interconnection between the discharging elements and a supply voltage node to provide a voltage at the node of interconnection greater than a maximum design voltage reached by the pin under normal conditions, said biasing element biasing said node of interconnection such that leakage current is limited during normal operation of the integrated circuit.
Claim 3
Dependent Claim
16 words
An integrated structured as recited in claim 1 wherein each discharging element includes a Zener diode.
Claim 4
Dependent Claim
16 words
An integrated structure as recited in claim 2 wherein said biasing element includes a Zener diode.
Claim 5
Dependent Claim
30 words
An integrated structure as recited in claim 2 wherein said biasing element includes a lateral NPN structure having a resistive connection between a base region and an emitter region thereof.
Claim 6
Dependent Claim
62 words
An integrated structure as recited in claim 2 wherein the supply voltage (Vx) satisfies the following condition: Vbz1>Vin(-)+(Vx-Vfd) wherein Vbz1 is the voltage drop across a first Zener diode, Vin(-) is a maximum negative design voltage with respect to ground which the voltage on the pin may reach under normal operating conditions, and Vfd is a voltage drop across the biasing element.
Claim 7
Dependent Claim
29 words
An integrated structure as recited in claim 1 wherein each discharging element includes a lateral NPN structure having a resistive connection between a base region and emitter region thereof.
Claim 8
Dependent Claim
16 words
An integrated structure as recited in claim 6 wherein said biasing element includes a Zener diode.
Claim 9
Dependent Claim
30 words
An integrated structure as recited in claim 6 wherein said biasing element includes a lateral NPN structure having a resistive connection between a base region and an emitter region thereof.
Claim 10
Dependent Claim
63 words
An integrated structure as recited in claim 6 wherein the supply voltage (Vx) satisfies the following condition: Vbz1>Vin(-)+(Vx-Vfd) wherein Vbz1 is the voltage drop across a first lateral NPN structure, Vin(-) is a maximum negative design voltage with respect to ground which the voltage on the pin may reach under normal operating conditions, and Vfd is a voltage drop across the biasing element.
Claim 11
Dependent Claim
15 words
An integrated structure as recited in claim 1 wherein said biasing element includes a diode.
Claim 12
Dependent Claim
16 words
An integrated structure as recited in claim 1 wherein said biasing element includes a Zener diode.
Claim 13
Dependent Claim
30 words
An integrated structure as recited in claim 1 wherein said biasing element includes a lateral NPN structure having a resistive connection between a base region and an emitter region thereof.
Claim 14
Dependent Claim
107 words
An integrated structure for protecting integrated components connected to a pin of an integrated circuit which may be hit by an electrostatic discharge, the structure comprising: a pair of means for discharging connected in series between the pin and ground, with the discharging means opposing one another; and means for biasing connected between a node of interconnection between the discharging means and a supply voltage node to provide a voltage at the node greater than a maximum design voltage reached by the pin under normal conditions, said biasing means biasing said node of interconnection such that leakage current is limited during normal operation of the integrated circuit.
Claim 15
Dependent Claim
107 words
An integrated structure for protecting integrated components connected to a pin of an integrated circuit which may be hit by an electrostatic discharge, the structure comprising: a pair of means for discharging connected in series between the pin and ground, with the discharging means opposing one another; and means for biasing connected between a node of interconnection between the discharging means and a supply voltage node to provide a voltage at the node greater than a maximum design voltage reached by the pin under normal conditions, said biasing means biasing said node of interconnection such that leakage current is limited during normal operation of the integrated circuit.
Claim 16
Dependent Claim
18 words
An integrated structure as recited in claim 13 wherein each of said discharging means includes a Zener diode.
Claim 17
Dependent Claim
30 words
An integrated structure as recited in claim 14 wherein the biasing means includes a lateral NPN structure having a resistive connection between a base region and an emitter region thereof.
Claim 18
Dependent Claim
30 words
An integrated structure as recited in claim 13 wherein each discharging means includes a lateral NPN structure having a resistive connection between a base region and an emitter region thereof.
Claim 19
Dependent Claim
16 words
An integrated structure as recited in claim 15 wherein the biasing means includes a Zener diode.
Claim 20
Dependent Claim
30 words
An integrated structure as recited in claim 16 wherein the biasing means includes a lateral NPN structure having a resistive connection between a base region and an emitter region thereof.
Claim 21
Dependent Claim
30 words
An integrated structure as recited in claim 13 wherein the biasing means includes a lateral NPN structure having a resistive connection between a base region and an emitter region thereof.
Claim 22
Dependent Claim
16 words
An integrated structure as recited in claim 14 wherein the biasing means includes a Zener diode.
Claim 23
Dependent Claim
15 words
An integrated structure as recited in claim 13 wherein the biasing means includes a diode.
Claim 24
Dependent Claim
16 words
An integrated structure as recited in claim 13 wherein the biasing means includes a Zener diode.
Claim 25
Dependent Claim
134 words
A protective network for protection of integrated components connected to pins of integrated circuits which may be hit by electrostatic discharges, the network comprising: a discharge zener diode connected between ground and an intermediate node of the network to which intermediate node a cathode of a protection diode of the network is connected, the anode of the protection diode being connected to a pin to be protected; and a biasing element connected between the intermediate node and a supply rail of the integrated circuit, to provide a voltage at the intermediate node greater than a maximum design voltage reached by the pin under normal operating conditions the biasing element including a forward biased junction, said biasing element biasing said intermediate node such that leakage current is limited during normal operation of the integrated circuit.
Claim 26
Dependent Claim
134 words
A protective network for protection of integrated components connected to pins of integrated circuits which may be hit by electrostatic discharges, the network comprising: a discharge zener diode connected between ground and an intermediate node of the network to which intermediate node a cathode of a protection diode of the network is connected, the anode of the protection diode being connected to a pin to be protected; and a biasing element connected between the intermediate node and a supply rail of the integrated circuit, to provide a voltage at the intermediate node greater than a maximum design voltage reached by the pin under normal operating conditions the biasing element including a forward biased junction, said biasing element biasing said intermediate node such that leakage current is limited during normal operation of the integrated circuit.
Claim 27
Dependent Claim
43 words
An integrated structure as recited in claim 23 wherein cathodes of a plurality of protection diodes of the network are connected to the intermediate node, each of the diodes having an anode connected to a pin of the integrated circuit to be protected.
Claim 28
Dependent Claim
129 words
A protective network for protection of integrated components connected to pins of integrated circuits which may be hit by electrostatic discharges, the network comprising: means for discharging connected between ground and an intermediate node of the network to which intermediate node a cathode of a protection diode of the network is connected, the anode of the protection diode being connected to a pin to be protected; and means for biasing connected between the intermediate node and a supply rail of the integrated circuit, the biasing means including means for providing a voltage at the intermediate node greater than a maximum design voltage reached by the pin under normal conditions, said biasing means biasing said intermediate node such that leakage current is limited during normal operation of the integrated circuit.
Claim 29
Dependent Claim
129 words
A protective network for protection of integrated components connected to pins of integrated circuits which may be hit by electrostatic discharges, the network comprising: means for discharging connected between ground and an intermediate node of the network to which intermediate node a cathode of a protection diode of the network is connected, the anode of the protection diode being connected to a pin to be protected; and means for biasing connected between the intermediate node and a supply rail of the integrated circuit, the biasing means including means for providing a voltage at the intermediate node greater than a maximum design voltage reached by the pin under normal conditions, said biasing means biasing said intermediate node such that leakage current is limited during normal operation of the integrated circuit.
Claim 30
Dependent Claim
43 words
An integrated structure as recited in claim 25 wherein cathodes of a plurality of protection diodes of the network are connected to the intermediate node, each of the diodes having an anode connected to a pin of the integrated circuit to be protected.
Claim 31
Dependent Claim
140 words
An electrostatic protective device for protecting an input pin of an integrated circuit against an over voltage condition caused by an electrostatic discharge, the device including a pair of discharging elements connected in series between the pin and a voltage reference point, the pair of discharging elements including a parasitic transistor having a collector coupled to the pin, an emitter coupled to the voltage reference point, and a base coupled to an intermediate node of the pair of discharging elements, the improvement comprising a biasing element coupled between the intermediate node and a voltage supply rail, and wherein the biasing element provides a voltage at the intermediate node greater than a maximum design voltage reached by the pin under normal conditions to bias the parasitic transistor to an off state to limit leakage current through the pair of discharging elements.
Claim 32
Dependent Claim
140 words
An electrostatic protective device for protecting an input pin of an integrated circuit against an over voltage condition caused by an electrostatic discharge, the device including a pair of discharging elements connected in series between the pin and a voltage reference point, the pair of discharging elements including a parasitic transistor having a collector coupled to the pin, an emitter coupled to the voltage reference point, and a base coupled to an intermediate node of the pair of discharging elements, the improvement comprising a biasing element coupled between the intermediate node and a voltage supply rail, and wherein the biasing element provides a voltage at the intermediate node greater than a maximum design voltage reached by the pin under normal conditions to bias the parasitic transistor to an off state to limit leakage current through the pair of discharging elements.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-04-23 | 1999-10-23 | 2000-04-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-04-23 | 2003-10-23 | 2004-04-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-04-23 | 2007-10-23 | 2008-04-23 | $7700.00 | Window Closed / Lapsed |