SEMICONDUCTOR DEVICE AND METHOD OF FORMING SAME FOR ESD PROTECTION
First Claim
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7. A method of forming a semiconductor device, comprising:
- forming an inverter including a p-type transistor and an n-type transistor coupled in series and having an inverter control node and an inverter output node, the p-type transistor further coupled to a positive voltage rail;
forming a trailing transistor coupled between the n-type transistor of the inverter and a negative voltage rail, and forming a trailing node between the trailing transistor and the n-type transistor of the inverter;
forming a clamp transistor coupled between the positive and negative voltage rails and having a clamp control node coupled to the inverter output node;
forming a latching transistor having a latching control node coupled the inverter output node, the latching transistor further coupled in series between a resistance and the trailing node, where the resistance is further coupled to the positive voltage rail; and
forming a resistor-capacitor (RC) circuit coupled in series between the positive and negative voltage rails and including a resistor and a capacitor, with the resistor coupled to the positive voltage rail and the capacitor coupled to the negative rail, an RC node defined by a junction of the resistor and capacitor, and wherein the RC node is coupled to the inverter control node.
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Abstract
In an embodiment a circuit provides protection against electrostatic discharge (ESD). A shunt device is controlled to provide a current bypass upon the occurrence of an ESD event. A trigger circuit controls operation of the shunt device and includes an inverter and a hysteresis means to prevent oscillation of the trigger circuit. A reference is used to trigger the control circuit and has a time constant associated with it to distinguish between power up events and ESD events.
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Citations
17 Claims
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7. A method of forming a semiconductor device, comprising:
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forming an inverter including a p-type transistor and an n-type transistor coupled in series and having an inverter control node and an inverter output node, the p-type transistor further coupled to a positive voltage rail; forming a trailing transistor coupled between the n-type transistor of the inverter and a negative voltage rail, and forming a trailing node between the trailing transistor and the n-type transistor of the inverter; forming a clamp transistor coupled between the positive and negative voltage rails and having a clamp control node coupled to the inverter output node; forming a latching transistor having a latching control node coupled the inverter output node, the latching transistor further coupled in series between a resistance and the trailing node, where the resistance is further coupled to the positive voltage rail; and forming a resistor-capacitor (RC) circuit coupled in series between the positive and negative voltage rails and including a resistor and a capacitor, with the resistor coupled to the positive voltage rail and the capacitor coupled to the negative rail, an RC node defined by a junction of the resistor and capacitor, and wherein the RC node is coupled to the inverter control node. - View Dependent Claims (8, 9, 10, 11, 12)
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13. An integrated circuit, comprising:
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a voltage differentiator circuit that tracks an input voltage between a positive input and a negative input to the integrated circuit and provides an output based on the input voltage that is time delayed by a preselected time constant; an inverter coupled to the output of the voltage differentiator circuit and responsive to a difference between the output of the voltage differentiator circuit and the input voltage, the inverter having an inverter output; a clamp device coupled between the positive input and the negative input and having an input coupled to the inverter output and responsive to the inverter output; and a fast switch and hysteresis control circuit including a trailing transistor coupled in series with the inverter and a latching transistor coupled between the positive input and a positive side of the trailing transistor. - View Dependent Claims (1, 2, 3, 4, 5, 6, 14, 15, 16, 17)
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15-1. The semiconductor device of claim 13, wherein the voltage differentiator circuit includes a series RC circuit with a resistor coupled to the positive input and a capacitor coupled to the negative input, and a junction of the resistor and capacitor forming the output of the voltage differentiator circuit, the capacitor is a metallic-oxide semiconductor field effect transistor having a gate, a drain, and a source, wherein the gate is connected to the resistor and the drain and source are both connected to the negative input.
Specification