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AssigneeSiliconix Incorporated
InventorsRichard K. Williams, Peter Hille, Robert G. Wrathall
Estimating the term…
An electrostatic discharge (ESD) device includes a pair of depletion mode MOSFETs connected drain-to-drain in a series path between an input terminal and an output terminal, the gate of each MOSFET being connected to its source. A first diode having a relatively high breakdown voltage is connected between ground and the common drain terminal of the MOSFETs, and a second diode having a relatively low breakdown voltage is connected between ground and the output terminal of the device. The second diode breaks down during a relatively low, long-lived voltage spike (in an automobile, sometimes referred to as a "load dump"), while the second MOSFET saturates, limiting the size of the current through the second diode. The first diode breaks down during a large voltage spike of short duration, such as occurs from an ESD.
An ESD protection circuit comprising an input terminal, an output terminal, two depletion mode MOSFETs connected in series between said input terminal and said output terminal, the source, body and gate of each of said MOSFETs being shorted together, the drains of said MOSFETs being connected together, a first diode having a cathode connected to said drains and an anode connected to ground, and a second diode having a cathode connected to the output terminal and an anode connected to ground.
A method of protecting an input of an integrated circuit, said integrated circuit being included in an integrated circuit device, from ESD pulses of relatively short duration as well as transient voltage of relatively longer duration, said method comprising:
An ESD protection circuit comprising two depletion mode N-channel MOSFETs connected in series drain-to-drain between an input and an output of said circuit, one of said MOSFETs having a gate, a body and a source shorted together, the other of said MOSFETs having a body and a source shorted together and having a gate connected to ground, a common drain mode between said MOSFETs being connected to ground through a first diode having a breakdown voltage of each of said MOSFETs, a source terminal of one of said MOSFETs being connected through a series resistor to said output and to a cathode of a second diode, an anode of said second diode being connected to ground.
As ESD protection circuit comprising two depletion mode N-channel MOSFETs connected in series drain-to-drain between an input and an output of said circuit, each of said MOSFETs having a gate, a body, and a source shorted together, a common drain node between said MOSFETs being connected to ground through a first diode having a breakdown voltage comparable to a breakdown voltage of each of said MOSFETs, a source terminal of one of said MOSFETs being connected through a series resistor to said output and to an anode of a second diode, a cathode of said second diode being connected to ground, said output of said circuit being connected to an anode of a third diode, the cathode of said third diode being connected to a supply voltage.
An ESD protection arrangement comprising two ESD protection circuits, each of said ESD protection circuits comprising two depletion mode N-channel MOSFETs connected in series drain-to-drain between an input and an output of said circuit, both of said MOSFETs having a gate, a body and a source shorted together, a common drain node between said MOSFETs being connected to ground through a first diode having a breakdown voltage comparable to a breakdown voltage of each of said MOSFETs, a source terminal of one of said MOSFETs being connected through a series resistor to said output and to a cathode of a second diode, an anode of said diode being connected to ground, one of said ESD protection circuits being connected to a signal input pin of an IC device, the other of said ESD protection circuits being connected to a power supply pin of said IC device.
An ESD protection arrangement comprising two ESD protection circuits, a first one of said ESD protection circuits comprising two depletion mode N-channel MOSFETs connected in series drain-to-drain between an input and an output of said circuit, both of said MOSFETs having a gate, a body and a source shorted together, a common drain node between said MOSFETs being connected to ground through a first diode having a breakdown voltage comparable to a breakdown voltage of each of said MOSFETs, a source terminal of one of said MOSFETs being connected through a series resistor to said output and to a cathode of a second diode, an anode of said diode being connected to ground, said first ESD protection circuit being connected to a signal input pin of an IC device, a second one of said ESD protection circuits comprising a depletion mode N-channel MOSFET connected between and an output of said second circuit, said third MOSFET having a gate, a body and a source shorted together, a drain of said third MOSFET being connected to ground through a third diode having a breakdown voltage comparable to a breakdown of said third MOSFET, a source terminal of said third MOSFET being connected to an output of said second ESD circuit and to a cathode of a fourth diode, an anode of said fourth diode being connected to ground, said second of said ESD protection circuits being connected to a power supply pin of said IC device.
An ESD protection circuit comprising a depletion mode N-channel MOSFET, said MOSFET having a gate, a body and a source shorted together, and a drain connected to ground through a first diode having a breakdown voltage comparable to a breakdown voltage of said MOSFET, a source terminal of said MOSFET being connected to an output of said ESD protection circuit and through a series resistor to a cathode of a second diode, an anode of said second diode being connected to ground.
Dependencies are inferred from the claim text.