Antenna switching circuitry comprises a plurality of communication ports, an antenna port, a plurality of switches, and an ESD protection device. The plurality of switches are adapted to selectively couple one or more of the communication ports to the antenna port in order to transmit or receive a signal. The ESD protection device is coupled between one of the plurality of communication ports and ground, and is adapted to form a substantially low impedance path to ground during an ESD event. Upon the occurrence of an ESD event, a received electrostatic charge passes through one or more of the plurality of switches to the ESD protection device, where it is safely diverted to ground. By using only one ESD protection device, desensitization of the antenna switching circuitry due to the parasitic loading of the ESD protection device is avoided. Further, the area of the antenna switching circuitry is minimized.

A semiconductor device includes high-voltage (HV) and low-voltage (LV) MOS's formed in a substrate. The HV MOS includes a first semiconductor region having a first-type conductivity and a first doping level, a second semiconductor region having the first-type conductivity and a second doping level lower than the first doping level, a third semiconductor region having a second-type conductivity, and a fourth semiconductor region having the first-type conductivity. The first, second, third, and fourth semiconductor regions are arranged along a first direction, and are drain, drift, channel, and source regions, respectively, of the HV MOS. The LV MOS includes the fourth semiconductor region, a fifth semiconductor region having the second-type conductivity, and a sixth semiconductor region having the first-type conductivity. The fourth, fifth, and sixth semiconductor regions are arranged along a second direction different from the first direction, and are drain, channel, and source regions, respectively, of the LV MOS.

A hot plug immune circuitry (100) for protecting against electrostatic discharge events comprises an input/output (I/O) pad (101) of an electronic system with a pad threshold voltage and connections to ground potential by a first circuit (110) and a parallel second circuit (130). The first circuit includes a MOS field-effect transistor (FET) (111) doubling as a parasitic bipolar transistor. The second circuit is a voltage level sensor formed as a voltage divider with a first impedance (131) tied by a link (133) in series with a second impedance (132). Link (133) is cross-tied (134) to the FET of the first circuit, and carries a shut-off voltage for the FET determined by the pad threshold voltage diminished by the ratio of the first and the second impedances.

A gate-grounded metal oxide semiconductor (GGMOS) device is disclosed. The GGMOS is an n-type (GGNMOS) transistor used as an electrostatic discharge (ESD) protection device. The GGMOS includes a base extension region under an elevated source. The elevated source and base extension regions increase L.sub.eff and reduce beta, increasing performance of the ESD protection.

The invention provides a semiconductor device layout structure disposed in an active region. The semiconductor device layout structure includes a first well region having a first conduction type. A second well region having a second conduction type opposite the first conduction type is disposed adjacent to and enclosing the first well region. A first doped region having the second conduction type is disposed within the first well region. A second doped region having the second conduction type is disposed within the first well region. The second doped region is separated from and surrounds the first doped region. A third doped region having the second conduction type is disposed within the second well region.

Described examples include an integrated circuit includes a protected node and a first transistor having a source coupled to the protected node, a gate and a drain coupled to a ground, wherein the first transistor is a MOSFET transistor. The integrated circuit also includes a second transistor having a first current handling terminal coupled to the protected node, a second current handling terminal coupled to the ground and a control terminal coupled to a reference potential, where the second transistor is configured to be off when a first voltage on the control terminal of the second transistor is less than a second voltage on the first current handling terminal of the second transistor.

An ESD protection device includes at least one semiconductor electronic switch electrically coupled in parallel with a diode. The semiconductor electronic switch and the diode each include at least one finger extending substantially parallel to a first direction. The fingers of the semiconductor electronic switch and of the diode are aligned with each other along this first direction.

A semiconductor device includes a semiconductor substrate having at least one element region in which a transistor is disposed, an interlayer insulating film disposed above the semiconductor substrate, and a semiconductor layer disposed above the interlayer insulating film. The semiconductor layer includes a first semiconductor layer of a first conductivity type connected to a gate of the transistor, a second semiconductor layer of a second conductivity type connected to the first semiconductor layer, and a third semiconductor layer of the first conductivity type connected to the second semiconductor layer and connected to a low potential terminal of the transistor.

An electrostatic discharge protection device is provided. The electrostatic discharge protection device includes a semiconductor substrate, a first well region, first, second and third doped regions, and a gate structure. The first well region having a first conductivity type is located in the semiconductor substrate. The first and second doped region having a second conductivity type are located on the first well region. The third doped region having the first conductivity type is located on the first well region. The second and third doped regions are located on opposite sides of the first doped region. The gate structure is disposed on a portion of the semiconductor substrate between the first and second doped regions. A conductivity type of the gate structure is different from a conductivity type of the first and second doped regions. The gate structure is electrically connected to the first and third doped regions.

An integrated circuit includes a Schmitt trigger circuit. The Schmitt trigger circuit includes a first, second, third and fourth transistor, a first and second feedback transistor, and a first and second circuit. The first transistor is connected between a first node and a first voltage supply having a first supply voltage. The fourth transistor is connected between the third transistor and a second voltage supply having a second supply voltage. The first circuit is connected to a second node, the first and second voltage supply, and configured to supply the second supply voltage to the second node in response to being enabled. The second feedback transistor is connected to a third node, and a fourth node. The second circuit is connected to the fourth node, the first and second voltage supply, and configured to supply the first supply voltage to the fourth node in response to being enabled.