Other

Motorola Corporation

Pan Jit Americas, Inc.

James R Washburn

George W Templeton

Lowell E Clark

John R Bender

Alfredo Ochoa

An over-voltage protection thyristor has reduced junction capacitance making it suitable for use in high bandwidth applications. The reduced capacitance is achieved through the introduction of a deep base region. The deep base region has a graded doping concentration which reduces with depth into the substrate. The thyristor is useful for protecting sensitive electrical equipment from transient surges.

Low capacitance over-voltage protection thyristor device

A semiconductor device for coupling a transient voltage at an input node to a reference node, the device having a bipolar transistor adapted to couple its collector to an input node and its emitter to the reference node and a driver device adapted to be coupled between the input node and the base terminal of the transistor such that the driver device is responsive to a transient voltage at the input node to turn on the transistor, thereby shunting the transient voltage to the reference node. Preferably, the input node is coupled to a high speed data transmission line that operates below 5 v and the reference node is coupled to ground and the transistor is an NPN transistor. The driver may preferably be a gate-drain connected MOS transistor with its gate-drain terminal coupled to the collector terminal of the transistor and its source terminal coupled to the base terminal of the transistor. Alternatively, the driver may be a light emitting diode (LED) or any other diode with a different material (band-gap) and die size than the LED, connected to the bipolar transistor to create a low voltage clamping device.

Electrostatic discharge protection device for high speed transmission lines

A bidirectional two-terminal ungated thyristor (9) having two wide-base portions (25, 27). The bidirectional two-terminal ungated thyristor (9) has a first semiconductor device having a first narrow-base portion (28) in series with a first wide-base portion (25), and a second semiconductor device having a second narrow-base portion (26) in series with a second wide-base portion (27). A width of the first wide base portion (25) and a width of the second wide base portion (27) are decreased to decrease a total base width. The first and second wide-base portions (25, 27) having a decreased width produce a low forward voltage drop across the bidirectional two-terminal ungated thyristor (9); thus, improving a power dissipation capability of the bidirectional two-terminal ungated thyristor (9).

Bidirectional two-terminal thyristor

An improved semiconductor device, particularly a gate controlled switch is provided by optimally fitting an involute spiral cathode-gate structure into a substantially square device. 4N cathode-gate branches radiate from a central gate portion and intersect the perimeter of the square device region at predetermined locations, N per side, where N is an integer. Four of the branches tangentially intercept the square perimeter at a distance R from a centerline where R is the radius of the central gate portion. The origin of the branches is angularly displaced from the line connecting the die center to the tangential intercept point by (L/R)- arctan (L/R) radians where L is half the edge length of the square device region. Improved thermal performance is obtained by thermally coupling the cathode heat spreader to the gate as well as cathode portions of the device.

Gate controlled switch

A split socket ratchet wrench is provided. The wrench has an elongate handle terminating at jaws at the head end of the wrench. The jaws receive a rotatable split socket and ratchet wheel rotatable therein. A manually actuable pawl has extending projections engageable with the ratchet teeth. A separate cable spool at the handle end of the wrench is fitted with a torsion spring. A cable or filament extends between the cable spool and the ratchet wheel. As the socket is rotated, it carries with it the cable which is spooled around a hub of the socket. When the wrench is disengaged from the nut, the pawl can be released and the cable spool will rewind returning the socket to the normal 'open' position at which point a registry stop on the socket prevents the socket from rewinding past the open position. A separate locking device senses when the cable spool is completely payed out and prevents the mechanic from further turning the socket.

Growing community of inventors

Scottsdale, AZ, United States of America

James R Washburn