Patents Assigned to Sprague Electric Company
  • Patent number: 4761714
    Abstract: A porous tantalum anode body is sintered onto a strip having an incurvate member which is embedded in the body and an elongated portion of the strip which serves as the anode connection.
    Type: Grant
    Filed: June 5, 1987
    Date of Patent: August 2, 1988
    Assignee: Sprague Electric Company
    Inventors: Jean Levasseur, Didier Gouvernelle
  • Patent number: 4751463
    Abstract: An integrated circuit voltage regulator is of the kind having a pass transistor connected collector-to-emitter between the input V.sub.CC conductor and the regulated-voltage output conductor, a current source circuit supplying a base bias current to the pass transistor and a voltage reference and feedback regulator circuit connected between the output voltage conductor and the base of the pass transistor. A protective circuit against high voltage transients adding to V.sub.CC voltage comprises a transistor connected collector-to-emitter between the pass-transistor base and ground has a resistor paralleling the base-emitter junction, which resistor is resistively coupled to the input V.sub.CC line to shunt away the pass-transistor bias current whenever the V.sub.CC voltage level exceeds a value just under the latch-back breakdown voltage of the pass transistor. A zener diode directly connected across the DC input voltage conduction renders the regulator even more tolerant of high voltage transients.
    Type: Grant
    Filed: June 1, 1987
    Date of Patent: June 14, 1988
    Assignee: Sprague Electric Company
    Inventors: Jacob K. Higgs, Hideki Kawaji, Ravi Vig
  • Patent number: 4749664
    Abstract: Water soluble precursors of ceramic compounds are emulsified in an organic fluid containing an organic surfactant. The emulsion is subsequently mildly heated at a pressure of about 0.05 atmospheres to remove the free water from the emulsion droplets. The resulting sludge consists of particles deriving from the dehydrated emulsion droplets. These particles may only be bound by the surfactant, all or most of the original organic fluid having been boiling off under low pressure. This sludge is then heated in a standard air atmosphere to char the surfactant, which char is to maintain the separation between the dried droplet-derived particles to prevent forming sintered or fused agglomerates thereof. With continued heating the transient char is subsequently burned off and the particles are calcined to controllably and simply produce a fine ceramic powder of spherical particles having a narrow size distribution and an average size in the particularly useful range of 0.1 micron to 1.0 micron.
    Type: Grant
    Filed: December 29, 1986
    Date of Patent: June 7, 1988
    Assignee: Sprague Electric Company
    Inventors: Sidney D. Ross, Galeb H. Maher, Clinton E. Hutchins
  • Patent number: 4745083
    Abstract: An integrated circuit including CMOS transistors and an EPROM device by a method including selectively implanting threshold adjusting atoms of P-type in the channel regions of the N-type transistors while exposing the whole device area of the P-channel transistor. Subsequently, the sources and drains of the N-channel transistors are selectively implanted using the gates as a self-aligning mask portion. The PN-junction capacitance of the sources and drains of the N-channel transistors are thereby kept low and not subject to the degrading effects of the threshold adjusting implant. The P-channel is also affected and source drain capacitances there are reduced so that the speed of all three types of transistors are enhanced. Only high-yield process steps are included.
    Type: Grant
    Filed: November 19, 1986
    Date of Patent: May 17, 1988
    Assignee: Sprague Electric Company
    Inventor: Wing K. Huie
  • Patent number: 4724219
    Abstract: A method for making semiconductor devices includes selectively simultaneously and momentarily irradiating a semiconductor substrate surface by a pulsed laser through a mask positioned between and spaced away from laser and substrate to briefly melt sub-regions of that surface. An optical beam reducer system is interposed between the relatively large separate mask and the substrate. An optical expander system is interposed between the laser and the mask to further increase the possible mask size and further reduce the radiation density at the mask. Wet photolithographic processing may be eliminated for selective diffusions of dopants, for selective epitaxy, for selectively converting polysilicon layers over silicon substrates to monocrystalline silicon layers and for selectively etching the substrate by a plasma induced by the patterned laser energy. Semiconductor device manufacture may thereby be greatly simplified.
    Type: Grant
    Filed: July 16, 1986
    Date of Patent: February 9, 1988
    Assignee: Sprague Electric Company
    Inventor: Michael R. Ridinger
  • Patent number: 4716058
    Abstract: The dielectric layer or layers in a ceramic capacitor having at least one buried electrode is deposited by a curtain coating process that includes obtaining a measure of the ceramic-paint-curtain thickness. A source of electromagnetic radiation, e.g. in the infrared range, is directed equally near the left and right edges of the curtain, and detectors at the opposite curtain surface side pick up the difference in the radiation transmissivity which is a measure of curtain thickness assymetry left to right. By adjusting the paint reservoir from which the curtain issues to make the difference zero and the curtain symmetrical, uniformity in paint coating thickness is achieved.
    Type: Grant
    Filed: August 25, 1986
    Date of Patent: December 29, 1987
    Assignee: Sprague Electric Company
    Inventor: Thomas M. Morin
  • Patent number: 4715936
    Abstract: An electrolyte capable of anodizing aluminum consists essentially of a solution of an amino acid having a pH of 5.5 to 8.5. The amino acid is preferably a 2-amino acid, more preferably a dicarboxylic acid, and specifically aspartic or glutamic acid. The electrolyte may be used to anodize aluminum foil to form a barrier layer oxide or as a fill electrolyte in aluminum electrolytic capacitors.
    Type: Grant
    Filed: April 2, 1984
    Date of Patent: December 29, 1987
    Assignee: Sprague Electric Company
    Inventor: Steven M. Florio
  • Patent number: 4709214
    Abstract: An integrated circuit includes an epitaxial layer. In a near central region thereof is formed a symmetrical array of four equal sized Hall cells that are connected in parallel to form one Hall element. A moat surrounds the Hall element consisting of two concentric isolation walls separated by a band of opposite conductivity epitaxial material. The output of the Hall element is connected to the input of an adjacent differential amplifier that has two extraordinarily large amplifying transistors with emitter areas each equal to about a half of a Hall area, for achieving much better control over the relative dimensions of these emitters and thus over the amplifier offset voltage from chip to chip. The emitter resistors are likewise made very wide and both pairs of components are physically arranged to have balanced thermal coupling to the Hall element for further enhancing control of offset voltage.
    Type: Grant
    Filed: April 28, 2986
    Date of Patent: November 24, 1987
    Assignee: Sprague Electric Company
    Inventor: Jacob K. Higgs
  • Patent number: 4706375
    Abstract: The dielectric stability of a hermetically-sealed solid-electrolyte tantalum capacitor during high temperature storage is improved by the introduction of a small controlled amount of water into the capacitor container before the final sealing step in the manufacture of the capacitor.
    Type: Grant
    Filed: August 15, 1986
    Date of Patent: November 17, 1987
    Assignee: Sprague Electric Company
    Inventors: Walter J. Bernard, E. James Fresia
  • Patent number: 4706102
    Abstract: A memory device, based upon a field effect transistor having a floating gate is constructed for use in a silicon integrated circuit array of similar memory devices. The memory device includes only two polysilicon layers, a portion of each polysilicon layer being connected to each other through a via hole in an intervening silicon dioxide layer to form the floating gate.
    Type: Grant
    Filed: November 7, 1985
    Date of Patent: November 10, 1987
    Assignee: Sprague Electric Company
    Inventors: David S. Pan, Kanak C. Sarma, Mark A. Halfacre, Alexander H. Owens, Brian K. Rosier
  • Patent number: 4705964
    Abstract: A silicon integrated circuit has a Hall-element, a differential amplifier and a Schmitt trigger circuit connected in tandem to form a Hall switch. It is demonstrated that only one set of component parameters, e.g. resistor values, exists that provides an optimally smooth temperature coefficient (TC) of Hall-switch operate-point. It is further shown that by adding an adjustable resistor from the Schmitt trigger circuit ground, which resistor has the same resistivity and TC as does the Hall element, adjustment of the operate-point to another particular operate-point is accomplished without substantially altering the above-noted optimum TC. Operate-point adjustment, e.g. by blowing fuse links, during manufacturing, at probe, can be effected to yield a narrow distribution of operate-points conforming to a customer specification.
    Type: Grant
    Filed: September 29, 1986
    Date of Patent: November 10, 1987
    Assignee: Sprague Electric Company
    Inventor: Jacob K. Higgs
  • Patent number: 4706163
    Abstract: A ceramic capacitor has a lead lanthanum titanate zirconate dielectric body including less than 1 weight % of an intergranular phase of a borate flux. Cadmium and/or zinc borate fluxes are found to be superior providing both efficient sintering and efficient gettering of the free lead that escapes the PLZT crystals during sintering so that a post anneal step to drive out the residual semiconducting lead oxide after sintering is no longer required to obtain high breakdown voltages and good accelerated life test results.
    Type: Grant
    Filed: February 25, 1987
    Date of Patent: November 10, 1987
    Assignee: Sprague Electric Company
    Inventor: Galeb H. Maher
  • Patent number: 4694430
    Abstract: A supply voltage switch circuit for use with programable arrays such as EPROMS includes a pair of P-channel transistor switches connected in series between a high programing supply voltage and a low read supply voltage wherein the circuit junction between the transistors is connected to a row/column-select supply line. A switch control circuit is connected to the switches to alternately connect the row/column-select supply line to one or the other of the supply voltages in response to a logic signal. A third P-channel transistor may be connected in the series circuit, under control of the logic signal, to prevent destructive transient currents from flowing when powering up the high supply voltage source, at which occasions both of the two principal switches tend to momentarily turn on.
    Type: Grant
    Filed: March 21, 1985
    Date of Patent: September 15, 1987
    Assignee: Sprague Electric Company
    Inventor: Brian K. Rosier
  • Patent number: 4692224
    Abstract: A dielectric film is formed on tantalum pellets by anodization up to 350 V in an electrolyte of an aqueous solution of an organic carboxylic acid with an ionization constant between 10.sup.-2 and 10.sup.-5. The tantalum pellets are suspended from aluminum-magnesium alloy bars into the electrolytic solution with the bar itself being suspended in the electrolyte. The organic carboxylic acid solute residue from anodization is readily volatile at 200.degree. C. The acid is sometimes combined in the electrolyte with ammonia or an amine having a boiling point less than 200.degree. C.; the electrolyte residues from anodization in these systems are also volatile at 200.degree. C. After anodization, tantalum pellet and aluminum-magnesium bar cleanup is thus accomplished by a brief heat treatment at 200.degree. C., eliminating the need for an extended rinse procedure.
    Type: Grant
    Filed: August 11, 1986
    Date of Patent: September 8, 1987
    Assignee: Sprague Electric Company
    Inventors: Walter J. Bernard, Steven M. Florio
  • Patent number: 4691262
    Abstract: An integrated circuit includes an NPN power transistor and a short-circuit-protection circuit which includes a voltage divider connected directly across the base and emitter of the power transistor. The voltage divider is a series circuit branch having two resistors and a diode connected in the polarity to turn on when the power transistor is on. A smaller NPN transistor has a base-emitter junction connected across a portion of the voltage divider, which portion includes only one of the resistors and the diode. The collector is connected to sink a bias current away from the power transistor when abnormally high currents flow in the power transistor to limit that current to a safe value.
    Type: Grant
    Filed: April 3, 1985
    Date of Patent: September 1, 1987
    Assignee: Sprague Electric Company
    Inventor: Edward Chalfin
  • Patent number: 4688322
    Abstract: A solid-electrolyte chip capacitor of improved volume efficiency and placement capability is attained by molding a solid-electrolyte capacitor section so that the cathode end of the capacitor section is not covered by the molding material, and the anode end of the molding is provided with a recess within which the riser from the anode of the capacitor section is accessible.
    Type: Grant
    Filed: February 6, 1986
    Date of Patent: August 25, 1987
    Assignee: Sprague Electric Company
    Inventor: Mary A. Fossey
  • Patent number: 4654075
    Abstract: Water soluble precursors of ceramic compounds are emulsified in an organic fluid that is subsequently heated to remove the free water from the emulsion droplets and further heated in a partial oxygen atmosphere to form a char. The carbon in the char maintains the separation between the dried droplet-derived particles. This char may then be heated in air to oxidize and remove the carbon, to calcine the ceramic, and to controllably produce a fine powder of spherical particles having a narrow size distribution.
    Type: Grant
    Filed: June 17, 1985
    Date of Patent: March 31, 1987
    Assignee: Sprague Electric Company
    Inventor: Ned E. Cipollini
  • Patent number: 4646124
    Abstract: An integrated circuit has small signal MOS logic transistors formed in an N-type basket which basket itself is formed in an N-type epitaxial pocket that is defined by an enclosing P-type isolation wall. In a second epitaxial pocket a relatively high-current carrying bipolar transistor is formed. The MOS containing N-type basket is tied to one DC voltage which the substrate and isolation walls are connected to a lower level DC voltage. Substrate currents that are caused by the high current in the bipolar transistor are prevented by the N-type basket from inducing voltage changes in the MOS transistors.
    Type: Grant
    Filed: July 30, 1984
    Date of Patent: February 24, 1987
    Assignee: Sprague Electric Company
    Inventor: Michael J. Zunino
  • Patent number: 4633366
    Abstract: A laminar electrical component has at least one ceramic dielectric layer of from 85 to 100 mole percent magnesium orthoborate (Mg.sub.3 B.sub.2 O.sub.6) which has a low dielectric constant and a high Q. A monolithic ceramic capacitor may have a predominantly magnesium orthoborate body with lithium oxide as a flux so that sintering may be as low as 850.degree. C. and in a reducing atmosphere accommodating buried copper electrodes. A predominantly Mg.sub.3 B.sub.2 O.sub.6 multi-level printed wiring substrate of low dielectric constant can include tightly adhered layers of a high dielectric constant ceramic for making buried high capacity filter capacitors, and can also include cofired base metal conductors.
    Type: Grant
    Filed: August 7, 1985
    Date of Patent: December 30, 1986
    Assignee: Sprague Electric Company
    Inventor: Galeb H. Maher
  • Patent number: 4626801
    Abstract: An integrated circuit relaxation oscillator having all NPN transistors includes three interconnected differential transistor pairs with an externally connected parallel R-C timing circuit. Each of the transistor pairs has a separate current source that compensates for temperature changes in the components of the corresponding transistor-pair circuits.
    Type: Grant
    Filed: October 25, 1985
    Date of Patent: December 2, 1986
    Assignee: Sprague Electric Company
    Inventor: Thomas L. Field