Patents by Inventor Andrew G. Varadi

Andrew G. Varadi has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5930719
    Abstract: A cordless system comprises a laptop computer with a modem connected to a modem data port on a cordless telephone handset. A direct sequence spread spectrum RF link is established between the cordless telephone handset and a base station. Both the telephone network and a desktop computer with a modem are connected to the base station. When the cordless telephone handset detects that the laptop computer wants to go off-hook, a selection signal is also sent by the cordless telephone handset to the base station to indicate whether the call is to be directed to the telephone network or the desktop computer. When the base station detects that the desktop computer wants to go off-hook, a selection signal is also sent by the desktop computer to the base station to indicate whether the call is to be directed to the telephone network or over the RF link to the laptop computer.
    Type: Grant
    Filed: September 19, 1996
    Date of Patent: July 27, 1999
    Assignee: Wireless Logic, Inc.
    Inventors: Daniel Babitch, Andrew G. Varadi, James Wong
  • Patent number: 4413401
    Abstract: This disclosure is directed to an improved semiconductor capacitor structure especially useful in an integrated semiconductor structure with an MOS device and fabrication methods therefor. This semiconductor capacitor is particularly useful for forming the capacitor portion of a single MOS memory cell structure in a dynamic MOS random access memory which utilizes one MOS device in combination with a capacitor. In one specific disclosure embodiment, the semiconductor capacitor comprises a boron (P) implanted region in a substrate of P- type conductivity followed by a shallow arsenic (N) implant into the boron implanted region. The boron implanted region provides a P type conductivity which has a higher concentration of P type impurities than the concentration of impurities contained in the substrate which is of P- type conductivity.
    Type: Grant
    Filed: July 6, 1981
    Date of Patent: November 8, 1983
    Assignee: National Semiconductor Corporation
    Inventors: Thomas Klein, Andrew G. Varadi, Charles E. Boettcher
  • Patent number: 4379259
    Abstract: A process performed by the manufacturer for testing integrated circuits (ICs) to insure better quality and higher reliability thereof and to eliminate the need for incoming inspection and board level testing by the chip customer. In the embodiment disclosed, in-process testing, wafer-probe testing, die separation, packaging, and one by one assembly line testing of the digital memory ICs for catastrophic failures all proceed according to conventional techniques. A large number of the ICs are then plugged into high-temperature, high signal integrity PC storage cards, each adapted for interconnecting the ICs in row-column arrays to form a memory board. The storage cards are mounted within an environmental chamber and are operatively coupled to corresponding PC driver cards mounted externally of the chamber. Next, accelerated dynamic burn-in of the ICs takes place.
    Type: Grant
    Filed: March 12, 1980
    Date of Patent: April 5, 1983
    Assignee: National Semiconductor Corporation
    Inventors: Andrew G. Varadi, Walid H. Maghribi
  • Patent number: 4290186
    Abstract: This disclosure is directed to an improved semiconductor capacitor structure especially useful in an integrated semiconductor structure with an MOS device and fabrication methods therefor. This semiconductor capacitor is particularly useful for forming the capacitor portion of a single MOS memory cell structure in a dynamic MOS random access memory which utilizes one MOS device in combination with a capacitor. In one specific disclosure embodiment, the semiconductor capacitor comprises a boron (P) implanted region in a substrate of P- type conductivity followed by a shallow arsenic (N) implant into the boron implanted region. The boron implanted region provides a P type conductivity which has a higher concentration of P type impurities than the concentration of impurities contained in the substrate which is of P- type conductivity.
    Type: Grant
    Filed: July 23, 1979
    Date of Patent: September 22, 1981
    Assignee: National Semiconductor Corp.
    Inventors: Thomas Klein, Andrew G. Varadi, Charles E. Boettcher
  • Patent number: 4120047
    Abstract: This disclosure relates to an MOS or FET memory array that uses a single voltage source (i.e., 5 volts) and operates basically as a static memory array rather than as a dynamic memory array that requires the gates of the MOS devices of the memory array to be periodically refreshed to restore or refresh the memory states contained therein. Each of the memory cells of the memory array contains four MOS devices that are cross-coupled into a flip-flop type of memory cell. All of the memory cells connected to a common word line are also connected to a common return line to which is connected a single resistor and a single large MOS or FET device. The large MOS device is turned on during the active operation of the memory array (during write and read operations) and is turned off during the standby operation of the memory array.
    Type: Grant
    Filed: April 20, 1977
    Date of Patent: October 10, 1978
    Assignee: National Semiconductor Corporation
    Inventor: Andrew G. Varadi
  • Patent number: 4115871
    Abstract: This disclosure relates to an MOS random access memory array which utilizes a very small memory cell having a single MOS device and a small size, high capacitance, semiconductor capacitor device connected together to form one bit or memory cell of an MOS dynamic, random access memory array. Preferably, either the source or drain region of the MOS device is connected to the semiconductor portion of the semiconductor capacitor device which is of the electrode-insulator-semiconductor type. The semiconductor capacitor has a very high capacitance due to the use of a very shallow arsenic (N type) implanted region within a boron (P type) implanted region so that the PN junction formed is located where the concentration of Boron impurities is high thereby increasing the capacitance of the semiconductor capacitor. For each memory cell of the memory array, one of the active regions of the MOS device, for example, the source region, is connected to a Bit/Sense line of the memory array.
    Type: Grant
    Filed: April 19, 1977
    Date of Patent: September 19, 1978
    Assignee: National Semiconductor Corporation
    Inventor: Andrew G. Varadi
  • Patent number: 4069474
    Abstract: In a memory circuit, first and second bit line portions, each having a plurality of memory cells coupled thereto are provided for reading and writing electrical potentials into and out of the coupled memory cells. A bistable flip-flop type sensing amplifier is coupled between the first and second bit portion for sensing the voltage difference therebetween and for latching into one of the two states in response to sensing either a "0" or a "1" accessed to one of the bit line portions from an addressed memory cell to be read out of the memory. A high input impedance amplifier is provided between the respective bit line portion and the respective input terminal of the sensing amplifier for isolating (buffering) the stray capacitance of the sensing amplifier circuit from the capacitance of its bit line. Switchable restore circuitry bypasses each of the isolating line amplifiers for the purposes of restoring electrical potentials read out of the addressed memory cells.
    Type: Grant
    Filed: April 15, 1976
    Date of Patent: January 17, 1978
    Assignee: National Semiconductor Corporation
    Inventors: Charles E. Boettcher, Joel A. Karp, John A. Reed, Andrew G. Varadi