Patents by Inventor John M. Callahan

John M. Callahan 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: 6657880
    Abstract: To alleviate the crosstalk between BL and BLN of the same column, the present invention provides vertical twisting for the bit line and the complementary bit line of a line pair connecting a column of memory bits to a sense amplifier. The BL and BLN run in the same direction, but never within same metal layer and never overlying each other. To provide vertical twisting, horizontal and vertical switching are done in the same crossover channels so that BL and BLN have the same length in order to keep the overall capacitance of each line the same. Triple standard twist regions can be used for both the horizontal and vertical twists. The capacitance between BL and BLN are substantially reduced as well as the capacitance to neighboring column BLs and BLNs. Capacitive coupling between a BL and a BLN of the same column is reduced to thereby prevent reduction of the voltage difference, or delta voltage, presented to the differential input terminals of a senseamp.
    Type: Grant
    Filed: December 4, 2002
    Date of Patent: December 2, 2003
    Assignee: Virtual Silicon Technology, Inc.
    Inventor: John M. Callahan
  • Patent number: 6593646
    Abstract: A double-sized chip assembly and method is provided for two back-to-back integrated-circuit chips which both have the same fabrication mask sets. An electrically-selectable bonding-pad connection option alternatively provides a standard, non-reversed, option NRO for a bonding-pad layout and a non-standard, reversed option RO for the layout of the bonding-pads. The double-sized, back-to-back, wire-bonded integrated-circuit chip assembly and method includes a pair of integrated-circuit chips, each having one or more reversible wire-bonding-pads. One of the chips has its wire-bonding-pads electrically reversed such that the wire-bonding pads on both chips are located near each other to accommodate wire-bonding to a common bonding finger of a lead frame. A bonding-option wire-bonding-pad has an external voltage applied to it to indicate whether the integrated-circuit chip is to provide a standard pattern for the reversible wire-bonding-pads, or a reversed pattern for the reversible wire-bonding-pads.
    Type: Grant
    Filed: January 25, 2002
    Date of Patent: July 15, 2003
    Assignee: Nanoamp Solutions, Inc.
    Inventor: John M. Callahan
  • Patent number: 6559678
    Abstract: A node predisposition circuit for driving an output node of an output buffer circuit is provided which is formed of a delay circuit, a pre-charge pull-up circuit, and a pre-charge pull-down circuit. The pre-charge pull-up and pull-down circuits are used for pre-charging the output node to approximately one-half of the power supply voltage with a single phase system. The predisposition circuit has significantly reduced supply bounce and ground bounce, but yet maintains a high speed of operation with minimal static current.
    Type: Grant
    Filed: December 24, 2001
    Date of Patent: May 6, 2003
    Assignee: Nanoamp Solutions, Inc.
    Inventor: John M. Callahan
  • Patent number: 6493414
    Abstract: An on-chip parallel/load, serial-shift shift register stores information bits for one or more chip parameters. The bits are represented by fuses that are connected to respective input terminals of the shift register. When the chip is not in test mode (TM), the fuses are electrically connected to respective cells of the shift register, and the output of the shift register is electrically isolated from an output buffer. When the chip is put into test mode, the electrical connections between the fuses and the shift register bits are broken, leaving the fuse information isolated in the shift register. The test mode also connects the output of the shift register to the output buffer and the output of the first shift register bit is seen on the output pin. The rest of the shift register information bits are serially shifted out of the shift register by toggling the CEB pin.
    Type: Grant
    Filed: August 2, 2001
    Date of Patent: December 10, 2002
    Assignee: Nanoamp Solutions, INC
    Inventor: John M. Callahan
  • Publication number: 20020175406
    Abstract: A double-sized chip assembly and method is provided for two back-to-back integrated-circuit chips which both have the same fabrication mask sets. An electrically-selectable bonding-pad connection option alternatively provides a standard, non-reversed, option NRO for a bonding-pad layout and a non-standard, reversed option RO for the layout of the bonding-pads. The double-sized, back-to-back, wire-bonded integrated-circuit chip assembly and method includes a pair of integrated-circuit chips, each having one or more reversible wire-bonding-pads. One of the chips has its wire-bonding-pads electrically reversed such that the wire-bonding pads on both chips are located near each other to accommodate wire-bonding to a common bonding finger of a lead frame. A bonding-option wire-bonding-pad has an external voltage applied to it to indicate whether the integrated-circuit chip is to provide a standard pattern for the reversible wire-bonding-pads, or a reversed pattern for the reversible wire-bonding-pads.
    Type: Application
    Filed: December 11, 2001
    Publication date: November 28, 2002
    Inventor: John M. Callahan
  • Publication number: 20020157038
    Abstract: A fuse-controlled, row-redundancy control system and method for a SRAM includes a multi-bit, defective-row storage array of static circuits that are programmed to store one of the address bits of a predetermined defective row of the SRAM and that includes a single fuse. The single fuse is blown to indicate a first state of the one of the address bits and is not blown to indicate a second state of the one address bit. The address bits of the predetermined defective row of the SRAM are compared with corresponding address bits of row-address signals received by the SRAM. The comparator includes a fuseless, exclusive logic circuit and provides a RFLAG control signal that indicates that the stored address bits of the defective row of the SRAM match the respective received row address bits for the SRAM.
    Type: Application
    Filed: March 5, 2001
    Publication date: October 24, 2002
    Inventor: John M. Callahan
  • Publication number: 20020140091
    Abstract: A double-sized chip assembly and method is provided for two back-to-back integrated-circuit chips which both have the same fabrication mask sets. An electrically-selectable bonding-pad connection option alternatively provides a standard, non-reversed, option NRO for a bonding-pad layout and a non-standard, reversed option RO for the layout of the bonding-pads. The double-sized, back-to-back, wire-bonded integrated-circuit chip assembly and method includes a pair of integrated-circuit chips, each having one or more reversible wire-bonding-pads. One of the chips has its wire-bonding-pads electrically reversed such that the wire-bonding pads on both chips are located near each other to accommodate wire-bonding to a common bonding finger of a lead frame. A bonding-option wire-bonding-pad has an external voltage applied to it to indicate whether the integrated-circuit chip is to provide a standard pattern for the reversible wire-bonding-pads, or a reversed pattern for the reversible wire-bonding-pads.
    Type: Application
    Filed: January 25, 2002
    Publication date: October 3, 2002
    Inventor: John M. Callahan
  • Patent number: 6355980
    Abstract: A double-sized chip assembly and method is provided for two back-to-back integrated-circuit chips which both have the same fabrication mask sets. An electrically-selectable bonding-pad connection option alternatively provides a standard, non-reversed, option NRO for a bonding-pad layout and a non-standard, reversed option RO for the layout of the bonding-pads. The double-sized, back-to-back, wire-bonded integrated-circuit chip assembly and method includes a pair of integrated-circuit chips, each having one or more reversible wire-bonding-pads. One of the chips has its wire-bonding-pads electrically reversed such that the wire-bonding pads on both chips are located near each other to accommodate wire-bonding to a common bonding finger of a lead frame. A bonding-option wire-bonding-pad has an external voltage applied to it to indicate whether the integrated-circuit chip is to provide a standard pattern for the reversible wire-bonding-pads, or a reversed pattern for the reversible wire-bonding-pads.
    Type: Grant
    Filed: July 15, 1999
    Date of Patent: March 12, 2002
    Assignee: Nanoamp Solutions Inc.
    Inventor: John M. Callahan
  • Patent number: 6240029
    Abstract: An incoming memory address signal is compared and matched with static signals provided by a fuse array that represents an address of a defective memory column that is being replaced by a redundant memory column in a memory chip. Each section of a memory is provided with a redundant memory column. Each redundant column of the memory is connected to a separate redundant-column sense amp that is activated by a memory section-select signal in combination with a BIGHIT signal. The BIGHIT signal indicates that the memory chip has received an address of a defective memory column. All of the output terminals of the redundant column senseamps are connected in common to a redundant internal data bus RDINTDB. A defective-column-address detector circuit compares an incoming multi-bit memory address signal to an address of a defective memory column and provides an address-hit signal ADDHIT if a match occurs therebetween.
    Type: Grant
    Filed: April 11, 2000
    Date of Patent: May 29, 2001
    Assignee: Nanoamp Solutions, Inc.
    Inventor: John M. Callahan
  • Patent number: 6181172
    Abstract: A voltage detector circuit discriminates between a 13 volt Programming signal and a 6 volt signal without creating a field across the gate oxide of a sensing transistor in excess of 7.0 MegaV/cm. A PMOS transistor has a source terminal and a substrate terminal connected, both connected to the input terminal, A gate terminal is connected to a VCC voltage level. A shunt NMOS transistor has a drain terminal connected to the drain terminal of the PMOS transistor and a source terminal connected to a ground terminal. A gate terminal of the shunt NMOS transistor is connected to the VCC voltage level. The NMOS transistor is turned on to provide a shunt resistance between the drain terminal of the PMOS transistor and ground. A drain terminal of a series NMOS transistor is connected to the drain terminal of the PMOS transistor. A gate terminal of the series NMOS transistor is connected to VCC. The source terminal of the series NMOS transistor is connected to a sensing output terminal.
    Type: Grant
    Filed: December 27, 1995
    Date of Patent: January 30, 2001
    Assignee: Philips Electronics North America Corp.
    Inventor: John M. Callahan
  • Patent number: 6167543
    Abstract: A memory-test-mode detection circuit for an integrated circuit uses one or more of the input pins of an integrated circuit to detect at least one non-standard signal level. To avoid false triggering several other non-standard logic levels can also be used with some of the other input pins. Each of the non-standard signal levels are detected by a separate signal level detection circuit. A predetermined combination of input signals then provides a control signal which sets the integrated-circuit into a predetermined test mode. A non-standard Vcc/2 signal level is detected by determining that it is above a predetermined low threshold level of 1/4 Vcc and below a predetermined high threshold level of 3/4 Vcc. Additional non-standard input signal levels which are close to Vcc and Vss are also used. A chip enable (CEX) signal is used to enable the signal level detection circuit when a chip is enabled.
    Type: Grant
    Filed: April 21, 1998
    Date of Patent: December 26, 2000
    Assignee: NanoAmp Solutions, Inc.
    Inventor: John M. Callahan
  • Patent number: 5942924
    Abstract: This invention relates to a digital circuit for controlling the power usage of an electronic device such as a read only memory (ROM) for a computer device, particularly a portable computer device that relies on a battery power source. The circuit includes the latch, a positive edge detecting circuit, a negative edge detecting circuit, a guaranteed reset circuit, and a delay circuit. Control signals from the device open and close the latch when either a rising or falling edge of these control signals is detected by the edge detecting circuits. The latch itself includes a three input NAND gate and a two input NAND gate. The guaranteed reset circuit ensures that the circuit is initiated. The delay circuit includes a series of inverters and loads. The edge detecting circuits generate a pulse when a rising or falling edge is detected, and include a pulse generating portion, a NAND gate and inverters.
    Type: Grant
    Filed: July 1, 1997
    Date of Patent: August 24, 1999
    Assignee: Enable Semiconductor, Inc.
    Inventor: John M. Callahan
  • Patent number: 5930180
    Abstract: A read only memory including: a plurality of memory cells arranged in x rows and y columns in an array; x wordlines each connected to y memory cells in a respective row; y bitlines each associated with x memory cells in a respective column; m reference bitlines each corresponding to n bitlines, each of the reference bitlines having x reference cells each connected to a respective wordline; and m sense amplifiers each having a first input terminal connected to a respective n bitlines and having a second input terminal connected to one of the reference bitlines, and each being responsive to a difference between a signal on one of the n bitlines and a signal on one of the reference bitlines.
    Type: Grant
    Filed: July 1, 1997
    Date of Patent: July 27, 1999
    Assignee: Enable Semiconductor, Inc.
    Inventor: John M. Callahan
  • Patent number: 5923598
    Abstract: A row identification circuit identifies which redundant-row fuse has been blown in a memory integrated-circuit by electrically interrogating the integrated-circuit using a switching circuit internal to the memory integrated-circuit. N data output terminals of the memory integrated circuit provide an n-bit binary-coded word which identifies a defective row. To bring out the binary fuse data, the chip is put into a test mode with a TESTF signal which shuts off a normal CMOS transmission gate as well as a latch feedback transmission gate and which turns on another CMOS transmission gate to pass a defective row address bit FUSEB to a data output terminal for the memory device. A switching circuit selectively switches either a defective row address bit TESTB or a data input signal DIN to a data output terminal of the memory integrated circuit. The switching circuit is selectively controlled by a test mode control signal TESTF.
    Type: Grant
    Filed: April 21, 1998
    Date of Patent: July 13, 1999
    Assignee: Enable Semiconductor, Inc.
    Inventor: John M. Callahan
  • Patent number: 5912861
    Abstract: A control circuit initiates operation of the ROM array and the RAM array in an ATD circuit includes an EXCLUSIVE NOR circuit having: a RAM SELECT input terminal for receiving a RAM SELECT (RAMCS*) signal, a ROM SELECT input terminal for receiving a ROM SELECT (ROMCS*) signal, and having a chip enable output terminal at which is provided a chip enable signal (CE) at an active LOW state whenever the RAMCS* and the ROMCS* are both the same logic level, both either HIGH or LOW. The control circuit further includes a compensating pulse circuit to compensate for operation of the EXCLUSIVE NOR circuit during a dead-time interval in which the EXCLUSIVE NOR circuit does not function when the RAMCS* and the RAMCS* both change during that dead-time interval. The compensating circuit includes a two pulse generators, each generating an output pulse having a pulse width which is greater than the dead-time interval of the EXCLUSIVE NOR circuit.
    Type: Grant
    Filed: November 6, 1997
    Date of Patent: June 15, 1999
    Assignee: Enable Semiconductor, Inc.
    Inventor: John M. Callahan
  • Patent number: 5898641
    Abstract: A resettable latch circuit provides a modified address transition detection (XATD) signal in response to receiving an address-change input pulse signal at a SET input terminal thereof. A RESET input terminal for the latch circuit receives a delayed reset signal from a resettable delay circuit which has its input terminal coupled to the output terminal of the resettable latch circuit to receive the XATD signal. The resettable delay circuit includes a reset control signal terminal to which is coupled an inverted address-change input pulse. One embodiment of the resettable delay circuit includes a series of inverters and MOSFET load resistors as well as shunt MOSFET transistors turned on by the address-change signal to shunt the output terminals of the inverters and reset the delay line. The SET input terminal of the latch circuit also receives a chip-select-change signal pulse which is similar to the address-change pulse.
    Type: Grant
    Filed: January 22, 1998
    Date of Patent: April 27, 1999
    Assignee: Enable Semiconductor, Inc.
    Inventor: John M. Callahan
  • Patent number: 5525921
    Abstract: A synchronizing means is provided for synchronizing an asynchronous interrupt signal to a synchronous clock signal for a computer system or the like. The synchronizing means includes a plurality of latch subsystems, where each of the latch subsystems has a sample input terminal for receiving a synchronous clock signal and a hold terminal for receiving a complementary synchronous clock signal. Set logic means are provided for generating a set output signal in response to certain predetermined output signals of the synchronizing means having a predetermined relationship therebetween, which occurs when an input interrupt signal has a duration greater than 1.5 periods of the synchronous clock signal. The set logic means includes AND gates and OR gates. Reset logic means are provided for generating a reset output signal. The reset logic means includes AND gates and OR gates.
    Type: Grant
    Filed: April 7, 1994
    Date of Patent: June 11, 1996
    Assignee: VLSI Technology, Inc.
    Inventor: John M. Callahan
  • Patent number: 5521875
    Abstract: A synchronous sense amplifier stage includes means for shunting the signal input terminal of the sense amplifier stage to ground during a precharge interval for discharging charge on a read bit line connected to the input terminal of the synchronous sense amplifier during the precharge interval. Means are also provided for precharging predetermined internal nodes and the output terminal of the synchronous sense amplifier stage to predetermined voltages during the precharge interval.
    Type: Grant
    Filed: December 30, 1994
    Date of Patent: May 28, 1996
    Assignee: VLSI Technology, Inc.
    Inventor: John M. Callahan
  • Patent number: 5495436
    Abstract: A "charge-kicker" programming circuit for programming anti-fuse links in integrated-circuit memory devices permits smaller feature sizes and a correspondingly lower breakdown voltage by using reduced internal voltage levels to generate a gate voltage for a series pass transistor. A series pass transistor gates a high voltage programming signal (typically 13 volts) to a high-voltage programming line. Selection circuits steer the high voltage programming signal to various columns of anti-fuse elements. A fixed voltage, insufficient to turn on the series pass transistor is applied to the gate terminal of the series pass transistor. An alternating voltage is applied directly onto the gate terminal of the series pass transistor through a capacitor so that the peaks of the alternating voltage turn on the series pass transistor which gates the programming voltage to the main high voltage programming line for the anti-fuse memory array.
    Type: Grant
    Filed: January 13, 1995
    Date of Patent: February 27, 1996
    Assignee: VLSI Technology, Inc.
    Inventor: John M. Callahan
  • Patent number: 5418486
    Abstract: A noise-suppression logic system suppresses a noise signal having a time duration which is less than a predetermined time. A delay circuit has a delay which is equal to the predetermined time. A logic combining circuit is coupled to the system input terminal and to the output terminal of the delay circuit. A R-S latch circuit, having a RESET input terminal, a SET input terminal, and an OUTPUT terminal provides a delayed output signal corresponding to an input signal which has a time duration greater than the predetermined time. A set circuit has a first input terminal coupled to the system input terminal, a second input terminal coupled to the output terminal of the delay circuit, and an output terminal coupled to the SET input terminal of the R-S flip-flop circuit.
    Type: Grant
    Filed: January 28, 1994
    Date of Patent: May 23, 1995
    Assignee: VLSI Technology, Inc.
    Inventor: John M. Callahan