Abstract: The circuit forms an edge-triggered D-Flip-Flop with a master/slave configuration. The master circuit has only one master switch controlled by a clock signal and followed by a first inverter. The slave circuit has a slave switch followed by a second inverter and a regenerative feedback-loop. The master and slave switches can easily be realized using n-MOS-transistors instead of transmission gates, thus achieving small chip area. The Flip-Flop can easily be amended by set and reset devices and it is suitable for mass applications such as memory and microprocessor chips.

Abstract: A method and a flip-flop is disclosed in which power consumption is reduced in a standby mode. In a first aspect, the flip-flop comprises a first latch adapted to be coupled to a first power supply and a second latch coupled to the first latch and adapted to be coupled to a second power supply. The first and second power supplies are independently controllable to minimize power consumption in a standby mode. In a second aspect, a method for minimizing the power consumption of a flip-flop is also disclosed. The flip-flop includes a first latch and a second latch coupled thereto. The method comprises providing a first independently controllable power supply coupled to the master latch; and providing a second independently controllable power supply coupled to the slave latch. The method further includes reducing the voltage of at least one of the first and second power supplies responsive to the detection of a power saving mode.

Abstract: A master latch implemented to receive feedback from a slave latch on a different input terminal than a input terminal on which data bits are received. Due to such receiving, the number of transistors/area and/or power consumption requirements (efficiently) may be minimized in implementing a flip-flop. The feedback path may be implemented using a single pass-gate, further enhancing the efficiency of implementation. In addition, clock enable/disable signals may be generated efficiently taking into account an externally received flip-flop disable signal and absence of transitions in the data input bits. When the flip-flop is implemented to support ATPG type sequential scanning testing, a multiplexor may be implemented efficiently to select either the data bits or scan bits.

Abstract: In an integrated circuit, a time-axis expanding circuit is provided in addition to a driver circuit for outputting a signal outside. The time-axis expanding circuit has an equivalent receiver circuit similar to an ordinary receiver circuit, and a D-type flip-flop circuit connected to the equivalent receiver circuit. Input signals from the pins of the time-axis expanding circuit are inputted to the gates of CMOS transistors of the equivalent receiver circuit, and equivalent differential receiving signals outputted from the drains of the CMOS transistors are inputted to the D input terminal of the D-type flip-flop circuit. A measuring clock signal is inputted to the clock input terminal of the D-type flip-flop circuit, and a time-axis-expanded signal is outputted from the Q output terminal of the D-type flip-flop circuit to an output terminal of the time-axis expanding circuit.

Abstract: A system for reducing current leakage in an integrated circuit. The system includes a first circuit component and a second circuit component in a path between a high voltage state and a low voltage state, such as ground. A feedback mechanism selectively provides feedback from an output of the second circuit component to an input of the first circuit component to selectively cutoff the path at the first circuit when the path is not cutoff at the second circuit. In a more specific embodiment, feedback mechanism preserves data in the integrated circuit via a multiplexer that selectively enables the feedback when the integrated circuit is in sleep mode. The first and second circuit components are High Voltage Threshold (HVT) CMOS inverters. The feedback path is chosen so that when the feedback path is activated, leakage paths through the CMOS inverters are cutoff.

Abstract: A dual edge-triggered flip-flop that may be programmably reset independent of a clock signal is provided. Using an externally generated reset value, the dual edge-triggered flip-flop may be asynchronously programmed to reset to either a logical high or a logical low. Further, a dual edge-triggered flip-flop that may be set to multiple triggering modes is provided. Using an externally generated enable signal, the dual edge-triggered flip-flop may be set to function as a single edge-triggered or a dual edge-triggered device. Thus, the dual edge-triggered flip-flop may be used multiple types of computing environments.

Abstract: In a master latch circuit, input data signal is received in a data through state and is held in a data holding state as output data signal. In a slave latch circuit, the output data signal is received in a data through state and is held and output in a data holding state. In a circuit setting control unit, in response to a clock signal, the disconnection of a first line from a power source and the connection of a second line to a ground terminal in an NMOS transistor are performed to set the master latch circuit and the slave latch circuit to the data through state and the data holding state respectively, and the connection of the first line and the disconnection of the second line are performed to change the states of the latch circuits.

Abstract: A low power, high performance flip-flop which does not require a full feedback path in the master stage includes a master stage driven by a data input, and an inverter. A slave stage includes a pass device for isolating the slave stage and the master stage, the slave stage having a feedback path for holding a data value passed to the slave stage.

Abstract: A hardened latch capable of providing protection against single event upsets (SEUs) is disclosed. The hardened latch includes a first latch and a second latch that mirrors a subset of gates of the first latch. The second latch is inserted in the feedback path of the keeper circuit of the first latch and is cross-coupled with the gates of the keeper circuit of the first latch. The latch is hardened against single event upsets and an arbitrary number of successive SEUs attacking a single node, provided that the time between successive SEUs is larger than the recovery time of the latch. An alternate embodiment of the hardened latch includes a split buffer output. This embodiment is capable of reducing the propagation of erroneous transients. Another alternate embodiment of the hardened latch includes a Miller C buffer output. This embodiment is capable of reducing the propagation of erroneous transients below the level achievable in a hardened latch employing a split buffer output.

Abstract: A differential latch includes a sample transistor section, a hold transistor section, a 1st gating circuit and a 2nd gating circuit. The sample transistor section is operably coupled to sample, when coupled to a supply voltage (e.g., VDD and VSS) a differential input signal. The hold transistor section is operably coupled to latch, when coupled to the supply voltage, the sampled differential input to produce a latched differential signal. The 1st gating circuit is operable to couple the sampled transistor section to the supply voltage in accordance with a 1st clocking logic operation and a 2nd clocking logic operation. The 2nd gating circuit is operable to couple the hold transistor section to the supply voltage in accordance with a 3rd clocking logic operation and a 4th clocking logic operation.

Abstract: In a master latch circuit, input data signal is received in a data through state and is held in a data holding state as output data signal. In a slave latch circuit, the output data signal is received in a data through state and is held and output in a data holding state. In a circuit setting control unit, in response to a clock signal, the disconnection of a first line from a power source and the connection of a second line to a ground terminal in an NMOS transistor are performed to set the master latch circuit and the slave latch circuit to the data through state and the data holding state respectively, and the connection of the first line and the disconnection of the second line are performed to change the states of the latch circuits.

Abstract: A differential D flip-flop is disclosed including respective master and slave cells. The master cell comprises a first data set circuit and a first data store circuit. The data set circuit has a first differential input and a first differential output. The first data store circuit couples to the output of the first data set circuit. The cell further includes a differential clock circuit and a differential reset circuit. The clock circuit having complementary clock inputs to alternately set and store data in the data set and data store circuits. The differential reset circuit ties to the differential output and is operative in response to a reset signal to force the differential output to a predetermined logic level. The differential reset circuit includes matched complementary reset drivers to exhibit like capacitances. The slave cell is formed substantially similar to the master cell, and includes a second differential input coupled to the first differential output of the master cell.

Abstract: A differential latch includes a sample transistor section, a hold transistor section, a 1st gating circuit and a 2nd gating circuit. The sample transistor section is operably coupled to sample, when coupled to a supply voltage (e.g., VDD and VSS) a differential input signal. The hold transistor section is operably coupled to latch, when coupled to the supply voltage, the sampled differential input to produce a latched differential signal. The 1st gating circuit is operable to couple the sampled transistor section to the supply voltage in accordance with a 1st clocking logic operation and a 2nd clocking logic operation. The 2nd gating circuit is operable to couple the hold transistor section to the supply voltage in accordance with a 3rd clocking logic operation and a 4th clocking logic operation.

Abstract: A flip-flop circuit (100) that may have a reduced delay time between an edge of a clock input signal and a data output signal has been disclosed. A data signal may be received at a data input terminal (1), a clock input signal may be received at a clock signal input terminal (2), and data may be provided at a data output terminal (3). Data may be transferred from a master latch to a slave latch through a transfer circuit in response to an edge of a clock input signal. A transfer circuit may include a transfer device (6) which may have a control terminal connected to a clock signal input terminal (2) and a transfer device (5) which may have a control terminal connected to a buffered clock signal (C). In this way, delay time may be reduced while maintaining high-speed operations even if an input clock signal has a rounded or distorted waveform.

Abstract: A data latch circuit of the present invention, which corresponds to the semiconductor circuit, is provided with a master flip-flop and a slave flip-flop. The master flip-flop fetches a first signal in response to a first clock signal, holds first data corresponding to the first signal as binary data in response to the first clock signal, and also outputs the first data as a second signal. The slave flip-flop fetches the second signal in response to an OR-gated result obtained between the first clock signal and either one or a plurality of second clock signals, and the slave flip-flop holds second data corresponding to the second signal in response to the OR-gated result, and also the slave flip-flop outputs a third signal corresponding to the second data.

Abstract: Various logic elements such as SR flip-flops, JK flip-flops, D-type flip-flops, master-slave flip-flops, parallel and serial shift registers, and the like are converted into non-volatile logic elements capable of retaining a current output logic state even though external power is removed or interrupted through the strategic addition of ferroelectric capacitors and supporting circuitry. In each case, the building blocks of a cross-coupled sense amplifier are identified within the logic element and the basic cell is modified and/or optimized for sensing performance.

Abstract: A master-slave latch circuit for a multithreaded processor stores information for multiple threads. The basic cell contains multiple master elements, each corresponding to a respective thread, selection logic coupled to the master elements for selecting a single one of the master outputs, and a single slave element coupled to the selector logic. Preferably, the circuit supports operation in a scan mode for testing purposes. In scan mode, one or more elements which normally function as master elements, function as slave elements. When operating in scan mode using this arrangement, the number of master elements in the pair of cells equals the number of slave elements, even though the number of master elements exceeds the number of slave elements during normal operation, permitting data to be successively scanned through all elements of the circuit.

Abstract: A flip-flop circuit comprising: a master latch circuit; a slave latch circuit coupled to the master latch circuit; and a correction circuit for increasing an amount of charge that can be absorbed by the master latch circuit in response to a soft-error event when the slave latch circuit is in a transparent phase and when both the master and slave latch circuits are storing the same data.

Abstract: An apparatus comprising a first circuit, a second circuit and a third circuit. The first circuit may be configured to receive a first input signal and a second input signal and present a first signal and a second signal. The second circuit may be configured to present a first output signal in response to the first input signal, the first signal and the second signal. The third circuit may be configured to present a second output signal in response to the second input signal, the first signal and the second signal.

Abstract: A dual rail flip flop with complementary outputs includes a master stage with embedded logic, a sensing stage, and one or more slave stages. The flip flop operates in a pre-charge state and an evaluate state. During the pre-charge state when a clock signal is low, the flip flop pre-charges internal keeper nodes to a high value. When the clock signal transitions high, the flip flop enters an evaluation state and one of the internal keeper nodes evaluates to a low value. The sense stage senses which of the internal keeper nodes is evaluating to zero, and drives it to zero faster. The slave stages reflect the state of the internal keeper nodes during the evaluate state, and maintain their states during the pre-charge state.

Abstract: It is intended to provide a dynamic flip flop that prevents a floating signal from maintaining a voltage below a substrate voltage level in a P-type semiconductor substrate and that prevents a floating signal from maintaining a voltage exceeding the substrate voltage level in an N-type semiconductor substrate. In the dynamic flip flop, an N-type MOSFET (5) controlled by an output signal MX from an inverter (2) and an N-type MOSFET (6) controlled by an output signal Q from an inverter (4) are provided as switches for short-circuiting a signal M and a signal QX to be brought into a floating state to a substrate.

Abstract: Flip-flops include a master stage and a slave stage. The master stage is responsive to a first clock signal and has a first pair of differential inputs and a first pair of differential outputs. The slave stage is responsive to a second clock signal and has a second pair of differential inputs coupled to the first pair of differential outputs and a second pair of differential outputs from which true and complementary outputs (Q, QB) of the flip-flop are derived. If the flip-flop is a D-type flip-flop, the first pair of differential inputs receive true and complementary data signals (DATA, DATAB). If the flip-flop is a set-reset (S-R) flip-flop, the first pair of differential inputs receive set and reset signals (SET, RESET).

Abstract: A method and apparatus for storing data in a master flip flop, comprising in combination receiving a clock signal having a first and second state, storing a master data state in a master storage device having a master storage input and a master storage output, storing a master complement data state in a master complement storage device having a master complement storage input and a master storage complement output, receiving a data input signal by a transmission gate, receiving a complement data input signal by a complement transmission gate, overriding the master storage complement output with the data input signal when the clock is in the first state, overriding the master storage output with the complement data input signal when the clock is in the first state, disconnecting the master storage complement output from the data input signal when the clock is in the second state, and disconnecting the master storage output from the complement data input signal when the clock is in the second state.

Abstract: A semiconductor integrated circuit includes a plurality of logical elements connected in series or parallel, the plurality of logical elements including a semiconductor substrate and an insulating layer provided on the semiconductor substrate; and a buffer circuit connected between a logical element group including at least two of the plurality of logical elements and another logical element group including at least two of the plurality of logical elements.

Abstract: A latch chain having improved input voltage sensitivity. The chain includes a first latch, an amplifier, and a second latch connected in series. The second latch is a conventional latch. The first latch is modified to have a higher sensitivity and lower output voltage swing than conventional latches. The modified latch includes a pair of matched output transistors that generate output voltages and a pair of matched biasing circuits to bias the bases of the output transistors with bias voltages. A sample stage is connected so as to apply first biasing currents to one of the biasing circuits in response to input voltages applied to the first latch during the sample period. In addition, a hold stage is connected so as to apply second biasing currents to the biasing circuits during a hold period. The sample and hold stages are configured to apply different voltage differences between the bases of the output transistors.

Abstract: A logical processing part is formed by a pass transistor logic element, and an output signal of the pass transistor logic element is applied to the gates of MOS transistors for differentially amplifying and latching the output signal in the latch stage. This latch stage is formed by master and slave latch circuits, and power supply to the master latch circuit is cut off while holding an information signal only in the slave latch circuit with the level of a power supply voltage thereto increased, reducing a leakage current in a sleep mode or a power down mode. A logic circuit correctly operating at a high speed with low current consumption under a low power supply voltage is provided.

Abstract: In a flip-flop circuit, a master latch has a data input circuit that reads data when a clock input signal is at a first level. When the clock input signal is at a second level, a first data holding circuit holds the data, and a signal switching circuit transfers the data to a slave latch. The slave latch reads the data from a data output circuit when the clock input signal is at the second level. When the clock input signal returns to the first level, a second data holding circuit holds the data read from the data output circuit.

Abstract: A latch circuit for temporarily storing an input signal and successively outputting the input signal is disclosed, that comprises an input transfer circuit for inputting a reference clock signal, a first inverter for inverting an output signal of the input transfer circuit, a second inverter for inverting an output signal of the first inverter, and a hold transfer circuit for inputting an output signal of the second inverter and outputting it to the first inverter, wherein a second clock signal is input to the gate of the hold transfer circuit, the signal level of the second clock signal becoming high with a predetermined delay against a leading edge of the reference clock signal and becoming low corresponding to a trailing edge of the reference clock signal.

Abstract: A flip-flop circuit comprises a master latch circuit (2), which receives an input signal (D), and, connected in series therewith, a slave latch circuit (3), the two latch circuits (2, 3) being actuated complementarily-to one another by a clock signal. The output signal value (Q,{overscore (Q)}) of the flip-flop circuit is emitted from the output of the slave latch circuit (3) not directly but via a non-differential output driver circuit (4), e.g. an inverter circuit.

Abstract: A latch includes a pair of inverters cross-coupled between a storage node and a feedback node. A capacitor is conditionally coupled to the feedback node through a pass gate such that the capacitor is coupled to the feedback node when the latch holds data and is not coupled to the feedback node when the latch is loading. The capacitor reduces the latch's susceptibility to soft errors when holding data, and does not appreciably slow the latch when data is loading. The capacitor is implemented using the gate capacitance of complementary transistors. A flip-flop includes cascaded latches, one or more of which have a switched capacitor on a feedback node.

Abstract: Flip-flops both operable at high speed and reliable at low voltage levels. A first flip-flop includes first and second cross-coupled latches. Whenever a high value is passed to one node of a latch in the flip-flop, a low value is passed to the other node of the latch. Therefore, the latches can safely ignore all high input values, which permits the flip-flops of the invention to function at very low voltages. Because writing a high value is normally slower than writing a low value, the flip-flops of the invention also function at very high clock rates, even at very low voltages. In some embodiments, pull-ups and pull-downs are coupled directly to the nodes of the latches, enabling the use of inverters instead of NAND and NOR gates to implement set and reset flip-flops, and thereby increasing the operating frequency of these flip-flops.

Abstract: A semiconductor integrated circuit device is provided with a selector that selects a normal operation signal or a circuit diagnosis input signal depending upon a first-mode input signal. A first latch and a second latch selectively execute one of (i) a scan mode for either holding or transmitting one of the normal operation signal and the circuit diagnosis input signal, selected by the selector depending upon a clock signal, and (ii) a long delay path function mode for transmitting a transmission signal irrespective of the clock signal, depending upon a second-mode input signal.

Abstract: A power efficient flip-flop includes a power switch regulating power supplied to a high speed latch in the flip-flop. When the power switch is activated, causing the high speed latch to receive power, the high speed latch captures data received by the flip-flop. The captured data is propagated by the high speed latch to the output of the flip-flop. Simultaneously, the high speed latch transmits the data to a low leakage latch connected to the high speed latch. Then, power is removed from the high speed latch, and the data retained in the low leakage static latch is now released to the output of the flip-flop. The power efficient flip-flop minimizes leakage current generated by the high speed latch by removing a path to ground when power is not provided to the high speed latch. A decoupling device is connected to the power switch to substantially eliminate a coupling effect.

Abstract: A low power, high performance flip-flop which does not require a full feedback path in the master stage includes a master stage driven by a data input, and an inverter. A slave stage includes a pass device for isolating the slave stage and the master stage, the slave stage having a feedback path for holding a data value passed to the slave stage.

Abstract: A dual rail flip flop with complementary outputs includes a master stage with embedded logic, a sensing stage, and one or more slave stages. The flip flop operates in a pre-charge state and an evaluate state. During the pre-charge state when a clock signal is low, the flip flop pre-charges internal keeper nodes to a high value. When the clock signal transitions high, the flip flop enters an evaluation state and one of the internal keeper nodes evaluates to a low value. The sense stage senses which of the internal keeper nodes is evaluating to zero, and drives it to zero faster. The slave stages reflect the state of the internal keeper nodes during the evaluate state, and maintain their states during the pre-charge state.

Abstract: A D-FF circuit comprises: a master flip-flop and a slave flip-flop which operate in accordance with a plurality of clock signals generated by a clock signal generating circuit; wherein the slave flip-flop comprises: a clocked inverter which is disposed on a first stage of the slave flip-flop and which operates in accordance with at least one of the plurality of clock signals generated by the clock signal generating circuit, and a two-stage inverter which is connected in series with an output terminal of the clocked inverter.

Abstract: A flipflop has master and slave interconnected through a buffer. The master has its inverters located outside the signal path from input to output, as the buffer provides the driving capability required for both IDDQ-testing and operational use. This configuration enables IDDQ-testing without further circuitry added to the flipflop and reduces propagation delay in the signal path.

Abstract: A data retention system has master-slave latches for holding data in an active mode; a data retention latch for preserving data read from the master latch in a sleep mode, which is connected to the master latch in parallel with the slave latch; a first multiplexer for receiving data externally provided and feedback data from the data retention latch, and selectively outputting either the data externally provided or the feedback data to the master latch in response to a first control signal; and a second multiplexer for transferring output data of the master latch to the slave latch and the data retention latch in response to a second control signal, wherein power for the data retention latch remains turned on in the sleep mode, while power for the data retention system except for the data retention latch is turned off.

Abstract: A differential cascode structure is configured to propagate a data state to a static latch at each active edge of a clock. A clock generator enables the communication of the data state and its inverse to the latch for a predetermined time interval. In a first embodiment, each cascode structure includes three gates in series, the gates being controlled by the clock signal, a delayed inversion of the clock signal, and the data state or its inverse. In an alternative embodiment, each cascode structure includes two gates in series, the gates being controlled by the clock signal and the delayed inversion of the clock signal. In this alternative embodiment, each of these cascode structures is driven directly by the data signal or its inverse. The static latch obviates the need to precharge nodes within the device, thereby minimizing the power consumed by the device. The latch preferably comprises cross-coupled inverters, which, being driven by the differential cascode structure, enhance the switching speed.

Abstract: In a flip-flop circuit, a master latch has a data input circuit that reads data when a clock input signal is at a first level. When the clock input signal is at a second level, a first data holding circuit holds the data, and a signal switching circuit transfers the data to a slave latch. The slave latch reads the data from a data output circuit when the clock input signal is at the second level. When the clock input signal returns to the first level, a second data holding circuit holds the data read from the data output circuit.

Abstract: A master-slave D type flip-flop circuit includes a power consumption masking circuit including a reference stage in parallel with a master and a slave stage of the flip-flop circuit. This structure advantageously provides a switching of the flip-flop circuit on each of the leading and trailing edges of the clock signal for the sequencing of the flip-flop circuit.

Abstract: A method and apparatus for storing data in a master flip flop, comprising in combination receiving a clock signal having a first and second state, storing a master data state in a master storage device having a master storage input and a master storage output, storing a master complement data state in a master complement storage device having a master complement storage input and a master storage complement output, receiving a data input signal by a transmission gate, receiving a complement data input signal by a complement transmission gate, overriding the master storage complement output with the data input signal when the clock is in the first state, overriding the master storage output with the complement data input signal when the clock is in the first state, disconnecting the master storage complement output from the data input signal when the clock is in the second state, and disconnecting the master storage output from the complement data input signal when the clock is in the second state.

Abstract: A latch and flip-flop are disclosed that have a reduced clock-to-q delay and/or a reduced setup time. This is preferably accomplished by providing both a data input signal and a complement data input signal to the latch or flip-flop. The data input signal and the complement data input signal are selectively connected to opposite sides of a pair of cross-coupled gates via a switch or the like. The switch is preferably controlled by an enable signal, such as a clock. With the switch elements enabled, the data input signal is passed directly to a data output terminal, and the complement data input signal is passed directly to a complement data output signal. Because the data input signal is passed directly to a data output terminal, and the complement data input signal is passed directly to a complement data output signal, the clock-to-q time may be reduced.

Abstract: Register and latch circuits are disclosed that can have faster operating speeds. According to one embodiment, a register circuit (100) may include a master latch circuit (102) and a slave latch circuit (104). The slave latch circuit (104) may include an n-channel transistor M13 between an input of the slave latch circuit (104) and the gate of a p-channel driver transistor M11. A p-channel transistor M14 can be provided between the input of the slave latch circuit (104) and the gate of an n-channel driver transistor M12. The driver transistors M11 and M12 can be driven by way of the source-drain paths of transistors M13 and M14, respectively.

Abstract: The high-speed, low setup time, voltage-sensing flip-flop of an embodiment of the present invention comprises a master stage and a slave stage. The master stage has a data input and a clock input. The slave stage receives two signal lines from the master stage. When the clock input is low, the two input lines to the slave stage are pulled high. This turns on two transistors and precharges the inputs to the slave stage. When the clock makes a high transition, the pullup transistors in the master stage are turned off which decouples the inputs of the slave stage from the output of the master stage. At this time, if the data input is high, the A input to the slave stage is discharged. If the data input is low, the B input to the slave stage is discharged. After the two inputs to the slave stage are decoupled from the master stage, any change in the data input signal causes the inputs to the slave stage to float low since the two lines are not pulled high or low.

Abstract: A latch having increased soft error rate tolerance includes cross-coupled inverters having transistors with varying sizes. Diffusion regions of transistors coupled to storage nodes are kept small to reduce the effect of charge accumulation resulting from particles bombarding the bulk of an integrated circuit die. Transistors having gates coupled to the storage nodes are increased in size to increase the capacitance on the storage nodes. The reduced size of diffusion regions and increased size of gates on storage nodes combine to reduce the effects of accumulated charge. Diffusion region area is further reduced by reducing the size of pass gates that load normal data and scan data. A large capacitor is coupled to a feedback node within the cross-coupled inverters to further reduce the effect of accumulated charge.

Abstract: An integrated circuit is provided with Fully Automated Scan Testing (FAST)-lite flip-flop. The integrated circuit has data, scan in, master-hold, clock, scan-into-master, and master to-scan-out inputs. A first transistor circuit is connected to the data, master-hold, and clock inputs and has a first transistor circuit output. A second transistor circuit is connected to the can in and scan-into-master inputs and has a second transistor circuit output. A first flip-flop is connected to the first transistor circuit and second transistor circuit outputs and has a first flip-flop output. A third transistor circuit is connected to the second transistor circuit output and the master-to-scan-out input and has a third transistor circuit output. A second flip-flop latch is connected to the third transistor circuit output has a second flip-flop output. The FAST-lite flip-flop uses the normal functionality of the first flip-flop and second flip-flop to operate either in a normal mode or a test mode for scan testing.

Abstract: The circuit forms an edge-triggered D-Flip-Flop with a master/slave configuration. The master circuit has only one master switch controlled by a clock signal and followed by a first inverter. The slave circuit has a slave switch followed by a second inverter and a regenerative feedback-loop. The master and slave switches can easily be realized using n-MOS-transistors instead of transmission gates, thus achieving small chip area. The Flip-Flop can easily be amended by set and reset devices and it is suitable for mass applications such as memory and microprocessor chips.

Abstract: In a flip-flop circuit, a master latch has a data input circuit that reads data when a clock input signal is at a first level. When the clock input signal is at a second level, a first data holding circuit holds the data, and a signal switching circuit transfers the data to a slave latch. The slave latch reads the data from a data output circuit when the clock input signal is at the second level. When the clock input signal returns to the first level, a second data holding circuit holds the data read from the data output circuit.

Abstract: A flip-flop circuit uses a multiple input conditional inverter activated by clock signals to transfer a sample of the input data to a keeper circuit. The keeper circuit signal is buffered to provide the flip-flop circuit output.