Abstract: Methodologies and an apparatus for measuring setup and hold times of fabricated semiconductor devices are provided. Embodiments include: providing a first digital frequency divider having an input and an output, the input of the first digital frequency divider receiving a first signal indicating an oscillating signal with a first delay; providing a second digital frequency divider having an input and output, the input of the second digital frequency divider receiving a second signal indicating the oscillating signal with a second delay; and providing a flip-flop having an input and an output, wherein the input of the flip-flop is coupled to the output of the second digital frequency divider and a data signal and clock signal for measuring a set-up time or hold time of a device under test are generated.

Abstract: Methodologies and an apparatus for measuring setup and hold times of fabricated semiconductor devices are provided. Embodiments include: providing a first digital frequency divider having an input and an output, the input of the first digital frequency divider receiving a first signal indicating an oscillating signal with a first delay; providing a second digital frequency divider having an input and output, the input of the second digital frequency divider receiving a second signal indicating the oscillating signal with a second delay; and providing a flip-flop having an input and an output, wherein the input of the flip-flop is coupled to the output of the second digital frequency divider and a data signal and clock signal for measuring a set-up time or hold time of a device under test are generated.

Abstract: Methods and structures for a double-sided semiconductor structure using through-silicon vias (TSVs) are disclosed. The double-sided structure has functional circuits on both the front and back sides, interconnected by one or more TSVs. In some embodiments, multiple double-sided structures are combined to create 3D semiconductor structures with increased circuit density.

Abstract: Method and apparatus for testing input/output circuits of an integrated circuit are described. An integrated circuit includes input/output circuits having input/output pads. The input/output pads are capable of being coupled together to a tester channel. The input/output circuits each are configurable via configuration circuitry to be in either a first mode or a second mode responsive to a select circuit of the configuration circuitry coupled to receive a first input for the first mode and a second input for the second mode. The select circuit is controlled responsive to a control select signal common to all or a portion of the select circuits of each of the input/output circuits.

Abstract: A programmable differential signaling system includes a programmable bias generator and a plurality of input/output modules. The programmable bias generator is operably coupled to generate a first global bias signal and a second global signal based on desired signal properties of one of a plurality of differential signaling conventions. The a plurality of input/output modules is operably coupled to convert between differential signaling and single ended signaling, wherein actual signal properties of the differential signaling are regulated based on the first and second global bias signals to substantially equal the desired signal properties.

Abstract: An Electrostatic Discharge (ESD) protection device extends the protection range of an ESD clamp circuit through hysteresis of the associated ESD clamp control circuit. Once the ESD clamp circuit is activated, an adjustment circuit applies a trigger level adjustment signal to the ESD clamp control circuit. The trigger level adjustment signal effectively increases the magnitude of the deactivation signal that is required to deactivate the ESD clamp circuit. Since the deactivation signal increases over time, a longer activation time of the ESD protection device is provided, which allows an extended protection range.

Abstract: A pre-driver for large I/O pull-up and pull-down transistors is provided so that the I/O pull-up and pull-down transistors do not experience crowbar current, and the pre-driver circuit likewise does not experience crowbar current or require large driver transistors. One pre-driver circuit includes two NAND gates and two NOR gates with delay circuitry provided by two series inverters from a data input to a first node, and two additional series inverters from the first node to a second node. A further pre-driver circuit includes feedback from the pre-driver outputs to ensure its NMOS and PMOS transistors do not turn on together to create crowbar, while allowing faster switching. With the pre-driver circuit embodiments, a conventional level shifter can be used. Further with the pre-driver circuitry, slew rate control can be provided in the pull-up and pull-down driver circuitry, rather than in the pre-driver circuitry.

Abstract: Low current differential signal/swing I/O interfaces and techniques can be implemented. An output interface converts input data signals to differential current signals for transmission over transmission lines. When the differential current signals are received by an input interface, they are converted to differential voltage signals and appropriately amplified.

Abstract: A programmable differential signaling system includes a programmable bias generator and a plurality of input/output modules. The programmable bias generator is operably coupled to generate a first global bias signal and a second global signal based on desired signal properties of one of a plurality of differential signaling conventions. The a plurality of input/output modules is operably coupled to convert between differential signaling and single ended signaling, wherein actual signal properties of the differential signaling are regulated based on the first and second global bias signals to substantially equal the desired signal properties.

Abstract: Clock multiplier circuits and methods use counters to define the positions of the output clock edges. A plurality of counters are each clocked by a count clock relatively much faster than the input clock. A first counter counts for one input clock period, and the counted value is stored. The stored value is then divided and the divided values are combined to provide counter stop values representing the numbers of counts in various fractions of the input clock period. A second counter counts from an initial value starting from a first edge of the input clock, and the count is compared in turn to the each of the counter stop values. When the value in the second counter matches one of the counter stop values, a pulse is generated on the output clock signal. Thus, the second counter generates a series of pulses at predetermined times in the input clock period.

Abstract: A configurable latch comprises a dual master stages arranged in parallel to share a single output node. The configurable latch provides a single slave stage at the single output node to be shared between the two master stages. Pass gates controlled by various phases of an input clock, controls access to the slave stage by the two master stages. Additional control is added to configure the latch for positive edge triggered and negative edge triggered flip-flop functionality as well as level sensitive functionality. Chip enable, set, and reset are also provided for additional control.

Abstract: The circuits and methods of the present invention relate to circuits for generating a multiplied clock signal based upon a reference clock signal, and circuits using the clock signal to deserialize data. According to one embodiment of the invention, a circuit comprising a counter is coupled to generate a count representative of the period of the input clock signal. A divider circuit coupled to the counter generates a divided count. Finally, a clock generator coupled to the divider circuit outputs an output clock signal having a period which is based upon the divided count. According to other embodiments, circuits and methods disclose receiving serial data using the output clock signal, and outputting the data as parallel data using the reference clock.

Abstract: Digital frequency synthesizer (DFS) circuits and methods use counters to define the positions of the output clock edges. A clock divider divides an input clock by a positive integer to provide a divided clock. A first counter circuit counts for one divided clock period, and the count is provided to a timing circuit that generates two or more sets of intermediate values. Each set represents a set of intermediate points within a period of the divided clock. Based on a specified multiplication value, one set of intermediate values is selected. Utilizing the divided clock, the selected set of intermediate values, and a second counter running at the same frequency as the first counter circuit, an output clock generator provides an output clock having an initial pulse at the beginning of each divided clock period, and a subsequent pulse at intermediate points represented by the selected set of intermediate values.

Abstract: A clock selection circuit includes an output multiplexer, control logic, and edge detection logic. The multiplexer includes inputs to receive multiple input clock signals, an output to generate the output clock signal, and a control terminal to receive a synchronized clock select signal. The control logic includes a first input to receive a clock select signal, a second input to receive a first control clock signal, a third input to receive a synchronization signal, and an output to selectively update the synchronized clock select signal with transitions in the clock select signal. The edge detection logic includes first inputs to receive the multiple input clock signals, a second input to receive a second control clock signal, and an output to generate the synchronization signal.

Abstract: Binary hysteresis comparator circuits, methods, and applications. A binary constant defines a window within which a binary input can change its value without triggering the comparator circuit output signal. An exemplary binary hysteresis comparator circuit includes a comparator circuit, an adder circuit, and a multiplexer circuit. The comparator circuit compares two multi-bit input values. A first comparator input is provided by the multiplexer circuit, which selects either a first value or a second value, depending on the comparator output signal. The first and second values differ by the binary constant, which is added to or subtracted from a multi-bit circuit input value by the adder circuit. An increase (or decrease) of less than the binary constant is ignored. Some embodiments include an optional overflow prevention circuit that prevents the selected value from exceeding predetermined parameters.

Abstract: Clock doubler circuits and methods use counters to define the positions of the output clock edges. A plurality of counters are each clocked by a count clock relatively much faster than the input clock. A first counter counts for one input clock period, and the counted value is stored. The stored value is divided by two to provide the number of counts in half of the input clock period. The divided value is provided to a second counter that counts from zero to the divided value. Thus, the second counter generates a pulse halfway through the input clock period. Other counters running at the same clock rate can be used to generate pulses at other times in the input clock cycle, as desired. The pulses from the counters are used in combination with the input clock signal to provide output clock edges at predetermined times during the input clock cycle.

Abstract: Area-efficient power-up and enable control circuits useful in PLD interconnection arrays. A control circuit can include a driver circuit, first and second pull-ups, and first and second pull-downs. The driver circuit has an output terminal coupled to a control circuit output terminal. The first and second pull-ups are coupled in series between the control circuit output terminal and power high. The first pull-up has a gate terminal coupled to an enable terminal. The second pull-up has a gate terminal coupled to a pull-up control terminal. The first and second pull-downs are coupled in parallel between the control circuit output terminal and ground. The first pull-down has a gate terminal coupled to the enable terminal. The second pull-down has a gate terminal coupled to a pull-down control terminal. In other embodiments, the first and second pull-ups are coupled in parallel, and the first and second pull-downs are coupled in series.

Abstract: A technique and circuit implementation are described for automatically detecting a change in a power supply voltage and selectively reconfiguring a circuit for optimized performance at the changed voltage. One application of particular interest is an auto-detect level shifter. The auto-detect level shifter can be used in an output driver and can be automatically enabled if it is needed to optimize performance for various I/O standards, including those that operate at different voltages.

Abstract: Area-efficient power-up and enable control circuits useful in PLD interconnection arrays. A control circuit can include a driver circuit, first and second pull-ups, and first and second pull-downs. The driver circuit has an output terminal coupled to a control circuit output terminal. The first and second pull-ups are coupled in series between the control circuit output terminal and power high. The first pull-up has a gate terminal coupled to an enable terminal. The second pull-up has a gate terminal coupled to a pull-up control terminal. The first and second pull-downs are coupled in parallel between the control circuit output terminal and ground. The first pull-down has a gate terminal coupled to the enable terminal. The second pull-down has a gate terminal coupled to a pull-down control terminal. In other embodiments, the first and second pull-ups are coupled in parallel, and the first and second pull-downs are coupled in series.

Abstract: Binary hysteresis equal comparator circuits and methods. An equal comparator does not indicate an equal condition until the two binary input values are exactly the same. However, after the two binary input values first become equal, a window of variation comes into effect, within which the first of the two values is allowed to vary while the circuit continues to report an equal condition. This window can extend only above the equal condition, only below the equal condition, or both above and below the equal condition. The width of the window is determined by providing one or two predetermined constant values, a first constant defining the amount of hysteresis provided above the second value, and a second constant defining the amount of hysteresis provided below the second value. Related methods are also described of performing equal comparisons while providing binary hysteresis.