Abstract: For one disclosed embodiment, a delay is to receive signals and to delay received signals for an amount of time at least partially dependent on a supply voltage to generate delayed signals. Logic is to help measure a characteristic relating to the supply voltage based at least in part on the delayed signals. Other embodiments are also disclosed.

Abstract: A circuit which facilitates TDF testing without having to purchase expensive new test equipment, such as a new test platform that is capable of supporting test frequencies well beyond the current 200 MHz limitation. A solution to current TDF testing problems by adding circuitry to the device-under-test (DUT) that is configured to receive two reference clock signals from automated test equipment (ATE), i.e. conventional ATE which does not provide test frequencies beyond 200 Mhz, and create two high-speed clock pulses that serve as the launch and capture clocks for the TDF test sequence on the DUT.

Abstract: A communications apparatus and method use tapped delay lines as multiplexers and demultiplexers. In one embodiment, a receiver (100) uses a tapped delay line (110) as a demultiplexer to acquire a burst communication at very high data rates in the range of 2.5 to 80 Gbps with low preamble overhead. A sliding window correlator (114) continually samples the delay line (110) to determine when a PN encoded word is contained therein. The transmission frequency is pre-acquired before any data is present through the use of a ring oscillator frequency calibration loop (130) that is imbedded within the tapped delay line (110).

Abstract: According to the methods of the invention, a further delayed DLL signal is compared to the reference clock and a delayed reference clock signal is compared to a DLL signal. These two comparisons are performed on the 360° signal and on the 180° signal. The delay introduced by the methods of the invention is preferably adjustable based on the results of a process monitor test. The process monitor test can be run continuously and accounts for process, voltage and temperature. The methods of the invention can also be used to test for clock skew in a clock tree on a chip.

Abstract: An analog delay circuit to impart a group delay to an analog input signal is described. The analog delay circuit may comprise a capacitor to impart at least a portion of the group delay to the analog output signal and a buffer circuit coupled between the capacitor and an input stage to substantially remove at least a portion of a capacitive load at the input stage.

Abstract: An improved built-in self-test (BIST) circuit and an associated method for measuring phase and/or cycle-to-cycle jitter of a clock signal, the BIST circuit implement a Variable Vernier Digital Delay Locked Line method. Specifically, the embodiments of the BIST circuit incorporate both a digital delay locked loop and a Vernier delay line, for respectively coarse tuning and fine tuning portions of the circuit. Additionally, the BIST circuit is variable, as the resolution of the circuit changes from chip to chip, and digital, as it is implemented with standard digital logic elements.

Abstract: Disclosed herein are embodiments of an improved built-in self-test (BIST) circuit and an associated method for measuring phase and/or cycle-to-cycle jitter of a clock signal. The embodiments of the BIST circuit implement a Variable Vernier Digital Delay Locked Line method. Specifically, the embodiments of the BIST circuit incorporate both a digital delay locked loop and a Vernier delay line, for respectively coarse tuning and fine tuning portions of the circuit. Additionally, the BIST circuit is variable, as the resolution of the circuit changes from chip to chip, and digital, as it is implemented with standard digital logic elements.

Abstract: Delay-locked loops, signal locking methods and devices and system incorporating delay-locked loops are described. A delay-locked loop includes a forward delay path, a feedback delay path, a phase detector and a timer circuit. The forward delay path alternatively couples to an external clock signal and to an internal test signal. The phase detector adjusts a delay line based upon the phase differences of a feedback signal and the external clock signal. The timer circuit switches the test signal into the forward delay path and measures the time of traversal of the test signal around the forward delay path and the feedback delay path and generates a time constant for configuring the phase detector's update period. The phase detector is thereafter able to stabilize at an improved rate.

Abstract: Methods and structure for improved high-speed TDF testing using an on-chip PLL and associated logic to generate high speed launch and capture pulses. A reference clock may be applied to a PLL circuit within the integrated circuit under test to generate a higher frequency PLL Clock. Gating Logic features and aspects within the integrated circuit may apply the PLL Clock signal to a TDF Clock signal when so directed by a TDF Enable signal from an external test system. The PLL Clock is applied to the TDF Clock signal path for precisely two clock pulses for use as a launch and capture pulse sequence for TDF testing at higher speeds than the external automated test system may achieve.

Abstract: A method for calibrating a timing clock is provided. The method includes the steps of calibrating a shift amount of an edge of a shift clock by using a period of the timing clock as a reference by detecting an edge of the timing clock more than once while changing the shift amount of the edge of the shift clock; shifting and generating the edge of the shift clock by a predetermined shift amount by the calibrated shift clock generating section; and calibrating a required delay amount for delaying the timing clock by time corresponding to the predetermined shift amount by detecting the edge of the shift clock shifted by the predetermined amount while changing a delay amount of the timing clock.

Abstract: The present invention is a system and method that facilitates measurement of timing variations (e.g., timing delays) in a semiconductor chip. The timing variations are measured and presented as digital values without extensive off chip measurement and analysis equipment. The timing variation measurements provides insight into timing variations (e.g., delays) inside a semiconductor chip and across different chips, including timing impacts experienced in end use after manufacturing. A timing variation measurement system includes a variation test signal generator for passing a signal through a portion of a circuit and generating a variation test signal. A variation test signal tracking component digitally counts cycles in a variation test signal and a control component controls the counting (e.g., the length of time the cycles are counted). Timing variation information, including a digital value associated with the variation test signal cycle count, can be communicated via pins and/or a processor interface.

Abstract: The present invention provides a system and method for monitoring a short clock cycle on a semiconductor chip. The system includes a phase-locked loop (PLL) for receiving a reference clock as input and for outputting a PLL clock out. The system includes a delay-locked loop (DLL) for receiving the PLL clock out as input and for outputting a DLL phase offset clock. The DLL is locked to a frequency of the PLL clock out. The system may include an edge comparator for receiving the PLL clock out and the DLL phase offset clock as input. The edge comparator is suitable for monitoring each edge of the PLL clock out and each edge of the DLL phase offset clock, and for reporting a short clock cycle when an edge of the PLL clock out comes before an edge of the DLL phase offset clock.

Abstract: A delay-locked loop (DLL) of an integrated circuit (IC) with testing circuitry and a method for testing a DLL. During test mode, a phase comparator of the DLL receives a test clock in place of the reference clock and determines the phase difference between the test clock and the clock fed back to the DLL from a clock buffer tree. A variable delay element of the DLL then shifts the reference clock in time by an amount that depends on that phase difference. The variable delay element can be exercised by varying the phase of the test clock with respect to the reference clock by a known phase offset to cause the variable delay element to produce a range of delays. Whether the variable delay element is functioning properly can be determined by checking whether the phase of the test clock is aligned with the phase of the feedback clock.

Abstract: A method and circuit arrangement for determining performance of a digital circuit to a critical degree by the transit time of signals of the longest signal path, also called the critical path. Since the signal transit time is influenced by the operating voltage, by regulating the operating voltage, to compensate for the effects caused by temperature and process fluctuations on the signal transit time in the digital circuit. In particular, the operating voltage can be regulated as a function of the signal transit time in such a way that a required minimum operating frequency can always be achieved. To determine signal transit time, the digital circuit has associated with it a number of replicas of the critical path in the digital circuit upon which the signal transit time is determined. In order to determine the transit time, the signal path replicas are exposed to the same operating conditions as the digital circuit.

Abstract: A delay lock circuit includes a measuring path, a forward path, and a feedback path. The measuring path samples a pulse with a reference signal in a measurement to obtain a measured delay. The forward path delays the reference signal based on the measured delay to generate an internal signal. The feedback path includes a calibrating unit for generating the pulse based on a plurality of feedback signals generated from the reference signal. The delay lock circuit further includes a monitoring unit for monitoring the measurement. Based on the monitoring, the monitoring unit enables the calibrating unit to conditionally adjust the width of the pulse.

Abstract: A method of determining the critical path of a circuit includes first determining the paths, their mean path transit times and their path transit time fluctuations. Paths having similar statistical parameters are combined to form one path group. For each path group, a statistical group figure is, then, calculated and, for the totality of paths considered, a statistical total figure is calculated. Finally, the critical paths of the circuit are determined by taking into consideration the total figure, comparing the group figures at or above a critical path transit time Tc.

Abstract: A delay locked loop (DLL) circuit and method for testing the operability of the circuit utilizes one or more test signal sources and a test signal receiver to selectively transmit test signals, for example, static test signals, through an array of delay elements of the DLL circuit. The resulting output signals of the array are used to determine whether any delay element or a tap selector of the DLL circuit has malfunctioned, e.g., stuck-at fault.

Abstract: The apparatus for detecting the effects of interconnect resistance and capacitance (RC) in a logic circuit includes a first ring oscillator with the interconnect RC parasitics in a logic circuit and a minimum reference ring oscillator without the interconnect RC parasitic in a logic circuit multiplexed to have common stages to obtain delay with and without the parasitics of the interconnect RC. The frequency difference between the first ring oscillator frequency and the minimum reference ring oscillator frequency is determined to detect the effects of the interconnect RC in the logic circuit.

Abstract: A method of testing a delay lock loop circuit is provided which comprises receiving an input signal and configuring the delay lock loop to generate a delay lock loop output signal based on the input signal. The method further comprises generating a test output signal from the input signal and delay lock loop output signal indicative of a relationship between a transition on the input signal and a transition on delay lock loop output signal.

Abstract: An integrated circuit has connecting pads for outputting digital signals, a connection for a time reference signal, and an assessment circuit to measure and assess a phase shift between one of the digital signals and the time reference signal. A receiver circuit is connected to a respective junction between one of the connecting pads and an associated output driver. A device for matching propagation times of signals applied to the receiver circuit is provided. The assessment circuit is connected to the receiver circuit and has an output to output a measured result. In each case, the phase shift of the signals to be output in relation to the time reference signal is measured and assessed separately. An offset of the switching edges of the signals to be output can be determined relatively accurately and corrected.

Abstract: A delay lock circuit includes a measuring path, a forward path, and a feedback path. The measuring path samples a pulse with a reference signal in a measurement to obtain a measured delay. The forward path delays the reference signal based on the measured delay to generate an internal signal. The feedback path includes a calibrating unit for generating the pulse based on a plurality of feedback signals generated from the reference signal. The delay lock circuit further includes a monitoring unit for monitoring the measurement. Based on the monitoring, the monitoring unit enables the calibrating unit to conditionally adjust the width of the pulse.

Abstract: A delay-locked loop (DLL) of an integrated circuit (IC) with testing circuitry and a method for testing a DLL. During test mode, a phase comparator of the DLL receives a test clock in place of the reference clock and determines the phase difference between the test clock and the dock fed back to the DLL from a clock buffer tree. A variable delay element of the DLL then shifts the reference clock in time by an amount that depends on that phase difference. The variable delay element can be exercised by varying the phase of the test clock with respect to the reference clock by a known phase offset to cause the variable delay element to produce a range of delays. Whether the variable delay element is functioning properly can be determined by checking whether the phase of the test clock is aligned with the phase of the feedback clock.

Abstract: An apparatus accurately measures the time difference between two signal edges by optically detecting the emission from a “beacon device” that is modulated as a function of time difference. Through the use of this modulation it is possible to perform timing measurement accurately. Embodiments of a voltage modulator circuit modulate timing information into emission intensity. The method and system of the present invention can be used in applications such as clock skew and pulse width measurements.

Abstract: Measurement of the period of a relatively slow but precise reference clock in terms of a high speed oscillating clock, such as from a voltage controlled oscillator (VCO). The reference clock is known to be accurate and stable and values of the time measurement unit are output that determine the integer and fractional number of the high speed oscillating clock periods which occurred during one reference clock cycle. The measurements are very accurate and all cycles of the reference clock are measured. Such measurements enable various frequency control schemes over the high speed oscillating clock source.

Abstract: Method and apparatus for determining delay of a circuit. A clock signal is provided to a variable delay and then to the circuit. The clock signal obtained from the circuit is provided to a data register, such as a flip-flop, as a clock input. The clock signal is provided to the flip-flop as a data input. Output of the data register is provided to a controller to incrementally adjust phase shift until the data input and clock input are substantially aligned in phase. All incremental adjustments in phase shift are counted to provide an indication of delay of the circuit.

Abstract: In recent years, much effort has been placed on improving the performance of timing and jitter measurement devices using Delay Locked Loop (DLL) and Vernier Delay Line (VDL) techniques. However, these approaches require highly matched elements in order to reduce differential non-linearity timing errors. In an attempt to reduce the requirement on element matching, a component-invariant VDL technique is disclosed that enables the measurement device to be synthesized from an RTL description. The present invention is based on a single-stage VDL structure, which is used to mimic the behavior of a complete VDL. Furthermore, as test time is an important consideration during a production test, a method and system is provided that reduces test time at the expense of additional hardware.

Abstract: The apparatus for detecting the effects of interconnect resistance and capacitance (RC) in a logic circuit includes a first ring oscillator with the interconnect RC parasitics in a logic circuit and a minimum reference ring oscillator without the interconnect RC parasitic in a logic circuit multiplexed to have common stages to obtain delay with and without the parasitics of the interconnect RC. The frequency difference between the first ring oscillator frequency and the minimum reference ring oscillator frequency is determined to detect the effects of the interconnect RC in the logic circuit.

Abstract: A delay locked loop implementing design-for-test features to test for, among other, stuck-at-faults is provided. The delay locked loop uses multiplexers as design-for-test devices for controllability purposes and flip-flops as design-for-test devices for observability purposes. Such implementation of design-for-test features within a delay locked loop allows for pre-packaging delay locked loop verification and testing.

Abstract: A method and apparatus are provided for testing linearity of two or more programmable delay chains in an integrated circuit. A first delay chain is successively programmed to a first sequence of delay settings and, for each delay setting in the first sequence, a second delay chain is successively programmed to a second sequence of delay settings. The second sequence sweeps a propagation delay through the second delay chain from a delay value less than a present propagation delay through the first delay chain to a delay value greater than the present propagation delay. For each delay setting of the second delay chain, a logic transition is applied to inputs of the first and second delay chains and the output of one of the first and second delay chains is latched as a function of the output of the other of the first and second delay chains to produce a sample value.

Abstract: A method and apparatus are provided for testing linearity of two or more programmable delay chains in an integrated circuit. A first delay chain is successively programmed to a first sequence of delay settings and, for each delay setting in the first sequence, a second delay chain is successively programmed to a second sequence of delay settings. The second sequence sweeps a propagation delay through the second delay chain from a delay value less than a present propagation delay through the first delay chain to a delay value greater than the present propagation delay. For each delay setting of the second delay chain, a logic transition is applied to inputs of the first and second delay chains and the output of one of the first and second delay chains is latched as a function of the output of the other of the first and second delay chains to produce a sample value.

Abstract: A phase detecting device, including a phase detector, an inversion logic circuit, a latch and an OR logic circuit, is used for detecting the phase difference between a reference signal and a feedback signal and for outputting a delay control signal. The phase detector generates a detected signal according to the status of the feedback signal captured by the reference signal. The inversion logic circuit inverts the detected signal, and the delay device delays the detected signal. The delayed inverted detected signal is then fed into the latch device to generate a latch signal. As the detected signal and the latch signal are fed into the OR logic circuit, the OR logic circuit feeds the delay control signal into the counter so that the delay circuit can generate different delay time, such as T/4, T/2 or 1T, for meeting different signal-delay requirements.

Abstract: A servo controller for correcting a read position of a head when reading data recorded on a recording medium. In accordance with the amplitude ratio of data signals read from each segment of a servo section defined on a recording medium, the servo controller generates an AGC signal corresponding to the next segment before reading the next segment. The data signal read from a phase detection segment of the servo section is amplified to an amplitude greater than the predetermined determination range. The amplified data signal is converted to a two-value digital signal in accordance with the determination range. The phase used during servo control is calculated in accordance with the digital signal.

Abstract: A pulse detector detects if a clock pulse signal is in phase with a reference clock pulse signal in an efficient manner with very high accuracy. The pulse detector includes a first delay unit adapted to receive an input clock pulse signal and to delay the input clock pulse signal by a first pre-specified delay for output as output clock pulse signal, and a second delay unit adapted to delay the output clock pulse signal by a second pre-specified delay. A sampling unit is adapted to sample the input clock pulse signal and the output of the second delay unit at a sampling time defined by a reference clock pulse signal and to output the samples for phase delay indication.

Abstract: A phase comparator for calculating the phase difference between a test wave form and an output wave form in a disk drive includes a phase converter, a first multiplier, a first integrator, a second multiplier, a second integrator and a phase angle calculator. The phase converter for delaying the test wave form for a specific time based on the frequency thereof. The first multiplier electrically coupled to the phase converter for performing a first operation by multiplying the delayed test wave form with the output wave form. The first integrator electrically coupled to the first multiplier for integrating the result of the first operation for a period to generate a first weighted value. The second multiplier for performing a second operation by multiplying the test wave form with the output wave form. The second integrator electrically coupled to the second multiplier for integrating the result of the second operation for the same period to generate a second weighted value.

Abstract: A device for testing a semiconductor integrated circuit device has a test board on which the semiconductor integrated circuit device to be tested is removably mounted, and a two-pulse generator mounted on the test board, for generating two pulses spaced from each other by a pulse interval equal to the period of a test clock for the delay test, from the test clock, and supplying the generated two pulses to the scan path test circuit. The device also has a PLL circuit for multiplying the frequency of the test clock and supplying a signal having the multiplied-frequency to the two-pulse generator.

Abstract: A delay-locked loop circuit is provided which includes a delay-locked loop, a delay element and a multiplexer. The delay-locked loop has a reference clock input, a feedback clock input and a clock output. The delay element has a delay input which is coupled to the clock output and a delay output. The multiplexer has a first multiplexer input which is coupled to the clock output, a second multiplexer input which is coupled to the delay output and a multiplexer output which is coupled to the feedback input.

Abstract: An integrated circuit having a delay locked loop (DLL) connected to a test circuit. The DLL includes a plurality of taps connected to a plurality of register cells. The test circuit is capable of enabling any register cell to select a tap to test the DLL.

Abstract: A delay lock loop circuit is disclosed which includes a delay block which receives the clock signal and delays the clock signal by a selected amount to generate the delayed clock signal. A phase detector receives the clock signal and the delayed clock signal, compares the phases of the two signals and generates a phase comparison signal. A lock detector receives the clock signal and the delayed clock signal, compares the timing of the two signals and generates a potential lock indication signal, A controller receives the phase comparison signal and the potential lock indication signal and provides a delay control signal to the delay block to change the selected delay amount in response to the phase comparison signal. The controller interrupts the clock signal to the delay block for a selected interval in response to the potential lock indication signal, and generates a true lock indication signal in response to the potential lock indication signal after the interruption of the clock signal to the delay block.

Abstract: An Instantaneous Frequency Measurement (IFM) receiver that receives a signal from a target and determines the frequency of the signal. The IFM receiver includes delay lines selected in lengths forming relatively prime ratios or by using the preferred method of the present invention which minimizes the total number of different delays required to achieve a given accuracy in frequency measurement.

Abstract: For testing, a reference clock signal is applied to a first delay path having a fixed delay and a second delay path having a variable delay. The delay paths are connected to inputs of a clocked circuit to initiate data transfer and they apply a clock signal and a data signal, respectively. The variable delay is set within the range [tF−n&Dgr;t/2; tF+n&Dgr;t/2]. The fixed delay tF is at least n&Dgr;t/2. For calibration, the setting range of the variable delay and the fixed delay are each increased to the k-fold value and the variable delay is incremented in steps from n=0 until three phase changes are detected. The value of n at the first phase cycle completion corresponds to the variable delay for the set-up time and the value of n at the third phase cycle completion corresponds to the variable delay for the hold time.

Abstract: To detect if a clock pulse signal is in phase with a reference clock pulse signal in an efficient manner with very high accuracy there is proposed a pulse detector, comprising a first delay unit (12) adapted to receive an input clock pulse signal (&phgr;(t)) and to delay the input clock pulse signal (&phgr;(t)) by a first pre-specified delay (d1) for output as output clock pulse signal (&phgr;out(t)) and a second delay unit (14) adapted to delay the output clock pulse signal (&phgr;out(t)) by a second pre-specified delay (d2). A sampling unit (16) is adapted to sample the input clock pulse signal (&phgr;(t)) and the output of the second delay unit (14) (&phgr;out(t−d1−d2)) at a sampling time defined by a reference clock pulse signal (&phgr;R(t)) and to output the samples (v1, v2) for phase delay indication.

Abstract: A method and arrangement for determining the phase difference between two timing signals provides that the first timing signal is ed to a delay line multiple times, whereby the number of passes through the delay line is obtained. The phase difference is determined in that a first transit time information is determined that corresponds to that number of delay elements of the delay line that are passed through by the first timing signal during a differential time-span between the two timing signals. Second transit time information is further obtained corresponding to that number of delay elements passed through by the first timing signal during a timing pulse period of time second timing signal. The determination of the first and second transit time information occurs dependent on the number of total passes of the first timing signal through the delay line, respectively, which is obtained at the respective determination time.

Abstract: A power source voltage controller which can set the optimal margin for a replica circuit and shorten the time for the power source voltage to converge to the optimal value, having a replica circuit for monitoring a delay time of a critical path by propagating a reference signal having a power source voltage-delay characteristic approximately equivalent to a critical path in a semiconductor circuit, a phase difference detection circuit and an encoder receiving a delay signal by the replica circuit and the reference signal and detecting the phase difference of the delay signal from the reference signal and outputting the detection result as phase difference information, voltage control circuits for generating a power source voltage of a value based on a phase difference information signal and supplying it to the semiconductor circuit and the replica circuit, and a delay error correction circuit arranged at the input side of the reference signal of the replica circuit and correcting the delay difference with the

Abstract: A jitter unit converts a stable input test signal into a jittering output test signal used to test the jitter tolerance of electronic equipment. This jitter device allows any test or sample signal (analog or digital, video or audio) to be used for testing such equipment. Jitter is a type of timing error between the expected or ideal timing of a signal and the actual timing of a signal in which the characteristics of the timing error change with time. The characteristics of jitter include the level of error, the frequency of change in the error and whether the change is periodic or random. The jitter unit uses a variable delay unit to delay the signal and uses a controller to regulate the delay of the delay unit in order to transform the stable signal into a jittering signal.

Abstract: The invention prevents shift register circuits from malfunctioning. A distribution circuit outputs a trailing trigger pulse DTP and a leading trigger pulse UTP. A trailing edge control circuit and a leading edge control circuit delay the trailing trigger pulse DTP and the leading trigger pulse UTP, respectively. The delay time of each of these control circuits can be set. These delay times are determined according to a threshold voltage of a TFT constituting a shift register. An inverted clock signal CLYINV is generated according to output signals of the control circuits. The shift register is driven by a clock signal CLY and an inverted clock signal CLYINV.