Clock tree jitter analysis software

Based on the industrystandard tektronix dpojet eyediagram, jitter, noise, and timing. What are clock signals in digital circuits, and how are. By default, the spectral plot shows the entire jitter content of the signal. To address this industry need, silicon labs new si534x jitter attenuators and clock generators leverage industryleading frequency flexibility and clocktreeonachip integration to deliver an efficient, costeffective solution that combines all discrete timing functions into a singlechip clock ic solution. Deterministic jitter is typically caused by cross talk, emi, simultaneous switching outputs sso, device function dependency pattern dependant jitter and other regularly occurring interference signals. Verifying the true jitter performance of clocks in high. Therefore this effect needs to be modeled or uncertainty introduced to add enough margin. How to determine the sample resolution for accurate results how to move waveform data from the tds7000 to excel.

Cn1881224a estimating jitter in a clock tree of a circuit. A hybrid clock tree with multispine using automated design methodology for low cost and low power complex lsis. Clock jitter analysis clock jitter analysis keysight. Running on keysights e5052ab signal source analyzer, ssaj software enhances your ability to separate rj and pj from total jitter tj by combining time. Teledyne lecroy software options jitter analysis software. Estimating clock tree jitter using phase noise method 2 a second more precise approach to estimating clock tree jitter through two or more timing ics is to use device phase noise measurements for jitter generating devices in conjunction with data sheet specs for the fanout buffer. Jitter can also be generated from pll known as pll jitter. Software options jitter analysis software teledyne lecroy. By ensuring jitter design targets are properly met, system timing related problems can be avoided. Timedomain measurements on jitter trend, histogram, and rjpj separation of clock signals description to meet the demanding needs of todays advanced digital communication systems, keysight offers precision clock jitter analysis software e5001a ssaj for more precise and accurate characterization and evaluation of clock signal jitter. Agilent technologies ezjit and ezjit plus jitter analysis. This especially applies to the various components of the clock tree, where the jitter limits for reference clocks, clock buffers, and jitter. Jitter 101 analyzing clock jitter periodic signal straightforward with histogram analyzing data jitter aperiodic embedded clock must have clock recovery oscilloscope must create a virtual clock for jitter analysis 5282015 10 comparing edges, clock vs. Inter clock domain analysis for generated clocks 4.

A zdb zero delay buffer clock product containing a phaselocked loop pll for the purpose of frequency multiplication, buffering, or delay compensation will produce a certain amount of undesirable output clock jitter and delay. Xseries oscilloscope with the dsox6jitter jitter analysis option is the. Phase noise measurements are usually done using a spectrum analyzer with phase noise measurement capability or an instrument such as an agilent e5052b. The resulting curve shown in figure 4, gives the total probability of an edge being greater than t or less than t. Jitkit clock and clock data jitter analysis package fast and easy validation validating system jitter performance and analyzing systems with high jitter levels comprises a significant portion of a system engineers test and validation time. Maximize the number of measured values greater than 25,000 for a peaktopeak measured sigma at or near 4. Click the stop button 1 in screen for random jitter analysis to finish the measurement. As shown in figure 1, a typical clock distribution tree consists of a clock source and a series of clock distribution buffers that deliver multiple copies of the clock source to many locations in.

The main difference is the presence of the mesh net. System clock uncertainty, in the form of random skew and jitter, is beginning to a. The model is scalable and technology independent, which makes it suitable for integration in current clock tree synthesis algorithms. There are two equally valid ways to look at jitter. Jitter caused by phase noise consider a clock signal ideal. Cyclecycle jitter is defined as the deviation in the clock s output period from one cycle to the next. The total jitter is largely dominated by the noisiest contributor of the clock tree. Correlation is an important concept which appears in two separate contexts in jitter analysis. Understanding highspeed signals, clocks, and data capture. A computing jitter clock tree system, the system comprising. This software integrates the equivalent of more than 150 manyears of silicon labs dspll and timing technology and applications expertise.

The components have the following jitter characteristics. Method and semiconductor design program, october, 2008, oishi et al. Jun 19, 2018 clock generators and clock buffers are useful when several frequencies are required and the target ics are all on the same board or in the same fpga. Jitkit makes it simple and easy to understand the basic system jitter. Skew definition and jitter analysis by steve corrigan system specialist, data transmission reference edge sometimes the edge is here sometimes the edge is here the edges should be here unit interval noise margin jitter unit interval ui r ec iv r threshold voltage several characteristics of the eye pattern indicate the quality of a signal. A rich set of timing measurements for clock, clocktodata, and data stream analysis. The apx measurement software simplifies jitter tolerance testing with sweeps of output jitter either master clock. Agilent e5052a signal source analyzer with precision clock jitter analysis software.

When assessing jitter, its important that designers do tree analysis of the many jitter specifications and how they aggregate, make sure the. This function can be used to generate waveform data that can be uploaded onto an arbitrary waveform generator awg to simulate a real world digital clock with a known amount of jitter for noise immunity and other similar test applications. The tektronix tdsjit2 jitter analysis software will extend that capability by making jitter measurements on contiguous clock. Some sort of golden reference clock is compared to the timing of the transitions of either a test clock or the clock represented by the timing of data transitions on a signal. The system designer must consider several factors when using a clock oscillator in a circuit sensitive to clock jitter. How to measure the jitter component of a specific stage of a clock tree or simple buffer is defined in a parameter of delay. You can rapidly solve problems and meet your design goals and compliance requirements. Programmable software clock recovery including software pll 1.

Learn how infiniium series oscilloscopes give various display formats to view jitter measurements from horizontal waveform histograms to jitter spectrum waveforms. Digital converters are susceptible to clock jitter, which can be tested by jittering the digital input or clock to the device and measuring output audio distortion caused by the jitter. Jitkit clock and clockdata jitter analysis package fast and easy validation validating system jitter performance and analyzing systems with high jitter levels comprises a significant portion of a system engineers test and validation time. There will be a short delay while the application is loading. Select the run button 1 in screen for random jitter analysis. The clock tree has a clock source, clock tree cells, clock gating cells and buffers and loads. Clock structures conventional clock tree and clock mesh. This function can be used to generate waveform data that can be uploaded onto an arbitrary waveform generator awg to simulate a real world digital clock with a known amount of jitter. Balanced buffered h tree grid clock verification is more complex in dsm rc interconnect delays signal integrity capacitive coupling, inductance ir drop signal electromigration clock jitter ras lecture 6 24 clock jitter clock wo jitter clock w jitter time domain phase histogram clock w jitter. Now, jitter generation and measurement, pulse mask compliance xx012 application is available as a part of basic applications in t1 e1 analyzer. Clock circuit jitter sqrt t jrms 2 adc aperture jitter 2 using the adc08d as an example, the aperture jitter is given in the datasheet as 0. Reference design, digital asic clock tree synthesis cts ow, simulation procedure and library characterization are discussed in section 3.

Jitter timing and analysis software package standard on sda8 zi and dda 8 zi. Jitter and timing analysis for analog and digital clock and data signals. Estimating jitter in a clock tree of a circuit and synthesizing a. At, introduces jitter as well as voltage noise as a consequence of the signals. Silicon labs grabs for lowest clock jitter with clock tree. Sdc file synopsys design constraints file various files in vlsi design session4 duration. Estimating clock tree jitter using phase noise method 2 a second more precise approach to estimating clock tree jitter through two or more timing ics is to use device phase noise measurements for jitter. The jitter family tree jitter analysis technologies any jitter measurement can be reduced to the comparison of two clocks. Clock signal jitter simulation file exchange matlab central. Jitter frequency, the more commonly quoted figure, is its inverse.

Basic clock distribution to a software defined radio begins with low jitter clocks to the i and qchannel ad and da pairs of the receiver and transmitter, respectively. At first glance, this appears insignificant, but in a complicated, highspeed. It uses lecroys long memory and zoom architecture to capture and precisely measure. The clock mesh includes a clock source, premesh drivers, mesh drivers, the mesh net, clock gates and mesh receivers, and loads.

Analysis of a spread spectrum clock signal, showing the 39 khz triangular modulation on the 98 mhz clock. Clock tree jitter estimation electrical engineering stack. Jitter is always computed by comparing a clock signal called the nominal clock or the clock under test with a clock having superior accuracy called the reference clock. An example of a normally distributed jitter pdf is shown in figure 3. Ezjit and ezjit plus jitter analysis software for infiniium series oscilloscopes data sheet features of the ezjit plus software that optimize jitter analysis include. Clock jitter and the crystal oscillator1 electronic products. Reference clock jitter and data jitter ransom stephens.

Based on the industrystandard tektronix dpojet eyediagram, jitter, noise, and. This especially applies to the various components of the clock tree, where the jitter limits for reference clocks, clock buffers, and jitter attenuators are even tighter. View the verifying the true jitter performance of clocks in highspeed digital designs abstract for details on the verifying the true jitter performance of clocks in highspeed digital designs tech paper. From cycle to cycle the period and duty cycle can change slightly due to the clock generation circuitry. Keysight dsox6jitter jitter analysis option farnell. Example waveform of simple datadependent jitter ddj. Jitter is a measure of timing imperfection in the time domain. How to build a simple jitter analysis worksheet how to use excel to graph the results characterizing jitter, whether in the 100 picoseconds ps or 100 microseconds s range, can be a time. The tektronix tdsjit2 jitter analysis software will extend that capability by making jitter measurements on contiguous clock and data cycles from singleshot acquisitions. As shown in figure 1, a typical clock distribution tree consists of a clock source and a series of clock distribution buffers that deliver multiple copies of the clock. This application note discusses three common approaches to estimate total clock tree jitter with the focus on additive jitter when using a clock. Reference clock jitter and data jitter 5 systems with crosstalk, that amplitude noise. This application note discusses three common approaches to estimate total clock tree jitter with the focus on additive jitter when using a clock buffer.

Here, the trend is to increasingly use phase noise analyzers. In some applications, fpgaasics have multiple time domains for the data path, control plane and memory controller interface, and as a result, require multiple unique reference frequencies. Pam4, pcie, jitter limits move the needle in highspeed. Introduction at first glance, clock distribution trees are relatively simple. The jta2 software package for lecroy oscilloscopes provides advanced jitter and timing analysis capabilities. We will discuss about skew and insertion delay in upcoming posts. First, as the data rates in highspeed digital designs increase, the limits for overall system jitter become tighter. Clock tree jitter estimation electrical engineering. Clock jitter could also be defined as the crosstalk effect on the clock nets. Jitter measurement analysis using keysight oscilloscopes. This paper presents a simple jitter model for clock repeaters. Jitter period is the interval between two times of maximum effect or minimum effect of a signal characteristic that varies regularly with time. Support seven unique reference clock frequencies with this ultralow jitter, less than 90fs rms, pinselectable oscillator that generates commonly used reference clocks.

Using clock jitter analysis to reduce ber in serial data applications. Targeting the needs of the highspeed networking, communications and data center equipment serving as the foundation of todays internet infrastructure, silicon labs has just introduced its nextgeneration si534x clock tree onachip family of highperformance clock generators and highly integrated multipll jitter. In particular embodiments, a methodology for clock tree jitter analysis. Managing the jitter vs power tradeoff in clock trees. Does the software pll bandwidth automatically change if the input goes from prbs7 to clock d10. Pam4, pcie, jitter limits move the needle in highspeed digital. E5001a ssaj precision clock jitter analysis software. Clock generators and clock buffers are useful when several frequencies are required and the target ics are all on the same board or in the same fpga.

The contribution of jitter to the system ber is given by the probability that an edge. The apx measurement software simplifies jitter tolerance testing with sweeps of output jitter either master clock output at the sync output if the device is. Often, however, the demands of a system design will require a large, wide clock tree whose branches must operate at. Jitter is the shortterm variations of a signal with respect to its ideal position in time. For example, measuring a 100mhz clock that changes period every cycle say a longer period one cycle and a shorter period the next cycle will have jitter.

Aug 24, 2011 this function creates a user definable digital clock signal waveform with random jitter on it. To meet the demanding needs of todays advanced digital communication systems, keysight offers precision clock jitter analysis software e5001a ssaj for more precise and accurate characterization and evaluation of clock signal jitter. The tds7000 oscilloscopes have superb jitter analysis capabilities on noncontiguous clocks with their histogram and statistics capabilities. So in order to balance the skew and minimize insertion delay cts is performed. Jitter over one cycle can have very high frequency content relative to the fundamental frequency of the circuit being tested. Using clock jitter analysis to reduce ber in serial data. Process and environmental variationsand intersignalcouplingon a chip contribute signi. In the application menu bar, go to the measurements select menu. Most digital oscilloscopes have a oneshot measurement capability that is capable of capturing jitter.

Verifying the true jitter performance of clocks in highspeed digital. For clock jitter, there are three commonly used metrics. For example, measuring a 100mhz clock that changes period every cycle say a longer period one cycle and a shorter period the next cycle will have jitter at 50mhz. A in the time domain, with a perfect clock top and clock with jitter bottom showing minute time displacements phase shifts, and b in the frequency domain, with the same perfect clock top and clock with jitter. What are clock signals in digital circuits, and how are they. Clock tree synthesis clock tree synthesis cts is the process of inserting buffersinverters along the clock paths of the asic design to balance the clock delay to all clock inputs. Generally two random variables are correlated if changing one of the variables causes the other to change. Analyzing a design with jitter clock uncertainty in smarttime 6. Jitter is the variation of the clock period from edge to edge. Most, if not all, now have drivers that use external software that calculates jitter. The measurement starts, and the clock frequency 3 in screen for random jitter analysis and the random jitter rms value 4 in screen for random jitter analysis are displayed. Easytouse jitter wizard measure repetitive or arbitrary data waveforms constant frequency or pll clock recovery realtime measurement trend. Jitkit clock and clockdata jitter analysis package datasheet.

Since a clock tree is used, different clock branches can have different crosstalk and therefore different jitter. The frequency spectral density is a measure of the amount of power per. This function creates a user definable digital clock signal waveform with random jitter on it. Clock performance in series plls cypress semiconductor. A component with poor performance can compromise the whole systems performance. A step up is to use a fanout buffer as close to the converter cluster as possible, and start building a clock tree. T, critical clock tree parameter and dualv t concept are shown in section 2.

A highperformance widebandwidth oscilloscope with highspeed clock jitter analysis software must be used. Select file run application jitter analysis 3 or jitter analysis 3 essentials in the oscilloscope menu bar. The total jitter is the peaktopeak jitter in a clock or data signal within a specified confidence equal to 1ber. Clock signals are typically susceptible to duty cycle distortion dcd and periodic jitter. In part 1, i presented a matlab function to model an adc with jitter on the sample clock, and applied it to examples with deterministic jitter. In one embodiment, a method for computing jitter in a clock tree. Clock jitter, clock jitter in vlsi, cycle to cycle jitter, jitter, long term jitter, period jitter, sta, sta interview questions, static timing analysis clock skew keeping the clock skew to a minimum is considered to be a good measure of clock tree. Silicon labs launches industrys lowest jitter clock family. Easytouse jitter wizard measure repetitive or arbitrary data waveforms constant frequency or pll clock. Absolute jitter the absolute difference in the position of a clock s edge from where it would ideally be. Clock signal jitter simulation file exchange matlab.

Analysis and characterization of random skew and jitter in. E5001a ssaj precision clock jitter analysis software keysight. Clock jitter and the crystal oscillator1 electronic. Whether you need a quick clock jitter measurement or a thorough analysis of a ber performance problem, tektronix oscilloscopes and integrated software tools deliver. Effect of clock jitter on data jitter from the transmitter. Jitkit makes it simple and easy to understand the basic system jitter performance of.

The analysis of clock jitter has evolved as data rates have increased. Clock jitter, clock jitter in vlsi, cycle to cycle jitter, jitter, long term jitter, period jitter, sta, sta interview questions, static timing analysis clock skew keeping the clock skew to a minimum is considered to be a good measure of clock tree synthesis. Select the run button 1 in screen for random jitter analysis the measurement starts, and the clock frequency 3 in screen for random jitter analysis and the random jitter rms value 4 in screen for random jitter analysis are displayed click the stop button 1 in screen for random jitter analysis. Learn about the limitations of realtime oscilloscopes used for timedomain jitter analysis. Clock tree synthesis and soc clock distribution strategies. Techonline is a leading source for reliable tech papers. Jitter is the rms magnitude of all random timing errors following a gaussian distribution. Inter clock domain analysis with two asynchronous clocks 3. How do i estimate the output jitter of a clock tree consisting of a clock oscillator followed by a clock buffer. Jitterphase noise in clockdistribution topology digikey. A in the time domain, with a perfect clock top and clock with jitter bottom showing minute time displacements phase shifts, and b in the frequency domain, with the same perfect clock top and clock with jitter bottom, which appears as frequency shifting around the nominal value. Now well investigate an adc with random clock jitter, by using a. Agenda jitter in serial data applications the role of reference clocks in serial data applications reference clocks and phase noise reference clock quality analysis the toolset in this seminar we concentrate on clock jitter issues relevant to serial data systems. To examine the lowfrequency jitter components, the spectrum can be zoomed and measured with cursors.