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Signal integrity / PCB loss application notes 

AP8193

Using the Si9000 Loss Tangent Goal Seek

Measuring insertion loss yields the total losses of a transmission line, but sometimes it is useful to further process that information and deduce the contribution of copper losses and dielectric losses to the overall loss figure. The Si9000e Loss Tangent Goal Seek provides a useful estimate of the dielectric loss tangent for the substrate material. This application note describes the sequence of steps to goal seek for loss tangent.

AP9018

 

Specifying the timebase and line length settings for Atlas Delta-L tests

Polar's Atlas PCB insertion loss test sytem includes the Delta-L technique which uses long line short line measurement combined with innovative via de-embedding techniques. This note discusses the test parameter settings to ensure best results over a range of test line lengths.

AP8192

Modelling Delta-L insertion loss measurements with the Polar Si9000e

The Si9000e models insertion loss on a wide range of PCB structures and stackups. The models are accurate boundary element field solved calculations of insertion loss that will correlate with a variety of insertion loss measurement techniques. This note briefly discusses modeling the s-parameter loss characteristics of a PCB substrate measured with the Delta-L methodology.

 

Signal integrity – design and test

Using the Si9000

Using Atlas

AP9018

 

Specifying the timebase and line length settings for Atlas Delta-L tests

Polar's Atlas PCB insertion loss test sytem includes the Delta-L technique which uses long line short line measurement combined with innovative via de-embedding techniques. This note discusses the test parameter settings to ensure best results over a range of test line lengths.

AP8192

 

Modelling Delta-L insertion loss measurements with the Polar Si9000e

The Si9000e models insertion loss on a wide range of PCB structures and stackups; the models are accurate boundary element field solved calculations of insertion loss that will correlate with a variety of insertion loss measurement techniques, this note briefly discusses modeling the s-parameter loss characteristics of a PCB substrate measured with the Delta-L methodology.

AP8170

RIE loss / attenuation measurement method and PCB manufacture

This application note provides a brief introduction to RIE (Root Impulse Energy) testing, one of 4 PCB material loss (attenuation) measurement methods shortly to be published by IPC. RIE testing is aimed at the PCB manufacturing shop floor to provide an easily deployed and relatively straight-forward method of monitoring the high frequency performance of PCBs to ensure they stay within an acceptable loss budget.

AP8166

Vias, stubs and minimizing their visibility to high speed signals

Many of our PCB design customers ask us about modelling plated through hole (PTH) vias with respect to impedance. However, from a signal integrity standpoint, unconnected via stubs have a far larger effect on the signal than the geometry of the via itself. This note explains how the Polar Si9000 can help you check if, at your desired bit rate or operating frequency, you need to take steps to reduce or remove the effects of via stubs. 

AP8164

An introduction to forward and reverse crosstalk

Crosstalk is the unwanted coupling of energy between two or more adjacent lines. The electromagnetic fields between two closely coupled lines interact with each other and will affect the behaviour of the signals on both lines. This note discusses near and far-end crosstalk and includes formulas that will enable the maximum peak effect to be predicted.

AP171

Nickel-gold plating copper PCB traces

Nickel plating of copper PCB traces, widely practised in the microwave industry, is acceptable on short lengths of pad to accommodate gold plating; plating the whole trace length is generally not a good idea. This application note explains the effect that nickel will have on high frequency transmission lines.

AP158

Locating Critical Tracks on PCB Inner Layers

From susceptibility to electrical interference to control of track cross-sectional dimensions — this note provides several good reasons why you shouldn’t put critical tracks on the surface layer of a PCB.

AP155

Transmission line testing — VNA or TDR?

Sometimes board fabricators are asked to test PCB transmission lines at a given frequency.  In some cases boards are tested using a Vector Network Analyser (VNA) and in others a Time Domain Reflectometer (TDR); both instruments should offer similar readings. This note sets out to explain expected differences in measurement results, and points out where differences are due to incorrect test setup rather than any material problem.

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AP8193

Using the Si9000 Loss Tangent Goal Seek

Measuring insertion loss yields the total losses of a transmission line, but sometimes it is useful to further process that information and deduce the contribution of copper losses and dielectric losses to the overall loss figure. The Si9000e Loss Tangent Goal Seek provides a useful estimate of the dielectric loss tangent for the substrate material. This application note describes the sequence of steps to goal seek for loss tangent.

AP8192

 

Modelling Delta-L insertion loss measurements with the Polar Si9000e

The Si9000e models insertion loss on a wide range of PCB structures and stackups; the models are accurate boundary element field solved calculations of insertion loss that will correlate with a variety of insertion loss measurement techniques, this note briefly discusses modeling the s-parameter loss characteristics of a PCB substrate measured with the Delta-L methodology.

AP8190

Impedance variation with frequency can be counter intuitive!

Although transmission line impedance is broadly constant over a wide range of frequencies, as the dielectric constant of a PCB transmission line tends to fall slightly with increasing frequency you might anticipate that Z0 would increase as you sweep through the frequency range. A quick calculation with a range of frequencies in the Si9000e transmission line field solver shows this is not the case. This application note explains why…

AP8188

Using the Si9000e's sensitivity analysis to graph multiple impedances

Some transmission system guidelines specify routing signals with constraints on both differential impedance and common impedance. This note describes how to use the Si9000e's sensitivity analysis to achieve both the differential (Zdiff) and common (Zcommon) impedance specifications.

AP8187

Using the Si9000e's sensitivity analysis to graph crosstalk

The Si9000e's sensitivity analysis includes graphing for differential, common, odd and even mode impedances along with near and far-end crosstalk. This note describes how you can use the Si9000e's sensitivity analysis to graph the effect on crosstalk (NEXT and FEXT) of changing both the separation, S1, and trace width, W1 and W2, of a differential pair while maintaining constant impedance.

AP8184

Si9000 frequency dependent calculations

Causal interpolation of dielectric constant is implemented in the Si9000e lossy line field solver via the Extended Substrate Data option. Using the Extended Substrate Data option the Si9000 can accept tables of multiple values of dielectric constant and loss tangent or use a single value to enable Svensson-Djordjevic frequency dependent permittivity modelling.

AP8173

Laminates, losses & the Si9000e – choosing a PCB laminate

New "mid market" core and prepreg materials offer increased high speed performance and more standard processing methods than more exotic laminates and have presented the designer with a bewildering array of choices from ease of processing through to reliability requirements and onwards to signal integrity capability. This note explains how to use the Si9000e to make the best choice of laminate materials when trading cost versus signal integrity performance.

AP8155

Surface roughness effect on PCB trace attenuation / loss

Designers and fabricators are increasingly concerned with the effects on PCB transmission line losses of the surface roughness of the copper layers within a stackup. With the Si9000 versions 9.01 and above you can include values for surface roughness in frequency dependent calculations. Charting dielectric losses along with conductor losses and attenuation values that include compensation for surface roughness can help isolate the contributions of the different loss mechanisms. 

AP8154

Modelling and testing broadside-coupled differential pairs without ground

From a modelling standpoint the broadside-coupled differential pair without ground is like a paired wire transmission line. This structure does not appear directly in the Si8000/9000 field solver; this application note discusses how to use one of the standard Si8000/9000 structures to predict the finished impedance and suggests a method of testing for this differential structure.

AP8153

Modelling and testing differential pairs without ground

From a modelling standpoint the differential pair without ground is like a paired wire transmission line. Although this structure does not appear in the Si8000/9000 field solver this note shows how to use one of the standard Si8000/9000 structures to predict the finished impedance and suggests a method of testing for this differential structure.

AP192

Displaying s-parameters with Smith charts on the Si9000

The Si9000 v7 and later allows graphical representation of s-parameters S11 and S21 via a Smith Chart, a tool widely used for graphic solution of transmission-line networks. This note briefly discusses how reflection and transmission coefficients S11 and S21 of a typical 50 Ohm controlled impedance structure, represented as a transmission line, are graphed by the Si9000.

AP189

Ground plane thickness in Si9000 frequency dependent calculations

This application note describes how the Si9000 PCB Transmission Line Field Solver fully takes into consideration power plane thickness in frequency dependent calculations.

AP188

Introduction to s-parameters

The Si9000 extracts RLGC matrices and 2-Port (single-ended) or 4-Port (differential) s-parameters and rapidly plots transmission line information for the structure under design. This application note provides a simple introduction to the concepts of s-parameters, or scattering parameters, which describe the "scattering", reflection and transmission of travelling waves when a linear network is inserted into a transmission line.

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AP194

Polar recommended signal integrity reading

For those who would like more information on signal integrity issues, this note contains a list of books recommended by Polar.

AP182

Critical length of transmission lines - Dr. Eric Bogatin

This new application note gives a clear and easy to read explanation of the critical length of a transmission line.  Written for Polar by Dr. Eric Bogatin this article is an ideal place to broaden your knowledge of PCB transmission line behaviour.  If you like this you will also find a broad range of PCB signal integrity related training materials on the Bogatin Enterprises website. www.bogent.com 

AP168

Effect of risetime on the TDR measurement of impedance

This application note is intended to give guidance to those making impedance measurements on industry standard 6 inch long coupons. The note will show that in this situation the use of risetimes shorter than 200ps will yield no advantage and in fact may prove more difficult to use.

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AP9017

Insertion loss testing frequently asked questions

Frequently asked questions on insertion loss testing with Polar Atlas using SET2DIL and SET2SEIL.

AP8186

Atlas insertion loss correlation study

This insertion loss correlation study assesses the correlation between the following single ended and differential test methods and modelling techniques, Vector Network Analyser, SPP (Short Pulse Propagation) test method, SET2DIL (Single Ended TDR to Differential Insertion Loss) / SET2SEIL (Single Ended TDR to Single Ended Insertion Loss) and Polar Instruments Si9000e Insertion loss GHz PCB transmission line field solver.

AP8182

Si9000e – Atlas modeled v measured insertion loss correlation study

The Si9000e – ATLAS Modeled v Measured Insertion Loss Correlation Study assesses the correlation between insertion losses predicted by the Si9000e transmission line field solver and the attendant test results obtained from single ended and differential test methods Vector Network Analyser, SPP (Short Pulse Propagation) test method, SET2DIL (Single Ended TDR to Differential Insertion Loss) / SET2SEIL (Single Ended TDR to Single Ended Insertion Loss.)