Zachariah Peterson | Created: November 22, 2021 | Updated: June 25, 2023 Table of Contents Differential Impedance Defined Formulas for Differential Impedance Should You Use Characteristic or. Please refer to the pcb trace calculator for dimensioning to achieve the target differential impedance. Most often, the only specified requirement of a differential pair is its differential impedance. Board Setup. The Differential microstrip impedance calculator is used to compute the differential (Zd) and single-ended impedance (Zo) of an edge-coupled microstrip line just by entering the width, separation and thickness of the trace along with the dielectric thickness and constant of the coupled line. The Si8000m adds enhanced modelling to predict the finished impedance of multiple dielectric PCB builds and also takes into account the local variations in dielectric constant on close spaced differential structures. Dial down these variables, calculate exactly what you’re impedance needs to be. The IPC-2141 trace Impedance calculator will help make initial design easier by allowing the user to input basic parameters and get a calculated impedance according to the IPC-2141 standard. Getting the Most Accurate Impedance Calculations. The two most common impedances. Using this calculator, I found 100 Ohms by giving 9 mils of track width, 5 mils of track separation, 8 mils of dielectric. Menu. 5ohms and the fact that it’s nearly flat above about 800kHz). Before we can start routing the PCB, we need to define Design Rules for our differential traces. Going to route the following signals: 100R differential pair (Zo = 50R) 90R differential pair (Zo = 45R) Planning to use the stack up JLC7628, with a 4 layer PCB, in total 1. Calculating the specific differential impedance requires knowledge of the trace width. Single-ended signals are fairly straightforward. The microstrip is a very simple yet useful way to create a transmission line with a PCB. At the receiver, the signal is recovered by taking the difference between the signal levels on. Consider some of these vital PCB routing guidelines: Keep fixed impedance traces for a particular interface or signaling protocol on the same. The main difference between a 2 and a 4 layer board is the distance to the ground plane: On a 4 layer board the typical distance between the outer and inner layer is around 0. Also, calculate the trace spacing needed if differential pair routing guidelines are needed. Following is the formula for differential impedance for a Microstrip. Depend-ing on the logic family used, trace length difference of 500 mil can be tolerated. The top surface and the sides of the traces are exposed to air and are referenced to a power or ground plane. Given the defaults (1. But I see that the EEWeb free tools don’t have. A coplanar waveguide calculator will operate in one of two ways. The surface finish is neglected. Whether you’re an electronics enthusiast or a professional, this tool will. There are some advantages to using a microstrip transmission line over other alternatives. 4 Comments. (5mil prepreg) But in your case if using a 10 mil dielectric; Impedance is almost constant ratiometric to the conductor geometry ratios if <2:1 ratios for planar and < 3:1 for differential coplanar. To calculate the impedance, I use Saturn PCB impedance calculator software, Inc - PCB Toolkit V8. The IPC-2141 trace Impedance calculator will help make initial design easier by allowing the user to input basic parameters and get a calculated impedance according to the IPC-2141 standard. By controlling the PCB impedance, unexpected damages or errors can be limited to some extent. If you are using differential pairs, think about trace coupling. Let's match the impedance of the same signal since differential pair routing is completed when the impedance is matched properly. Excite the other end of the trace with the function generator. When calibrated,Differential Pair Routing. Differential pairs are very simple: they are composed of two traces, routed side-by-side, and that carry equal magnitude and opposite polarity signals on each trace. KB: Fail to install possibly due to lack of admin privilege or virus protection software. There are many calculators available online, as well as built into your PCB design software. Vias (plated holes) are used to route electrical signals among different layers of a multilayer. 3 V, etc. If your design has controlled impedance traces, you can use our built-in impedance calculator. trace geometry, and use this to calculate impedance. Missing by 25 microns on a 100 micron trace throws off the alignment by 25%. 254mm. The default units for all given values, except the subtrate. Enter dimensions: Trace width (W) mils. High-speed designs carry a requirement for controlled impedance, crosstalk control, and the. Edit: also, think ahead if you are going to use ground pours around the traces. Tuning for your traces to the desired impedance value occurs by adjusting trace width and distance from the reference plane. 1 of the Microstrip Calculator using H2 in place of h, εr,eff can be computed as specified in Eq. Equation 2 is the most commonly used equation for surface microstrip transmission line impedance calculations. This is why in most cases the differential impedance of a pair of traces is a little less than twice the single ended impedance of each trace. This is more than the to times trace width which is recommended (also read as close as possibly). If you're trying to get your own pcb design project , you should use this tool. Use the results from #3 to calculate the width profile with. You can use all the calculators you want if you don't know the exact board make up they're using; they should be able to help you. Going Forward with a Trace Impedance Calculator. If it is off substantially, the PCB trace dimensions should be adjusted to provide a match. some trace calculation examples. By inputting the known values. I'm designing a custom PCB around the Raspberry Pi RP2040 MCU. Working with coplanar structures:. Vias (plated holes) are used to route electrical signals among different layers of a multilayer. This calculator helps you calculate the characteristic impedance of a coaxial cable given its dimensions. when i use Saturn PCB design to match the differential impedance to 100ohms i get 0. For this calculation, the units of d,h, t and w can be ignored as long as they have the same units (mils, mm, inches). Just enter the given values for trace thickness. Trace stubs must be avoided. Activate the mixer to its normal operating conditions. 68 mils. While this calculator will provide a baseline, any final design considerations should be made towards loss, dispersion. This transmission line calculator. Just to give designers a starting point, take a look at these differential impedance calculators you can use to get an initial estimate of the differential. To prevent reflections the PCB trace pair’s impedance should be matched to the interconnect/media. The signal is now too slow and there will be no reflections due to impedance mismatch. Engineering/Technical. Ohm’s Law provides the framework for solving network analysis problems; when the curtain gets pulled back, Ohm’s Law updates to become the relationship between voltage, current, and impedance, not resistance. TheseIt always defaults to 10mil. 4mil; Dielectric Thickness:. This calculator finds both odd and even transmission line impedance. For example, a single 0. We have upgraded our Impedance Calculator, a free 3D field solder, which now uses the 2D numerical solution of Maxwell’s equations for PCB transmission lines. Differential Impedance is the impedance between two differential pair signal traces. Stack Symmetry – enable to add layers in matching pairs, centered around the mid-dielectric layer. How to calculate track widths and layout controlled impedance traces (e. Z diff = 2* Z o (1 - 0. The default units for all given values, except the subtrate. signals. Click on Setup -> Constraints > Electrical Constraints Set - > Differential Pair Value - > Calculator >. I've used the Polar Instrument calc, the ADS LineCalc software, and have got two additional stackup constructions for our fab houses, and have talked to numerous people on this. The guides says spacing under 0. The closer you place the pairs together, the differential impedance gets smaller because LM and CM get larger. The trace width and spacing for a certain impedance may be obtained using impedance calculators. Differential Stripline Impedance Calculator. At some point the amplitude will stay constant. Advanced differential impedance calculator facilitates design and production of latest-generation PCBs. 5mm, T=0. 03) it gives me almost 160 Ohm - and even if use 53mil conductor height or. Instant online PCB quote, get PCBs for only $2. Go to this 100-ohm class and select the nets which are there in this. In other words, if you are designing to hit a differential impedance target (such as. The IPC-2141 trace Impedance calculator will help make initial design easier by allowing the user to input basic parameters and get a calculated impedance according to the IPC-2141 standard. 6mm spacing with a trace width of 0. FWIW, the calculator I've used in the past is called Polar SI8000 which apparently has been superceded by Speedstack PCB. 5mil trace + 4mil spacing - which is close to their absolute minimum). High speed measurement tools. 5. A 3D view of a complex impedance controlled PCB in. Single Ended Impedance Ω. $egingroup$ So basically your answer shows that the JLCPCB impedance calculator results are generally in the same ballpark as the proven field simulators. Edge Coupled Microstrip Impedance Calculator. When you use a line calculator with a proper 'diff pair' mode, it will take account of the geometry and the correct driving conditions, and provide you with a pair of lines that has 100 ohms differential impedance, and two lines of 50 ohms impedance when the other line is driven with an inverted signal. Image Credit: Maxfield EEWeb - Stacking the traces calls for a tight layer to layer registration requirement. Also note that your best bet may actually be VERY SHORT (few mm) traces, a thinner board or a 4 layer board :-) Thanks for your suggestions. has two length-matched 45 Ohm lines. The Layer Stack Manager's impedance calculator uses the Wideband Debye model, with a default frequency. To update trace width, select the traces of interest and use the "Route > Retrace Selected" command. Stripline. Click on Setup -> Constraints > Electrical Constraints Set - > Differential Pair Value - > Calculator > If you put 10 in the Line Width, the calculator calculates the single ended as well as differential impedance. This calculator requires symmetry in the trace widths and location between plane layers. 063” FR4 PCB has about 52Ω impedance. . 3mm of the microcontroller), therefore i rounded the width to 0. Every trace has series inductance. Note: The results are only for approximation and rough estimation, the final values and the. How to calculate differential impedance: Notes. The capacitor value may be traded off to. where Z 0,surf can be computed as specified in Eq. Differential Stripline Impedance Calculator. EEWeb offers a free online twisted pair impedance (transmission line) calculator. ZL =. Differential impedance. Stripline Impedance Calculator Embedded Microstrip Impedance Calculator Microstrip Impedance Calculator Dielectric Thickness (mils) C Dual Stripline Impedance Calculator Asymetric Stripline Impedance Calculator Zo Equation: IPC-D-317A (Eq. pair impedance with predifined traces’ gap. When selecting trace geometry, priority should be given to matching the differential impedance over the single ended impedance. Printed Circuit Board Width Tool . 0. The formula used in this calculator is an approximation for the characteristic impedance of a coplanar waveguide: scssCopy code. Atlas Si for VNA – Insertion loss test system – Delta-L 4. To summarize, the common and differential. Regarding the impedance of USB signal traces the layout guidelines state: DP, DM Differential trace impedance = [DP(45ohm) + DM(45ohm)] = 90 ohm, and do not jump the DP DM signals that cause impedance miss match. x allows an easy way to make differential pairs and keep control of the trace length, thus the phase or skew between the traces. Check here: UltraCAD's new Differential Impedance calculator will calculate single-ended and differential impedance for the common configurations we all deal with: Microstrip. Use several of them and compare. 3 Answers. This calculator. This assumes ~0 trace thickness. It renders accurate results suitable for use in circuit board. Single ended. Microstrip allows for thinner flexible. This permits higher differential trace impedance and wider, lower loss traces. with the following layout parameters (width|space|width): Ohm. Such a microstrip is constructed with two traces referenced to the same reference plane with a dielectric material between them. Differential impedance: This is the impedance of a pair of transmission lines. The following formula is used to calculate the differential impedance of a microstrip: To calculate the differential impedance of a microstrip, divide the characteristic impedance of the microstrip by 2. 2mm from the ground plane below. The differential 100 Ohms line has width 0. 5. Since PIe edge connector’s character impedance is 85Ω, the traces between the connector and I should be 85Ω -- the rest is usually set to 100Ω. Place your components, vias, coupling capacitors. KB: Fail to install possibly due to lack of admin privilege or virus protection software. This makes the problem of determining impedance much more complex, and building an initial lossless model requires a larger set of formulas. The Differential Pair Impedance Calculator is a specialized tool used in electrical engineering and signal integrity analysis to determine the characteristic impedance of a differential pair of transmission lines. Impedance control in flex stack-ups is essential to reduce signal reflections and achieve dependable signal integrity. The formula used in this calculator is an approximation for the characteristic impedance of a coplanar waveguide: scssCopy code. 15 mm and separation 0. 5. Microstrip impedance calculator. x. 2. 6mm 4 layer PCB, 1oz outer copper, 0. Inform the manufacturer about the number of layers, the value of. PCB Trace Width Calculator. Simply put, differential impedance is the instantaneous impedance of a pair of transmission lines when two complimentary signals are transmitted with opposite polarity. Get latest updates and offers. Controlled impedance traces can minimize signal reflections and thereby reduce propagation delay. x allows an easy way to make differential pairs and keep control of the trace length, thus the phase or skew between the traces. I created coplanar waveguide on the same layer as the differential pair to serve as a coupling for the diff pair. Using a differential pair to avoid common mode noise is common in audio circuits. Z diff = 2* Z o (1 - 0. Although JLCPCB can produce boards with 2 oz external copper, the calculator only supports 1 oz because (1) the wider tolerance of 2 oz traces hinders impedance control, and (2) most signal traces only carries small currents. Select a trace impedance profile over the length of the taper. 29 mm width traces to obtain 100 Ohms ZDiff while using 0. Basically this is 2 parallel traces with a ground plane either side of the traces above a ground. Several Web sites such as the examples listed below contain additional reference information. Copper. The High speed protocol that is being designed for determines what the single and differential trace Impedance the traces need to meet as well as the tolerance for the impedance (e. Still, as you correctly analyzed it is much better to think of the individual lines in a differential pair as two length-matched single-ended lines, both with the half impedance. Coplanar Waveguide With Ground Characteristic Impedance Calculator. As the driving frequency increases, mutual inductance between circuits in your board will cause the impedance of your power delivery network to increase. For example, with a thickness of 0. 1mm (3. 3mm of the microcontroller), therefore i rounded the width to 0. Note: valid for (w/h) from 0. calculate the impedance and capacitance of PCB traces. Performing PCB trace length matching vs frequency correctly requires considering the entire bandwidth of a propagating signal on a trace. 77 mm gave me a differential impedance very close to 90 Ω. Differential pairs are commonly found in high-speed data communication systems, such as those used in computer interfaces (e. 1. The ground plane helps. I've used ADI's Diff Amp Calculator since I started this circuit (quite a long time ago) and it helped a lot. g. Remember to maintain 100 Ω differential impedance. 1 or 4. It is admittedly small, but it is non-zero. 8. Cancel; Up 0 Down; Cancel;. The calculator is set up to handle an asymmetric arrangement, where traces are not centrally located in the PCB layer stack. Target impedance and tolerance analysis for a particular trace . Speedstack is the stackup design tool of choice for professional PCB Designers fabricators and brokers who have a requirement to document and design stackups drill plans and material requirements complete with high speed transmissionline information. Embedded Microstrip. Changing the stack-up will affect the calculated trace width for impedance-controlled traces; however it will not automatically update existing traces. pair impedance with predifined traces’ gap. 6mm thick. Home;. 0 specs requires a differential impedance of 90 Ohms and a common mode impedance of 30 Ohms (with some tolerance). When enabled. Figure 5. 8. 36) Co Equation: IPC-D-317A (Eq. Standard 4-Layer Stackup. In terms of how these calculators work, the impedance of a transmission line in a PCB can be calculated in four ways: Use the R, L, C, G parameters from the Telegrapher’s equations to calculate the impedance of the transmission line. 6. You can use Equation 5 to calculate the impedance of a microstrip trace. Ensuring impedance-controlled routing also requires knowledge of the substrate’s dielectric constant and your required trace width. Back to Resources Use our free impedance calculator to ensure your design is error-free! Impedance Calculator Structure Type Single Ended Differential Trace width (W) mils Trace. There are 3 types of single-ended models: single-ended non-coplanar, coplanar single-ended, and coplanar single-ended without ground. Impedance captures the real and complex. 5 mil (0. A 3D view of a complex impedance controlled PCB in Altium Designer. This calculator allows you to add the impedance model and compute the desired trace geometry and spacing for a target impedance. Is there any reason not to use these values? If you can fit a design with larger gaps and wider traces, then the differential impedance will be less sensitive to over-etching or under-etching during pcb fabrication. Input the known values, and let the calculator determine the unknown. W is calculated to achieve a trace impedance (Z0) of ~50W and S is calculated to achieve a differential trace impedance of 90W. We get a lot of questions about trace impedance and how to calculate the right trace size to hit a specific impedance in a manufacturable PCB. Z 0 Differential impedance (Ω): Calculate. some trace calculation examples. I found that a W of 0. If you put 10 in the Line Width, the calculator calculates the single ended as well as differential impedance. This would be more manageable. AC Termination: AC Termination of a line results in the lowest power drain, but also requires two parts. Speedstack is the stackup design tool of choice for professional PCB Designers fabricators and brokers who have a requirement to document and design stackups drill plans and material requirements complete with high. If the width of the trace is two times the height of the dielectric (for FR4, Dk from 4 to 4. To get the correct parameters, we have to use the specifications from our PCB house and the provided calculator. Trace thickness is 0. Atlas Si for TDR. Distance between tracks (s) = 254 micron. Example. 2. Z diff equals Ra||(2Rb) (p model) or 2R 1 (T model). Most popular calculators don’t even have a box height parameter. So, let’s finish this. We get a lot of questions about trace impedance and how to calculate the right trace size to hit a specific impedance in a manufacturable PCB. Use an impedance calculator to determine the trace width (W) and spacing (S) required for the specific board stack-up being used. Enter the differential impedance you want, the trace width, the dielectric height, the dielectric constant, and the trace thickness, and click the. Sierra Circuits’ Via Impedance Calculator uses the physical dimensions of a via to calculate its capacitance, inductance, and impedance. While this calculator will provide a baseline, any final design considerations should be made towards loss, dispersion, copper roughness, phase shift, etc. Need to consider this if the data rate is 5 Gbps and above. Unit: Options are mm, mil, μm,. To the extent that the differential impedance is less than 100 Ohms, it is due to mutual coupling. The edge couple differential microstrip transmission line is a common technique for routing differential traces. Differential impedance is a two-step process, first Calculate the single ended impedance Zo and then use this value. I would like to increase the width of my traces whilst maintaining the same ~50 Ohm nominal characteristic impedance of my line. So, the trace width and distance to adjacent reference plane is determined by the desired. Impedance and PCB Stacking The trace impedance is affected by many factors such as the width of the trace, th e thickness of the copper, the PCB material, the PCB stacking specification, and the spacing between the differential pairs. Go to ‘ Design’ >> ‘Classes’ >> ‘Net classes. Description. 1. This sets the single-ended impedance AND differential impedance to the target value, even if there is no. 25, but gives me nice trace from the module to the stub then to microcontroller. D = Distance between two differential pair signals; W = Width of a trace in a. Assuming both are accurate enough. 1. Microstrip Trace Impedance vs. Also, be aware, 90 ohms is the differential impedance, the characteristic or single ended impedance will be more than half (ie. Impedance Calculator - Sierra Circuits. They will often lead you astray, unless you only have one trace on your board, or surrounding traces are a centimeter away. Using a power plane as signal reference. My board house can do 5/5 mil trace/space. 9 Ohms). 093. The calculator below uses Wadell’s. Class creation for controlled impedance routing using Altium Designer. Just as important as determining an appropriate trace width for a single-ended trace is. To maximize signal integrity, proper routing techniques for differential signals are important for high-speed designs. Going to 100 ohms diff you would be looking at 15 mil parallel traces. PCB Trace Impedance Calculator. While commonly constructed using printed circuit boards, this structure can also be built using other materials as long as there is a conductor separated from. Single and differential coplanar structures; Multiple adjacent dielectric layers, with different dielectric properties. Microstrip Impedance -Differential Stripline Impedance -Differential W = Width of the trace H = Height of dielectric above theThe trace width is important as it determines the single-ended and differential impedance, capacitance, and inductance. Make it 100 mil wide, 20 mil wide, 4 mil wide, doesn't matter. The DC resistance is determined by the trace's conductivity and the cross-sectional area. ISO 11898 requires a cable with a nominal impedance of 120 Ω; therefore, you should use 120 Ω resistors for. 75 mm track on a 0. I've used 7 mil trace width with 5 mil spacing, top and bottom layers (35um copper) are 0. The JLCPCB results are more reliable than (some of) the simple formula-based approaches. • Ground planes must not be broken in the GND reference layer immediately beneath he transmission line. Instead, field solvers normally focus on impedance and calculating the current distribution around the trace. H= Distance between signal trace and ground plane. Figure 25 shows a differential pair using the microstrip layout. Trace impedance control is a simple matter of properly sizing traces. The PCB Impedance Calculator in Altium Designer. Differential Stripline Impedance Calculator. 0. Mode Pattern for Identical Traces Hyperlynx simulation +1v -1v +1v +1v Mode: odd, or 1, or a Mode: even, or 2, or b Corresponds to differential driven Corresponds to common driven I odd x I. 3. SATA: 90Ω ±15%: 55Ω ±15%: 3. Asymmetric Stripline. 3 shall be used. Stripline. For context, as I understand it, the Ethernet pairs between the PHY and magnetics need to be impedance controlled to 100ohm and they need to be routed (ideally) in parallel, and the trace space and trace width are important variables in the impedance control. The tool implements numerical solutions of Maxwell’s equations to render accurate and consistent results. 2H, the formula for the non-embedded. If the negative trace in a differential signal is a higher voltage than the positive trace, then you have a high logic state, and if it’s the other way around, then you have a low logic state. Several online tools can calculate the required trace width to carry rated current while keeping the trace temperature below a specified limit. This calculator finds both odd and even transmission line impedance, including four different types of impedance used in characterizing differential trace impedances, for microwave antennas, couplers and filters applications. Edit: also, think ahead if you are going to use ground pours around the traces. Differential Pair Impedance Calculator Our impedance calculator features two main types of impedance models, single-ended and differential, within each trace structure. Thus a "differential pair" any long distance apart will have an impedance of 98 ohms, without any coupling between the lines, i. The extracted model includes distributed parameters for resistance, capacitance, and inductance, as shown in Figure. The differential impedance is always smaller than twice the single. when two coupled tracks are used to give a differential impedance. The reference plane is not far enough to accommodate 100-ohm differential impedance. PCB Impedance and Capacitance Calculator: Asymmetric Differential Stripline. Figure 25. Figure 8. The test sample consists of a pair of differential traces at the top layer, followed by a differential via to the inner traces, then a second differential via connects to the BGA landing pads at the top layer again. They will trim the trace width based on their experience with their stackup, accordingly. To meet those requirements I used some online impedance calculators to estimate the required trace properties for a. Differential Trace Routing. Back to Resources Use our free impedance calculator to ensure your design is error-free! Impedance Calculator Structure Type Single Ended. Question #1: How to determine the required spacing between length-matched signals or differential pairs and the adjacent layers? If you are length matching that implies that the interface is probably fast enough to require controlled impedance. I have a 2 layers board, using FR-4 (Er=4. Enter the relative permitivity, width of the trace, the ground plane spacing, and the substrate thickness to calculate the characteristic impedance. Stripline Impedance. Instructions are below the calculator and don’t forget we can make and test your controlled impedance printed circuit boards too. I used some online calculator to calculate parameters of trace so it has 50 Ohm impedance. 3 Answers. We get a lot of questions about trace impedance and how to calculate the right trace size to hit a specific impedance in a manufacturable PCB. Unfortunately Online Calculators are deceiving unless you actually draw the numbers and understand the ratios and tolerance effects. 1 to 3. 1 to 2. If you need to use differential pairs, you simply define traces in each layer as differential pairs and the impedance calculator will determine the correct spacing between traces. We get a lot of questions about trace. Adjust the length matching to achieve propagation delay. To use this tool, enter the values for trace thickness, substrate height, trace width, trace spacing and subtrate dielectric in the calculator above and press the "calculate" button. When routing the board, make sure to make that trace width unique. Multiply the result by the square root of the ratio of (1 + (2 * h / w)) to (1 – (2 * h / w)). Dielectric Constant, Ε r: Trace Width, w in mils : Trace separation, d in mils : Trace thickness, t in mils : Dielectric thickness, h in mils : OUTPUTS Characteristic impedance in Ohms : Differential microstrip impedance in Ohms : *Note: This calculator is valid for (W/h) in range from 0. EasyEDA directly supports controlled impedance designs for 4 and 6 layer PCBs only. 1 mm trace spacing chosen in your design. Z 0 = Single Ended Impedance. Typical impedance tolerances are 10% and 7%, and can go as low as 5% or 2% in the extreme cases. The source for formulas used in this calculator (except where otherwise noted) is the Design Guide for Electronic Packaging Utilizing High-Speed Techniques (4th Working Draft, IPC-2251, February 2001. Compatible with Flex PCBs and Turnkey PRO service. Enter the differential impedance you want, the trace width, the dielectric height, the dielectric constant, and the trace thickness, and click the. To get the correct parameters, we have to use the specifications from our PCB house and the provided calculator. 159 OS X 10_15_7 EasyEDA. For differential pairs of microstrips, the formulas involved are much more complicated because coupling between the traces in the differential pair must be included in the impedance calculation. But to find a PCB routing system that calculates trace widths automatically factoring dielectric constants and the board layer stackup, and then. com To use this tool, enter the values for trace thickness, substrate height, trace width, trace spacing and subtrate dielectric in the calculator above and press the "calculate" button. These important design features are incorporated into your design rules, making impedance-controlled routing quick and easy. One thing is for sure: When you are routing a high-speed PCB design you are going to be working with impedance-controlled routing and. 19mm) traces with 7. Microstrip Trace Impedance Calculator; Stripline Trace Impedance Calculator; Differential Trace Microstrip Impedance Calculator; Differential Trace Stripline Impedance Calculator; The. This calculator is designed to find the characteristic impedance of an asymmetric stripline - a flat conductor between two ground planes. mils: Distance between planes (B) mils: Relative Dielectric constant (Er) Differential. They are very simple to read, and the values in. Differential Impedance Ω. Figure 3. The calculator by Spok consulting, for example, gave the following result: Problem. DDR4 Impedance Values. Coplanar Waveguide Calculator. PCB Impedance-Calculation: Help with the dimensioning of the impedances of your circuit board. 1 Effective Permittivity and Characteristic Impedance of CPW. Tightly coupled pairs (within a pair) are quite common and this has the advantage of having a somewhat higher single ended impedance on a per track basis within a differential pair which is often easier to implement. Press the Analyze button to calculate the electrical parameters. Separation between the coupled differential trace pairs must be 1x.