. EEWeb offers a free online broadside coupled stripline impedance calculator. Differential Pair Impedance Calculator. 1mm (3. Just as important as determining an appropriate trace width for a single-ended trace is determination of an appropriate spacing between two traces in a differential pair. Click here to see the user guide of our impedance calculator. distance between the differential stripline pair: er: relative permittivity of the dielectric: Electrical Parameter Definitions: Zo:In PCB design software with a built-in impedance calculator function, you can calculate impedance quickly. For double termination, we want the source to provide R S = 50 W on each side for 100-W differential output impedance, and we want the input of the FDA to present a 100-W dif-ferential load. The calculator shown below uses Wadell’s. Visit to learn more about our other electrical engineering tools and resources. Most online calculators do not account for copper roughness. It uses the lan9512 reference schematic. We’ll go over how differential pairs can hel. D+ and D-) _P/_N (e. g. This will create the differential pair. 3mm of the microcontroller), therefore i rounded the width to 0. To calculate this, you need some values. Although widely applied to coaxial cables against EMI susceptibility problems, the Zt parameter can be easily extended to coaxial cables EMI emissions. A web-based tool to calculate the impedance of your PCB traces and vias. – Microstrip lines are either on the top or bottom layer of a PCB. For Si engineers & PCB technologists. Use an online differential stripline impedance calculator. In the time domain, we only care that the two ends of the differential pair cross the halfway transition between the HI and LOW states (assuming binary) at the same instant in time. Differential Impedance in Constraint Manager Advanced Constraints can be used to view the Differential Impedance in Constraint Manager. Ethernet lines are differential pairs with a differential impedance of 100 Ohms. It's true that generally the impedance value is determined by the following parameters; trace layer (microstrip or stripline), trace width, distance. They are recommening to use 3th party calculators. This transmission line calculator was. Those pairs connect via a dedicated FFC cable. g. Converts short and long line . D_P and D_N) KiCad looks for these suffix pairs when using the differential pair routing tool during PCB layout. Compatible with Flex PCBs and Turnkey PRO service. Spacing and width value pairs that will give a differential impedance of 100 Ohms on Dk = 4. KiCad has a built-in impedance calculator!The common-mode rejection ratio is a key figure of merit of any differential system because its primary role is to reject undesired common-mode currents with minimal impact on the desired differential-mode currents. The resultant current is called common-mode current. The trace impedance calculators that design tools often provide can be used to. 3. Two single-ended transmission lines with coupling are also known as a differential pair, as shown in Figure 5. Single-ended signals are fairly straightforward. Phone: +44 (0)1425 489 111 / +49 (0) 8104 628 0. Use that. Note: If this post answers your question, please click the Correct Answer button. Before we can start routing the PCB, we need to define Design Rules for our differential traces. The procedure for calculating the differential impedance of an interconnect with a differential via transition is iterative; you calculate the input impedance from the. When you are creating your schematic, you must use one of the following suffixes when naming your differential pair nets: +/- (e. The differential pair—sometimes called the long-tailed pair—is a widely used building block in electronic circuits, particularly in op amps. A mistake was made when designing a set of mother and daughter PCBs, resulting the daughter board to have its LVDS pairs at ~100Ω differential impedance, while the motherboard ~90Ω. Use via-s (absolutely not recommended for impedance-critical routes) hack the connector and remove some of its SMD pins, and wire one pair under those pins. Not too tricky. . 5mil clearance on a 63 mil board (1. This value is often given the name “differential impedance. If you use two of those and operate them differentially !!! then the characteristic impedance can be treated as a 100 Ohms differential impedance. 1. In this study, Keysight’s Path Wave Advanced System Designer, ADS, which has an integrated 2D field solver, was used for the analysis of a virtual prototype. At the receiver, the signal is recovered by taking the difference between the signal levels on. Click on Net -> All Layers -> Line under the Spacing Constraint Set. Choose a calculator to tune your PCB design. When we talk about single-ended transmission lines with coupling, we are usually interested in their single-ended properties like characteristic impedance (Zo), phase delay, and NEXT/FEXT relationships as described above. ) and the LOW level is defined as zero. USB traces must be 90 Ohms differential. to NFThe impedance of the structure is the ratio of the voltage between, and the current in, the conductors. . Microstrip Impedance Calculator. The differential impedance will be a bit less than 2x the single-ended impedance. The return path is defined by the reference plane near the pairs and the distance between the two pairs. Compatible with Flex PCBs and Turnkey PRO service. Differential pairs are becoming common place in high speed design reducing. Ask the board manufacturer for the values. These values are trace width, substrate heights, substrate dielectric, and trace thickness. Components such as capacitors, resistors or active devices are generally soldered on the PCB. Differential Protocol: Select the desired protocol from the dropdown list, this list will autofill the Target ZDiff edit box. Some differential impedance requirement for differential pairs, where the signals must be routed together Just as an example, consider a 2-layer board on standard thickness 62 mil core (Dk = 4. 4mils/35um of copper thickness. No, the single-ended impedance provided in differential line calculators does not matter. The calculator is available in the Electrical Domain in Constraint Manager, from theTable 1-1. . Differential Impedance ($$Z_{0_{diff}}$$): The impedance between the two lines with opposite polarity signals. The auto-router will add a trace to match the longest trace as shown in Figure 5. Altium Designer’s differential line impedance calculator will set up your impedance-controlled differential pair routing widths for you. ETA: USB 2. 5 mil (0. I used the KiCAD PCB calculator, asked the PCB manufacturer about the tangent loss (0. First, consider a microstrip. Anyone know of any free software that can do that? The only one I was able to find was Si9000 and Si8000m by Polar instruments, but they aren't free. D_P and D_N) KiCad looks for these suffix pairs when using the differential pair routing tool during PCB layout. Now let’s incorporate the finite output resistance: And next we recall that the small-signal analysis technique. Twisted Pair Impedance Calculator . Download Saturn Pcb Design Toolkit. We recommend the software from Polar Instruments if you want to get exact impedance calculation. 300" away from the Ethernet front end. The two traces of a pair should be symmetrically routed. To use these to design for a target impedance, simply cycle through various geometric values for the trace width until the calculator returns the target. 6), the impedance will be approximately 50 Ohms. The JLCPCB results are more reliable than (some of) the simple formula-based approaches. 5mm pitch has about 100 ohm differential impedance in the configuration where a differential data pair wires are between ground. 01) and dielectric constant (3. 1 is an example of making tradeoffs between routing layers and power plane capacitance for a ten-layer PCB. The single 50 Ohms is the impedance of a single-ended transmission line that has a ground connection. Differential pairs are defined on the schematic by placing a Differential Pair directive (Place » Directive) on each of the nets in the pair. With t = 35 um (typical for copper with plating on a pcb), Z odd drops to 44 ohms, according to LineCalc. The calculation looks correct, but the tracks are too wide. where Z 0,surf can be computed as specified in Eq. 035 mm. Design Parameters. This curve defines. When dealing with differential pairs, thi. Modeling approximation can be used to understand the impedance of. It is assumed that the output impedance of the. THESE FORMULAS ARE APPROXIMATIONS! They should not be used when a high degree of accuracy is required. Z 0 now meets your requirements. We care about maintaining the same differential impedance for. We will again use the formula method instead of the 2D field solver. The best differential coplanar waveguide calculator can account for all of these effects simultaneously and without a complex 3D field solver. Agilent's LineCalc tool calculates Z odd = 50. In the case where you are routing differential pairs, then the potential between the two pairs will always be opposing (i. Our Impedance Calculator uses a 2D field solver to calculate near-end crosstalk based on the following equation: NEXT = V b /V a = ¼ (C mL / C L + L mL / L L). Simply put, differential impedance is the instantaneous impedance of a pair of transmission lines when two complimentary signals are transmitted with opposite polarity. Differential pairs with vias and right-angle bends are acceptable. Differential pairs should be tightly coupled throughout their entire length, so try to avoid variations due to pads, vias, or components along the routing path. 03556mm. 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. If you do something else with the. This calculator is designed to calculate the characteristic impedance of an edge-coupled microstrip. Ideally the traces in the differential pair only interact with each other, as another answer said. We often say that PCB traces should simply have 50 Ohm impedance, but this becomes more complicated when dealing with coupling between differential pairs. 25mm between the differential pair with a width of 0. Read high-speed and HDI PCB design strategies by Syed Ubaid Ali Warsi to get expert advice on high-speed and HDI. 5; w, t, s, h > 0;Changing the stack-up will affect the calculated trace width for impedance-controlled traces; however it will not automatically update existing traces. The even mode impedance is simply the impedance of a single line when the two lines are driven. Sierra Circuits’ Via Impedance Calculator uses the physical dimensions of a via to calculate its capacitance, inductance, and impedance. This calculator is designed to calculate the characteristic impedance of a broadside couple stripline (see diagram below). The topology pre-dates the solid-state era and is generally attributed to Alan Blumlein, when it appeared in one of his patents in 1936. This tool will also provide the signal propagation delay,. As the signals are also referenced to ground, each differential pair signal also has a single ended impedance. Altium Designer makes it easy to calculate geometry when you need to calculate impedance for differential pairs. And since no return current flows through ground (or so it is assumed) then the terminating resisters are connected in series between Traces 1 and 2, and the correct terminating impedance is calculated as 2(Zo – Z12). PCB Impedance and Capacitance Calculator: Asymmetric Stripline. Now it has only one narrow track/via for GND connection. This sets the single-ended impedance AND differential impedance to the target value, even if there is no. Capacitance (C) = pF/ cm. Zdiff is the impedance between the two traces of a differential pair which equals 2 x Zodd Zcom is the impedance between the two traces of a common mode pair which equals Zeven / 2 Edit: You may have noticed that the mantaro calculators give a slightly different result of 12 mil and 12 mil. edu; Home; Members. I tried using different line width (10mils,15mils,20mils,25mils,30mils) of the differential pair but it doesn’t help me. Then Right click -> Create-> Differential pair. But in your differential pair, each line will have its own characteristic impedance, lower than 100 Ohms but higher than 50 Ohms (for instance a quick computing in Saturn PCB give me 77. This is the same reason we have to consider spacing between traces in differential pairs: the two conductors interact with each other to determine the odd-mode (and differential) impedance . The guides says spacing under 0. This technique is used for routing internal layer differential pairs. It can't be used with differential pairs, which are dominantly used with impedance-controlled high-speed signals;. e. 2. Using this calculator, I found 100 Ohms by giving 9 mils of track width, 5 mils of track separation, 8 mils of dielectric (prepregs usually have a dielectric constant of 3. Fig 1 Typical Pi termination for a coupled line pair. Joined Jan 22, 2008 Messages 51,800 Helped 14,703 Reputation 29,682 Reaction score 13,944 Trophy points 1,393 LocationWhile there are a number of online calculators that calculate the characteristic impedance from the input geometry, they are all based on approximations. 5oz inner copper, 8 mil trace spacing) and a target differential impedance of 100 ohms, JLC's calculator suggests a trace width of 8. The Smith Chart achieves this by superimposing a grid on S11 that maps load impedance. look at a differential source driving a twisted pair to the FDA. 1,235. It incorporates many features that PCB designers and engineers are in regular need of like current capacity of a PCB trace, via current, differential pairs and much more. The differential impedance target, as well as the single-ended impedance of each trace, is maintained by keeping the spacing between the two traces constant. 0. The closer you place the pairs together, the differential impedance gets smaller because LM and CM get larger. The stackup design is very crucial for the manufacturing of a controlled impedance PCB. When enabled. Critical Signals (continued) Signal Name Description HDMI_DATA1x High-Definition Multimedia Interface (HDMI) differential data pair, positive or negativeFor example, the equation for the trace impedance in a differential pair of asymmetric striplines includes an approximation on the dielectric constant and geometry. Choose a calculator to tune your PCB design. The maximum skew introduced by the cable between the differential signaling pair (i. Disc Air Capacitor Calculator; Impedance Calculator : XL, XC; Inductors, Transformers. • Keep the intra-pair and inter-pair skew between the device and RJ45 to less than 50 and 600 mils. 0. Download Saturn Pcb Design Toolkit. • Differential pairs should be routed away from all other traces. 6 ohms and Z even = 110 ohms for your geometry, very close to your result. Adjust the distance "s". Another example of using large distances to separate out unwanted components might be to calculate the impedance of a. Layers: Total number of copper layers in. 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. 8 substrates of various thicknesses. The resistance value chosen for the two resistors will be referred to as R D (for d rain resistance). too. PCB Trace Impedance Calculator; Electromagnetic Compatibility Laboratory. Enter the relative permitivity, width of the trace, the ground plane spacing, and the substrate thickness to calculate the characteristic impedance. To set the rules for the classes we created above, we will follow these steps: Go to ‘Design’ >> ‘Rules. The PCB Impedance Calculator in Altium Designer. The main takeaway for me: To get to around 80 ohms, I should not pull ground on the signal. You can calculate it with the following equation: Z (z) = V (z)/I (z). 1. is the impedance between two differential pair signal traces. The differential pair impedance depends on the characteristic impedance and the spacing between each end of the differential pair. For complex impedance matching, the input impedance is important as this is the impedance seen by a. Dimensional units: mm mils. When you are creating your schematic, you must use one of the following suffixes when naming your differential pair nets: +/- (e. These calculators give us essential trace spacing and differential pair spacing if needed. To use this calculator, simply input your microstrip geometry and Dk value, and the tool will return the differential impedance value for a pair of microstrip traces. The track widths should. It also explains the factors that affect the impedance, such as trace width, dielectric constant, and frequency. While this calculator will provide a baseline, any final design considerations should be made towards loss, dispersion. This will give us the appropriate trace width and trace separation for the desired differential impedance. The other yellow rectangle is the USB connector. 75 inches without impedance control; Keep the differential pair length mismatch within 0. If you control impedance, you place a tolerance in the fabrication notes. Sierra Circuits’ Via Impedance Calculator uses the physical dimensions of a via to calculate its capacitance, inductance, and impedance. No matter what the case was, if you did not have an impedance calculator, you had to rely on measurements, or some other data set to get an accurate value for trace width in your PCB. Calculating the impedance . Coaxial Line Impedance. D+ and D-) _P/_N (e. Careful differential pair routing, impedance control, grounding, and noise reduction techniques are key factors for performance optimization. The same applies to differential pairs. Build a model from experimental data of impedance vs. Several equations are. Note: Use the following guidelines when using two differential pairs: D = Distance between two differential pair signals; W = Width of a trace in a differential pair; S = Distance between the trace in a differential pair; and H = Dielectric height above the group plane. 9. If you have placed Differential Pair directives on nets in the schematic, the default project options settings will result in the differential pairs members being created on the PCB. Unfortunately, stating “should match the input impedance of the differential vias/pads” in Point #3 is easier said than done. Advanced simulation and analysis tools can. This is more than the to times trace width which is recommended (also read as close as possibly). 3. 10, 11. You will want to control impedance with smaller variations in gap. Voltage Divider Calculator 1 (Fixed) Voltage Divider Calculator 2 (Adjusteable) Capacitors. Just enter the given values for trace thickness. As discussed previously, the lengths of the two lines in the pair must be the same length. I have a 2 layer 1. Track and gap widths are of concern in controlled impedance, but unless your speaker and mic connections (I assume audio frequencies) are going a long way you should not have any particular requirement for controlled impedance. Simply put, differential impedance is the instantaneous impedance of a pair of transmission lines when two complimentary signals are transmitted with opposite polarity. Several equations are. Track and gap widths are of concern in controlled impedance, but unless your speaker and mic connections (I assume audio frequencies) are going a long way you should not have any particular. In case you need to calculate single ended or differential pair impedance on your PCB, try following links: I use Microstrip & Stripline calculator developed by Jean Nicolle. DP, DM Differential trace impedance = [DP(45ohm) + DM(45ohm)] = 90 ohm, and do not jump the DP DM signals that cause impedance miss match To meet those requirements I used some online impedance calculators to estimate the required trace properties for a 2-layer FR4 PCB. 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 differential pairs. LVDS PCB layout guidelines can be used for optimizing system performance by ensuring reliable signal integrity and reducing the chances of noise interference. Use an online differential microstrip impedance calculator. , equal in magnitude but opposite in polarity). Use several of them and compare. One of the features of this type of microstrip is the coupling between lines. Download the file here. Differential impedance is defined as impedance between the two lines when the line pair is driven differentially. Differential Pair Impedance Calculator Calculates the differential pair impedance of a balanced line. balanced), above a ground plane, have an impedance. Coplanar Waveguide With Ground Characteristic Impedance Calculator. The twisted pair helps create a more. Such a stripline is. Since stripline traces are typicallyThis is why the differential impedance of a differential pair is often (but not always) slightly lower than two times the single-ended impedance of an individual trace. As you route your board, the built-in trace length calculator will check your routing against your design rules and flag errors for correction. . Only a 2D field solver can accurately calculate the differential impedance. The two ends of a differential pair must be the same length. You can define Min Line Spacing, Primary Gap, Primary Width, Neck Gap, Neck Width, + and – Tolerance as either a Physical or Electrical CSet. 90 Ohm Differential Pair: 0. 6mm FR4 PCB with 7628 type stackup (4 layers), the above specifications usually result in 4. PCB manufacturer normally provides information about PCB stackup and track geometry. To achieve this, I used the built-in Calculator in KiCad. e. Board. manufactures will have a preferred tool that PCB designers can use to calculate the Impedance but there are also many available online. 4 Comments. 5mil trace + 4mil spacing - which is close to their absolute minimum). . Note: Units do not matter for this calculation as long as they are consistent. It renders fairly accurate results suitable for use in circuit board manufacturing and engineering analysis. 3. The characteristic impedance is given by: Eq. Mutual inductance and capacitance exist between the two traces in a differential pair. The reason for this is that the input impedance is what matters, and the input impedance at the via transition will look like the trace impedance (i. • If finite tail impedance and asymmetry are both. Use via-s (absolutely not recommended for impedance-critical routes) hack the connector and remove some of its SMD pins, and wire one pair under those pins. I have no luck finding an asymmetric differential stripline impedance calculator online. trace geometry, and use this to calculate. These calculators will return an impedance value for pairs of trace width, substrate thickness, and copper weight values. ; To. It combines the power of an N-channel MOSFET with a P-channel MOSFET in a single package. For microstrip traces, a solid ground plane is needed under the signal traces. 2Distance units: Substrate Height, H Trace Width, W Thickness, TFigure 1. Advanced simulation and analysis tools can. 25, but gives me nice trace from the module to the stub then to microcontroller. 08mm - this is the border of manufacturability, I don't think it is practical to go there but for the calculation it is just fun - and I get some 31Ohms. There is a slightly different, but tightly coupled question here with this impedance calculator: "stripline differential impedance": Stripline here seems to be placed in some inside layer. Modeling approximation can be used to design the microstrip trace. If I calculate it for embedded edge coupled differential pair, it is still only 39. Impedance Calculator - Sierra Circuits. Enter your board parameters and get instant results. 1. Differential pair impedance depends on a lot of variables in reality,. 5mil (7628 prepreg) when tracks are inside. button. (2. This is an approximate critical ratio. A PCB impedance calculator is necessary to set the constraints for trace structures during fabrication; they can vary in complexity, speed, and accuracy. For differential pairs, see the addition at the end of the tutorial. Such a stripline is constructed with two traces referenced to the same reference planes above and below the traces with a dielectric material between them. Even mode impedance for commonly-driven transmission lines . A pair of tracks of the same cross-section (i. PCB manufacturer normally provides information about PCB stackup and track geometry. I am trying to design a CAN bus node. look at a differential source driving a twisted pair to the FDA. 25. I believe the 100-ohm differential equates to 50-ohm single ended because you can think of the two 100-ohm impedances as being in parallel resulting in an effective 50-ohm single-ended equivalence. Staff member. Differential pair routing. 2 High-Speed Signal Trace Lengths As with all high-speed signals, keep total trace length for signal pairs to a minimum. If R G = 402 W, we then need R T to be 114. Grounded Differential Coplanar Wave Guide. This sheet has the FTDI chip which converts the input serial signal into a USB differential signal. Even mode impedance is defined as impedance of a single transmission line when the two lines in a pair are driven with a common mode signal (the same amplitude and the same polarity). 100 Ohm Differential Pair: 0. Typical values for most common differential signal types are 90 ohms differential, 100 ohms differential or 120 ohms differential. the odd mode inductance and capacitance per unit length. Just as important as determining an. Twisted pairs are used with balanced signals. Differential impedance is twice the odd mode impedance. This is a tool that has been designed to determine the characteristic impedance (Z 0) of a twisted-pair cable. Return loss is an important parameter that indicates how well the impedance matches with aFor differential vias, stitching vias can affect the impedance, but the impedance is much more sensitive to antipad sizes and layer arrangement/Dk value on each layer. This rule maintains the desired signal impedance. a BJT differential pair that voltage is infinite. Learn how to design. To calculate the values, the designer needs to know the following information: Number of board layersDifferential Microstrip Impedance Formula or Equation. 3 V, etc. The required Impedance Profile is selected in the applicable Routing Width design rule (for individual nets), or Differential Pairs Routing design rule. Right-click and choose Change from the pop-up menu. Schelkunoff in 1934, is a very convenient parameter for the prediction and control of EMI coupling through cable shields. Using the formula, you can calculate the Differential Impedance (Zd) as follows: Zd = 2 * 100 / sqrt (1 + (2 * 100 / 20)) Zd = 200 / sqrt (1 + 10) Zd = 200 / sqrt (11) Zd ≈ 60. 0037” line/0. 8). There are single end trace impedance and distance between traces in the pair. The questions are mostly on the inner layer differential impedance item [4] below. As discussed in the first section of The MOSFET Differential Pair with Active Load, the magnitude of this amplifier’s gain is the MOSFET’s transconductance multiplied by the drain resistance: AV = gm ×RD A V = g m × R D. The differential impedance is the impedance measured across the two lines with the pair driven differentially. It is designed for precision signal. pairs for aciving 85 Ohm diff. I am routing LVDS pair on a flex board. The following are typical line widths and spacings for the more common impedance values when using ½ OZ copper: 50 Ohm Single Ended: 0. 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. You can make your own spread sheet using formulas provided by Wedell's book "Transmission Line Design Handbook" page 196, 197, 198 (attached)Relative dielectric constant (er) mm. The targeted impedance for diff pair is 100 ohms, which is dependent on the width/space between conductors and hight to the reference plane. For a printed circuit board (PCB) this is a pair of traces, also known as a differential pair. Differential Microstrip Impedance From Zo. Description. Zo (diff) is calculated to be 244 ohms, so dividing by two yields a value of 122 ohms for the semi-coplanar structure. How field solvers such as the Si8000/9000 calculate impedance. Yes, that's right. Vias (plated holes) are used to route electrical signals among different layers of a multilayer. Against the two rows select the. Stack Symmetry – enable to add layers in matching pairs, centered around the mid-dielectric layer. Maximum near end channel to channel cross talk for 100 Ohm, 5 mil wide differential pairs, as the channel to channel edge spacing increases. USB 2 e. Twisted Pair Impedance (Transmission Line) Calculator. . The differential impedance will be a bit less than 2x the single-ended impedance. g. 5 and I took 3. Finally, all calculators provide theoretical impedance values as they cannot take in to account the variables. There are 3 types of single-ended models: single-ended non-coplanar, coplanar single. MX6 Design recommendations about 100 Ohms for differential pair is quite reasonable for FlexCAN. Parallel Wire Impedance, Inductance, Capacitance and Propagation Delay Calculator Results. Fig 2b Equivalent. The i. In high-speed digital protocols, data is sent over single-ended traces in a PCB that is impedance controlled; each individual trace is designed to have a specific impedance. Check design with the online gerber viewer, Easy and quick PCB Price Calculator from JLCPCBTech Consultant Zach Peterson is talking Signal Integrity again today with a deep dive into Differential Impedance. In Altium Designer you can easily change the width of both of the differential pair tracks, but if you do so the gap of the diff pair changes depending on the change of the width. 1 of the Microstrip Calculator using H2 in place of h, εr,eff can be computed as specified in Eq. Modeling approximation can be used to understand the impedance of the edge couple differential stripline transmission line. 5) and 1. Using the KiCad Impedance Calculator. 0. 1. 9-Hole Score Differential Calculator. Signal layer. Therefore i tried using this paper to calculate a characteristic impedance of 60Ohm for a coplanar strip attaching the CAN-Transceiver to a Twisted Pair cable, the CAN bus medium. The ratio of cross-hatch conductor width (HW) to cross-hatch pitch (HP) plays an important role while characterizing the cross-hatch plane. Preferably, the length of the clock trace should be somewhere in between. Critical Signals (continued) Signal Name Description HDMI_DATA1x High-Definition Multimedia Interface (HDMI) differential data pair, positive or negativeFor example, the equation for the trace impedance in a differential pair of asymmetric striplines includes an approximation on the dielectric constant and geometry. Simons, "Coplanar Waveguide Circuits, Components, and Systems", Wiley. The calculator shows 90 ohms can be achieved using. Trophy points. Going through Saturn PCB Calculator - which is free and useful software for engineers. The impedance throughout the interconnect can be viewed by selecting the Impedance Vision option, which will again show a heat map with color-coded impedance values.