However, specific recommendations may vary, so it’s essential to refer to the planting instructions provided for each flower variety to ensure proper. There are a few different types of microvias. Either the desired impedance at a specific frequency is used to determine the waveguide width, or the width is entered and the impedance is calculated. )Flat Stripline Using PCB Techniques right after WWII. Cite. Figure 1: 3-D diagram of a single via . Any electronic device you design must be compliant with EMI standards set by regulatory boards like. Pick up the bar between the stitch you knit and the one you’re about to knit, bringing the needle from front to back. Increase evenly across a round: (k14, m1) repeat 4 times. By default, Finished Hole sizes (ENDSIZES) equal to or smaller (≤ or <=) 0. to make a solid 3D ground. 5). 6mm FR4, for 50Ω characteristic impedance (trust me). We might layout longer welds (4. (rignt click over plane edge,-> properties and name NET as GND) 2º make Back Ground plane. 77GHz is obtained. Note that vias are made out of plated copper which typically has a resistivity of 1. To determine the number of rows in the sleeve shaping, complete the following: (length of cuff to underarm - ribbing length - 2”) x row gauge = # of rows in sleeve shaping (round your answer to an even number) You will begin your sleeve shaping. 78 decimal inches (~ 3 3/4"). What is the formula for hooks? There’s no specific formula for hooks as they are typically spaced based on practical needs and aesthetics. Based on the resulting bandwidth, calculate the quarter wavelength to determine the maximum ground stitching via spacing. An additional method is to set the grid to the via spacing you would like (say 2. This tool helps in determining the current-carrying capacity in circuit boards. Angle: the inclination angle of the staircase. No. The design of vias, selection of board materials, board thickness, etc. In this case, I would always calculate exactly how many vias I will need to carry current. A via fence, also called a picket fence, is a structure used in planar electronic circuit technologies to improve isolation between components which would otherwise be coupled by electromagnetic fields. Place these stitching vias symmetrically within 200 mils (center-to-center, closer is better) of the signal transition vias. At PCB Trace Technologies Inc . Additionally, via stitching can be utilized to link isolated copper areas to their respective net. High-speed designs carry a requirement for controlled impedance, crosstalk control, and the need for interplane capacitance. e. area = √ 115. Step #5: Subtract the total divider width (14 in Step #4) from the total space width (48 in Step #1) to get a total space width of 34 decimal inches (48 - 14 = 34). Stop creating stitching holes before you hit the curve. . Like many aspects of a physical PCB layout, via stitching and copper pour can be like acid: quite useful if implemented properly, but also dangerous if used indiscriminately. 717 ton. 1, No. Effectively you have a grounded coplanar waveguide with the vias connecting the grounds. Figure 9 shows a good distribution of ground vias with each via marked by a ‘+’. This will create a new rule and display its details as you can see in the picture below. 6 - Restore all polygons (t + g + e) and repour all (t + g + a) Here is the result: Share. 65, in that case I use a 4mm stitch spacing, no crease and 3. Add 1 to this value and round up the answer to the next whole number: 7. Most board manufactures will have a preferred tool that PCB designers can use to calculate the Impedance but there are also many available online. For low-frequency designs, we recommend incorporating λ/20, and for high-frequency circuits, λ/10 spacing between stitching vias, where λ is the signal operational wavelength. In the article, The Darker Side – RF and high-speed PCBs: How to avoid basic mistakes”, Circuit Cellar 253, Robert Lacoste says, “Designing a double-sided PCB becomes complex when the ground plane gets shared. edge of the stitching via (d) is 17. Then. As I know, there exist limits on maximum current, a pcb via can tolerate before it melts before the via's temperature rises unacceptably high above ambient (say 10-100 C above ambient depending on application). Satin Spacing Space Settings. Coplanar waveguides are open quasi-TEM waveguide geometries that use copper pour and a ground plane to provide shielding along the length of a PCB trace. 5(double-sided PCB). in line with complexity. The use of copper pour and via stitching is sometimes framed as an always-never type of decision, and with a variety of explanations to justify its use or omission. In this case, 3 and 2. 5 MM away from either edge. I want to calculate what. Just drop vias were you want them. Currently plate "PA" is welded with a continuous 1/2" fillet weld top and bottom for the full length of the plate. is a necessity of design, but it can lead to some unpleasant consequences in a PCB layout if improperly harnessed. I am looking to reduce a continuous weld to a stitch weld to prevent warping during fabrication. “Guide spacing in fishing rods ensures even stress distribution and optimal casting. 020 inch (0. At PCB Trace Technologies Inc . A four-layer PCB with a GND-VCC-VCC-GND power bus Does the frequency actually relates to the fencing/stitching space, or placing the vias closer than the smallest λ/20 (for fencing) and λ/8 (for stitching) is all that matters? The frequency and the wavelength are intimately related, so the operating frequency has just as much to do with the via spacing as the wavelength does. Should I add ground stitching vias? 0. The Trapunto effect automatically moves underlying travel runs to the edges of an object so that they can’t be seen. With a single line of topstitching or edgestitching, stop at the corner with your the the down position, and pivot. Otherwise you can add say 4 0. This is based on the IEEE paper "Modeling Via Grounds in Microstrip" IEEE Microwave and Guided Wave Letters, Vol. You may also need to provide the space between each row. This calculator allows you to add the impedance model and compute the desired trace geometry and spacing for a target impedance. Control, structure and syntax of calculations. The IPC-2222 standard specifies minimum hole diameters for plated through-hole vias for different classes of vias as follows: Minimum hole size = Maximum lead diameter + 0. ”. This will change the number in the Plant spacing (s) field. This is the thickness of the copper on the top, bottom, in the vias and pads of the pcb. The space of Via GND can reduce to 4mm if you want. The general current carrying capacity equation is: I = (K) (𝝙T𝜷1) (A𝜷2) Where, I denotes the current in amperes, 𝝙T is the temperature change with respect to ambient temperature in °C, A is the cross-sectional area in mils, K is the correction factor which equals to 0. Stitch weld spacing formula. Here you will find calculators and charts to help with yardage and dimensions of circle, flare, and pleated skirts, You will be able to determine fabric based on waist circumference, waist height, depth and number of. What a Differential Pair Impedance Calculator Misses. For topstitching, quilting and decorative stitching use a longer stitch length (2. Tuning for your traces to the desired impedance value occurs by adjusting trace width and distance from the reference plane. Here is a much simpler approach! Divide the remainder in roughly equal whole numbers. 2 High-Speed Signal Trace Lengths As with all high-speed signals, keep total trace length for signal pairs to a. I designed a very compact 4 layer PCB that has many PCIe 2. A pier or beam basement usually consists of. You can follow the same procedure to calculate maximum voltage and minimum spacing for all the. See the sample books for examples of various types of fills. What are standard values or rules of thumb for the maximum current (or current density. Fotor’s Photo Stitching Tool. You can figure out the plant spacing for your gardens and hedgerows using this plant spacing calculator. The via spacing is about 1. It works for ground vias as well. Intermittent Technique Welding. Two variables are swept in the simulation: Via Diameter and PCB Height. Standard PCB Capabilities. Zg = Rg + jωLg. 24 RF / Microwave Design - Line Types and Impedance (Zo) Transmission Line History -)Two Coplanar Strips in 1936. and ½”. Spread the love. The tools shows that the required minimum spacing is 160 mils. 2E-6 Ohm-cm. If you don't already know which PCB fab will make your board, 0. 10 Updates & Additions: Added aspect ratio limits for vias. Too many vias can make EMI worse. 3. Conversely, in very narrow columns, stitch density may be too high and needle penetrations damage the fabric. 100 Linux EasyEDA 5. Input parameters are the via density class and soldermask density class (as defined in EDM-D-005 ), the dimensions of the thermal pad, the PCB thickness and the via drill diameter. For a two-sided board, the via can be drilled from the bottom side without disrupting the pad on the top layer. 72 mil or exactly 3 via radii. Via-in-pad design is the practice of putting a via into the metal pad of a surface-mount component footprint. Click to expand. In my resulting test stitch, you can clearly see the differences between each of these stitch areas. Constant Ground Via Stitching. Via stitching can be used to help manage high-current routing in circuit boards. The ground vias (yellow circles) are spaced at about 250 mils on average. Holes should be 10 mil in diameter and spaced 25 mil apart. Pivot and stitch up the second side, ending at the upper left corner where you. Remember that wavelengths are shorter through dielectrics by a factor of 1/sqrt (Dk). Thermally this will ensure the entire board stays at the same temp most likely. 5 mm dia pads under, or immediately around, the drain of the transistor. Adequate spacing b/w controlled impedance traces, other traces, and components (3W. spacing d be at least greater than one via diameter to ensure. Approximately 8-10 guides are recommended. The typical plating thickness is 1 mil which equates to 0. Tech Consultant Zach Peterson jumps into a stitching vias exploration in this video. Select and Re-Calculate to display. This spacing is referred to as the 5W rule. Continue this process until you’ve go all the way around the edge. 54mm for High speed) - Vias GND for free space is 5mm (5. Fill Types To adjust the fill type of an object, right-click on the object, select Object Properties, then the Fill Stitch tab. Tech Consultant Zach Peterson jumps into a stitching vias exploration in this video. Larger aspect ratios of 1:1, or even as high as 2:1, can be fabricated, but they bring reliability. The set can be removed by running the Tools » Via Stitching » Remove Via Stitching Group command, then clicking on any via in the group. Re-calibrate the guide to set the stitching line between the rows of decorative stitching. 4 mm to . Else via should be placed at > via center to center spacing and < 100mils away from the via • Signal vias should have pads removed on unused internal layer Keep 135⁰ trace bends instead of 90⁰ while routing high-speed signals. As discussed above, via stitching is used for different applications like thermal management, EMI shielding, and power/ground net distribution. -The space of Vias GND for reduce EMI around the edge of PCB : 2. If unable to maintain the same GND reference, via-stitch both GND planes together to ensure continuous grounding and uniform impedance. Diameters. The PCB trace width and the spacing to the grounded copper regions need to be designed to set the designed impedance to the desired value. Clicking this button will load the Preferred rule settings. But all that is of course dependent on how much force the seam will need to withstand, how thick the leather is, and what kind of leather. A four-layer PCB with a GND-VCC-VCC-GND power bus stack, as shown in Figure 3, was selected as the test bed for the. Position the cursor then click or press Enter to place a pad/via. This is the most common form of via stitching used in PCB construction. 1 Differential Signal Spacing To minimize crosstalk in high-speed interface implementations, the spacing between the signal pairs mustRF Via fences/stitching spacing. Please tell me I’m not the only one who struggles with the math for figuring out buttonhole placement on a sweater. 5 – 3. 030 inches (0. There are no rules for this and you need to input more via in free space as much as possible. o. Utilize solid ground planes on multi-layer PCBs to provide a low-impedance return path for signals. The first step is to determine the length of your cast-on stitches by calculating a ratio to the number of stitches in the original pattern gauge divided by 4 inches to the number of cast-on stitches the pattern calls for divided by X or the length you’re trying to find. Capacitor stitching for high speed differential pairs. So the choice is based on other concerns. In the example you have given, 4 stitches in 18mm will give you 4 stitches with a stitch length of 18/4 = 4,5mm. Here is a link to a paper that shows this. Like they say, you can never have too many ground pins. For Tatami fill, stitch density is determined by row spacing. Either the desired impedance at a specific frequency is used to determine the waveguide width, or the width is entered and the impedance is calculated. On the next page is an image of the Constraint Value Calculator. (since normal such vias are very cheap). Spacing Calculations Take the result of the calculator divided by 20 to get RF trace via fencing max distance. Enclosure-level solutions are often a last re-The 'Thermal Via Design Calculator' calculates the optimal design (size, spacing, distribution) for thermal plated through vias in a PCB thermal pad. Smaller epoxy-filled vias require less material; however, depending on board thickness, smaller vias may necessitate laser drilling. The via diameter is not critical to the shielding performance (for designs I've worked on). . You can use the Stitch Angle tab to adjust the direction of the stitch. You need to ensure the spacing between vias is at least 1/10th wavelength of the highest frequency you aim to shield. Click to expand. To increase density, enter a smaller value. Maximum Spacing and Edge Distance) "The longitudinal spacing of fasteners between elements consisting of a plate and a shape or two plates in continuous contact shall be as follows: (a) For painted members or unpainted members not subject to corrosion, the spacing shall not exceed 24 times the thickness of the thinner part or 12 in. This could be a sub-menu item under "Place Copper Pour. e. Stitch this flat. (click to enlarge) Use a chisel with two teeth to mark out the. 2×6 rafters are stronger and can span longer distances than 2×4 rafters. com ©. Divide this height by 9 1/2 inches, which is the code requirement for the maximum tread rise height for spiral staircases, to get: 144 / 9. Holes should be 10 mil in diameter and spaced 25 mil apart. Electrical properties of via elements*As Trace Spacing from Ground Increases, Impedance Increases. Modified 5 years, 8 months ago. 1 Traditional image stitching. Added a differential via calculator to the Via Properties tab. 3163. Via grid arrangement. Type in stitch counts and click Calculate. You can use Sierra Circuits’ via current capacity calculator to design an optimum via. Step 1: Marking Sewing Lines With a Stitch Groover. For the bottom seam, fold the fabric inwards 2". Have a look at Nigel Armitages videos on. Enter the number of inches (or centimeters) you are measuring on your gauge swatch. This prediction matches with the frequency of occurrence of S21 minima in Fig. The diagonal holes have less copper than the diameter of the vias. Actual results may vary depending on application and conditions. Other reported via stitching works include controlling theIn Refs. In these scenarios, you don’t need to mark them as “via-in-pad” features using Sierra Circuits online quoting. The standard fence spacing, optimum for privacy and general purpose, is 2-3 meters. 2E-6 Ohm-cm. . 6, June 1991, by Goldfarb and Pucel. For paper piecing use a shorter stitch length of 1. 2MHz Synchronous Step-Down Converter. A via fence reduces crosstalk and EMI in RF circuits. According to the datasheet we have the following possible frequencies: See full list on resources. Table 1-1. 020 inch (0. 7. Traditional image stitching methods can be divided into the following two categories: spatially. This also helps to suppress odd-modes or substrate modes. [10][11][12][13][14] [15] [16], a via-stitch guard to isolate two microstrip lines of transmitting signals was utilized. spacing. Anti-pads are the circular clearances in each power or ground layer that prevent electrical short to the plane. As the number of via holes increases, these 1-4244-0293-X/06/$20. 0394" (1. 024 in internal conductors and 0. The EMI at 3 meters for different via stitch spacing and layer thickness is modeled with FDTD modeling. Many who work in construction favor this technique as it saves on material costs and helps to avoid heat distortion, but it is vital to measure the. 4GHz this results in a via distance of maximum 3. For an example of stitching vias, see Figure 7. These important design features are incorporated into your design rules, making impedance-controlled routing quick and easy. 2. tors to the ground and power pin on top layer. maximum via current carrying capacity pcb. 7 oz copper. You can then copy and paste all or part of that row of vias to other. We added three circles of quilting stitches between rows 1 and 2, 2 and 3, 4 and 5. ) based on mechanical, electrical, thermal needs. If you're stuck with an end gap that's too small, or double end members, try Adjust Both Ends Equally to open and spread the gap to each end. 75” or less. For striplines, "a rule of thumb is to place the fences at least four times the trace to ground plane distance away from the line being guarded" Source: Via fence - Wikipedia:1 - Copy/paste board outline track on top layer. The Adjustable Stitching Groover is a great tool. Spacing of Intermittent Welds Table. g. 3C). It should be about 3mm wide on a 1. Panel Requirements for PCBA . This tool is also called d-spacing calculator because you can easily find the interplanar spacing with it. The recommended stitching distance between vias should be at most λ/4, with λ/10 as an optimum. This spacing is referred to as the 5W rule. RF Via fences/stitching spacingHelpful? Please support me on Patreon: thanks & praise to God, and with thanks to t. 5mm and that should be the necessary spacing for the ground stitching (Er = 4. A via stitching is a process where multiple numbers of vias are used to drill the copper areas on different layers and then connected. 1. This is generally referred to as via stitching, and it's generally used to reduce either the high-frequency electrical impedance or the thermal resistance between layers. 277 looks better at 5spi. 2. through a specific thermal path, it is often possible to use calculators or simplified approaches during the system design phase. In addition to the internal ground planes, I want to fill the signal layers with copper, and have vias between the pairs to serve as ground stitching and fencing. Drag the Centres or Total Length slider to see the effect of double end members. 6, June 1991, by Goldfarb and Pucel. 4 GHz, and with routing on outer-layer (microstrip) traces, the formula gives us a stitching via spacing of 3. This is a 3A, 18V, 1. 9. g. Stitch down the first side, pivot at the bottom corner, then stitch across the bottom. You can select spacing or length as a percentage of the original – from 10% to 1000% – or as an absolute value – e. 5 mm dia pads under, or immediately around, the drain of the transistor. (KNITTING DECREASE CALCULATOR) Input numbers below to determine how to decrease evenly across your row or round of knitting. In addition to the characteristic impedance of a transmission line, the tool also calculates. Placing many vias can help reduce this effect around a crossing line, or you can take. All of the above is great for validating your via spacing. etc. $egingroup$ as explained in the DELETED ANSWER, at high enough frequencies the skin effect and surface roughness cause the foils to become serious dampeners of any stored energy, which prevents the buildup of standing waves. These data represent Z values on a grid for which spacing and shape are known so there is no problem reshaping the 1D array into the the shape of the grid and plotting with plt. If your design has controlled impedance traces, you can use our built-in impedance calculator. Via current capacity calculation using IPC-2152. Make your pieces oversize an cut to size after stitching. It is shown that the ground plane stitching effectively reduces the radiated EMI that. o. Spacing Increases and Decreases Evenly Across a Row or Round. Drag the Centers or Total Length slider to see the effect of double end members. 8. Enable the Constrain Area option to restrict stitching vias to a user-defined area. Where it. The vias on a particular PCB should all be the same size. If using vias becomes inevitable, pad-to-via connections should be less than 10 mils in length. Then, remove the project from the machine and pull the top threads to the back. The vias spread over areas is called "via stitching", very common when there are power/ground planes/traces on two sides. Power bus noise induced EM1 and radiation from the board edges is the major concern herein. This information for example, is useful when designing. 4. 1. 8-2. In addition, not all SERDES signal need to have. )Flat Stripline Using PCB Techniques right after WWII. You can see the top copper layer and the bottom copper layer. Calculate Stitches. Stitching ViasThe EMI at 3 m for different via stitch spacing and layer thickness is modeled with the finite-difference time domain (FDTD) method. The Keepout shapes can be set for any layer or one of the copper area layers so that Vias between those layers will be ‘kept out. The EM1 at 3 meters for different via stitch spacing and layer thickness is modeled with FDTD modeling. It can be used with Circle or Digitize Blocks input tools. This feature interfaces directly with your other design tools using a rules-driven design engine. 4 (for typical FR-4 PCB material [6]). the via spacing. . RF Via fences/stitching spacingHelpful? Please support me on Patreon: thanks & praise to God, and with thanks to t. For example, a 30 ps rise/fall time results in 0. Lacing stitches and spot ties shall be placed as detailed in Table 9-1 (Requirement). For example, a 0. . Handy Calculators. 5 Stitch Spacing. Fold the top seam up 1/2 inch. Sew along both lines, making sure to leave long thread tails at the beginning and end. However, you want to increase your stitch length to its maximum. So my questions are as follows:The economics and structural strength and stresses all come into consideration. 08 Updates & Additions:This is because, along the length of a through-hole via, the dielectric constant that determines signal propagation is an effective dielectric constant with value of ~14 when Dk = 4. However, 23 x 8 + 8 increases = 192 and we need 194 stitches, so in this case you would need to add two extra increases. Tip: When you increase stitch spacing, Auto Underlay should be turned off. Leverages DFA spacing table. What are the spacing between vias and the size of via for via stitching on either side of a 50 ohm 2. Ensuring impedance-controlled routing also requires knowledge of the substrate’s dielectric constant and your required trace width. If you remove the islands, then they won't radiate at all - and you don't have to pay for vias or remember to stitch that area if you change the layout. And that extra 0,5mm will hardly be noticeable. The estimation of cost per track length unit is feasible by using the following formulas: (1) n sleepers / L e n g t h, U = L d (2) CTL= (n sleepers / L e n g t h, U)  · C t (3) CTL = L d  · C t where CTL is the total costs of sleepers per track length, which is L length of the track, d the sleepers’ spacing (constant in that length) and Ct is the cost of the. Small diameters cost slightly more (below about 12 mil, anyway), while. Use effective trace width and spacing tips Routing surface traces and vias are not separate activities. There are many advantages to using VIP design, and here are a few of them: VIPs help with the escape routing of large parts that have fine pitch pins, such as . This circuit operates perfectly well with this via spacing with no signs of ground impedance issues. PCB Assembly Calculator. Stair stringer: it's the construction that the steps are mounted on. To determine how to evenly space increases or decreases, divide the number of stitches on your needle by the number of stitches that you want to increase or decrease. planes, high density via stitching, and re-routing signals on inner layers to try and solve the problem. • Via pad size should be 25 mils or less and a finished hole size of 14 mils or less • Provide GND stitch to improve signal impedance transition • Location of via should be simulated. Stitching has a few uses as you have indicated, both very different Thermal, is of use to move heat. Using the ‘Show Stitches’ icon. RF Design tools for RF and PCB parallel design reduce time-to-market, deliver accurate simulation, reduce over-design margins, and enable cross-team collaboration between RF and PCB design teams. Step #6: Divide the result in Step #5 (34) by the number of dividers plus one (8 + 1 = 9), which equals 3. If the column is x wide then use y spacing value, this can be further adjusted to say use a percentage of the value in the settings tab. If unable to maintain the same GND reference, via-stitch both GND planes together to ensure continuous grounding and uniform impedance. The calculator has options for the edge rate, dielectric constant, and also the height between the layers to determine the constraint values. Version 7. )First use of Microstrip Reported in 1949. Key takeaways: Arrange ground planes one dielectric away from signal and. Consequently, the integrity of the via-stitch spacing is not always maintained in board areas of high design density, and the EMI effectiveness of the approach is compromised. 08mm for inch unit). If using vias becomes inevitable, pad-to-via connections should be less than 10 mils in length. Design curves and an empirical equation are extracted from a parametric study to summarize the variation of the radiated EMI as a function of layer thickness and stitch spacing. As mentioned in another comment, using your total thickness is a good place to start, however I find that pushes the stitch line in to far. The question was for Veer007, since I felt the design was odd - slab and joists supported by a plate stitch. Before you actually punch sewing holes in your leather you have to give yourself a guideline to show where the sewing holes are going to go. For example, a 30 ps rise/fall time results in 0. A tie or stitch shall be placed immediately before and immediately after any breakout of the wire or cable from the harness (Requirement). 03 = 11. 3. All the rest are 2-1/2 inches. Pier foundation calculator instructions | JustCalc. Added a differential via calculator to the Via Properties tab. fromfile. In this video I show you how to calculate the amount of stitching you'll need for a project in order to reduce the amount of thread wastage and most importan. It is shown that the groundThere are several types of vias used in PCBs: Through-hole vias span across the entire PCB stackup and can connect to any layer. . This is a 3A, 18V, 1. If you want to use 1 A and signal, you have to use hole via about 0. The first version of the 3W rule states the spacing between adjacent traces should be at least 3x the width of the traces. Via stitching is generally used for high frequencies (100sMHz and GHz). Information on the syntax and control of the calculation can be found in the document "Control, structure and syntax of calculations". Combination stitch consisting of a single-needle chainstitch (401) and a 2-thread Overedge stitch (503) that are formed simultaneously. 3º Fill both ground planes. Landing: a platform connecting two flights of stairs. Designers place multiple vias on multilayered PCBs as close together as possible, and these are known as stitched vias. 72 mil or exactly 3 via radii. Key takeaways: Arrange ground planes one dielectric away from signal and power planes. Diameters. In what follows, we’ll consider plated through-hole vias on rigid PCBs. This Javascript web calculator calculates the resistance, voltage drop, and power loss of printed circuit board vias. To calculate the proper spacing for your stitch welds, you will need to know the thickness of the material being welded. The EM1 at 3 ground plane stitching is to conduct a series of EM1 meters for different via stitch spacing and layer thickness is measurements in a chamber. The stitch length is set to 12 stitches per inch (SPI). Some machines, including many of the Janome models in our Sew4Home studio, actually have a twin needle setting. 30 millimeters. 80 mm. As Matt S & jimi have stated, in many cases you can set the length of stitching in advance, and thus plan on having an even number of stitches. Click here to enlarge image. They connect either the top to the bottom of all layers within the board. The via current capacity and temperature rise tool operates based on our PCB conductor spacing and voltage calculator. To get each rib lace row to line up straight the full length of the wing a few of mine are spaced at 2-3/4". Viewed 12k times. Let's say we want to use 2-cm wide spindles for a stair railing with a total horizontal railing length of 85 cm from an existing post to the outer side of a 10-cm square end post. . The differential trace width and air gap spacing between the two traces of the pair need to be elected to achieve the impedance target. The primary tool used to correctly design layer transitions for high-speed vias and RF vias is stitching vias. Via Stitching Control. 0. Whether via stitching vs. Solved it! The via settings, including the Net (GND) is remembered so stitching is easy. Design curves are generated to demonstrate the variation of EM1 as a function of the layer thickness and stitch spacing.