Parallel Wire Impedance (Zo) = Ohms. If R G = 402 W, we then need R T to be 114. Differential Impedance in Constraint Manager Advanced Constraints can be used to view the Differential Impedance in Constraint Manager. 3. The odd mode impedance is the impedance of one transmission line when the pair is driven differentially. Figure 4. Formula: Applicability: w ÷ t ≤ 0. Copper. Even mode impedance for commonly-driven transmission lines . 2 High-Speed Signal Trace Lengths As with all high-speed signals, keep total trace length for signal pairs to a minimum. This is more than the to times trace width which is recommended (also read as close as possibly). While it is not necessary or a requirement to match the PCB 'stubs' it's probably a good idea if the speeds of your RS485 bus are high (+50MHz). Figure 81 shows the topology. Single-ended and differential pairs of coplanar waveguides. Differential: Ohms Overview This calculator is designed to calculate the characteristic impedance of an edge coupled stripline. 25, but gives me nice trace from the module to the stub then to microcontroller. The Impedance Calculator is a tool which allows a quick pre-layout estimation of several kinds of line impedances between different layers. The two traces of a pair should be symmetrically routed. Cohn, Seymour B. 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. It uses the lan9512 reference schematic. 1. Our impedance calculator features two main types of impedance models, single-ended and differential, within each trace structure. 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. Also, it has got. For example, a single 0. This will leave the rest of the signals which are rather non-critical like I2C, power good signals, etc. So, the trace width and distance to adjacent reference plane is determined by the desired. SAVE & ACCEPT. 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. 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. Details: In the list below, [1] is the reference design stackup information; [2] and [3] are the processes to get the result close enough to the reference design target so as to know the tool is valid; and [4] is the calculation in question because it is either 5. Figure 3 shows the respective p and T models used to calculate the differential impedance (Z diff). This is a calculator used for determining the characteristic impedance of a microstrip. 5. I am trying to design a CAN bus node. D+ and D-) _P/_N (e. . Twisted Pair Impedance Calculator . We care about maintaining the same differential impedance for. In some cases, we can also use 75-ohm differential impedance. Differential pairs with vias and right-angle bends are acceptable. The factors that influence differential pair via impedance will affect the input impedance seen at the vias. Sorted by: 1. 50Ω. Fig 2b Equivalent. . Note that the y-axis is on a logarithmic scale for clarity. 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. Ready to give CircuitStudio a try? Click here to get started: impedance. A twisted-pair cable is simply two wires that are twisted together so as to reduce radiated EMI (electromagneticinterference) and mitigate the effects of received EMI. Placing a Differential Pair directive on each pair net applies a parameter to the net,. The tool implements numerical solutions of Maxwell’s equations to render accurate and consistent results. The trace impedance calculators that design tools often provide can be used to. Zo (diff) is calculated to be 244 ohms, so dividing by two yields a value of 122 ohms for the semi-coplanar structure. Defining the Differential Pairs on the Schematic. An input voltage between the two gate terminals produces an output current in the drain terminals. MX6 Design recommendations about 100 Ohms for differential pair is quite reasonable for FlexCAN. 1. 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). Spacing and width value pairs that will give a differential impedance of 100 Ohms on Dk = 4. 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. 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. This is a tool that has been designed to determine the characteristic impedance (Z 0) of a twisted-pair cable. 25, but gives me nice trace from the module to the stub then to microcontroller. This calculator is designed to find the characteristic impedance of an asymmetric stripline - a flat conductor between two ground planes. 1. ’ Go to the ‘Differential pair rules’ >> ‘New rule. Staff member. Take note that this assumes that the distance between the conductor and the planes is not the same for both reference planes; hence the asymmetric term. USB traces must be 90 Ohms differential. Most of the dedicated TL tools doesn't have this option, only if you use a full EM simulator. ALTIUM DESIGNER. 3. I have no luck finding an asymmetric differential stripline impedance calculator online. and thats the first time iam doing ethernet things. This can also be understood as the justification of the "3W rule", a rule of thumb on crosstalk - when there's a 3W separation distance between two traces, crosstalk is. . Differential Pair Impedance Calculator Calculates the differential pair impedance of a balanced line. 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. If the goal is to adjust the characteristic impedance, then you can likely do it by changing both width and spacing (keeping center-to-center the same) just as. I checked out TNT, but couldn't seem to be able to do the same with that either. 50 Ohms. Ask the board manufacturer for the values. I'm unsure if the reference plane would be the GND and the PWR layers. There are four different types of impedance used in characterizing differential trace impedances. 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. The other yellow rectangle is the USB connector. Both gives me only 20 Ohm differential impedance. This calculator is designed to calculate the characteristic impedance of a broadside couple stripline (see diagram below). This PDF document provides a comprehensive guide on how to calculate the impedance of various PCB structures, such as microstrip, stripline, and differential pairs. g. , the via is electrically short). . Typical impedance tolerances are 10% and 7%, and can go as low as 5% or 2% in the extreme cases. To achieve impedance control, PCB design software with an integrated field solver can help in designing the right trace width for the HDI layer stack-up. The edge couple differential microstrip transmission line is a common technique for routing differential traces. Your relay is single line with characteristic impedance of 50 Ohms. . (Differential Impedance, Ohms) = Note: 1oz = 1. Grounded Differential Coplanar Wave Guide. The answer lies in the spacing between the traces in the pair. A twisted-pair cable is simply two wires that are twisted together so as to reduce radiated EMI (electromagneticinterference) and mitigate the effects of received EMI. They are recommening to use 3th party calculators. These tools allow you to calculate a highly accurate impedance and propagation delay model for your differential pairs, and you can use these results to specify delay. KiCad has a built-in impedance calculator!The impedance calculator determines the signal properties and clearances (first image), use that clearance in the via shielding Distance setting. with the following layout parameters (width|space|width): Ohm. Gigabit Ethernet requires 100 Ω differential routing. Enter your board parameters and get instant results. Stripline is another type of transmission line that can be easily built on a pcb. g. Given the constrain of comparing the same differential impedance and the same line width, loosely coupled differential pairs have less cross talk. Differential Stripline Impedance Calculator. Use that. Unfortunately Online Calculators are deceiving unless you actually draw the numbers and understand the ratios and tolerance effects. It is important to determine the characteristic impedance of a twisted-pair cable because this impedance should match the impedance. Anyone have suggestion of one? Thanks Alan . To be honest, I am no idea of the impedance on. 19mm) traces with 7. First, consider a microstrip. I have no luck finding an asymmetric differential stripline impedance calculator online. Altium Designer makes it easy to calculate geometry when you need to calculate impedance for differential pairs. edu; Home; Members. Figure 4. It seems I could largely do without any impedance matching considerations, given what the trace lengths are. g. This value is often given the name “differential impedance. Impedance Calculator - Sierra Circuits. (2. Vias (plated holes) are used to route electrical signals among different layers of a multilayer. If I calculate it for embedded edge coupled differential pair, it is still only 39. At the receiver, the signal is recovered by taking the difference between the signal levels on. g. In microstrip, this technique is ideal for routing differential pairs. Calculation tip for defined Z 0 as well as Z Diff. Use an online differential microstrip impedance calculator. 9. Once the option is active, click on the shortest trace and move the mouse. Twisted pairs are used with balanced signals. The differential impedance. To calculate this, you need some values. The required Impedance Profile is selected in the applicable Routing Width design rule (for individual nets), or Differential Pairs Routing design rule. D+ and D-) _P/_N (e. Eurocircuits’ Impedance calculator uses real values as defined in the supplier’s data sheets. Incidentally, the trace thickness parameter does have a significant effect. Note: If this post answers your question, please click the Correct Answer button. With t = 35 um (typical for copper with plating on a pcb), Z odd drops to 44 ohms, according to LineCalc. • If finite tail impedance and asymmetry are both. Differential Termination Techniques - • Textbook Reading Assignments 1. Going through Saturn PCB Calculator - which is free and useful software for engineers. Following is the list of useful converters and calculators. Actually the "odd impedance" is the correct impedance to look at for the USB requirement of 90 Ohms differential impedance. D_P and D_N) KiCad looks for these suffix pairs when using the differential pair routing tool during PCB layout. 4000 Enterprise Drive, Rolla, MO 65401 (573) 341-4139 (573) 341-4477; ygtpv@mst. If your differential pair has 100 ohm (differential) characteristic impedance, you should just design the uncoupled parts of the lines to have 50 ohm (single-ended) characteristic impedance. GEGCalculators. g. . Hence, without loss of generality, one. Differential Impedance Differential Impedance: the impedance the difference signal sees ( ) ( ) 2 2( ) Z 0 small I V I V diff Z diff one one = = ≈ − Differential impedance decreases as coupling increases +1v -1v I one x I two How will the capacitance matrix elements be affected by spacing? C 12 C 11 C 22 Eric Bogatin 2000 Slide -18. 0 high-speed. look at a differential source driving a twisted pair to the FDA. Keeping the final. The specific trace width and the spacing are required to calculate the particular differential impedance. If we want to hit the standard 50 Ohms impedance target, then we need to have a trace width of almost 110 mils!Differential microstrip and stripline pairs have common-mode noise immunity if they are routed symmetrically, but they also need to have controlled differential impedance to ensure impedance matching and consistent propagation delay throughout an interconnect. This means that the channel dimensions of both FETs must be the same and that R 1 must equal R 2. Z 0 now meets your requirements. 6mm thick. 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. We’ll go over how differential pairs can hel. Coupling can, however, be used to advantage in the form of differential impedance. PCB impedance calculator – Single ended / Differential pair PCB manufacturer normally provides information about PCB stackup and track geometry. 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. These calculators ALL use wrong naming for "differential impedance". This is a calculator used for determining the characteristic impedance of a microstrip. Based on Zo Equation Per: IPC-D-317A:. Comparator tab . 5. 6. 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. 6), the impedance will be approximately 50 Ohms. 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. From it, apart from making all traces the same length from camera sensor to cable connector, I believe the rules I need to follow are: Differential impedance of 100 Ohm. Distance between pairs should be (traces on top layer = microstrip) 4 times the layer. . 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. Spacing and width value pairs that will give a differential impedance of 100 Ohms on Dk = 4. The default units for all given values, except the subtrate. The ratio of cross-hatch conductor width (HW) to cross-hatch pitch (HP) plays an. Download Saturn Pcb Design Toolkit. To use this tool, enter the values for. There are four different types of impedance used in characterizing differential trace impedances. W is calculated to achieve a trace impedance (Z0) of ~50W and S is calculated to achieve a differential trace impedance of 90W. The PCB Impedance Calculator in Altium Designer. A common approach is to create a net class or differential pair class that includes these nets, then create a routing rule that targets this class, as shown in the images below. Dielectric Constant The. Differential pairs are commonly found in high-speed data communication systems, such as those used in computer interfaces (e. For an embedded (internal) microstrip, the formulas provided in paragraph 4. Capacitance – the impedance calculator uses the Impedance value to calculate the capacitance per unit length. The IPC-2141 trace Impedance calculator will help make initial design easier by allowing the user to input basic parameters and get a. If a different frequency is required, pick. With PCBWay impedance calculator, you can calculate the approximate impedance of your PCB / high frequency circuit board. Simons, "Coplanar Waveguide Circuits, Components, and Systems", Wiley. 4 Comments. But I am not able to match this impedance. Cross-hatched copper plane in a flex stack-up for controlled impedance. 5 mil (0. But, you usually want some decent coupling between the traces, so a good single-ended impedance target for each trace is between. is the impedance between two differential pair signal traces. If you do something else with the. 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. 90 Ohm Differential Pair: 0. This application note provides a brief theoretical background to the impedance calculation methods used in the Polar Si series field solvers. The differential skew is adjusted with a tiny blip on one line towards the bottom of this image. This is a lot of terms to calculate in a simulation!Hi, I am working on my board Stack-up to tune Single/Differential impedances of my board in Allegro PCB 16. The formula used in this calculator is an approximation for the characteristic impedance of a coplanar waveguide: scssCopy code. Impedance in your traces becomes a critical parameter to consider during stackup. Download Saturn Pcb Design Toolkit. The impedance of each trace of the differential pair references to ground. This video will cover how to create, setup rules, and route differential pairs. Description. 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. One of the features of this type of microstrip is the coupling between lines. 1 mm, therefore very small. The designer needs to create a stackup for the board and then calculate the trace values for differential pairs and single-ended nets. Enter your board parameters and get instant results. Adjust the distance "s". Ask the board manufacturer for the values. They will give very similar answers. 50 - 55 ohms). In the image below, I am comparing differential vias with merged. ’ Give a name to this rule (100 ohms in this case) and double-click. where Z 0,surf can be computed as specified in Eq. The Signal Integrity tool is examining the series termination needed based on the line's characteristic impedance If you are examining a trace in a differential pair, the Signal Integrity tool is still only used the characteristic impedance, not the odd-mode impedance. A cross-hatch plane is shown in the image below. For instance, I want a 100 Ω controlled impedance pair, and have used "differential" before which seemed to work fine. The differential amplifier can be implemented with BJTs or MOSFETs. For instance, when IB I B = 40 uA, I estimate that a collector current range of 8 mA to 8. Differential pair routing. Visit to learn more about our other electrical engineering tools. 100 Ohm Differential Pair: 0. How to Use the Calculator. LVDS PCB layout guidelines can be used for optimizing system performance by ensuring reliable signal integrity and reducing the chances of noise interference. If you use two of those and operate them differentially !!! then the characteristic impedance can be treated as a 100 Ohms differential impedance. e. The Sierra Circuits Impedance Calculator uses the 2D numerical solution of Maxwell’s equations for PCB transmission lines. 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. I need to route 100ohm differential pair without GNd I can't find any PCB calculator for parallel routing on one layer. 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. 2Distance units: Substrate Height, H Trace Width, W Thickness, TFigure 1. Jan 31, 2016 #2 FvM Super Moderator. 0 for analysis with Si9000e. Use 3. Using the KiCad Impedance Calculator. 8 substrates of various thicknesses. This routing width rule targets a class of DRAM nets. So move to your left, use Omni's Cable impedance calculator and enjoy. When dealing with differential pairs, thi. The characteristic impedance is given by: Eq. The microstrip is a very simple yet useful way to create a transmission line with a PCB. It may have either one output or a pair of outputs where the signal of interest is the voltage difference between the two outputs. The Saturn PCB Toolkit is the best freeware resource for PCB related calculations you can find. CSI-2 interface data pairs require a 100 ohm differential impedance. , D+ and D- (TSKEW)) must be less than 100 ps and is measured as described in. 1-11. Make sure to follow below for efficient RS485. Instant online PCB quote, get PCBs for only $2. 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. Grounded Differential Coplanar Wave Guide. 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. 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. 1,235. In a previous article, we have seen how to route a differential pair signal. Follow the 8W spacing for differential clocks (or explore other rules) Even greater spacing is needed for high-speed differential signals. 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. Backwards crosstalk creates a pulse width that is twice that of the propagation time of the pulse traveling the coupling distance. The differential pair impedance depends on the characteristic impedance and the spacing between each end of the differential pair. Let’s move onto another example. This calculator finds both odd and even transmission line impedance. Learn how to configure, define, and use your design’s impedance requirements for single-sided and differential on each layer, with Altium Designer’s Layer St. 0 and 0. ”7. Differential pairs: even or common mode?PCB impedance calculator – Single ended / Differential pair. Most often, the only specified requirement of a differential pair is its differential impedance. 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 stackup on the left side of Figure 2. The surface finish is neglected. Differential impedance is defined as the impedance between the two lines when the line pair is driven differentially. Select the Calculator button. Note: valid for (w/h) from 0. In general, it is double the odd-mode impedance, which is the value we care about for differential signaling, as it is used in high-speed PCB design. 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. transmitted across a twisted pair cable by a differential line driver and sensed at the far end by a. 3) to calculate trace width and. When enabled. 5 mil as the thickness of 3313 prepreg when the controlled impedance tracks are on top/bottom, use 5. It is important todetermine the characteristic impedance of a twisted-pair cable because this impedance should match the impedance. 0. For Si engineers & PCB technologists. 1<W/H<3. To calculate the impedance, I use Saturn PCB impedance calculator software, Inc - PCB Toolkit V8. 0055” spacing. Now let’s incorporate the finite output resistance: And next we recall that the small-signal analysis technique. Modeling approximation can be used to understand the impedance of the edge couple differential stripline transmission line. The grounded differential coplanar wave guide is the differential version of the grounded coplanar wave guide and is used in high-speed digital systems that require maximum noise immunity. With the differential microstrip impedance calculator in Altium Designer,. Impedance Calculation for PCB Designers - Altium. Impedance and Differential Pairs in KiCad. User Interface. The differential impedance is the impedance measured across the two lines with the pair driven differentially. 6 inches - this is very easy to do; If you can access a differential impedance calculator, then use differential. Modeling approximation can be used to understand the impedance of. Before we can start routing the PCB, we need to define Design Rules for our differential traces. Use an impedance calculator to determine the trace width (W) and spacing (S) required for the specific board stack-up being used. This assumes ~0 trace thickness. ; To. Zeven: This is the even-mode impedance of the differential pair. Polar or rectangular grids only allow direct reading of S11. With t = 35 um (typical for copper with plating on a pcb), Z odd drops to 44 ohms, according to LineCalc. 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. Near 50 ohms, many of these approximations are within a few percent accurate. 331 1 2 5. 6mm FR4 PCB with 7628 type stackup (4 layers), the above specifications usually result in 4. ETA: USB 2. The same applies to common mode impedance, except that common mode impedance arises under common mode driving. Thus, for optimal performance the resistors and MOSFETs must be matched. The resistance value chosen for the two resistors will be referred to as R D (for d rain resistance). If you control impedance, you place a tolerance in the fabrication notes. Speedstack Si – Insertion loss & impedance PCB stackup design including Si9000e. 35,851. 30967mm) is slightly larger the size of the smallest pad (0. Altium Designer makes it easy to calculate geometry when you need to calculate impedance for differential pairs. 300" away from the Ethernet front end. differential routing without GND. Just as. There are single end trace impedance and distance between traces in the pair. 1 of the Microstrip Calculator using H2 in place of h, εr,eff can be computed as specified in Eq. We’ll go over how differential pairs can. A web-based tool to calculate the impedance of your PCB traces and vias. A value of Z Line = 100 Ω is common for twisted-pair cables. 006” spacing. That's why the numbers Mikrocontroller. 8. The CAN bus shall be split-terminated with 120Ohm, 60Ohm for each line. In case I reduce the width and the distance of tracks to 0. Eurocircuits also calculates the correct Differential Impedance values using the correct formula and not a ‘Rule of Thumb’ method. Enter the relative permitivity, width of the trace, the ground plane spacing, and the substrate thickness to calculate the characteristic impedance. The Coplanar Differential Pair Impedance Calculator is a tool that helps you calculate the characteristic impedance of a coplanar waveguide (CPW). Simply put, differential impedance is the instantaneous impedance of a pair of transmission lines when two complimentary signals are transmitted with opposite polarity. I use the software a lot to calculate impedance, maximum current for t. I see that Dielectric Constant is 4. Advanced simulation and analysis tools can. Modeling approximation can be used to understand the impedance of. 2. It renders fairly accurate results suitable for use in circuit board manufacturing and engineering analysis. Transferring the Differential Pairs to the PCB Editor from Schematics. The impedance of a differential via pair cannot be treated with a single via impedance calculator unless the vias are spaced far apart. Simply put, differential impedance is the instantaneous impedance of a pair of transmission lines when two complimentary signals are transmitted with opposite polarity. The differential pair is all about balance. What is the characteristic impedance of twisted pair cables? 100 ohms. 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). When you click on the track, you can see the length of skew. Atlas Si for Touchstone – PCB Insertion loss processing with Delta-L 4. This calculator finds both odd and even transmission line impedance. Given the defaults (1. The types of traces where impedance control is applied are: Single-ended and differential pairs of microstrip lines. model impedance by combining Polar's proven boundary element field-solving engine with easy graphing of process windows. It works in parallel with the standard. Enter your board parameters and get instant results. Differential pair on a reference plane for differential mode (left picture) and common mode (right picture) line impedance In addition to the four line impedance types the Impedance Calculator is also able to calculate the Coupling Factor between two traces on either the same signal layer (horizontal coupling) or between two traces on different. The most commonly used instrumentation. Voltage Divider Calculator 1 (Fixed) Voltage Divider Calculator 2 (Adjusteable) Capacitors. The tool implements numerical solutions of Maxwell’s equations to render accurate and consistent results. Against the two rows select the. To get the correct parameters, we have to use the specifications from our PCB house and the provided calculator. This is assuming that you have a Design Rule in place which links the impedance profile to a. Board. . 25mm between the differential pair with a width of 0. 1,393. The trace width and spacing for a certain impedance may be obtained using impedance calculators. Now I'd like to get into this topic and the first task would be to create a ~ 10cm board to board interconnect flex PCB with 90 ohm (USB) and 100 ohm (LVDS) controlled impedance traces on it. Capacitance (C) = pF/ cm. 30967mm) is slightly larger the size of the smallest pad (0. 8 substrates of various thicknesses.