so i want to know that it is called micro-strip or strip-line? i have check the calculators like. 65mm width. Frequency Chart 1: RO4000 Series Materials Dielectric Constant vs. trace thickness = 0,2 mm (from pcb datasheet) height of dielectric above return plane = 1,6 mm (from datasheet) I obtain a Z0 of 70,8 ohm. Maybe make all lines and matching to 75 Ohm lines? Than would be much thinner. If room is limited, it may be helpful to add ground at both sides of the signal lines, making differential surface coplanar strips with ground. Here are a few qualities of FR4 materials that make them popular: Wide range of operating temperature (50°C to 115°C) Higher T g value (about 180°C)Input Your Specs to Get Started. Calculates the characteristic impedance and per-unit-length parameters of typical printed circuit board trace geometries. 1/2Oz copper 1. User mini profile. Equation 6 can be used to calculate the characteristic impedance for an FR4 board. 5mm wide (over 0. On standard FR4, a 100 MHz signal wavelength is about 8. Prepreg FR4 8. Reference Planes and Clearances. You might want a certain trace width and. Now. 6mm. The answer to this question, Characteristic impedance of a trace, shows that a 120 mil trace is required to get this impedance. This calculator takes into account the PCB material, the copper thickness,. The chart above shows how widening the trace width (with corresponding substrate height increase) can reduce the total transmission line loss. crutschow. On each site, the trace width that results approximately 50 Ohms is different. εr:For our board material (FR4) the relative permeability is about 4, yielding a width of W = 2H for 50 Ohm trace impedance. 20 Fig. • FR4, 4 layers, PCB Thickness: 0. In order to avoid the long power line acting as an antenna, an ferrite bead is used as an rf choke. 3 Ohm resistor (0402, 1%, using thermal relief on GND). Impedance in your traces becomes a critical parameter to consider during stackup design for high-speed PCBs, but the. Home. 4 mil FR4 dielectric thickness o No differential coupling to neighboring differential channels Using other trace geometries or materials will lead to different results than shown here. Cancel; Up 0 True Down;On the right is a model for the causal dielectric constant of an FR4 material using measured data. We have simulated this 5 cms long CPW trace on HFSS using DK of 4. Share. Here D is the conductor. 65mm width. For 50 ohms on FR4, as a rough rule of thumb, just keep the linewidth at 2x substrate height. 8 which gives me a trace width of 1. T is the trace height or copper thickness. While this calculator will provide a baseline, any final design considerations should be made towards loss, dispersion, copper roughness, phase shift, etc. 8 mm Relative permittivity: 4. The length of the 50 ohm RF trace ( CPW - 15 mil trace width & 18 mil spacing to ground ) , is approximately 5 cms . 50 Ohm Trace Width; Top Layer: 0. Today's digital designers often work in the time domain, so they focus on. Voltages are referenced to 50 Ohms. A 1mm dielectric seems a bit too thin to me. 50 Ohms. 5 All Polyimide: DK=3. dielectric height is a standard 2 layer board, it is 1. Example ofEnter values for W and L for a microstrip line to determine its Zo and Electrical Length. This was derived from equation 3. PCB Impedance control, differential pair/single end ohm. The width and length of the microstrip line is calculated using ADS linecalc method which is obtained to be width:3. The Dk is. This says that ALL 50 Ohm transmission lines in FR4 have exactly the same capacitance per length. The total number of layers required for a given design is dependent on the complexity of the design. 048 x dT0. 5 for FR4. Where electronics enthusiasts find answers. 035mm. 55 mil should give 50 Ohms. 393 mm, the required trace width for this particular inductance value is w = 0. 50 ohm trace width fr4. 4 mil Top Cu+Plating 0. Your 50 Ohms trace width will be dependent on the stackup that your manufacturer will use to manufacture the board. 6mm boards at essentially the same price as standard pcb and, the shipping will be lower than standard PCB. If you were to take an ohmmeter to it you would probably. 92445. That magic 50 Ohm is calculated from ZL=sqrt (L'/C') of the transmission line, where L' and C' are capacitance and inductance per unit length. = 1. The 50 ohm impedance refers to the "characteristic impedance" of the "transmission line". Just How Wide Should a PCB 50 Ohm Trace Width Be?. 6 mil Prepreg 2116/4. The differential 100 Ohms line has width 0. This says that ALL 50 Ohm transmission lines in FR4 have exactly the same capacitance per length. Figure 1. By understanding the microstrip transmission line. 5 (FR4 PCB) PCB width: 1 mm. 6mm thickness and the connector is a SMA. Some guidelines: 0. I am designing my first 50 ohm impedance trace on a PCB that connects to a single wire antenna. Since all the 6 antenna coils are on the same PCB, we have to run traces from the switch IC to each antenna. 4 GHz top layer and bottom layer with 50 Ohm Trace width is 6 mil 3. 100 Ohms differential impedance is achieved with 4 mil traces and 10 mil spaces on the Top and. A microstrip width calculator can calculate the width of a microstrip. board materials have distinct dielectric constants, which are related to the resin materials used. And yes, its very wide. 4 mil FR4 dielectric thickness o No differential coupling to neighboring differential channels Using other trace geometries or materials will lead to different results than shown here. The unit of impedance is Ohms (Ohm= volt/ampere). Yes, that's right. 2. After quite a reading I got to know that as the track width of a cline is decreased, there is a decrease in the impedance, Trace width is indirectly proportional to impedance. For standard FR4 (pcb material) the electric permeability constant is ~4. jconradt. Relative_Dielectric_Const depends on board material and is ~4. 4. FR4 was no longer the best option and lower loss laminates are needed to support routing over the distances you would see in a rackmount unit or motherboard. The issue with 2 layers is that the separation between the layers is too large to practically build impedance-controlled 50 ohm traces. FR4 material has an Er of approximately 4. 25 mil trace width o 2 mil trace copper thickness o 5. 8. I don't. W: trace width: T: trace thickness: H (/H1)Re: 50 Ohm Matching microstrip OSH park 4 layer process. Larger ground clearance lowers capacitance, increasing impedance. > > The length of the 50 ohm RF trace ( CPW - 15 mil trace width & 18 mil spacing > to ground ) , > is approximately 5 cms . Width, mils :. = 1. But the trace width that results from this is different. This tool uses formulas from IPC-2221 to calculate the width of a copper printed circuit board conductor or "trace" required to carry a given current while keeping the resulting increase in trace temperature below a specified limit. 1 Gbps). Typically the thickness between layers 1-2 and 3-4 are close together (approx. The 168mil is wider than the 50 Ohm trace, so an impedance dip is expected at each location. 6 mm is used) can anybody help me how to calculate 100 ohm impedance with above data. 55 mil should give 50 Ohms. For a Dk = 4. 6 nH. 0mm (4L-02) When using our free Defined layer buildup 4L-02, you will reach the desired impedances e. Line Width: 4mil (0. 3 Ohm resistor (0402, 1%, using thermal relief on GND). Losses in PCB Transmission Lines - Sierra Circuits. 6mm thick PCB with 4 different traces on it, 8, 10, 12 and 14 mil wide. With PCBWay impedance calculator, you can calculate the approximate impedance of your PCB / high frequency circuit board. [SI-LIST] Re: Inserion loss of fr4 , 50 ohm trace . 2 and 4. So, for example the length for a 100 ps delay with FR4 is. 4. Where I is maximum current in Amps, k is a constant, dT is temperature rise above ambient in °C, & A is cross sectional area of trace mils². Obviously the IC pad is smaller, and it's ok to use narrower traces for short distances as you connect the SMD components, but as soon as possible, do a smooth taper up to the 2. This is my first RF project so need guidance about that. (We can process . I need a Z0 of 50 ohms. Temperature Chart 3: Microstrip Insertion LossSparkFun Forums . Layer topology is 2 layers FR4 0. This suggests that all 50Ω microstrip lines on FR4 substrate should have the same aspect ratio. As I understand it FR4 is pretty much the cheapest/easiest material to use, but will have poor performance at high frequencies. Trace 1 (TP1/TP2) – Single ended 50 Ohm trace; Trace 2 (TP3/TP4) – Single ended OhmBeatty standard; Trace 3 (TP5/TP6) – Single ended trace with two impedance steps 3000 mils apart. The Smith Chart achieves this by superimposing a grid on S11 that maps load impedance. 1mm)Better to distance the RF trace away from other traces and pads, and if you can move the connector to the left 2 mm or the IC right 2mm would be better. Minimum Trace Width Signal Run Length, up to Minimum trace width 10 in / 25 cm 4 mil / . Home. For EMI reasons, I did a ground fill on the component. You only need to worry about trace impedance matching at high frequencies, where the propagation delay of the trace length becomes a significant fraction of the waveform time period for one cycle of an RF signal or a significant portion of the rise-time for digital signals. The transmission line needs to be 50 ohms as it connects directly with a 50 ohm matched impedance IC, of which the leads are around 0. Control 50 ohm impedance In the environment of common board (FR4, etc. (Simulation will verify this. Height: Height of the substrate. Nickel (a component of ENIG plating) has a resonance at. Consider that the bond wire inside the IC package neither continuous 50 ohms impedance. 1 mm FR4 between Top high speed lines and next ground plane. There are some advantages to using a microstrip transmission line over other alternatives. The chart below visually shows this: Figure 1. In this case you have to be aware of what is their standard stackup for the. For your 3-6GHz PCB, better use RO4003 or another low loss substrate. For example, there are a few factors that will limit your available trace width to get to 50 Ohms in a 4-layer stackup: Available. (approximation for FR4) C = 11. What Is Important About PCB 50 Ohm Trace. As long as your manufacturer's process can handle it, you can choose any thickness you like for your. This works fine, I ordered impedance control several times - no need to change the width. The Trace Width is the parameter in question which should be 8. T=trace height . For the signal trace of width W and thickness T, separated by distance H from a ground (or power) plane by a PCB dielectric with dielectric constant εr, the characteristic impedance is So i want to know that how to calculate 50 ohm transmission line trace width. 018 . This page covers Microstrip Width Calculator. 7 10^ (-6) Ohm-cm. Joined Mar 14, 2008. Is it so? More usually, the feasible line width is far below that required for 50 ohms. My 50-Ohm trace is on component side and the ground layer is the next layer (10-mil distance). Page 6 of 9 impedance, at low frequency. This will be routed to an RF Switch IC (HRF-SW1030), where it's switched between 6 channels. . View All Tools. For other standard impedances, for example the 75-Ω video standard, adjust "W" to about 8. trace thickness = 0,2 mm (from pcb datasheet) height of dielectric above return plane = 1,6 mm (from datasheet) I obtain a Z0 of 70,8 ohm. 4 GHz a 50 Ohm transmission line at standard FR4 62 mill that is about 100 - 120 mill wide. heater trace must be 0. e. 02 similar to FR4 and the conductor losses turned on. Signal Speed. Impedance vs Line Width at 10 GHz 0. 2-4. 4 ohms Trace width: 30 mils, clearance: 6 mils, impedance: 50. Modeling approximation can be used to design the microstrip trace. crutschow. 4mm pour 50 Ohms impedence. 0 at 1GHz. 4 and Bluetooth low energy applications built on FR4 substrates, the methods of transmission lines typically take. 02) with 50 Ohm characteristic impedance with parallel termination. 8 mil traces, and that is assuming no space. 4 GHz top layer and bottom layer 50Ω gap width: 6 mils Table 1-1. Gen2. Trace DeBoer against the British Columbia Chicken Marketing Board (Chicken Board), Counsel for Trace DeBoer requested the Board consider further evidence in the form of. 8 mils is a standard range for solder mask thickness; Altium Designer uses 0. This is one reason you should leverage your fabricator's experience and material set when designing the stackup and determining impedance. 74mm. 6mm, dielectric is FR4 (which I know isn't ideal and doesn't specify exact performance - cost reduction is important to this design). If you’re routing with 50 Ohm impedance and you need to design a 4-layer stackup, read our guide to se. 73mm, and the pitch of the LQFP-144 is 0. $egingroup$ A trace on FR4 of dielectric thickness t above a ground plane will present a suitable 50 ohm impedance if it has a width of 2t. Some manufacturers will accommodate other specific thicknesses of 0. Table 3. FR4 is the most common grade dielectric material that is used in the fabrication of circuit boards. 1 Answer. Home. There are some advantages to using a microstrip transmission line over other alternatives. When you want to determine the width and length of a microstrip line for any given characteristic impedance and electrical length, or vice versa, a microstrip calculator is the right tool to do so. 8mm. 8 for the relative permittivity of FR4 source (FR4) And using the EEWeb Calculator to find that . (dielectric constant Dk=4. 2 Traces 2. Also, standard FR4 is very lossy at GHz frequencies. 5 for FR4. If it were built in ½ oz. 0 x 106 MΩ-cm. 8 * W + T)]) ohms. Where electronics enthusiasts find answers. Learn more about designing 50 Ohms on a 4-layer. I want to derive the relationship like above between the other. In that case I need to design a transmission line which has characteristic impedance of 50 ohms. 7mm is correct for 1. 6 mm thickness, 1 oz. Then, I used the design of the PCB trace given by RN-171 datasheet. 5E7 mhos/meter At very low frequencies – until about 1MHz, we can assume that the entire conductor participates in the signal current and hence Rsig is the same as the ‘alfa’ C resistance of the signal trace, which is: Where: ρ = Copper resistivity in ohm-inch . According to their 2 Layer PCB Specs the PCB substrate has a dielectric constant of 4. While commonly constructed using printed circuit boards, this structure can also be built using other materials as long as there is a conductor separated from. Re: Max current density for 35 µm Cu FR4 PCB? « Reply #3 on: March 19, 2015, 09:48:14 am ». Home. Trace thickness: for a 1oz thick copper PCB, usually 1. usually the. At 2. 2mm. 048 x dT0. Feed. To achieve 100 ohms with 1. This is good enough so we can now switch to the “Coupled Microstrip Line” calculator. The lossless case was compared with the lossy case using a Df = 0. for N=1; Zoe=70. so i want to know that it is called micro-strip or strip-line? i have check the calculators like. Reverse phone lookup for finding someone quickly. Dispersion is sometimes overlooked for a number of reasons. You should know the dielecric thickness from the reference plane, trace thickness, dielectric constant of the. The legend for all three curves is shown on the middle curve and that is a transmission line built on a 10mil thick RO4350B. Following are my parameters-PCB - FR4 with a Dielectric constant of 4. Even low layer count PCBs might need 50 Ohm impedance. I watched that entire Michael Ossmann: Simple RF Circuit Design video, and I've tried plugging those 2-layer PCB specs into the same impedance. Its 4 layer card with 2 power plane in inner layer. I tend to deal with microstrip on multilayer boards where the trace width is very similar to the width of. In my PCB, antenna feed line will be coplanar waveguide with bottom ground plane. – Tony Stewart EE75 Jun. TurboPC. 6mm board and then your trace width (per the rule-of-thumb that you want to use) will be 1. This application note from Fairchild (alternative link), which is one of the top Google results, says that D+ and D- trace single-ended impedance should be 45 ohms. 2mm, it may be better idea to use microstrip line, with. For example, if you wish to input "25000000", just type "25M" instead. The microstrip is a popular device in microwave radio technology. The trace impedance on your PCB that carries RF signals can also be made 50 ohms by adjusting its width appropriately. Based on the documentation submitted, the copper layer is photo plotted and exposed to UV-rays. Note: The results are only for approximation and rough estimation, the final values and the. 02). The IC only has room for 18. 50 Ohm Trace Width Calculator Psp System Update 6. • FR4, 4 layers, PCB Thickness: 0. finished (outer layers) and . 7 Buck Layout GuideI get the idea of a 50 ohm trace. 9, the effective dielectric constant. Now, I could find right track length using Smith chart, or modify the values to obtain 50 ohm value. PCB Impedance-Calculation: Help with the dimensioning of the impedances of your circuit board. A trace in a package might be 2 mils wide and 500 mils long. The required inputs are the Dk value for the dielectric constant of the PCB substrate, and the. 3 as fr4 material with 1. The output will be primarily used with my 50 ohm spectrum analyzer, and my design will cater to its Zo. 0001), and because it has low dielectric constant the line widths for 50 ohms are much fatter than other substrates, which reduces metal loss. 6mm – Internal to External (0. 17 pF per inch will not provide much inter-plane capacitance for supply decoupling. Just as important as determining an appropriate trace width for a single. Surface resistivity is expressed in units of ohms or ohms per square. 5; results odd impedance: 45. 575 mm FR4 requires a width-to-height ratio of about 2, so the trace is about 3 mm wide. 01 mil Total thickness 31. Let’s take a look at what exactly a 50 ohm trace is, and how you should go about figuring out what trace width to route it at. 4 mil SM solder mask 0. 024 x dT0. 500000 Kindly suggest. 98 99. USB 2 e. 007". 7 mil width for the rough microstrip line, we'll have larger impedance mismatch over the entire 100 MHz to 20 GHz frequency range shown below. 7 x 10-6 ohm-cm αcopper (temperature coefficient) = 3. 5mm FR4, but then the. For example, a 50 Ohm line 2 inches long has a total loop inductance of about 16. 2 mil trace width o 2 mil trace copper thickness o 5. resistance of the PCB traces plus the 10 Ohm resistor. From the performance of PCB traces, low impedance is generally better. 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. The characteristic impedance of the signal path is a continuous 50 ohm path relative to the closest ground. Also, standard FR4 is very lossy at GHz frequencies. High-speed designs carry a requirement for controlled impedance, crosstalk control, and the need for interplane capacitance. Trace Inductance calculator for wide traces over a ground plane with trace width (W) much larger than substrate thickness (T). )Transcribed image text: The output port of a 915 MHz tranciever IC has an impedance of 50 Ohm. For a quarter wavelength antenna, it becomes λ /4 to be fixed. 00 8. 1. If we make the line width wider, we have to make the dielectric thicker to preserve the 50 Ohms, and this keeps the loop inductance the same. 6 fF/mil width capacitor there if you’re on FR4 with a 50-ohm microstrip line (because you’re adding about a half line-width extra capacitance. The microstrip is a very simple yet useful way to create a transmission line with a PCB. εr 14 RF / Microwave Design - Basics)Sometimes Dielectric surrounding Trans-mission Line isn’t Constant (Outer Layer Trace on PCB). This application note from Fairchild (alternative link), which is one of the top Google results, says that D+ and D- trace single-ended impedance should be 45 ohms. = room temperature (25⁰C) L= Length of trace. We would like to show you a description here but the site won’t allow us. This material is incorporated in single-sided, double-sided, and multi-layered boards. Just How Wide Should a PCB 50 Ohm Trace Width Be? Even low layer count PCBs might need 50 Ohm impedance. I have to calculate the Transmission line Trace width for 50 ohm FR4 6 layer PCB. 2, than the standard FR4. Remember, these stackups aren’t for every design. A 50-Ohm stripline has a total dielectric spacing between the planes equal to twice the line width. 5mm, gap between feed trace and copper pour is 0. A. The surface resistivity of the most commonly used PCB material FR4- for example FR370HR- is 3. Simple rough calculation: A 1mm track on 1. 8, depending on the glass weave style, thickness, resin content, and copper foil roughness. Drawing 50. The benefits are significant for both standard FR4 (orange) and a low loss laminate. 4, loss tangent = 0. I am using 0. I am planning to use coplanar waveguide with bottom ground layer as transmission line. If im using an FR4, how much loss can i expect with a 60ohm 1inch trace vs a 50ohm one? If i have a 2inch trace and a 4Ghz high band antenna matching…The Datasheet says that the target impedance of the RF Trace should be 50 Ohms as a controlled impedance. • FR4, 4 layers, PCB Thickness: 0. [SI-LIST] Re: Inserion loss of fr4 , 50 ohm trace . Here are a few qualities of FR4 materials that make them popular: Wide range of operating temperature (50°C to 115°C) Higher T g value (about 180°C)Microstrip lines have three parameters that we can change to achieve 50 ohm impedance: copper thickness (T) substrate thickness (T) track width (W) Due to design constraints, there is only one parameter (track width,) left to achieve 50 ohm. I am using 0. For a 90 degree bend, it’s like putting a 1. 5 oz Cu Microstrip with H = 2 mil 25 50 75 100 23 4 5 Line Width (mil) Impedance (Ohms) Low DK Flex: DK=2. The answer to this question, Characteristic impedance of a trace, shows that a 120 mil trace is required to get this impedance. 376V, before it gets disturbed. You can access serveral online sites to help calculate a trace with Z0 of 50 Ohm. The layout is here: I also placed vias to ground near the 50 Ohms trace at 1/20th of the. 83 ohm at 130 degrees, so should my temperature rise be 105 deg or 130 deg?. 2, the wavelength increases to 12 inches – a 40. Figure 5. 4 ohms; differential impedance: 90. This material is incorporated in single-sided, double-sided, and multi-layered boards. When I tried to calculate trace width on . This tool uses formulas from IPC-2221 to calculate the width of a copper printed circuit board conductor or "trace" required to carry a given current while keeping the resulting increase in trace temperature below a specified limit. Where: R– Trace Resistance in Ohms. 3) Z 0 Ω Impedance ca. FR4 PCB material should be fine with the frequencies you are talking about. 024 x dT0. How to route a trace on PCB with 50 Ohm impedance? Asked 7 years, 11 months ago Modified 7 years, 11 months ago Viewed 5k times 5 I used some online. A higher scale works, but avoid moving into a scale close to 1k ohms or higher. Similarly, we can plot the propagation delay versus dielectric constant. For 1 oz. These both offer higher performing thermal characteristics than a general purpose FR4. (2 layers board, 1. Common consideration The impedance of the line is mainly depending on your. 3. **Note: Like our stripline impedance calculator, all of our RF calculators allow SI prefix input. 38mm height – FR4 thickness to GND plane)T=1/f Where T = Time F = frequency So, for an antenna, operating at 50MHz, t =1/f = 0. 5mm, T=0. strip thickness is 1 oz copper, 0. They have mentioned 7. Using the formulas, I found that the trace should be around 17 mils thick to obtain the 50-ohm controlled impedance. 0008). 4 mil trace thickness. The physical parameters of the trace i. 1 mm 20 in / 50 cm 6 mil / . Why does a 4 layer PCB board significantly reduce the trace Width needed for a 50 ohm transmission line when compared to a 2 layer PCB board? Hot Network QuestionsTrace 50ohm±5%; Multilayer pcb; fr4 pcb; Product description: when to use controlled impedance 50 ohm controlled impedance what is impedance matching in pcb how to specify pcb impedance an introduction to the design and manufacture of controlled impedance pc; INQUIRY. Gen4. N. 4mil required impedance 50 Z frequency 100Mhz calculated width of trace = 110 Mils This says that ALL 50 Ohm transmission lines in FR4 have exactly the same loop inductance per length. 5mm FR4, I am getting almost same capacitance per cm. Enter a 7-digit number in our reverse phone number. 5 Ghz ) on a Fr4 > substrate . 48 mm plane-to-plane thickness/0. 4mil required impedance 50 Z frequency 100Mhz calculated width of trace = 110 MilsThis says that ALL 50 Ohm transmission lines in FR4 have exactly the same loop inductance per length. ZED-F9P High precision GNSS module Integration manual Abstract This document describes the features and application of the ZED-F9P, a multi-band GNSS module with integrated RTK offering centimeter-levelthe antenna input. Among these 3 variables, the trace width I the one that is within the complete control of the designer. I wanted to use Altium to calculate the width of the trace automatically, so that it had a 50 Ohm impedance. 7 mils, which resulted in a modeled impedance of 50. eu. For double sided FR4 with 1. 1 ohms; In addition to those calculation I found some other resources with some sample trace properties: Mikrocontroller. The outer/inner surface. And I got 24 mils for the 100 Ohms differential traces from IC to balun, and 55 mils for the 50 Ohms trace from balun to antenna. The impedance of the line is mainly depending on your PCB characteristics. 0175 Ohm mm²/m is the specific electrical resistivityThe initial portion of the simulation waveforms for the load end voltage (green waveform), for a 1V step injected into a 50ohm Z0 transmission line with delay=70ps, with source resistance =200ohms and output capacitor 1pF, showing the capacitor voltage charging to Vfinal(1-e-2Td/Z0C)= 0. Using a field solver, this aspect ratio is found to be about 2:1. You will have a 50 ohm line. Those familiar with high-speed design know that trace geometry, trace location, and board substrate all affect signal speed, impedance matching, and propagation delay. Resistivity of copper foil = 1. 220. 6mm board and then your trace width (per the rule-of-thumb that you want to use) will be 1. I am a rookie on both RF and PCB design and I am currently trying to do a 50 ohm 11 watt dummy load project for 100MHz-1GHz. The current-carrying capacity of a piece of copper is determined, to a first-order approximation, by two factors — the rate of heat generation and the rate of heat dissipation. substrate. 9 mil.