PCB Trace Width Calculator and Equations. Until recently, the main source for calculation of the printed circuit board PCB trace width for temperature rise were plots derived from the experiments conducted more than half a century ago. They are reproduced in Figure 6 4 of IPC 2. B and can be described by the equation iKT0. Ac. 0. 7. 25, where i current in amps, T temperature rise in o. C, Ac conductor cross sectional area in square mils, K constant equals to 0. Sco Openserver 5.0.5 Iso here. There are a number of online calculators that implement the above formula. The new standard IPC 2. It provides more than 1. PCB and conductors, distance to a copper plane, etc. Our calculator will do all this for you, but Ill still provide some basic explanations for those who would like to know the details. We will use IPC 2. Zmtc.png' alt='Pcb Trace Width Calculator' title='Pcb Trace Width Calculator' />Figure 5 2, which represents a typical application. It contains i vs. Ac charts for the polyimide boards 0. They are given for certain discrete values of temperature rise and they all are linear in logarithmic scales. We know that a straight line on log log graph represents a polynomial. This means that AciK1i. Learn To Speak French Deluxe 10 Free Download. K2, where K1 and K2 are some constants. For a selected T one can derive K1 and K2 by estimating the slope and intercept point of an appropriate plot in Fig. Jack Olson from Caterpillar has calculated these and other coefficients and provided them in his spreadsheet and a related article. I would like to thank Jack for allowing me to utilize his numbers. Note that both the multiplier K1 and the exponent K2 vary depending on T. I thought it would be convenient to have a unified formula for cross sectional area as a function of electric current, so we could quickly find it for any arbitrary T. For this I have interpolated K1T and K2T between 2 and 1. C by using a curve fit function that employs least squares power curve regression. The result is as follows Acsq. JWb.png' alt='Pcb Trace Width Calculator' title='Pcb Trace Width Calculator' />T 0. T 0. 1. 081. 1. Once you determined Ac, you can find the required trace width for a given copper weight widthActhickness, where thicknessmiloz1. The above equation provides reasonably accurate approximation of the generic Fig. For example, for i1. A and T2. 0o. C the IPC gives Ac5. Calculations based on these data should fit most applications and here will be referred to as universal or generic. If you have a multi layer PCB with a copper plane near your conductor, the actual T will be substantially lower. However, for the boards less than 7. Therefore IPC referring to Fig. Guest book. Contact Nick ANSI PCB Trace Width Calculator. Help us improve these pages If you have any comments about the content here or would like to see. Online calculator for harmonics frequencys. You may use one of the following SI prefix after a value ppico, nnano, umicro, mmilli, kkilo, Mmega, Ggiga. PCB_trace_outer2.png' alt='Pcb Trace Width Calculator' title='Pcb Trace Width Calculator' />
Anyway, to reflect the conditions of a specific application, one can introduce a correction modifying factor as the ratio between estimated actual and generic T. Our widget approximates these factors for various cases based on the data in IPC appendix and shows them just for reference, so you can see how much each of them affected the result. If their product is less than 1, you can still use the universal numbers for design margin. However, if you dont have enough board space and want to reduce the size of the PCB tracks, you may choose to use more application specific modified results. Let me explain how our calculator does it with the following example. Suppose you want T2. C and the net correction is 0. It means that if you use the universal Ac, your actual temperature rise will be 2. HowToPCB/HowToPCB-images/HowToPCB-Copper.gif' alt='Pcb Trace Width Calculator' title='Pcb Trace Width Calculator' />C. So, we want to revise Ac to get your desired 2. C. Since the Ac varies non linearly with respect to T, we cant just reduce it proportionally. Instead, our script first calculates virtual temperature, which is your input T divided by the product of all correction factors. This is like a reverse modification of the chart value. In our example it will be 2. C. Then the script plugs this number into our generic formula. In our tool this result is referred to as revised. For comparison, we also provided the numbers based on legacy IPC2. You can see that the old standard overstated current carrying capacity of external tracks. Therefore it seems that for small boards without planes the designs that relied on the historical charts might have resulted in underrated external traces. That document also arbitrarily assumed that internal conductors could carry only half of the current of the outer ones. In reality, as mentioned in the new standard, inner layers may actually run cooler because the dielectric has 1. Therefore, because of the wrongful assumption, the legacy recommendations for internal tracks happened to be conservative. Note that the new rule suggests the same copper size for all boards layers. By the way, it may seem counterintuitive, but thicker conductors have lower current carrying capacity than thinner ones because of the smaller trace width at a given AC. For those who work with metric units, here is a quick conversion reference 1 mm0. Notes. All the results here are obtained by interpolation of the IPC plots, so there is always some inaccuracy. For simplicity, our calculations dont include the effect of the board material FR4 is worse than polyimide just by 2. The analysis is valid for traces spaced apart by more than 1 which often may not be practical. If parallel tracks are spaced closer, their temperatures will increase. In this case, you need to use combined current to determine their combined cross sectional area. The presence of heat dissipating components may also raise the temperature. The tests that formed the basis of the new standard were conducted for electric currents up to 3. T up to 1. 00 degree C. The output data here do not include any derating. It is always recommended to add some safety margin. The information and the widget are provided here with no liability of any kind whatsoever. They reflect only personal opinion of the author and do not constitute a professional or a legal advice. For final decisions consult the appropriate standards and your boss. Also see our general Disclaimer linked below. Mac Os X 10.4 Tiger Cd. IPC 2. 15. 2 is Copyright 2. IPC, Bannockburn, Illinois, USA.