ANSI=20 PCB Track Width Calculator

From: "Saved by Internet Explorer 11" Subject: ANSI PCB Track Width Calculator Date: Fri, 29 May 2015 13:12:42 -0700 MIME-Version: 1.0 Content-Type: multipart/related; type="text/html"; boundary="----=_NextPart_000_0000_01D09A11.25462560" X-MimeOLE: Produced By Microsoft MimeOLE V6.1.7601.17609 This is a multi-part message in MIME format. ------=_NextPart_000_0000_01D09A11.25462560 Content-Type: text/html; charset="utf-8" Content-Transfer-Encoding: quoted-printable Content-Location: http://www.desmith.net/NMdS/Electronics/TraceWidth.html =EF=BB=BF =20 = ANSI=20 PCB Track Width Calculator=20 =20 =20 =20 =20 =20 =20 = =20 =20 =20 =20 =20 =09

ANSI IPC-2221A PCB Trace Width Calculator

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Help us improve these pages - If you have any comments about = the=20 content here or would like to see improvements or a different = calculator=20 added, please use the guest = book.

This is the NEW version of my calculator. The original = version=20 is HERE= . =20

New features in this version include:

use of metric or imperial units for all major fields
the ability to change units for any applicable field on the = fly
minor enhancements to some of the calculations - IPC-2221(A) = changes=20 the curve fit
saving of all parameters in a cookie to keep your = preferences=20 between visits

This page calculates approximations to the ANSI / = IPC-2221/IPC-2221A=20 design standards for PCB trace width - this is the replacement = for=20 IPC-D-275.

The approximations and rationale are described in Temperature=20 Rise in PCB Traces, equations 13 & 15. by Douglas = Brooks,=20 UltraCAD Design, Inc. The original idea for this approach was = from=20 Brad Suppanz.

The figures returned by this calculator are to be taken as a = guide=20 only. I will not be held responsible for any mishap or loss, = either=20 direct or consequential, that may occur as a result of relying = on the=20 figures herein.

The trace width formulas are:

Internal traces : I =3D 0.024 x=20 dT^0.44 x A^0.725
External = traces: I=20 =3D 0.048 x dT^0.44 x = A^0.725

=20 where:

I =3D maximum current in Amps
dT = =3D=20 temperature rise above ambient in =C2=B0C
A =3D = cross-sectional area in=20 mils=C2=B2

Please note that IPC-2221(A) equations are subtly different = from=20 those in IPC-D-275 in that they are typically slightly more=20 conservative and are impicitly derated to compensate for = manufacturing=20 effects, i.e. they should be more reliable in = practice.

The values calculated here compare very closely with those = derived by=20 the UltraCAD PCBTEMP utility, and like the diagrams in the = standards=20 documents, are valid up to 35A for external traces and 17.5A = for=20 internal, 400mil widths and a maximum temperature rise of = 100=C2=B0C.

I've added a recommended track clearance value based on the UL=20 rule:

clearance in inches =3D 0.023" + = (0.0002" x=20 V)

The formulae as it stands is simplistic, but is reasonable for = V >=20 50. Note that there are many international standard for this = sort of=20 thing, e.g. EN60065:1994, which for European mains of 230V, = allows for=20 about 120mil for Class I (protected by earthing) and 240mil = for Class=20 II (double isolated). Note that if there is no conformal = coating and=20 the environment is dirty/humid/condensing then all bets are = off.=20 Please read the standards documents yourself.

= Ideally, keep=20 "hot" and "cold" areas of your board well apart.

Change a value in an input field, then press TAB to move to the = next=20 field. The results tables will be updated automatically.

ANSI PCB Trace Width=20 Calculator
Input Data	Results Data
		Internal Traces	External Traces
Field	Value	Units	Trace Data	Value	Units	Value	Units
Current (max. 35A)		Required Trace Width
Temperature Rise (max. 100=C2=B0C)		Cross-section Area
Cu thickness		=	Resistance	=CE=A9 Ohms	=CE=A9 Ohms
Ambient Temperature		Voltage Drop	Volts	Volts
Conductor Length			Loss	Watts	Watts
Peak Voltage	Volts	Required Track Clearance

Back=20

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3D"Valid =20

=C2=A9 2004,2010 Nick de Smith = Webmaster
=20 Last edited: 13^th July 2010, Site powered by = Notepad!=20

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