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From: markh@gamwich.hw.stratus.com (Mark Himelfarb)
Newsgroups: sci.electronics
Subject: Re: pc board design tips
Message-ID: <3219@lectroid.sw.stratus.com>
Date: 26 Nov 90 22:17:06 GMT
References: <36183@cup.portal.com>
Sender: usenet@lectroid.sw.stratus.com
Reply-To: markh@gamwich.sw.stratus.com (Mark Himelfarb)
Organization: Stratus Computer, Hardware Engineering
Lines: 18


More points: Separate power and ground planes.  This is absolutely
essential in noise reduction.

Do not allow traces to run parallel for long runs.  Crosstalk has a nasty
habit of occurring at the wrong times.

Those series resistors may not necessarily be at 100 ohms; the actual value
will depend upon the impedance of the pc board.  I have seen series resistors
used in DRAM arrays with values from 22 ohms to 47 ohms.

Series resistors should also be used with newer technology devices
(AS and FCT) which have etches longer than approximately 6 inches.

There are lots of other issues, but the better pc layout software packages
should flag these issues and others.

							Mark Himelfarb