Article View: sci.electronics
Article #3774Re: Transmission Lines - What Are They??
From: Mark Robert Thorson
Date: Sat, 18 Nov 1989 17:34
Date: Sat, 18 Nov 1989 17:34
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ngc@chanel.UUCP (Chris Ng) says: > In article <24023@cup.portal.com>, mmm@cup.portal.com (Mark Robert Thorson) wri > tes: > > A good cookbook rule for TTL is: > > 1) Series termination -- 10 to 100 ohms placed right near the driver. I.e. > > > > 2) Parallel termination -- 220 ohms to Vcc and 330 ohms to ground, placed > > Parallel termination draws current constantly while > series termination does not. May be it doesn't matter in your design, > just a side note. Another cookbook rule: use series termination where short lines with few loads are being drived, such as a microprocessor driving a few peripheral and memory chips, or an address multiplexer driving a bank of DRAM chips. Use parallel termination where the line is long and has many loads, like a system clock line that snakes all over your board.
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<868@encad.Wichita.NCR.COM> <1989Nov12.013850.7756@utzoo.uucp> <24023@cup.portal.com> <46e0fd1a.1fbc0@chanel.UUCP>Show Full Headers
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Path: arc1-ca.pugleaf.net!utzoo!yunexus!ists!jarvis.csri.toronto.edu!mailrus!cs.utexas.edu!samsung!usc!apple!fox!portal!cup.portal.com!mmm From: mmm@cup.portal.com (Mark Robert Thorson) Newsgroups: sci.electronics Subject: Re: Transmission Lines - What Are They?? Message-ID: <24187@cup.portal.com> Date: 18 Nov 89 17:34:31 GMT Article-I.D.: cup.24187 References: <868@encad.Wichita.NCR.COM> <1989Nov12.013850.7756@utzoo.uucp> <24023@cup.portal.com> <46e0fd1a.1fbc0@chanel.UUCP> Organization: The Portal System (TM) Lines: 19