Article View: sci.electronics
Article #17907Re: TTL Questions
From: John Eaton
Date: Tue, 11 Aug 1987 15:54
Date: Tue, 11 Aug 1987 15:54
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<<<< < In the recent discussion on TTL there seem to be numerous < recommendations to use a series resistor when connecting an unused < input to +5 volts. This is an unnecessary waste of a resistor, the PC < board space to mount it, and the foil trace to connect it. Can't we < finally give pullup resistors a decent burial? Unused inputs should < be connected DIRECTLY to the appropriate (+5 Volt or Gnd) supply rail! ---------- I suspect that the real reason that everybody does this is that they all suspect that the circuit may not work as designed. Having some unused inputs not tied to a rail is very handy if you have to cut traces and add little yellow wires to a board to get it into production. John Eaton !hplabs!hp-pcd!john
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Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: arc1-ca.pugleaf.net!utzoo!mnetor!uunet!husc6!mit-eddie!ll-xn!ames!ucbcad!ucbvax!hplabs!hp-pcd!hpcvlo!john From: john@hpcvlo.HP.COM (John Eaton) Newsgroups: sci.electronics Subject: Re: TTL Questions Message-ID: <1090002@hpcvlo.HP.COM> Date: Tue, 11-Aug-87 11:54:41 EDT Article-I.D.: hpcvlo.1090002 Posted: Tue Aug 11 11:54:41 1987 Date-Received: Sat, 15-Aug-87 01:32:35 EDT References: <1395@crash.CTS.COM> Organization: Hewlett-Packard Co., Corvallis, OR, USA Lines: 18