Article View: comp.arch
Article #12775Re: computer devices
From: System Mangler
Date: Fri, 12 Dec 1986 16:39
Date: Fri, 12 Dec 1986 16:39
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1376 bytes
In article <7396@utzoo.UUCP>, henry@utzoo.UUCP (Henry Spencer) writes:
> we need a high-gain amplifier device so that minor
> variations in gain won't matter.
Even in fairly well-behaved technologies like MOS, the gain is often
not very high. In PMOS, which used enhancement-mode pullups, a gain
of -3 was considered good. 4-transistor dynamic RAMs amplify on the
same principle and have a tough time getting a gain of -1.5. Even
CMOS may have gains as poor as -4 due to short-channel effects; it
gets worse at high supply voltages and small feature sizes.
Some forms of GaAs logic allow the pulldown transistor to conduct
quite a bit when it is nominally off (due to limitations on where
the threshold can be set), and these too have trouble getting much
gain.
Don Speck speck@vlsi.caltech.edu {seismo,rutgers,ames}!cit-vax!speck
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Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: arc1-ca.pugleaf.net!utzoo!mnetor!seismo!ll-xn!cit-vax!mangler From: mangler@cit-vax.Caltech.Edu (System Mangler) Newsgroups: comp.arch Subject: Re: computer devices Message-ID: <1335@cit-vax.Caltech.Edu> Date: Fri, 12-Dec-86 11:39:47 EST Article-I.D.: cit-vax.1335 Posted: Fri Dec 12 11:39:47 1986 Date-Received: Mon, 15-Dec-86 04:35:25 EST References: <7396@utzoo.UUCP> Organization: California Institute of Technology Lines: 17 Summary: gain often not very high