Top ten analog engineers
in [Design]
|
From: Jim Thompson on 23 Dec 2009 21:13 On Wed, 23 Dec 2009 12:56:10 -0500, Phil Hobbs <pcdhSpamMeSenseless(a)electrooptical.net> wrote: >Tim Williams wrote: >> "Jim Thompson" <To-Email-Use-The-Envelope-Icon(a)My-Web-Site.com/Snicker> >> wrote in message news:bft2j5dkctqm7mb0c21cqs2uqdc6v0va2f(a)4ax.com... >>>>> It might be amusing to suggest a class (SED lurkers) problem... design >>>>> (at the CMOS transistor level) a three-input NAND, so that delays to >>>>> output from each input are identical. >>>> Not enough data, I think... >>>> JF >>> Not just to satisfy equal delays... match paths, I care not the >>> absolute delay for this question. >>> >>> It's a trick question (as if you didn't know ;-) >> >> Well, the traditional three-NMOS-in-series, three-PMOS-in-parallel layout is >> equal, to a first approximation. If you want to count parasitic capacitance >> of each transistor to substrate, that will make things uglier, since the >> bottom NMOS has to discharge the two NMOS above it, plus all three PMOS and >> the wiring. Likewise, the rising edge becomes faster when 2 or 3 inputs are >> driven low simultaneously (PMOS working in parallel). >> >> Tim >> > >Well, you can do it by cheating--build an NMOS gate in a CMOS process. >Takes some quiescent current though. > >Cheers > >Phil Hobbs > >(Who's enjoying the buildup although he isn't a CMOS guy at all.) Naaaah! Nothing like that.... _C_MOS but a simple symmetry trick guarantees equal delays. ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | Help save the environment! Please dispose of socialism responsibly!
From: Jim Thompson on 23 Dec 2009 21:13 On Wed, 23 Dec 2009 11:02:56 -0800 (PST), whit3rd <whit3rd(a)gmail.com> wrote: >On Dec 22, 5:46�pm, Jim Thompson <To-Email-Use-The-Envelope-I...(a)My- >Web-Site.com/Snicker> wrote: > >> >>It might be amusing to suggest a class (SED lurkers) problem... design >> >>(at the CMOS transistor level) a three-input NAND, so that delays to >> >>output from each input are identical. > >> It's a trick question (as if you didn't know ;-) > >Yeah, I found myself wondering if CMOS includes resistors nowadays >(it never used to). Nope. ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | Help save the environment! Please dispose of socialism responsibly!
From: Jim Thompson on 23 Dec 2009 21:15 On Wed, 23 Dec 2009 11:44:10 -0800 (PST), whit3rd <whit3rd(a)gmail.com> wrote: >On Dec 22, 5:46�pm, Jim Thompson <To-Email-Use-The-Envelope-I...(a)My- >Web-Site.com/Snicker> wrote: > >> >>It might be amusing to suggest a class (SED lurkers) problem... design >> >>(at the CMOS transistor level) a three-input NAND, so that delays to >> >>output from each input are identical. > >> Not just to satisfy equal delays... match paths, I care not the >> absolute delay for this question. > >Got it. Twelve active devices, looks ugly. Uglier still when >the outputs and inputs are buffered. Ugly is in the mind of the beholder. Christmas shopping (something I avoid except for once per year) today, I observes that 99% of women are quite palatable ;-) ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | Help save the environment! Please dispose of socialism responsibly!
From: Paul Hovnanian P.E. on 23 Dec 2009 21:07 Jim Thompson wrote: > > It might be amusing to suggest a class (SED lurkers) problem... design > (at the CMOS transistor level) a three-input NAND, so that delays to > output from each input are identical. V+ o---------------------------+-+----+-+-----+--+ | | | | | | | +---+ | | | | | A o-------+------------------+ +->---+ | | | | | | +-+ | | | | | | | | | | | | | +--+ | | | B o-------|-----+--------------------+ +->--+ | | | | | | +-+ | | | | | | | | | | | | | +---+ | C o-------|-----|-----+---------------------+ +->----+ | | | | | | +-+ | | | | | | | | | +-------+------+-------o OUT | | | | | | | | +--+ | | +-----+ +-<---+ | | | +--+ | | | | | | | | +--+ | | +-----------+ +-<---+ | | +--+ | | | | | | +--+ | +-----------------+ +-<---+ | +--+ | | | | | +--+ | V -- Paul Hovnanian mailto:Paul(a)Hovnanian.com ------------------------------------------------------------------ Quantum Mechanics: The dreams stuff is made of.
From: Paul Hovnanian P.E. on 23 Dec 2009 21:14
krw wrote: > > On Wed, 23 Dec 2009 18:39:37 -0700, don <don> wrote: > > >Paul Hovnanian P.E. wrote: > >> Bill Sloman wrote: > >>> On Dec 23, 11:20 am, Fred Abse <excretatau...(a)invalid.invalid> wrote: > >>>> On Tue, 22 Dec 2009 22:38:25 -0700, Paul Hovnanian P.E. wrote: > >>>>> Hedy Lamarr? > >>> The co-inventor of frequency-hopping > >>> > >>> http://www.inventions.org/culture/female/lamarr.html > >> > >> When you realize that she had no formal technical training and what she > >> knew, she picked up listening to her first husband when she was 19 years > >> old, think of what she could have done had she actually trained and > >> worked in the field. > >> > >I think her own work was more rewarding and profitable. > > ...and that's just the pin ups. It makes one wonder what the world would have been like if Cindy Crawford had pursued her chemical engineering degree. -- Paul Hovnanian mailto:Paul(a)Hovnanian.com ------------------------------------------------------------------ The world is coming to an end ... SAVE YOUR BUFFERS!!! |