On a sunny day (Thu, 25 May 2017 10:40:17 -0700) it happened Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote in <ng5eic12cs7ucsq5jq569odd9cp0dsoq17@4ax.com>:>Why the need for such inaccurate/klutzy symbol representations? > >I generally use... > ><http://www.analog-innovations.com/SED/MOS_Symbol_Discussion_(SED).png>Why the circle / inverter symbol at the gates, don't these always invert?
Can we PLEASE stop using these shitty symbols?
Started by ●May 22, 2017
Reply by ●May 25, 20172017-05-25
Reply by ●May 25, 20172017-05-25
Jan Panteltje wrote on 5/25/2017 2:03 PM:> On a sunny day (Thu, 25 May 2017 10:40:17 -0700) it happened Jim Thompson > <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote in > <ng5eic12cs7ucsq5jq569odd9cp0dsoq17@4ax.com>: > >> Why the need for such inaccurate/klutzy symbol representations? >> >> I generally use... >> >> <http://www.analog-innovations.com/SED/MOS_Symbol_Discussion_(SED).png> > > Why the circle / inverter symbol at the gates, don't these always invert?Yep, that's why it's there. -- Rick C
Reply by ●May 26, 20172017-05-26
"Jan Panteltje" <pNa0nStpealmtje@yahoo.com> wrote in message news:og76a8$1o61$1@gioia.aioe.org...>>Why the need for such inaccurate/klutzy symbol representations? >> >>I generally use... >> >><http://www.analog-innovations.com/SED/MOS_Symbol_Discussion_(SED).png> > > Why the circle / inverter symbol at the gates, don't these always invert?What, you mean someone's arbitrary symbology is confusing? Imagine that! ;-) I think the circle symbol is better understood to mean "active low pin", rather than "negated". In that sense, a NOT gate is really a buffer that converts active-high to active-low logic. It's perfectly reasonable to draw logic circuits with active low inputs or outputs, because those often arise in practice: a single transistor is either active high/low, or hi-Z. Activity is logically when it's "on", and so, if you build your circuit out of one polarity of transistors (such as the historical NMOS or TTL logic families), it's logical to use one state as "active". So of course, all the classic data buses used active-low signals, or NPN open collector ("wired-OR", and notice it's logical-OR in negative logic only) lines. But even so, it's redundant, since the body connection is shown, defining the transistor as N or P. How could you ever /not/ have an "active low" PMOS? :) So, I don't object to the IC designers' notation; if body is left off (because it's almost always VDD or VSS), the circle serves to note polarity, and D/S distinction is meaningless for symmetrical devices, so no arrow is needed on them. It serves its purpose, without contravening existing understanding, and without making contradictory or confusing compromises. :) Tim -- Seven Transistor Labs, LLC Electrical Engineering Consultation and Contract Design Website: http://seventransistorlabs.com
Reply by ●May 26, 20172017-05-26
On a sunny day (Fri, 26 May 2017 09:07:26 -0500) it happened "Tim Williams" <tiwill@seventransistorlabs.com> wrote in <og9ckd$qvj$1@dont-email.me>:>"Jan Panteltje" <pNa0nStpealmtje@yahoo.com> wrote in message >news:og76a8$1o61$1@gioia.aioe.org... >>>Why the need for such inaccurate/klutzy symbol representations? >>> >>>I generally use... >>> >>><http://www.analog-innovations.com/SED/MOS_Symbol_Discussion_(SED).png> >> >> Why the circle / inverter symbol at the gates, don't these always invert? > >What, you mean someone's arbitrary symbology is confusing? Imagine that! >;-) > >I think the circle symbol is better understood to mean "active low pin", >rather than "negated". In that sense, a NOT gate is really a buffer that >converts active-high to active-low logic. > >It's perfectly reasonable to draw logic circuits with active low inputs or >outputs, because those often arise in practice: a single transistor is >either active high/low, or hi-Z. Activity is logically when it's "on", and >so, if you build your circuit out of one polarity of transistors (such as >the historical NMOS or TTL logic families), it's logical to use one state as >"active". So of course, all the classic data buses used active-low signals, >or NPN open collector ("wired-OR", and notice it's logical-OR in negative >logic only) lines. > >But even so, it's redundant, since the body connection is shown, defining >the transistor as N or P. How could you ever /not/ have an "active low" >PMOS? :) > >So, I don't object to the IC designers' notation; if body is left off >(because it's almost always VDD or VSS), the circle serves to note polarity, >and D/S distinction is meaningless for symmetrical devices, so no arrow is >needed on them. It serves its purpose, without contravening existing >understanding, and without making contradictory or confusing compromises. :) > >TimMaybe I am too old for this, but I was thinking why not use a picture of a flower, say red rose for NPN, yellow for Tex.. PNP, and 2 leafs for the wires, one folded leaf to signal emitter, THEN our circuit diagrams would look much nicer, modern programs and printers have no problem with that. My problem with the 'o' at the gate: it indicates an inverting inverter :-)
Reply by ●May 26, 20172017-05-26
On Fri, 26 May 2017 09:07:26 -0500, "Tim Williams" <tiwill@seventransistorlabs.com> wrote:>"Jan Panteltje" <pNa0nStpealmtje@yahoo.com> wrote in message >news:og76a8$1o61$1@gioia.aioe.org... >>>Why the need for such inaccurate/klutzy symbol representations? >>> >>>I generally use... >>> >>><http://www.analog-innovations.com/SED/MOS_Symbol_Discussion_(SED).png> >> >> Why the circle / inverter symbol at the gates, don't these always invert? > >What, you mean someone's arbitrary symbology is confusing? Imagine that! >;-) > >I think the circle symbol is better understood to mean "active low pin", >rather than "negated". In that sense, a NOT gate is really a buffer that >converts active-high to active-low logic. > >It's perfectly reasonable to draw logic circuits with active low inputs or >outputs, because those often arise in practice: a single transistor is >either active high/low, or hi-Z. Activity is logically when it's "on", and >so, if you build your circuit out of one polarity of transistors (such as >the historical NMOS or TTL logic families), it's logical to use one state as >"active". So of course, all the classic data buses used active-low signals, >or NPN open collector ("wired-OR", and notice it's logical-OR in negative >logic only) lines. > >But even so, it's redundant, since the body connection is shown, defining >the transistor as N or P. How could you ever /not/ have an "active low" >PMOS? :)You're only thinking logic, or hard switching. Once upon a time all that CMOS was used for was for logic... and the body diode wasn't shown at all, since they were _always_ connected to VDD or VSS depending on device-type, and the circle was to indicate PMOS as opposed to NMOS. I left it as a visual indicator for my own benefit.> >So, I don't object to the IC designers' notation; if body is left off >(because it's almost always VDD or VSS), the circle serves to note polarity, >and D/S distinction is meaningless for symmetrical devices, so no arrow is >needed on them. It serves its purpose, without contravening existing >understanding, and without making contradictory or confusing compromises. :) > >TimAs soon as Analog CMOS appeared, PMOS body connections in separate wells became common. Also we often have "dual-well" processes, allowing arbitrary NMOS body connections as well. The NPN/PNP-like arrows are totally incorrect, but certainly suffice for hackers >:-} ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | STV, Queen Creek, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | Thinking outside the box... producing elegant solutions. "It is not in doing what you like, but in liking what you do that is the secret of happiness." -James Barrie
Reply by ●May 26, 20172017-05-26
Tim Williams wrote on 5/26/2017 10:07 AM:> "Jan Panteltje" <pNa0nStpealmtje@yahoo.com> wrote in message > news:og76a8$1o61$1@gioia.aioe.org... >>> Why the need for such inaccurate/klutzy symbol representations? >>> >>> I generally use... >>> >>> <http://www.analog-innovations.com/SED/MOS_Symbol_Discussion_(SED).png> >> >> Why the circle / inverter symbol at the gates, don't these always invert? > > What, you mean someone's arbitrary symbology is confusing? Imagine > that! ;-) > > I think the circle symbol is better understood to mean "active low pin", > rather than "negated". In that sense, a NOT gate is really a buffer > that converts active-high to active-low logic.Nope! In logic the circle means inversion, period. When looking at any given part of a circuit you may or may not know if a signal is active high or low, but you know the bubble inverts. BTW, we seldom call it a "circle". It is called an "inversion bubble". http://bfy.tw/C1MK> It's perfectly reasonable to draw logic circuits with active low inputs > or outputs, because those often arise in practice: a single transistor > is either active high/low, or hi-Z. Activity is logically when it's > "on", and so, if you build your circuit out of one polarity of > transistors (such as the historical NMOS or TTL logic families), it's > logical to use one state as "active". So of course, all the classic > data buses used active-low signals, or NPN open collector ("wired-OR", > and notice it's logical-OR in negative logic only) lines.Huh? How is this related to the FET symbol?> But even so, it's redundant, since the body connection is shown, > defining the transistor as N or P. How could you ever /not/ have an > "active low" PMOS? :) > > So, I don't object to the IC designers' notation; if body is left off > (because it's almost always VDD or VSS), the circle serves to note > polarity, and D/S distinction is meaningless for symmetrical devices, so > no arrow is needed on them. It serves its purpose, without contravening > existing understanding, and without making contradictory or confusing > compromises. :)So what about devices that aren't symmetric? -- Rick C
Reply by ●May 26, 20172017-05-26
Jim Thompson wrote...> > As soon as Analog CMOS appeared, PMOS body connections in > separate wells became common. Also we often have "dual-well" > processes, allowing arbitrary NMOS body connections as well. > > The NPN/PNP-like arrows are totally incorrect, but certainly > suffice for hackers >:-}If you're playing with the body substrate, full symbols are called for. But I've seen plenty of use of the simplified symbol in IC designs where they all simply go to their respective rails. -- Thanks, - Win
Reply by ●May 26, 20172017-05-26
On Fri, 26 May 2017 09:07:26 -0500, "Tim Williams" <tiwill@seventransistorlabs.com> wrote:>"Jan Panteltje" <pNa0nStpealmtje@yahoo.com> wrote in message >news:og76a8$1o61$1@gioia.aioe.org... >>>Why the need for such inaccurate/klutzy symbol representations? >>> >>>I generally use... >>> >>><http://www.analog-innovations.com/SED/MOS_Symbol_Discussion_(SED).png> >> >> Why the circle / inverter symbol at the gates, don't these always invert? > >What, you mean someone's arbitrary symbology is confusing?It's only confusing to you. -- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
Reply by ●May 26, 20172017-05-26
On 26 May 2017 10:08:31 -0700, Winfield Hill <hill@rowland.harvard.edu> wrote:>Jim Thompson wrote... >> >> As soon as Analog CMOS appeared, PMOS body connections in >> separate wells became common. Also we often have "dual-well" >> processes, allowing arbitrary NMOS body connections as well. >> >> The NPN/PNP-like arrows are totally incorrect, but certainly >> suffice for hackers >:-} > > If you're playing with the body substrate, full > symbols are called for. But I've seen plenty of > use of the simplified symbol in IC designs where > they all simply go to their respective rails.Working schematics, or datasheets? Examples? ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | STV, Queen Creek, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | Thinking outside the box... producing elegant solutions. "It is not in doing what you like, but in liking what you do that is the secret of happiness." -James Barrie
Reply by ●May 26, 20172017-05-26
Jim Thompson wrote...> >On 26 May 2017 10:08:31 -0700, Winfield Hill ><hill@rowland.harvard.edu> wrote: > >>Jim Thompson wrote... >>> >>> As soon as Analog CMOS appeared, PMOS body connections in >>> separate wells became common. Also we often have "dual-well" >>> processes, allowing arbitrary NMOS body connections as well. >>> >>> The NPN/PNP-like arrows are totally incorrect, but certainly >>> suffice for hackers >:-} >> >> If you're playing with the body substrate, full >> symbols are called for. But I've seen plenty of >> use of the simplified symbol in IC designs where >> they all simply go to their respective rails. > > Working schematics, or datasheets? Examples?Few of us have access to an IC engineer's actual working schematics, so we're talking published articles, datasheets, and similar materials. -- Thanks, - Win
