Forums

LT Spice powering opamps

Started by John Larkin November 5, 2015

I usually have a couple of "voltage" things off to the side, making +5
and -5 or whatever, and have each opamp with little doglegs on its
power pins, same net names.

Somewhere I thought I saw a circuit where the opamps were powered by
little boxes with "+5" or something inside, with no other supply
needed. Does that work? If so, how do you invoke it?




-- 

John Larkin         Highland Technology, Inc
picosecond timing   precision measurement 

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

On Thursday, 5 November 2015 19:51:19 UTC, John Larkin  wrote:
> I usually have a couple of "voltage" things off to the side, making +5 > and -5 or whatever, and have each opamp with little doglegs on its > power pins, same net names. > > Somewhere I thought I saw a circuit where the opamps were powered by > little boxes with "+5" or something inside, with no other supply > needed. Does that work? If so, how do you invoke it?
Also can one power ICs from circuit outputs on spice? ISTR finding the IC model I was using had no power pins. NT
On Thu, 5 Nov 2015 14:25:23 -0800 (PST), tabbypurr@gmail.com wrote:

>On Thursday, 5 November 2015 19:51:19 UTC, John Larkin wrote: >> I usually have a couple of "voltage" things off to the side, making +5 >> and -5 or whatever, and have each opamp with little doglegs on its >> power pins, same net names. >> >> Somewhere I thought I saw a circuit where the opamps were powered by >> little boxes with "+5" or something inside, with no other supply >> needed. Does that work? If so, how do you invoke it? > > >Also can one power ICs from circuit outputs on spice? ISTR finding the IC model I was using had no power pins. > > >NT
PSpice has power symbols thus: +5V O---x The "x" doesn't show, but it's the pin. It netlists as: V1 x 0 +5V I tried to draw a circle in LTspice, but the drawing tool is the most obtuse POS I've ever seen. In PSpice you choose Draw/Circle, click on the center point, then drag it out to the desired diameter. ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
On Thu, 05 Nov 2015 16:06:51 -0700, Jim Thompson
<To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote:

>On Thu, 5 Nov 2015 14:25:23 -0800 (PST), tabbypurr@gmail.com wrote: > >>On Thursday, 5 November 2015 19:51:19 UTC, John Larkin wrote: >>> I usually have a couple of "voltage" things off to the side, making +5 >>> and -5 or whatever, and have each opamp with little doglegs on its >>> power pins, same net names. >>> >>> Somewhere I thought I saw a circuit where the opamps were powered by >>> little boxes with "+5" or something inside, with no other supply >>> needed. Does that work? If so, how do you invoke it? >> >> >>Also can one power ICs from circuit outputs on spice? ISTR finding the IC model I was using had no power pins. >> >> >>NT > >PSpice has power symbols thus: +5V O---x > >The "x" doesn't show, but it's the pin. > >It netlists as: > >V1 x 0 +5V > >I tried to draw a circle in LTspice, but the drawing tool is the most >obtuse POS I've ever seen. > >In PSpice you choose Draw/Circle, click on the center point, then drag >it out to the desired diameter. > > ...Jim Thompson
In LTspice, you're detrmining anchor points of a bounding box. You can choose whether these anchor points are visible or not under the 'view' menu. RL
On Fri, 06 Nov 2015 09:30:17 -0500, legg <legg@nospam.magma.ca> wrote:

>On Thu, 05 Nov 2015 16:06:51 -0700, Jim Thompson ><To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: > >>On Thu, 5 Nov 2015 14:25:23 -0800 (PST), tabbypurr@gmail.com wrote: >> >>>On Thursday, 5 November 2015 19:51:19 UTC, John Larkin wrote: >>>> I usually have a couple of "voltage" things off to the side, making +5 >>>> and -5 or whatever, and have each opamp with little doglegs on its >>>> power pins, same net names. >>>> >>>> Somewhere I thought I saw a circuit where the opamps were powered by >>>> little boxes with "+5" or something inside, with no other supply >>>> needed. Does that work? If so, how do you invoke it? >>> >>> >>>Also can one power ICs from circuit outputs on spice? ISTR finding the IC model I was using had no power pins. >>> >>> >>>NT >> >>PSpice has power symbols thus: +5V O---x >> >>The "x" doesn't show, but it's the pin. >> >>It netlists as: >> >>V1 x 0 +5V >> >>I tried to draw a circle in LTspice, but the drawing tool is the most >>obtuse POS I've ever seen. >> >>In PSpice you choose Draw/Circle, click on the center point, then drag >>it out to the desired diameter. >> >> ...Jim Thompson > >In LTspice, you're detrmining anchor points of a bounding box. You can >choose whether these anchor points are visible or not under the 'view' >menu. > >RL
I know, but that method it difficult to align objects. ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
On Fri, 06 Nov 2015 07:40:56 -0700, Jim Thompson
<To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote:

>On Fri, 06 Nov 2015 09:30:17 -0500, legg <legg@nospam.magma.ca> wrote: > >>On Thu, 05 Nov 2015 16:06:51 -0700, Jim Thompson >><To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: >> >>>On Thu, 5 Nov 2015 14:25:23 -0800 (PST), tabbypurr@gmail.com wrote: >>> >>>>On Thursday, 5 November 2015 19:51:19 UTC, John Larkin wrote: >>>>> I usually have a couple of "voltage" things off to the side, making +5 >>>>> and -5 or whatever, and have each opamp with little doglegs on its >>>>> power pins, same net names. >>>>> >>>>> Somewhere I thought I saw a circuit where the opamps were powered by >>>>> little boxes with "+5" or something inside, with no other supply >>>>> needed. Does that work? If so, how do you invoke it? >>>> >>>> >>>>Also can one power ICs from circuit outputs on spice? ISTR finding the IC model I was using had no power pins. >>>> >>>> >>>>NT >>> >>>PSpice has power symbols thus: +5V O---x >>> >>>The "x" doesn't show, but it's the pin. >>> >>>It netlists as: >>> >>>V1 x 0 +5V >>> >>>I tried to draw a circle in LTspice, but the drawing tool is the most >>>obtuse POS I've ever seen. >>> >>>In PSpice you choose Draw/Circle, click on the center point, then drag >>>it out to the desired diameter. >>> >>> ...Jim Thompson >> >>In LTspice, you're detrmining anchor points of a bounding box. You can >>choose whether these anchor points are visible or not under the 'view' >>menu. >> >>RL > >I know, but that method it difficult to align objects. > > ...Jim Thompson
Possibly makes more sense when the line connection can only resolve at rt angles on the grid and not to a center. RL