On Wed, 09 Oct 2013 16:43:39 -0700, Jim Thompson
<To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote:
>On Wed, 9 Oct 2013 19:51:30 +0000 (UTC), "Rich K."
><Mungedto@nowhere.cc> wrote:
>
>>Why do you think the op. used this topology over the simple circuit 1
>>example? I thank you for your opinions in advance.
>>
>>Attached: LTSpice file.
>>
>>------------------------------------------------------------------------
>>Version 4
>>SHEET 1 880 680
>[snip]
>>TEXT 368 -88 Left 2 ;The designer used this in a 100kz amp.
>>TEXT 368 -32 Left 2 ;The orignal op amps were TL084's
>
>It may be just a scheme to improve _net_ loop-gain-bandwidth-product.
>
>I have a paper somewhere on such multi-OpAmp schemes. I'll post when
>I find it.
>
> ...Jim Thompson
Simulation of circuit (using original TL084 specifications) yields
strange results...
3.5dB peaking at 239KHz, then roll-off normally
Phase flatness extends slightly, then is exactly 45� at the frequency
peak, then returns to follow same curve as a single OpAmp
implementation does.
I have no clue what originator was trying to accomplish.
...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| 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.
Reply by Tim Williams●October 11, 20132013-10-11
Always found it strange that there have been so many chips in DIP14 (and
SO-14 and others since) with scads of N/C pins. uA723, LM319, even a
MCP4922 DAC I'm playing with. They'd fit quite nicely in 10 pin packages,
but no one ever invested in that, DIPs have always gone 4, 6, 8, 14, 16,
...
I have seen MSOP and DFN styles with nontraditional pin counts. I guess
miniaturization is finally forcing frugal pin counts on such things.
Tim
--
Seven Transistor Labs
Electrical Engineering Consultation
Website: http://seventransistorlabs.com
"Jim Thompson" <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote
in message news:sjfg595javrr6tsfj3pcet3445fjfdlb7l@4ax.com...
> On Fri, 11 Oct 2013 18:42:12 +0100, John Devereux
> <john@devereux.me.uk> wrote:
>
>>jurb6006@gmail.com writes:
>>
>>>>"if you are
>>> using a quad, so you can easily get a complex zero as well. "
>>>
>>> I wonder why there are so few with three, or five in the package. Why
>>> not seven ?
>>
>>Is it something to do with common centroid design?
>
> Pin count and package size.
>
> ...Jim Thompson
> --
> | James E.Thompson | mens |
> | Analog Innovations | et |
> | Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
> | San Tan Valley, AZ 85142 Skype: Contacts Only | |
> | 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.
Reply by Jim Thompson●October 11, 20132013-10-11
On Fri, 11 Oct 2013 12:16:26 -0700 (PDT), George Herold
<gherold@teachspin.com> wrote:
>On Friday, October 11, 2013 2:36:13 PM UTC-4, Jim Thompson wrote:
>> On Wed, 9 Oct 2013 19:51:30 +0000 (UTC), "Rich K."
>>
>> <Mungedto@nowhere.cc> wrote:
>>
>>
>>
>> >Why do you think the op. used this topology over the simple circuit 1
>>example? I thank you for your opinions in advance.
>>
>> >
>> >Attached: LTSpice file.
>> >
>>
>> >------------------------------------------------------------------------
>> >Version 4
>>
>> >SHEET 1 880 680
>>
>> >WIRE 176 -384 48 -384
>>
>>
>>
>> [snip, full listing at Message-ID: <l34c42$ihl$1@dont-email.me>]
>>
>>
>>
>> >TEXT 368 -88 Left 2 ;The designer used this in a 100kz amp.
>>
>> >TEXT 368 -32 Left 2 ;The orignal op amps were TL084's
>>
>> Getting back to actually looking at it, I'm not sure if it does
>> _anything_ at all.
>
>I cut out the cap's and then pushed the freq up around 1MHz or so and it showed the some Bandwidth improvement. (But I didn't check any numbers... just played.)
>
>George H.
>>
>>
>>
>> I'll write-out the full-up loop equations and see for sure when I have
>>
>> a free moment ;-)
>>
>>
>>
>> ...Jim Thompson
>>
>> --
>>
>> | James E.Thompson | mens |
>>
>> | Analog Innovations | et |
>>
>> | Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
>>
>> | San Tan Valley, AZ 85142 Skype: Contacts Only | |
>>
>> | Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
>>
>> | E-mail Icon at http://www.analog-innovations.com | 1962 |
>>
>>
>>
>> I love to cook with wine. Sometimes I even put it in the food.
Goo idea! Easy to implement with my LoopGain checker macro.
...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
Reply by George Herold●October 11, 20132013-10-11
On Friday, October 11, 2013 2:36:13 PM UTC-4, Jim Thompson wrote:
> On Wed, 9 Oct 2013 19:51:30 +0000 (UTC), "Rich K."
>
> <Mungedto@nowhere.cc> wrote:
>
>
>
> >Why do you think the op. used this topology over the simple circuit 1
>example? I thank you for your opinions in advance.
>
> >
> >Attached: LTSpice file.
> >
>
> >------------------------------------------------------------------------
> >Version 4
>
> >SHEET 1 880 680
>
> >WIRE 176 -384 48 -384
>
>
>
> [snip, full listing at Message-ID: <l34c42$ihl$1@dont-email.me>]
>
>
>
> >TEXT 368 -88 Left 2 ;The designer used this in a 100kz amp.
>
> >TEXT 368 -32 Left 2 ;The orignal op amps were TL084's
>
> Getting back to actually looking at it, I'm not sure if it does
> _anything_ at all.
I cut out the cap's and then pushed the freq up around 1MHz or so and it showed the some Bandwidth improvement. (But I didn't check any numbers... just played.)
George H.
>
>
>
> I'll write-out the full-up loop equations and see for sure when I have
>
> a free moment ;-)
>
>
>
> ...Jim Thompson
>
> --
>
> | James E.Thompson | mens |
>
> | Analog Innovations | et |
>
> | Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
>
> | San Tan Valley, AZ 85142 Skype: Contacts Only | |
>
> | Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
>
> | E-mail Icon at http://www.analog-innovations.com | 1962 |
>
>
>
> I love to cook with wine. Sometimes I even put it in the food.
Reply by Jim Thompson●October 11, 20132013-10-11
On Wed, 9 Oct 2013 19:51:30 +0000 (UTC), "Rich K."
<Mungedto@nowhere.cc> wrote:
>Why do you think the op. used this topology over the simple circuit 1
>example? I thank you for your opinions in advance.
>
>Attached: LTSpice file.
>
>------------------------------------------------------------------------
>Version 4
>SHEET 1 880 680
>WIRE 176 -384 48 -384
[snip, full listing at Message-ID: <l34c42$ihl$1@dont-email.me>]
>TEXT 368 -88 Left 2 ;The designer used this in a 100kz amp.
>TEXT 368 -32 Left 2 ;The orignal op amps were TL084's
Getting back to actually looking at it, I'm not sure if it does
_anything_ at all.
I'll write-out the full-up loop equations and see for sure when I have
a free moment ;-)
...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| 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.
Reply by Jim Thompson●October 11, 20132013-10-11
On Fri, 11 Oct 2013 18:42:12 +0100, John Devereux
<john@devereux.me.uk> wrote:
>jurb6006@gmail.com writes:
>
>>>"if you are
>> using a quad, so you can easily get a complex zero as well. "
>>
>> I wonder why there are so few with three, or five in the package. Why not seven ?
>
>Is it something to do with common centroid design?
Pin count and package size.
...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| 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.
Reply by John Devereux●October 11, 20132013-10-11
jurb6006@gmail.com writes:
>>"if you are
> using a quad, so you can easily get a complex zero as well. "
>
> I wonder why there are so few with three, or five in the package. Why not seven ?
Is it something to do with common centroid design?
--
John Devereux
Reply by ●October 11, 20132013-10-11
>"if you are
using a quad, so you can easily get a complex zero as well. "
I wonder why there are so few with three, or five in the package. Why not seven ?
Reply by Jim Thompson●October 11, 20132013-10-11
On Fri, 11 Oct 2013 06:27:20 -0700 (PDT), George Herold
<gherold@teachspin.com> wrote:
>On Thursday, October 10, 2013 8:38:05 PM UTC-4, Jim Thompson wrote:
>> On Thu, 10 Oct 2013 12:41:33 -0700 (PDT), George Herold
>>
>> <gherold@teachspin.com> wrote:
>>
>> >On Wednesday, October 9, 2013 10:44:09 PM UTC-4, bloggs.fred...@gmail.com wrote:
>> >> On Wednesday, October 9, 2013 7:43:39 PM UTC-4, Jim Thompson wrote:
>>> See Analog Devices App Note AN-107 Active Feedback Improves Amplifier Phase Accuracy - James Wong (1987) .
>> >
>> >Interesting, thanks. (another old trick that I didn't know.
>> >
>> >Say would this improve (reduce) the Q-enhancement one sees in State-variable filters? (Or other integrating filter topologies)
>> >
>> >George H.
>> The easy way to cure that, AND dissipation factor problems as well...
>> <http://www.analog-innovations.com/SED/StateVariableFilter(P+1).pdf>
>>
>Interesting, Thanks!.. I've never had much of an issue with cap dissipation.. (I just use expensive caps :^)
>
>One 'issue' with your circuit is it's got a lot more R's to change if one wants to change the Q or freqeucny. (Hmm can I get a Q higher than 2?)
>
>You should write a book with your circuit ideas, implementations. I'd pay a few hundred for it... maybe you can get some cute young thing to help with editing...(as long as the wife doesn't object. :^)
>
>George H.
>
>> Discovered that while trying to make very low frequency hybrid filters
>> for Teltone in the early '70's
>
>
>> >>
>> >> > It may be just a scheme to improve _net_ loop-gain-bandwidth-product.
>> >> > I have a paper somewhere on such multi-OpAmp schemes. I'll post when
>> >> >
>> >> > I find it.
>> >>
>> >> > ...Jim Thompson
>> >> > | James E.Thompson | mens
>> >> > | Analog Innovations | et |
>> >> > | Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
>> >> > | San Tan Valley, AZ 85142 Skype: Contacts Only | |
>> >> > | 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.
When I was manufacturing those filters, I was making them by the
bucket-load, resistors were thick-film, sand-blasted to trim, all
automated.
An added feature is that you still have one OpAmp available if you are
using a quad, so you can easily get a complex zero as well.
...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| 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.
Reply by George Herold●October 11, 20132013-10-11
On Thursday, October 10, 2013 8:38:05 PM UTC-4, Jim Thompson wrote:
> On Thu, 10 Oct 2013 12:41:33 -0700 (PDT), George Herold
>
> <gherold@teachspin.com> wrote:
>
> >On Wednesday, October 9, 2013 10:44:09 PM UTC-4, bloggs.fred...@gmail.com wrote:
> >> On Wednesday, October 9, 2013 7:43:39 PM UTC-4, Jim Thompson wrote:
>> See Analog Devices App Note AN-107 Active Feedback Improves Amplifier Phase Accuracy - James Wong (1987) .
> >
> >Interesting, thanks. (another old trick that I didn't know.
> >
> >Say would this improve (reduce) the Q-enhancement one sees in State-variable filters? (Or other integrating filter topologies)
> >
> >George H.
> The easy way to cure that, AND dissipation factor problems as well...
> <http://www.analog-innovations.com/SED/StateVariableFilter(P+1).pdf>
>
Interesting, Thanks!.. I've never had much of an issue with cap dissipation.. (I just use expensive caps :^)
One 'issue' with your circuit is it's got a lot more R's to change if one wants to change the Q or freqeucny. (Hmm can I get a Q higher than 2?)
You should write a book with your circuit ideas, implementations. I'd pay a few hundred for it... maybe you can get some cute young thing to help with editing...(as long as the wife doesn't object. :^)
George H.
> Discovered that while trying to make very low frequency hybrid filters
> for Teltone in the early '70's
> >>
> >> > It may be just a scheme to improve _net_ loop-gain-bandwidth-product.
> >> > I have a paper somewhere on such multi-OpAmp schemes. I'll post when
> >> >
> >> > I find it.
> >>
> >> > ...Jim Thompson
> >> > | James E.Thompson | mens
> >> > | Analog Innovations | et |
> >> > | Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
> >> > | San Tan Valley, AZ 85142 Skype: Contacts Only | |
>
> >> > | 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.
>
>
>
> ...Jim Thompson
>
> --
>
> | James E.Thompson | mens |
>
> | Analog Innovations | et |
>
> | Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
>
> | San Tan Valley, AZ 85142 Skype: Contacts Only | |
>
> | 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.