Odd Circuit, OP Amp over OP Amp

Dunno- have never worked with them.

Thanks all. Much food for thought.

The easy way to cure that, AND dissipation factor problems as well...

Discovered that while trying to make very low frequency hybrid filters for Teltone in the early '70's.

...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.

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.

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.

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

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

| 1962 | I love to cook with wine. Sometimes I even put it in the food.

[snip, full listing at Message-ID: ]

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.

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.

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.

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:

"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com...

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.