John Curl's Blowtorch preamplifier part II

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The upstream IC (LT1028) has min GBW=50MHz and is operated at a gain of 39, so its bandwidth is about 1.3 MHz. The AD844 is operated at a gain of 14 and at that gain, has BW of about 33 MHz (ADI datasheet Fig 24). It seems to me the AD844 was used because its bandwidth is 25X higher than the first stage, thus it "stays out of the way" and allows the other, slower, circuits to determine full loop bandwidth. Which appears to be, extrapolating Figure 4, about -3dB @ 400 kHz (-1dB @ 100 kHz).

Hmmm. Makes sense, but still the AD844 is kind of an outlier here. Surely there must be some 'real' opamps that could foot the bill.
Ohh well, designers have their quirks I guess. Present company included ;-)
 
No, 8.42

These small excerpts must be enough.
I don't want that Winfield kills me next time I meet him on s.e.d.

The book is nearly 1200 pages of really good information.
Worth every cent.

Gerhard
 

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Speaking from my personal opinion, I can't read and retain stuff off a computer. Anyone who would download from the link should probably just go buy a paper copy. They aren't expensive (mine was $25 at a Hamfest). I much prefer reading from something that doesn't need batteries or can be erased easily. To each his own.

There really isn't anything like the feel of a book and sitting under the sun reading, or sitting in a comfortable chair, sipping on whatever you like while reading. I usually have an hour or so to kill waiting for doctors, so there is ample time to enjoy a good read.

I am hoping people might look at the material long enough to discover it is well worth buying. So don't take our word for it, go look and decide for yourself.

-Chris
 
Robert, I think you're good, Scott's point seems aimed elsewhere.

I'm due to update to the third edition. I partially blame aoe 2nd edition for going EE in undergrad.

Chris, I'd be lost if I had to read everything on paper, but our jobs are different for sure. 🙂
 
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