mosfet RF amplifier with resistance

[...]

Thanks, Jure. I see that.

The only transistor supplying voltage gain is M2. M1 and M3 basically kill Miller Effect and provide a low impedance drive to the next stage.

I wonder if that is the most effective use of the gain capability of the three devices. For example, my understanding is the Tek 7400-series scopes made a dramatic change in the way gain was obtained. Instead of going for voltage gain in each stage, the designer went for current gain instead.

This obviously killed Miller effect, and reduced power consumption since the only place voltage swing was needed was the last stage driving the crt. Correct me if I'm wrong - the schematics really didn't tell much about what was going on inside the chips. But that seemed a very effective way of getting the high gain-bandwidth needed with a flat response.

Another configuration is travelling-wave, where low-gain transistors are placed along a transmission line and operate in parallel. There, each one contributes to the output signal. Horribly wasteful of power, but it apparently satisfies a need.

So how do you decide which is the most overall effective use of the gain potential of each device? Assume a 50 ohm environment and a reasonably low noise figure.

BTW, I like your ascii art. Other people use a lot of funny characters, and I have to reprogram my editor so it doesn't think they are erroneous punctuation marks and try to correct them:)

Regards,

Mike Monett

Mike, I think that you may have read the book by Jim Williams: Analog Circuit Design: Art, Science and Personalities . True ?

There is a chapter by John Addis: 14. Good Engineering and Fast Vertical Amplifiers.

the T-Coil, the ft doubler, the cascomp and other amplifier topologies are referenced, very interesting !

Thanks , Jure Z.

Hi Jure,

I haven't read it yet, but I thank you for the recommendation. It looks very interesting. It is not very expensive compared to most:

Engineers/dp/0750670622

Regards,

Mike Monett

Mike,

it seems that you may have read the book by Jim Williams : Analog Circuit Design: Art, Science and Personalities.

there is a chapter by John Addis : 14 Good Engineering and Fast Vertical Amplifiers.

There are references to the topics : T-Coil , distributed amplifier, Ft doubler,Battjes, cascomp, Quinn, Hallen, Traa, "Traashcomp".

these names may also be used as keywords in freepatents online ...

Thanks, Jure Z.

Here is a patent list ( my compilation) of the Ft doubler , cascomp amplifier and derivatives ( use freepatents online)

US Patent No. Inventor Descr

3633120 Battjes 3868580 Battjes bootrastrapped amp .pdf 4146844 Quinn Feed forward amp.pdf 4236119 Battjes monolithic amplifier.pdf 4267516 Traa CE Ft doubler .pdf 4267516 Traa Ft doubler.pdf 4322688 Schlotzhauer Cascode Feed Forward.pdf 4484147 Metz shunt fb amp.pdf 4491803 Metz current limiting .pdf 4528515 Gross HF diff amp.pdf 4528515 Winthorp HF Diff amp.pdf 4528517 Schlotzhauer.pdf 4692712 Quinn Diff Z neutralization .pdf 4720685 Garuts FET amp.pdf 4730124 Battjes high gm PNP .pdf 4779057 Woo cascode w improved transient resp.pdf 4835488 Garuts Wideband Lin Emitter FB amp.pdf 4862102 LaVoie Minimizing Self heating Diff amp.pdf 4890067 Lamb CB Ft multiplier.pdf 5307024 Metz linearized level shifting amp.pdf 5331289 Battjes Translinear ft multiplier.pdf 5399988 Knierim Ft doubler.pdf 5424510 Gusinov Thermal Compensation.pdf 5495201 Alini Gm stage .pdf 5506536 Yeung Diff amp w-exp gain.pdf 5587689 Bowers voltage controlled amp .pdf 5677646 Entrikin Diff Pair amp.pdf 6320467 Thor Hallen Ft multiplier.pdf

Thnks , Jure Z.

3633120 : Battjes 3868580 : Battjes bootrastrapped amp 4146844 : Quinn Feed forward amp 4236119 : Battjes monolithic amplifier 4267516 : Traa CE Ft doubler 4267516 : Traa Ft doubler 4322688 : Schlotzhauer Cascode Feed Forward 4484147 : Metz shunt fb amp 4491803 : Metz current limiting 4528515 : Gross HF diff amp 4528515 : Winthorp HF Diff amp 4528517 : Schlotzhauer 4692712 : Quinn Diff Z neutralization 4720685 : Garuts FET amp 4730124 : Battjes high gm PNP 4779057 : Woo cascode w improved transient resp 4835488 : Garuts Wideband Lin Emitter FB amp 4862102 : LaVoie Minimizing Self heating Diff amp 4890067 : Lamb CB Ft multiplier 5307024 : Metz linearized level shifting amp 5331289 : Battjes Translinear ft multiplier 5399988 : Knierim Ft doubler 5424510 : Gusinov Thermal Compensation 5495201 : Alini Gm stage 5506536 : Yeung Diff amp w-exp gain 5587689 : Bowers voltage controlled amp 5677646 : Entrikin Diff Pair amp 6320467 : Thor Hallen Ft multiplier

Hi Jure,

Thanks very much for the above list. I'll bet that took a lot of work to compile. I will download these files and study them.

Also, thank you very much for the ones you sent by email. That was very nice of you, but I'm on dialup and they took a long time to download. Also, I noticed afterwards my email client missed decoding about half of them, so I was planning on downloading them anyway.

These are very interesting patents. They show many ways to bypass the conventional limits on bandwidth. They also show there were a lot of very smart people back in the old days:)

Regards,

Mike Monett

Mike, Sorry for having sent the files without asking first. I thought that I was the last one on dialup when I changed to DSL 16 months ago... (grin)

Thanks, Jure Z.

Hi Jure,

Thanks - I really appreciate your help and all the info you have posted. I sure am glad you are interested in this topic and have collected all these patents. They will keep me busy for a while.

There's not much choice for highspeed services here in Midland, so the prices are high. Sympatico has switched over to Microsoft software, so you never know when the system will go down or for how long. If you call tech support to ask about any problem, they say it's your computer and you are the only one having trouble. Later, you find on the forums that everyone was having the same problem, and they lied about where the problem was.

Typical Microsoft crap. They couldn't tell the truth if it was printed on their eyeballs. I will never use any service that depends on Microsoft. I try to stay with services that run on Linux. Much more reliable, any problems are fixed in minutes instead of weeks, and they tell you the truth.

Rogers cable has service here, but the price is too high. It is bundeled with television, which I never watch. I don't even have a TV set. So it is way too expensive for just the high speed.

There is another service I just heard about yesterday. It's $29.95/month for 5M/800K for residential, which may be ok.

I'll let my friends use it for a while and see how they like it, then look at their contract and maybe consider switching over. In the meantime, dialup is very reliable, so any new service I try will have to meet very high standards.

Regards,

Mike Monett

ADSL is well worth it Mike, it transforms the browser performance and things like that DoS attack on SED last night...... 5776 articles, 50MB to download! On ADSL that was just a timewaster rather than a Denial of Service.

IMO reliability with ADSL starts with your internal cabling and the quality of the line to the DSLAM in the exchange. This is helped by having a good Router, one where you can see the line diagnostics for yourself. In the UK, Netgear seems to have a good reputation for being able to handle marginal lines.

Don't be tempted by the highest speeds. A rock solid 2Mb/s is far better than a flakey 5Mb/s.

--
Tony Williams.

Hi Tony, thanks for posting this info.

Unlike Firefox, Opera is very fast on dialup. I'm sure I will eventually go to ADSL, as soon as I can find a reputable vendor (not Symatico) that doesn't gouge too much and can keep the system up for long periods.

The DOS attack on SED was no problem for XNews. Newsposts are stored on two separate servers - the headers are on one, and the body text on another. Xnews downloads the headers which contain the subject. This is very fast. It was a simple matter to quickly scan the topics and see they were all crap, then tell XNews to mark them all as read. So I never had to download the 50MB of actual text.

Thanks - that is good info to keep in mind. I didn't know that and will look into it when I switch over.

A flakey anything is always worse than nothing:)

Regards,

Mike Monett