Amplifier Topology

[jam]

Has any seen this patent?

High speed, high resolution ... - Google Patent Search

It might have some possibilities................

Jam

.................so where is Jan Didden when you need him.

[SSassen]

I'd say fire up the simulator

Cheers,

Sander.

[jam]

Hi Sander,

I have never used a simulator and probably never will..............

Regards,
Jam

P.S. ..........by the way, nice choice of avatar.

[SSassen]

That's exactly why I mentioned it

Your only alternative in that case is to build up a proto incorporating these ideas, I for one am not going to bother, after I found the LME489xx ICs building amplifiers has become trivial, whether it is FET, CFP, Darlington or stock output stages.

Cheers,

Sander.

[jcx]

or it could be another instance of poor patent examination practice - at a glance it doesn't ref Halcro or Wurcer (although the bootstrapped current mirror gain stage may be Wildar's)

I've also seen a decades older IEEE paper on bootstrapping the input stage for a S/H IC thats relevant

[tiefbassuebertr]

an another URL of this patent document with higher resolution:
Boliven Patents - US7071781: High speed, high resolution amplifier topology - Reader
No, I don't know about this patent.
But I do not rule out the possibility that this could be the internal circuit of the relatively new ICs from "National Semiconductor" (LME series) respective the new OP AMP series from "Analog Devices" (ADA series)

[jcx]

spent a little more time reading the patent - it appears to cover the bootstrapped current mirror gain stage without mentioning Wurcer's AD797

and a cascode for the output pre-driver

as far as I can tell it is entirely within prior art

[scott wurcer]

Where's Vee? This looks like half a circuit in a way the output can't swing very negative as shown.

[jcx]

I suspect they're trying to be clever and concealing the necessary folding of the diff pair cascode you used

ps: I suspect you (AD) do try to keep up with what the competition is up to - do you know what the "secrete sauce" is for National's recent low distortion parts LM4562/LME46710?

[tiefbassuebertr]

Originally Posted by scott wurcer

Where's Vee? This looks like half a circuit in a way the output can't swing very negative as shown.

The same question also I ask. I think, there is only show the pos. half, and the neg. half is the same, but mirror symmetric. Regardless of this there are two voltage gain stages in series instead of only one like AD797.

In this case this URLs are of interest:
AD797 discrete clone - comparison of seven variations
John Curl's Blowtorch preamplifier (from #17954)
John Curl's Blowtorch preamplifier