How fast do modern op-amps go?

R

renan

Guest
Hello people!

What is the maximum bandwidth that can be achieved
with modern op-amps? Are op-amps of, let's say 500MHz,
already available?

Thanks!
 
In article <2hqipeFg9qurU1@uni-berlin.de>, renan <marreka@ig.com.br>
wrote:

Hello people!

What is the maximum bandwidth that can be achieved
with modern op-amps? Are op-amps of, let's say 500MHz,
already available?

Thanks!
Click to expand...
Not traditional op-amps because the feedback loop is too slow. There
are fast differential amps on a chip with abilities into the GHz range.
They're what's in all the tiny GHz gadgets these days (WiFi, phones,
etc.).
 
"renan" <marreka@ig.com.br> wrote in message
news:2hqipeFg9qurU1@uni-berlin.de...
Hello people!

What is the maximum bandwidth that can be achieved
with modern op-amps? Are op-amps of, let's say 500MHz,
already available?
Click to expand...
Elantec has just announced the EL51671C with a fixed 2X gain bandwidth of
800 MHz. It's actually good for 1.4 GHz.

Leon
--
Leon Heller, G1HSM
http://www.geocities.com/leon_heller
 
"Kevin McMurtrie" in
news:mcmurtri-FE758C.22542928052004@corp-radius.supernews.com...
In article <2hqipeFg9qurU1@uni-berlin.de>, renan <marreka@ig.com.br
wrote:

Hello people!

What is the maximum bandwidth that can be achieved
with modern op-amps? Are op-amps of, let's say
500MHz, already available?

Not traditional op-amps because the feedback loop is too slow.
There are fast differential amps on a chip with abilities into the
GHz range. They're what's in all the tiny GHz gadgets these days
(WiFi, phones, etc.).
Click to expand...
Come ON Kevin McMurtrie, Optical Electronics Inc. (OEI) in Arizona was
selling 1000 MHz traditional op amps in the 1970s. (Developed for a
specific market but sold to the public.) I have their literature and so do
many other people. Modern monolithic traditional op amps have GBWs into the
100s or low 1000s of MHz as necessary. Applying such products is not for
beginners -- one picofarad at 1000 MHz is only 160 ohms of course, for
example. (Op amps at extremes of performance are generally specialized
devices optimized for the extreme of interest.)

On the other hand, I agree completely with the later sentences. GHz
specialized differential amps have been around for decades but recently
important and refined in portable wireless products. Customized amplifiers
are often optimal solutions in demanding applications even at low
frequencies. George A. Philbrick himself reportedly regretted overselling
the op-amp concept to the extent that it became the knee-jerk approach to
amplification tasks, including those where a custom design would be better
or cheaper -- to some extent it displaced the skill of amplifier design.
(Though supporting employment for op-amp designers -- eh, Jim? ;-)
 
renan wrote:

Hello people!

What is the maximum bandwidth that can be achieved
with modern op-amps? Are op-amps of, let's say 500MHz,
already available?
Click to expand...
If you include current feedback amplifiers it extends into the GHZ
range. See for example the THS3202.

--
Cheers
Stefan
 
On Sat, 29 May 2004 14:52:17 +0200, Stefan Heinzmann
<stefan_heinzmann@yahoo.com> wrote:

renan wrote:

Hello people!

What is the maximum bandwidth that can be achieved
with modern op-amps? Are op-amps of, let's say 500MHz,
already available?

If you include current feedback amplifiers it extends into the GHZ
range. See for example the THS3202.
Click to expand...

THS4303 is a current-feedback amp with internal feedback resistors set
for a gain of 10. Its closed-loop bw is 1.8 GHz, for a net gbw of 18
GHz. I think that's the current record for a real opamp.

Too bad Vcc max is so wimpy.

John
 
renan wrote:
Hello people!

What is the maximum bandwidth that can be achieved
with modern op-amps? Are op-amps of, let's say 500MHz,
already available?
Click to expand...
Strange enough they (usually CFAs) are called 'Low noise' or
'Ultra low noise' for their low noise density. However
the root-bandwidth adds up to a significant factor.

Examples : THS3201 with 1.8GHz GBW, THS 4275 with 1.4GHz GBW,
They also feature impressive slew rates, such as 10V/ns for the first.
And they drive 50 Ohms. Only 5V though.

Rene
--
Ing.Buero R.Tschaggelar - http://www.ibrtses.com
& commercial newsgroups - http://www.talkto.net
 
Hi Renan,

Even back in the late 70's early 80's you had those:

uA733 was a not so well know but cheap video amp that could do more than
100MHz no sweat. Used these a lot.

This may have been the hot rod of amps back then: Philips NE5539,
1.2GHz, October 1986.

Regards, Joerg

http://www.analogconsultants.com
 
"Rene Tschaggelar" <none@none.net> wrote in message
news:40b8e213$0$716$5402220f@news.sunrise.ch...
renan wrote:
Hello people!

What is the maximum bandwidth that can be achieved
with modern op-amps? Are op-amps of, let's say 500MHz,
already available?

Strange enough they (usually CFAs) are called 'Low noise' or
'Ultra low noise' for their low noise density. However
the root-bandwidth adds up to a significant factor.

Examples : THS3201 with 1.8GHz GBW, THS 4275 with 1.4GHz GBW,
They also feature impressive slew rates, such as 10V/ns for the
first.
And they drive 50 Ohms. Only 5V though.

Rene
Click to expand...
Many CFA designs have one input with pretty low En, but
invariably the current noise density is very poor on the negative
input.

There are a few voltage feedback op amps out there with GBW
approaching 4GHz, decent En (<1nV/rtHz) and In (<3pA/rtHz).
AD8099, OPA847 for example. These don't have the slew rate
of the CFA's, coming in at 950-1450 V/usec.

As Rene mentioned, the really fast parts have decent drive
capability, but only run off +/-5V rails.

The AD8351 is a differential amp rather than an op amp, but
does do 2.2GHz at 12dB gain, with 13kV/usec slew rate. DC
operation can be tricky. That one uses a +5V rail.

Regards
Ian
 
It really depends on what you want to do with an op-amp.
True op-amps, ie amplifiers that have their operation controlled by the
external feedback components, are limited by the environment in which
they are used. External capacitance and conductance usually limit
performance to the mid hundreds of MHz.
Price is also an issue at the high end of the performance scale.

Low cost ones like the Max4451 have a small signal -3dB bandwidth of 210MHz.

William

renan wrote:
Hello people!

What is the maximum bandwidth that can be achieved
with modern op-amps? Are op-amps of, let's say 500MHz,
already available?

Thanks!
Click to expand...
 
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