Comparator & Amplifier ICs with High Bandwidth

Guest
Dear All,

I'm constructing a circuit which requires some comparators and
amplifier with high bandwidth. What ICs should I use for bandwidth more
than 10MHz? How about above 100MHz?? Is LM139 suitable for bandwidth
above 10MHz? I looked at the datasheet but it did not show anything
regarding bandwidth.
Any comments would be very appreciated.

Regards,
Will
 
chickenwing2010@yahoo.com.hk wrote:

Dear All,

I'm constructing a circuit which requires some comparators and
amplifier with high bandwidth. What ICs should I use for bandwidth more
than 10MHz? How about above 100MHz?? Is LM139 suitable for bandwidth
above 10MHz? I looked at the datasheet but it did not show anything
regarding bandwidth.
Any comments would be very appreciated.
Click to expand...
There are comparators and line receivers being as fast
as 200ps or so available as standard products.
What input voltage range and logic levels were you thinking
of ? The jitter can also be specified, though there the
risetime of the signal comes in.
The 100MHz can be done with a MC100EL16 & MC100ELT23,
above ECL, LVDS and CML become standard.

Rene
--
Ing.Buero R.Tschaggelar - http://www.ibrtses.com
& commercial newsgroups - http://www.talkto.net
 
chickenwing2010@yahoo.com.hk wrote:
Dear All,

I'm constructing a circuit which requires some comparators and
amplifier with high bandwidth. What ICs should I use for bandwidth
more
than 10MHz? How about above 100MHz?? Is LM139 suitable for bandwidth
above 10MHz? I looked at the datasheet but it did not show anything
regarding bandwidth.
Any comments would be very appreciated.

Regards,
Will
Click to expand...
They quote propogation delay for comparators, not frequency.

The LM139 has a typical response time of 1.3us - not even fast enough
for 1 MHz.

I used the Analog Devices AD8561 "Ultrafast 7 ns Single Supply
Comparator" for converting sine waves to TTL at 16 MHz. That's not
it's maximum frequency - but it won't do 100 MHz.
 
chickenwing2010@yahoo.com.hk wrote:
Dear All,

I'm constructing a circuit which requires some comparators and
amplifier with high bandwidth. What ICs should I use for bandwidth more
than 10MHz? How about above 100MHz?? Is LM139 suitable for bandwidth
above 10MHz? I looked at the datasheet but it did not show anything
regarding bandwidth.
Any comments would be very appreciated.

Regards,
Will
Click to expand...
Get lost!- and don't post to this newsgroup again.
 
chickenwing2010@yahoo.com.hk wrote:

Dear All,

I'm constructing a circuit which requires some comparators and
amplifier with high bandwidth. What ICs should I use for bandwidth more
than 10MHz? How about above 100MHz?? Is LM139 suitable for bandwidth
above 10MHz? I looked at the datasheet but it did not show anything
regarding bandwidth.
Any comments would be very appreciated.

Regards,
Will

A comparator data sheet will talk about "response time" or "delay". If
Click to expand...
it's a decent data sheet it'll have a chart of delay vs. differential
voltage (they're generally slower with smaller inputs).

Figuring out how the delay impacts the speed that your circuit can
operate is left as an exercise to -- you.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com
 
Hi Fred,

I'd like to apologize to you. I feel really sorry if I did anything
wrong before.
And thanks to those who helped me regarding my questions.

Will
 
On 26 Jan 2005 07:43:08 -0800, chickenwing2010@yahoo.com.hk wrote:

Hi Fred,

I'd like to apologize to you. I feel really sorry if I did anything
wrong before.
And thanks to those who helped me regarding my questions.

Will
Click to expand...
Will, Fred is our resident wacko. You would be best served by
kill-filing him.

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.
 
Fred Bloggs wrote:

chickenwing2010@yahoo.com.hk wrote:

Dear All,

I'm constructing a circuit which requires some comparators and
amplifier with high bandwidth. What ICs should I use for bandwidth more
than 10MHz? How about above 100MHz?? Is LM139 suitable for bandwidth
above 10MHz? I looked at the datasheet but it did not show anything
regarding bandwidth.
Any comments would be very appreciated.

Regards,
Will


Get lost!- and don't post to this newsgroup again.

you didn't have your Java yet this morning Fred ?
Click to expand...
 
On Wed, 26 Jan 2005 07:43:08 -0800, chickenwing2010 wrote:

Hi Fred,

I'd like to apologize to you. I feel really sorry if I did anything
wrong before.
And thanks to those who helped me regarding my questions.

Will
Click to expand...
Please don't pay any attention to Fred Bloggs. Stick around awhile, and
you'll there are a few noisemakers here. I assure you, they're all quite
harmless. :)

Cheers!
Rich
 
On Wed, 26 Jan 2005 15:20:13 +0000, Fred Bloggs wrote:
Get lost!- and don't post to this newsgroup again.
Click to expand...
You might be well-served to take your own advice. I know
everybody else would.
--
The Pig Bladder From Uranus, Still Waiting for
Some Hot Babe to Ask What My Favorite Planet Is.
 
As everybody has already said, the LM139 isn't suitable for bandwidths
above 10MHz.

Comparators are usually built with several stages of gain and no
frequency compensation, unlike op amps - so their gain usually stays
flat out to quite high frequencies, then falls off rapidly when each of
the gain stages starts running out of gain at the same frequency.

Comparator data sheets rarely specify this frequency, but the data
sheet for Linear Technology "ultrafast" LT10106, which has a 10nsec
propagation delay, includes an application circuit which uses it to
make a crystal oscillator - specifically a 10MHz to 25MHz crystal
oscillator, which suggests that it isn't much use over 25MHz.

The application notes also includes the claim that the LT1016 has a
gain bandwidth product of about 50GHz, which - for a part that has a
typical gain of 3000, implies a bandwidth of 17MHz.

There are faster parts around - the Honeywell, then SPT and now
Fairchild SPT9689 has its 3dB point at 900MHz, but it costs $20 and
Arrow Electronics list a two week delivery time.

http://www.fairchildsemi.com/ds/SP/SPT9689.pdf

Maxim have parts that are cheaper, and tolerably fast

http://pdfserv.maxim-ic.com/en/ds/MAX9691-MAX9693.pdf

which do seem to be able to cope with 100MHz signals - the data sheet
examples are of 100MHz square waves.
Newark have 175 MAX9691ESA in stock for $6.00 each.
------------
Bill Sloman, Nijmegen
 
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