My intended use for this opamp is to make a time-to-amplitude converter, hopefully with 25ps resolution. The circuit is basically an input pulse-width integrator. Here's a set of scope traces for 3.3V pulses into 1.1k and 10pF integrator. 1.5ns to 2.5ns long, in eleven steps, each longer by 100ps. You can see that my 25ps measurement goal is easily met.
Interesting, a 935MHz opamp making 25ps measurements.
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Thanks,
- Win
What did you use to generate the 100 ps steps?
Here's the other direction, making 100 ps time steps with an analog ramp, DAC, and a comparator:
I have a 10 ps version around here somewhere...
-- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
I used an HP 81110A pulse generator with 81112A output board, bought on eBay, natch. Its pulse length can be conveniently set in 5ps increments, although thay can't always be believed. I meant to show a sample pulse on the picture. Its risetime is about 800ps.
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Nice. What was the comparator? I'll bet you wish it had a faster output stage.
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Thanks,
- Win
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Three weeks ago I ordered some samples from a a company in California for shipping here to Taiwan. They requested me to sign some form stating what the intended application is. They arrived with a COC stating place of production: Taiwan :-)
Just crazy bureaucrats. I am always tempted to put some crazy application and final destination into such forms. Just to find out if anybody is really reading and caring for this.
-- Reinhardt
That one uses an LVDS line receiver as the comparator. Some of the LVDS chips make great rrio comparators, dirt cheap. The output in the pic is downstream of the comparator and some logic.
To go really fast with sub-ps jitter, you need a real comparator, an ADCMP sort of part.
Funny that ADI makes almost all the DDS chips and fast comparators.
There are US export restrictions on high slew rates, so we have to slow down some of our products! It's crazy, when you can use a part manufactured in Maylasia, available anywhere in the world, that, when soldered to a PCB, can't be exported.
-- John Larkin Highland Technology, Inc picosecond timing laser drivers and controllers jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
We collect the end-use statements, but nobody audits them. If some Bad Thing happened, we need to have them on record.
I know some guys who shipped some fairly klunky NIM modules to India, and got into big trouble. It cost them over $250K in legal fees and fines, and they were very lucky not to go to jail.
We used to share a building with a drug dealer. He was a licensed pharmacist who sold benign drugs, like antibiotics and insulin, no narcotics, all over the world. He sold some stuff to someone in Iran, and got busted. There were white vans on the sidewalk, and six or eight guys in flak jackets with guns. They wouldn't all fit into his tiny office.
-- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
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