EEVblog > EEVblog Specific

EEVblog #316 - More PFANG, More 13GHz Scope, & More Pulser

(1/7) > >>

EEVblog:


Dave.

KTP:
There are some comparitors with 50ps rise/fall times

This paper talks about making a low cost fast rise time pulse gen:

http://www.ise.pw.edu.pl/~tomi/papers/wilga2006_50ps.pdf

The ADCMP580 used in that discussion data sheet is here:

http://www.analog.com/static/imported-files/data_sheets/ADCMP580_581_582.pdf

Sells for $18 at digikey...ouch.

From the data sheet:

"The ADCMP580/ADCMP581/ADCMP582 are ultrafast voltage comparators fabricated on the Analog Devices, Inc. proprietary XFCB3 Silicon Germanium (SiGe) bipolar process. The ADCMP580 features CML output drivers, the ADCMP581 features reduced swing ECL (negative ECL) output drivers, and the ADCMP582 features reduced swing PECL (positive ECL) output drivers.
All three comparators offer 180 ps propagation delay and 100 ps minimum pulse width for 10 Gbps operation with 200 fs random jitter (RJ). Overdrive and slew rate dispersion are typically less than 15 ps.
The ±5 V power supplies enable a wide ?2 V to +3 V input range with logic levels referenced to the CML/NECL/PECL outputs. The inputs have 50 ? on-chip termination resistors with the optional capability to be left open (on an individual pin basis) for applications requiring high impedance input."

veryevil:
Hey, The letter says that you should have used a 20Mhz SINE WAVE not square wave input! Guessing that would have cut down on the ringing.

Now you have to build one and try it again!

SeanB:
I did something similar dead bug style to get a better clock out from a PC interface card. 54S14 dead bugged 4 high, with a 0.1uF across the top, and a 10uF 25V wet tantalum as well over that.  Just used 1 inverter from the bottom to drive the 3 above it, and they in turn drove the rest of the inverters in parallel. Had no problem driving a 24MHz clock direct to 110R twinax with only end termination. Did run a little warm though, but the cerdip package was happy with that. If they had toasted I would have made another and would have added copper strip fins between the packages.

Nermash:
One thing intrigues me about that 13 GHz scope, I kind of expected to see SMA or more advanced sexless connectors on it (can't remember the name).
From all the sources I have read, BNC is good only up to 3 GHz?

Navigation

[0] Message Index

[#] Next page