Re: Fast sampler

On Thu, 6 Mar 2025 14:12:14 -0800, Joerg <news@analogconsultants.com>
wrote:

On 3/6/25 12:51 PM, john larkin wrote:

On Thu, 6 Mar 2025 12:33:35 -0800, Joerg <news@analogconsultants.com>
wrote:
 

On 3/6/25 8:29 AM, Bill Sloman wrote:

On 7/03/2025 3:06 am, john larkin wrote:

On Thu, 6 Mar 2025 10:54:20 -0500, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:
>

On 2025-03-06 10:24, john larkin wrote:

>
[...]
>
>

When I was young and foolish, I used to do time delays with linear
ramps and ECL comparators.
>

>
The line receivers don't seem to have any significant amount of kickout,
either--we can sweep the Rx pulse across the Tx pulse with no apparent
funnies due to interaction.  Have you folks seen any kickout issues?
>
Of course the kickout might be delayed, I suppose.
>
Cheers
>
Phil Hobbs

>
We didn't test for that. When a comparator fires, all sorts of stuff
happens downstream, that could jostle adjacent channels.
>
Our comparators typically drive a 1 ns Tiny Logic flipflop as the next
step in the signal chain.
>
Standard ECL wasn't as fast as 15 cent Tiny parts are now.

>
But it's current steering logic and the supply rails stay a lot cleaner
than you see with CMOS switches.
>

>
Not a big problem, just place pillows around it, RC filters on the
supply. Drive was never an issue in my case but on rare occasions I have
used cheap signal transformers to isolate that.
>
The larger concern with supply rails is low frequency noise coming in,
causing phase noise. That is where capacitance multipliers can shine.

 
I measured one FPGA at around 1 mV per picosecond prop delay, on the 1
volt core supply. Prop delay is about inverse on voltage in cmos.
 

>
In my last TDR psec-jitter would have made the client unhappy. The
sampling window was 100psec but it wasn't supposed to move unless told to.
>

>
>

And what's Standard ECL now? It was Motorola 10k back when I was young,
and Motorola/Philips/Fairchild 100k a few years later. Motorola ECLinPs
took over a about when I stopped using it, about when I started posting
here, some twenty years ago.
>

>
AFAIK it's 100E but I have not used any in ages because I always found
them overpriced. I don't like it when two ICs cost more than a crate of
beer :-)

 
MC10EPxx, SiGe Eclips Lite.
 
Really fast and really expensive is Gigacomm, which is actually CML.
The NB7V52M flop is only about $13 in quantity.
 

>
So far I've only needed "semi-analog", meaning just one bit and then I
did it using RF transistors. It is amazing, you can buy >100GHz fT for
less than 20 cents in qties.
>
When I was a kid I had to shell out around $3 for an AF116 Ge-transistor
that had an fT of 75MHz. In 1970's Dollars, which really hurt. Digital
wasn't any better. I needed a 1kbit RAM for a project and that set me
back about 10 bucks. It still works.

My first transistor was a Raytheon CK722 germanium. I think Ft was
measured in KHz. It cost $7, about a month's allowance, or dinner for
two at a decent restaurant.

I got tubes for free.