[time-nuts] Zero-Crossing Detector Design?

[Gerhard Hoffmann]

Am 20.07.2012 00:57, schrieb Richard (Rick) Karlquist:
> A fast comparator seems like a good idea, and it
> is simple, however it is actually the last thing
> you want to use.  High thermal sensitivity and high jitter.
>
> Rick
>
> On 7/19/2012 1:35 PM, Dan Kemppainen wrote:
>> Or use a fast comparator such as an ADCMP600 series. Much lower delays,
>> and faster rising/falling edges.
>> FYI, I've had good luck with this at 30Mhz. You could transformer couple
>> this one, or simply couple it through a cap.

The ADCMP580 could be an excellent choice for the output stage
of a Collins type device. Running quite cool and showing only
180 ps _total_ delay is a good start.

Good rise/fall times on home-etched 0.5 mm FR4 (and some semi-rigid):

http://www.imagesup.de/bild-_Mgif-119362.htm


regards, Gerhard, dk4xp