[hpsdr] Re. QSD's

[Ahti Aintila]

Dan,

You obviously mean MC100EL31DTG.

I have not used these new generation emitter coupled logic circuits,
but really did have problems with the older generation of Motorola
ECLs.

I suppose you are aware that ECLs are made to work with negative power
supply, but using the proper tricks, they can be made to work in PECL
mode (positive supply up to +5V and TTL/CMOS compatible). Just for
safety, check the Application Note AN1406/D
<http://www.onsemi.com/pub/Collateral/AN1406-D.PDF> and possibly also
AN1568/D, if you need to inteface them with LVDS circuits.

On the circuit board, avoid  any DIRECT CAPACITIVE COUPLING between
the ECL power plane and the CMOS/TTL power plane and bypass the both
planes to a common ground with low inductance capacitors!

By the way, clocking the multiplexer switch SN74LVC2G53 at 500 MHz may
be tough, but certainly the ECL driver can speed up the switching.

Good luck and 73,
Ahti OH2RZ


On 09/10/06, Dan Andersson <dan.andersson at ieee.org> wrote:
> ***** High Performance Software Defined Radio Discussion List *****
>
>
>
> Gent's
>
> I've been following the discussion on QSD's and the "need for speed".
>
> I found a couple of    MC10EL31DTG D-Type flip flops with set and reset.
>
> These can be toggled up to 2.8Ghz, and should subsequently do nicely in a
> QSD for up to 2800/4 MHz. ( ON Semiconductor )
>
> This is by far better than the "normal" 150MHz AC-logic versions I found so
> far.
>
> Is there anyone that have been playing with these chips and have any comments?
>
> They seems to be priced around 3 - 4 $ each and are available both for
> sampling and as standard inventory.
>
> I'm ordering a couple of these and intend to clock them with 2GHz as I want a
> 500MHz DC receiver to play with so any thoughts are welcomed.
>
> Cheers
>
> Dan
>
> --
> Dan Andersson, M0DFI
> dan at andersson.co.uk                         dan.andersson at ieee.org
>
>
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