Hello Mark,

>I want to
>use differential ECL drivers and recievers over twisted pair wires.  I do not
>want to add a negative supply so I am using the ECL devices in the VCC (+5v)
>referenced configuration described by the manufacturers as positive-ECL
>(PECL).  The data books that I have indicate that TTL-PECL and PECL-TTL
>translators are becoming popular but I have not been able to find any of
>these devices.  Does anyone know of one of these devices?  I sure could use
>some part numbers.  Thanks for any help.
>
>Mark A. Corio
>e-mail:  Mcorio@aol.com
>

I've got quite a bit of experience using these translators (although last
time I did this was wuite a few years ago. I'm not sure ECL is the way to go
with todays LOWER POWER and CONTROLLED JITTER drivers. But anyway:
1. TTL to ECL translation is easy in a PECL system: it's just a 3 resistor
ladder (I think it's 180/270/620, but I'm not sure). You can find it in the
MOTOROLA ECL DATABOOK.
2. You will also find ECL to TTL translators there. These are IC devices,
and aren't cheap I think. You could also construct one from discrete
devices. Altogether, the translators don't preserve jitter distribution
since they are not differential.
If you still need some more info, please email me directly.
regards,
              Amnon

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