Hello Everyone who clicked me,

I am new to ECL and for the most part things were going well until I came across a few IC's with the Vbb pin. I am not quite sure of the functionality of this pin.

Specifically, the IC's MC100ELT25 and MC10125.

I have one ECL signal (sine wave) and as the chips suggest I am wanting to convert the ECL signal into a TTL signal. So I have a single ended input, thus according to datasheets Vbb should be shorted to the unused differential input?

Also, if possible can someone please further explain Vbb in general.

Thank you

 

You may not find too many folks here with MECL experience.

VBB is an output pin that provides a -1.3V reference voltage when using single ended inputs.

Connect the unused input to VBB and decouple with 0.1uF capacitor to GND.

This sets the unused input to the halfway point between logic LOW at -1.75V and logic HIGH, -0.9V.

 

Out of curiosity, why is that?
...Thanks for the information, It clears pretty much everything up.

 

Why is that? What is that?