Wired OR

[TomasL]

I am trying to do some design where I need to tie several outputs together, using wired-or technology
I am using ECL hence Open Emiter, and by default all inputs is pulled down to low with resistors.

Now it seems that all output symbols only can have two states High or Low, is it possible to create an output that can have High and High-Z instead.

[admin]

Hi,
Of course, it’s possible. There are two tristate elements available for you they are between Not and And elements.

[TomasL]

Well, Tristate is not what I am, looking for, since they require an extra control-signal.

[admin]

Is it what you are looking for?

High-HighZ.Jpeg (4.22 KiB) Viewed 15165 times

Please look at the circuit attached
The dash in the probe means high impedance.

[TomasL]

Ok, that might be usable, what happens to the inputs when the connected outputs is HiZ, are they pulled low by default.

[admin]

It the same as just disconnect the input. For And it treated as 1 for Or as 0.

[TomasL]

Ok, so in the ORgate the input is pulled low.