For such buffer, signal transition from input to output is equal to 0. It is mainly used for high speed clock distribution on a board.
Clock source is connected to several buffer inputs and is distributed to different branches.
By having 0 delay between inputs and outputs, raising and falling edge of the clock occurs in the same time, on each branch of the distribution.
Zero delay in the sense... upto what freq it will work .. i mean what is the dealy time ?? its in nano sec or pico sec ??
is this a tech or some ICs are used for the same ..
More information is available from IDT (https://www.idt.com/products/clock_management.html). IDT is developing a lot of devices for clock management. For specification about Zero Clock Buffers take a look at here: **broken link removed**
You also should note that one of pins is a feedback pin to control the clock screw. the pin should have same load with other pins. The phrase of the output clock may be adjust by this way.