I have a 50 ohm clock line that I need to feed to four other inputs?

Question

but the details of the IC that will receive the clock are still pending. Is there any time when a clock can be wired in parallel?

I am planning on implementing a splitter on the circuit.

I want to do it like this, but this is for two ports and I need four.

How do I implement a four port resistor splitter?

two port resister splitter: http://www.eecircle.com/applets/017/pwrSplitter.html

PS: There is no more room for active components, unless they are available in SOT23!

Answer 1

Depending on the frequency, for short runs on a PC board, you may be able to just connect them all in parallel, and just terminate the last one with a 50 ohm resistor.

That assumes the receivers are high impedance. If they are internally terminated in 50 ohms, then you need a 4 way splitter.

Whether or not you need an amplifier is determined by the sensitivity of the receivers. If they can operate on the amplitude of the clock as attenuated by the splitter, fine. If you need more signal, then you need an amp. Simple as that.

4 way splitters are easily designed, see any textbook.

here is one to show you they exist.

http://www.radioshack.com/sm-satellite-4...

Answer 2

Unless the driver is very robust you better plan on an amplifier. By the time you drive four loads and go through three 1-2 splitters or a 1-4 splitter you have a lot of load. Remember there are losses in splitters.

If you wire the four clocks in parallel you no longer have a 50 ohm load.

With a resistive splitter you will lose 3 db (half) power and the remaining power is split between the two outputs so it is halved (3dB) again. so only 25% (6dB) of the power from the input goes to the each output. Using 1-2 (resistive) splitters to go from one output to 4 inputs means one splitter feeding two splitters. So 100% output = 25% at the first splitter and 25% X25% =~5% at the four outputs.

Sounds like you better find room for an amplifier.