Chaining 25 74HC595 shift registers together

Question

Situation:

I am doing a project which requires me to chain 25 74HC595 shift registers together. They ate controlled by an Arduino microcontroller.

Question:

1. Will it work when chaining that number of shift registers together?
2. Will there be any problem such as the clock signal false and data transmission errors because of the long transmission distance?
3. Do I need something like a buffer or capacitor to make sure the transmitted signal is correct? If needed, any recommended type and where to connect them?

Answer 1

In the ideal case, driving 25 HC595s will work just fine.

However, there are some things you can do to make it not ideal, especially easy if you have long lines or high current consumption.

If you have a very long clock and strobe lines, then reflections could be a problem and you need to treat them as transmission lines. Usually a series resistor at the source end of a single, long, unterminated line is sufficient.

If you have your power ground and logic ground as the same conductor, then current flowing in a long line could generate enough V=IR voltage drop to shift the ground voltage at the far end such that you don't make the logic levels for clock and strobe signals send from the control end. You might want to rebuffer the clock and strobe at each board, if you have a long string of boards, so the voltage shift doesn't build up.