74HC595 Power

Using Arduino Motors, Mechanics, Power and CNC
1

Hi guys! :slight_smile:

I'm working on a project where power is the operative word.
I have a 328 running on "fumes" and I intend to power on/off external components on demand, specifically a 74HC595.
As per its datasheet it states that max current is 80uA for that chip (pretty low right?) but I'm also trying to save those 80uA from continuous drain where they really aren't needed.

Powering the chip on/off is done by a simple passthrough transistor controlled by one the of 328's pins.

If this isn't a totally wacked idea :stuck_out_tongue: how much time should I wait before the chip stabilizes and start communicating with it?
Should I expect some garbled signals on the outputs between power cycles?

TIA,
Pedro.

2

Most CMOS logic chips typically take nanoamps when quiescent and no current load on the outputs. That 80uA
is worst case across the full temperature/voltage range (leakage current is exponential in temperature,
I suspect if you measure the current at room temperature it will be more like 1uA.