I am trying to calculate how much current some components will draw. However, it is not clear to me from the datasheets. I also have several other questions.
Firstly, the NL17SZ08 AND gate
- DC Input Diode Current -50mA
- DC Output Diode Current -50mA
- DC Output Source/Sink Current ±50mA
- DC Supply Current per Supply Pin or Ground Pin ±100mA
- Latchup Performance ±100mA
DC ELECTRICAL CHARACTERISTICS
- Input Leakage Current ±1.0μA
- Quiescent Supply Current 10μA
DC Supply Current sounds relevant but I don't understand the ± or the per Supply Pin or Ground Pin. 100mA seems like a lot of current for an AND gate, which I would expect to be simple and low power.
Secondly, the 6N137 optocoupler
ABSOLUTE MAXIMUM RATINGS
- Average forward current 20mA
- Enable input current 5mA
- Surge Current 200mA
- Output current 50mA
RECOMMENDED OPERATING CONDITIONS
- Input current low level 250μA
- Input current high level 15mA
- Reverse current 10μA
- High level supply current 7mA
- Low level supply current 7mA
- High level output current 1μA
- Input threshold current 5mA
- High level enable current -1.6mA
- Low level enable current -1.6mA
If the max average forward current is 20mA, then will the max forward current is 40mA? What is the High level supply current. That sounds reasonable for an LED + some other stuff
Lastly, the 74HC165 shift register
- Absolute maximum supply current 50mA - is this only relevant if this chip was connected in series with something which draws current? When connected "normally" in parallel with some circuit, would this ever be an issue?
- supply current 160 μA + additional supply current approx 2500μA = 2.7mA - is it really this low?