Different output configurations: Push-Pull, Open-Drain, Pull-Up, Pull-Down, etc

[Alex_reynold]

Hi Usualy I see terms called pushpull configuration,open drain, pull up ,pull down and so on.what are the difference between them

[Andrew Neil]

These are general electronics terms - nothing specific to STM32 or even ST:

• A Push-Pull output can actively drive both high ("push") and low ("pull"):
  https://en.wikipedia.org/wiki/Push%E2%80%93pull_output
   
• An Open-Drain (or Open-Collector) output can only "pull" low:
  https://en.wikipedia.org/wiki/Open_collector#Open_drain;
  https://en.wikipedia.org/wiki/Open_collector 
   
• A Pull-Up pulls "up" to the supply voltage
  https://en.wikipedia.org/wiki/Pull-up_resistor
   
• A Pull-down is just the complement of a Pull-Up - it pulls "down" to ground, rather than "up" to the supply voltage.

 

PS:

It is conventional to refer to the supply voltage as "up" and ground as "down"; hence:

• A Pull-Up pulls "up" to the supply voltage; 
• A Pull-Down pulls "down" to ground. 

Again, nothing specific to STM32.

 

PPS:

Source/Sourcing and Sink/Sinking are also common terms relevant here:

 

https://electronicsclub.info/ics.htm#:~:text=Sinking%20and%20sourcing%20current

 

• A Push-Pull output can both source and sink;
• An Open-Drain (or Open-Collector) output can only sink.

 

#SourceSink #SourcingSinking #PushPull #OpenDrain #OpenCollector #PullUp #PullDown

[Andrew Neil]

@Alex_reynold - did that answer your question?

If so, please mark the solution; if not, what needs clarification?