Me again,
I'm learning a bit about buffers/drivers, and after reading a little on the net it seems that the types of outputs can be divided as follows:
Open collector
____current sinking - NPN - needs pullup resistor
____current sourcing - PNP - needs pulldown resistor
Push-pull
____Totem pole - similar transistors
____Standard push-pull - different transistors
Tri-state
When I read datasheets, they will often say "open collector output", but I've found some where there is no specific type stated.
Example: SN75155 - there is no specific statement of the type, and they give a schematic which shows an output between diodes. So it doesn't really fit into the above schema. (What's up with that?)
Questions:
1 - If a datasheet doesn't state "open-collector" is there an assumption I can make about the type of output (in the absence of a schematic).
2 - In a tri-state buffer (e.g., DM74LS125A) what type of output can I assume it has when it is either HI or LOW? (not Z)
As usual, I thank you in advance.
I'm learning a bit about buffers/drivers, and after reading a little on the net it seems that the types of outputs can be divided as follows:
Open collector
____current sinking - NPN - needs pullup resistor
____current sourcing - PNP - needs pulldown resistor
Push-pull
____Totem pole - similar transistors
____Standard push-pull - different transistors
Tri-state
When I read datasheets, they will often say "open collector output", but I've found some where there is no specific type stated.
Example: SN75155 - there is no specific statement of the type, and they give a schematic which shows an output between diodes. So it doesn't really fit into the above schema. (What's up with that?)
Questions:
1 - If a datasheet doesn't state "open-collector" is there an assumption I can make about the type of output (in the absence of a schematic).
2 - In a tri-state buffer (e.g., DM74LS125A) what type of output can I assume it has when it is either HI or LOW? (not Z)
As usual, I thank you in advance.