open collector and open drain

[selva]

Hi all,

i need to know how an open collector and open drain works (both in transistor and MOSFET).
Is that open collector is used only to pass an single output to the wire (bus) or do it have an some other functionalities?.

replies much needed.

warm regards,
selva

 

[Resqueline]

Open collector outputs have the advantage that they can drive loads off of a different voltage than the IC's supply. They can therefore also be used as (logic) level shifters.
Their disadvantage is a relatively slow risetime (or turn-off time) due to their dependency of a pull-up resistor. (They have weak current sourcing capability.)

 

[ElectronWorks]

you can also connect many open collector outputs together, so if you have several circuits that need to signal to a microcontroller that a fault has occurred, make all the circuits open collector and short them all together. You then only have to use one micro pin to know you have a fault.

 

[selva]

if more than one output arises from a circuit, the open collector gives a high impedance signal as output. Is there any other way to direct produced outputs to their respective destination with or without open collector, causing non-impedance output (if open collector)
i am new to electronics. If i am wrong in any part. excuses, correction much expected.

warm regards,
selva