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open collector and open drain

selva

Apr 26, 2010
25
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Apr 26, 2010
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25
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

Jul 31, 2009
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Jul 31, 2009
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2,848
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

Aug 20, 2009
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Aug 20, 2009
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28
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

Apr 26, 2010
25
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Apr 26, 2010
Messages
25
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
 
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