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What are logic gates with open-collector or open drain outputs?
Open-drain outputs can be useful for analog weighting, summing, and limiting as well as digital logic. An open drain terminal is connected to ground when a high voltage (logic 1) is applied to the gate, yet presents a high impedance when a low voltage (logic 0) is applied to the gate.
Is open-collector the same as open drain?
An “open collector” is functionally the same as an “open drain”. An “open collector” refers to a current sink on a BJT transistor output, while an “open drain” refers to a current sink on a FET output.
How does an open-collector work?
An Open Collector Digital Output behaves similarly to a Solid State Relay, by toggling the state of the output, you can switch a circuit on and off. This type of output does not supply power to the load like an ordinary digital output, it simply switches a powered circuit to ground.
What is an open-drain output?
An open-drain or open-collector output pin is driven by a single transistor, which pulls the pin to only one voltage (generally, to ground). When the output device is off, the pin is left floating (open, or hi-z).
How are open drain outputs used in digital logic?
Open-drain outputs can be useful for analog weighting, summing, and limiting as well as digital logic. An open drain terminal is connected to ground when a high voltage (logic 1) is applied to the gate, yet presents a high impedance when a low voltage (logic 0) is applied to the gate.
What does open drain and open collector mean?
Open drain, drives high Typically these outputs connect the pin to ground to represent low, and disconnect to represent high, but they can also connect the pin to the supply voltage to represent high, and disconnect to represent low. This is still “open-collector” or “open-drain”, since the driving device is opposite polarity (PNP or P-channel).
How is the output connected to the open collector?
Open collector. The emitter of the transistor is connected internally to the ground pin. If the output device is a MOSFET the output is called open drain and it functions in a similar way.
When is an open drain terminal connected to ground?
An open drain terminal is connected to ground when a high voltage (logic 1) is applied to the gate, yet presents a high impedance when a low voltage (logic 0) is applied to the gate.