Distinguish between Totem Pole and Open collector
1. Totem Pole :
Totem pole consists of pull up and pull down transistors along with the diode resistor.Totem pole operates at high speed. The two transistors used drives a high output and another pulls it down in an Integrated circuit.
2. Open collector :
In case of open collector we only have pull down transistor and it operates at slow speed. Open collector behaves like a switch in which it is either connected or disconnected in an Integrated circuit.
Difference between of Totem Pole and Open Collector :
Totem Pole | Open Collector |
---|---|
Output stage of totem pole circuit consists of pull-up transistor, diode resistor and a pull down transistor. | Output stage of Open collector consists of only pull down transistor. |
Outputs of the two gates cannot be tied up together | output of two gates can be tied together using a wired AND method. |
Operating speed of totem pole circuit is high as compared to open collector | Operating speed is low for open collector |
External pull up resistor is not required in case of totem pole | External pull up resistor is required for proper operation of gate in open collectors |
Due to the presence of pull up transistor, power dissipation is low in totem pole circuits | In cae of open collector, power dissipation is high due to the current flowing trough the extra resistors. |