Advantages and Disadvantages of Asynchronous Sequential Circuits

Sequential Circuits:

- Sequential circuits are those kind of logic circuits whose output depends on the present values of its input signals and on the sequence of past inputs

- Two types of sequential circuits

A) Asynchronous Sequential Circuits

B) Synchronous Sequential Circuits

Advantages of Asynchronous Sequential Circuit:

- There is no clock signal in asynchronous circuits and hence less complex

- Since the outputs are independent of clock signal and hence less circuit delay. ( Only circuit propagation delay of logic gates)

- Less power consumption since the circuit density is less and no clock drivers reduces the power consumption

Disadvantages of Asynchronous Sequential Circuit:

- Output depends directly on the inputs and hence the circuit is more prone to glitches

- If transitions on two inputs arrive at almost the same time, the circuit can go into the wrong state depending on slight differences in the propagation delays of the gates which are known as race condition.

- Since, the output is not related to clock edge, its more difficult to test and debug

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