Difference Between Flip-flop and Latch

Latch Vs. Flip Flop: What is the Difference Between Latch and Flip Flop

The major difference between flip-flop and latch is that the flip-flop is an edge-triggered type of memory circuit while the latch is a level-triggered type. It means that the output of a latch changes whenever the input changes. On the other hand, the latch only changes its state whenever the control signal goes from low to high and high to low.

What is a Flip-Flop?

A flip-flop is a digital memory circuit that stores one bit of data. They are the primary blocks of the most sequential circuits. It is also called one-bit memory, binary, or a bistable multivibrator. Flip-flops act as memory elements in a sequential circuit. You can obtain the output in the sequential circuits using a flip-flop, a combinational circuit, or both.

A flip-flop state repeatedly changes at an active state of the clock pulses. They remain unaffected even when the clock pulse does not stay active. The clocked flip-flops particularly act as the memory elements of the synchronous sequential circuit- while the unclocked ones (latches) function as the memory elements of asynchronous sequential circuits.

There are mainly four types of flip-flops:

  • JK Flip-Flop
  • SR (Set-Reset) Flip-Flop
  • Data or Delay (D) Flip-Flop
  • Toggle (T) Flip-Flop

What Is a Latch?

A latch is an electronic device that changes its output immediately on the basis of the applied input. One can use it to store either 0 or 1 at a specified time. A latch contains two inputs- SET and RESET, and it also has two outputs. They complement each other. One can use a latch for storing one bit of data. It is a memory device- just like the flip-flop. But it is not synchronous, and it does not work on the edges of the clock like the flip-flop.

Difference Between Flip-flop and Latch

Parameter

Flip-Flop

Latch

Basic Principle Flip-flop utilizes an edge triggering approach. Latch follows a level triggering approach.
Clock Signal The clock signal is present. The clock signal is absent.
Designed Using You can design it using Latches along with a clock. You can design it using Logic gates.
Sensitivity Flip-flop is sensitive to the applied input and the clock signal. Latches are sensitive to the applied input signal- only when enabled.
Operating Speed It has a slow operating speed. It has a comparatively fast operating speed.
Classification You can classify a flip-flop into a synchronous or asynchronous flip-flop. A user cannot classify the Latch this way.
Working Flip-Flops work using the binary input and the clock signal. Latches operate only using binary inputs.
Power Requirement It requires more power. It requires comparatively less power.
Analysis of Circuit It is quite easy to perform circuit analysis. Analyzing the circuit is quite complex.
Type of Operation Performed Flip-flop performs Synchronous operations. Latch performs Asynchronous operations.
Robustness Flip-flops are comparatively more robust. Latches are comparatively less robust.
Dependency of Operation The operation relies on the present and past input bits along with the past output and clock pulses. The operation depends on the present and past input along with the past output binary values.
Usage as a Register A flip-flop is capable of working as a register as it contains clock signals in its input. A latch cannot serve as a register as the register requires further advanced electronic circuits (EC). Time also plays an essential role here.
Types J-K, S-R, D, and T Flip-flops. J-K, S-R, D, and T Latches.
Area Required It requires more area. It requires comparatively less area.
Uses They constitute the building blocks of many sequential circuits such as counters. Users can utilize these for designing sequential circuits. But they are still not generally preferred.
Input and Output A flip-flop checks the inputs. It only changes the output at times defined by any control signal like the clock signal. The latch responds to the changes in inputs continuously as soon as it checks the inputs.
Synchronicity A flip-flop is synchronous. It works based on the clock signal. A latch is asynchronous. It does not work based on the time signal.
Faults Flip-Flops stay protected against any fault. The latches are responsive to any occurring faults on the enable pin.

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