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.
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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 un-clocked 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 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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