Difference Between Latch and Flip-flop
By BYJU'S Exam Prep
Updated on: September 25th, 2023
The Difference Between Latch and Flip-flop is that the flip-flop uses an edge-triggered approach, and the latch uses a level-triggered approach. The flip-flop and latch are a type of memory circuit. The output change in both of them varies based on the signal triggered by the circuit.
Flip-flop is nothing but a pair of latches. Flip-Flop is edge-triggered, whereas latch is end-triggered. Check out the sections below to learn more about the difference between latch and flip-flop, along with a brief introduction about the flip-flop and latch.
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Difference Between Flip-flop and Latch
Flip-flops and latches are fundamental building blocks in digital electronics circuits, used for storing and manipulating binary data. The flip-flops and latch carry various differences, from basic principles to working and sensitivity. These differences help us choose a better memory device as per our requirements.
Latch vs Flip-flop
We have outlined the difference between flip-flop and latch in the table provided below:
| Flip-flops | Latch |
| It uses an edge-triggered approach. | It is a level-triggered approach. |
| Flip-flops are classified as synchronous and asynchronous. | No such classification of Latch. |
| Flip-flops have a clock signal. | Does not have a clock signal. |
| Flip-flops are built up from a latch. | They are built up from gates. |
| The operating speed is slow. | The operating speed is high. |
| Flip-flops require power more than a latch. | Required less power. |
| It covers more area. | Less area required. |
What is Flip-flop?
Flip-flops are used to save memory. Flip-flops are also known as one-bit memory or bistable multivibrators. It stores one bit of memory/information. They are the building blocks. They are the basic digital memory circuit. The flip-flops use the edge-triggered approach. There are four types of flip-flops:
- Data or Delay (D) Flip-Flop
- Toggle (T) Flip-Flop
- JK Flip-Flop
- SR (Set-Reset) Flip-Flop
What is a Latch?
A latch is a memory device and is also used to save memory. A latch is used to immediately change the output based on the input applied in electronic devices. Only stores 1 or 0 at a time. There are two inputs in the latch, i.e., SET and RESET. Based on these inputs, two types of outputs are generated. Various types of Latch are:
- JK Latch
- T Latch
- SR Latch
- Gated D Latch
- Gated S-R Latch
- D latch
Circuitry of Flip-flops and Latches
Flip-flops and latches are basic building blocks of digital electronics circuits. Both the devices are used for storing binary data. The fundamental difference between a flip-flop and a latch is in the way they change their state, which makes flip-flops edge-triggered while latches are level-triggered. In terms of circuitry, flip-flops consist of combinational logic gates and memory elements.
Flip-flops are further categorized into D, J-K, T, and SR flip-flops, based on their input and output configurations. On the other hand, latches are made up of gates that control the inputs to the memory element. One of the critical differences between flip-flops and latches is in their mode of operation. Flip-flops are synchronous devices. On the other hand, latches operate asynchronously, which means they respond to changes in their input signals without requiring a clock signal.
Differences in Timing and Performance of Flip-flops and Latches
Flip-flops are more commonly used in applications that require high-speed and high-performance, such as in microprocessors, digital signal processing, and communication systems. Flip-flops are faster and more precise than latches in terms of timing, and they can also tolerate a higher clock frequency.
Latches are simpler in design and have a lower latency than flip-flops, which makes them suitable for applications that require lower power consumption and moderate performance. Latches are classified into SR latch and D latch based on their configuration.
Applications of Flip-flops and Latches
Flip-flops and latches are extensively used in digital circuits for various applications such as memory, registers, counters, shift registers, and control units. Flip-flops are commonly used in microprocessors, microcontrollers, and digital signal processors to store binary data. Latches are mostly used in applications where the clock frequency is low, and power consumption is a concern, such as in mobile devices and battery-operated systems.
Choosing Between Flip-flops and Latches
The selection between flip-flops and latches depends on the requirements of the application. If the application requires high-speed operation, precise timing, and high performance, then flip-flops are preferred over latches. However, if the application requires low power consumption, simplicity, and lower latency, then latches are preferred. It is also important to consider the clock frequency, power consumption, area constraints, and other design specifications while choosing between flip-flops and latches.
Conclusion: Latch vs Flip Flop
- Flip flops are the improved versions of latches. Flip-flops are preferred over latches because of various advantages, such as using a clock signal and an edge-triggered approach.
- Even though flip-flop covers more area, it is still preferred because it eases the design interpretation.
