D-Type Flip-Flop

What Does D-Type Flip-Flop Mean?

A D-type flip-flop is a clocked flip-flop which has two stable states. A D-type flip-flop operates with a delay in input by one clock cycle. Thus, by cascading many D-type flip-flops delay circuits can be created, which are used in many applications such as in digital television systems.

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A D-type flip-flop is also known as a D flip-flop or delay flip-flop.

Techopedia Explains D-Type Flip-Flop

A D-type flip-flop consists of four inputs:

  • Data input
  • Clock input
  • Set input
  • Reset input

It also has two outputs, with one being logically inverse of other. The data input is either logic 0 or 1, meaning low or high voltage. The clock input helps in synchronizing the circuit to an external signal. The set input and reset input are mostly held low. A D-type flip-flop can have two possible values. When input D = 0, the flip-flop undergoes a reset, which means the output would be set to 0. When input D = 1, the flip-flop does a set, which makes the output 1.

A D-type flip-flop differs from a D-type latch, as in a latch a clock signal is not provided, whereas with a D-type flip-flop a clock signal is needed to change states. A D-type flip-flop can be constructed with a pair of SR latches and with an inverter connection between S and R inputs for single data input. The S and R inputs can never be both high or low at same time. One of the salient features of a D-type flip-flop is its ability to “latch” and store and remember data. This property is used in creating a delay in progress of the data in the circuit used.

There are several applications in which a D-type flip-flop is used, such as in frequency dividers and data latches.

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Margaret Rouse
Technology Expert

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.