IC 7474 – Dual D-Type Flip-Flop with Set and Reset

Overview

The IC 7474 – Dual D-Type Flip-Flop with Set and Reset is a dual D-type flip-flop integrated circuit that includes two independent flip-flops. Each flip-flop features a D (data) input, a clock input, a set input, and a reset input. This IC is commonly used for data storage, timing applications, and as a building block in sequential logic circuits.

Features

• Dual Flip-Flops: Contains two independent D-type flip-flops.
• Asynchronous Set and Reset: Each flip-flop has an asynchronous set (S) and reset (R) input for immediate state control.
• Edge-Triggered: Flip-flops are edge-triggered, meaning they capture the input data on the rising or falling edge of the clock signal.
• Q and Q’ Outputs: Each flip-flop provides a normal output (Q) and an inverted output (Q’).
• Standard Logic Levels: Operates with standard TTL logic levels.

Pin Configuration

The IC 7474 is typically available in a 14-pin Dual In-line Package (DIP) format. The pinout is as follows:

• Pin 1: Q1 (Output of Flip-Flop 1)
• Pin 2: Q1′ (Inverted Output of Flip-Flop 1)
• Pin 3: D1 (Data Input of Flip-Flop 1)
• Pin 4: CLK1 (Clock Input of Flip-Flop 1)
• Pin 5: CLR1 (Asynchronous Reset Input of Flip-Flop 1)
• Pin 6: PRE1 (Asynchronous Set Input of Flip-Flop 1)
• Pin 7: Vcc (Positive Supply Voltage)
• Pin 8: GND (Ground)
• Pin 9: CLR2 (Asynchronous Reset Input of Flip-Flop 2)
• Pin 10: PRE2 (Asynchronous Set Input of Flip-Flop 2)
• Pin 11: CLK2 (Clock Input of Flip-Flop 2)
• Pin 12: D2 (Data Input of Flip-Flop 2)
• Pin 13: Q2 (Output of Flip-Flop 2)
• Pin 14: Q2′ (Inverted Output of Flip-Flop 2)

Working Principle

The IC 7474 – Dual D-Type Flip-Flop with Set and Reset operates as follows:

1. Data Storage: The D (data) input is latched into the flip-flop on the edge of the clock signal, and the output Q represents the stored data.
2. Clock Signal: The flip-flops are edge-triggered, capturing data on the rising or falling edge of the clock signal.
3. Asynchronous Set/Reset: The set (PRE) and reset (CLR) inputs can immediately set or clear the flip-flop regardless of the clock signal, overriding normal operation.
4. Outputs: Each flip-flop provides both a true (Q) and an inverted (Q’) output.

Applications

• Data Storage: Used in digital circuits to store binary data.
• Registers: Forms registers in computers and digital systems for temporary data storage.
• Counters: Serves as a fundamental building block in digital counters and timers.
• State Machines: Implements state machines in digital logic for sequential operations.
• Pulse Shaping: Used in pulse shaping circuits and timing applications.

Example Circuit

• Flip-Flop Toggle: Connect the D input to a logic level, the clock to a pulse generator, and monitor the Q output for toggling behavior.
• Data Storage Register: Use the flip-flops to store and retrieve data in digital systems.
• Timing Circuit: Implement the flip-flops in timing circuits for pulse generation and event sequencing.

Advantages

• Dual Flip-Flops: Provides two independent flip-flops in a single package, saving space and cost.
• Asynchronous Inputs: Offers set and reset inputs for immediate control of flip-flop states.
• Edge-Triggered Operation: Ensures precise data capture on clock edges.
• Standard TTL Levels: Compatible with standard TTL logic levels for easy integration.

Conclusion

The IC 7474 is a versatile dual D-type flip-flop IC ideal for a variety of digital applications requiring data storage, timing, and sequential logic functions. Its ability to handle asynchronous set and reset operations, combined with edge-triggered data capture, makes it a valuable component in digital circuit design. With its dual flip-flop configuration, the IC 7474 offers flexibility and efficiency in implementing complex digital systems.