IC 4022 – 8-Stage Johnson Decade Counter

Overview

The IC 4022 is an 8-stage Johnson Decade Counter with decoded outputs, commonly used in digital circuits for counting applications. It belongs to the CMOS 4000 series logic family and is designed to divide the input clock frequency by a factor of 8. The counter is often used in sequential circuits, frequency dividers, and timing applications.

Features

• 8 Decoded Outputs: Provides 8 individual outputs, each representing a stage of the count.
• Johnson Counter Design: Operates as a Johnson counter, where each output goes high in sequence.
• Asynchronous Reset: A reset pin is available to clear the counter and start it from the initial state.
• Wide Operating Voltage Range: Supports operation from 3V to 15V.
• Low Power Consumption: CMOS technology ensures efficient power usage.
• High Noise Immunity: Reliable operation in electrically noisy environments.
• Standard Pin Configuration: Easy integration into existing CMOS circuits.

Pin Configuration

The IC 4022 is typically available in a 16-pin Dual In-line Package (DIP). The pinout configuration is as follows:

• Pin 1: Q5 (Output Stage 5)
• Pin 2: Q1 (Output Stage 1)
• Pin 3: Q0 (Output Stage 0)
• Pin 4: Q2 (Output Stage 2)
• Pin 5: Q6 (Output Stage 6)
• Pin 6: Q7 (Output Stage 7)
• Pin 7: Q3 (Output Stage 3)
• Pin 8: Ground (GND)
• Pin 9: Q4 (Output Stage 4)
• Pin 10: Clock Input (Triggers the counting process)
• Pin 11: Reset (Asynchronous Reset Input)
• Pin 12: Clock Inhibit (Pauses the counter when high)
• Pin 13: Carry Out (Can be used to cascade multiple counters)
• Pin 14: Q8 (Not used in the 4022; tied to Q0)
• Pin 15: Vcc (Positive Supply Voltage)
• Pin 16: Clock Input (Alternate clock input, often unused)

Applications

• Frequency Dividers: The IC 4022 is commonly used to divide input frequencies by 8, making it useful in clock generation and signal processing.
• LED Sequencers: It can drive a sequence of LEDs, each lighting up one after the other in a pattern.
• Digital Counters: Suitable for counting applications in digital clocks, event counters, and more.
• Sequential Logic Circuits: Useful in applications where a sequential output is needed, such as in state machines.
• Stepping Motor Control: Can be used to control the steps in stepping motors by providing sequential pulses.

Working Principle

The IC 4022 operates as a Johnson counter, where each clock pulse shifts the high logic state to the next output pin. This creates a sequence where only one output is high at any given time, and the sequence repeats after 8 clock cycles.

• Clock Input: The counter increments with each rising edge of the clock signal.
• Reset: When the reset pin is activated, the counter clears all outputs and starts from the initial state (Q0).
• Clock Inhibit: Pauses the counting process when held high.
• Carry Out: Used to cascade multiple counters for extended counting sequences.

Example Circuit

• LED Chaser: Connect 8 LEDs to the outputs Q0 to Q7, and the clock input to a pulse-generating circuit. As the counter increments, the LEDs will light up one after the other in a chasing pattern.
• Frequency Divider: Use the Q3 output to divide the input frequency by 8, which can then be used in timing applications.

Advantages

• Low Power Operation: Ideal for battery-powered devices due to its low power consumption.
• Wide Voltage Range: Compatible with various supply voltages, making it versatile in different circuit designs.
• High Reliability: CMOS design provides high noise immunity, ensuring stable performance in various environments.
• Sequential Output: Perfect for applications requiring sequential counting or timing.

Conclusion

The IC 4022 is a robust and versatile 8-stage Johnson counter that is ideal for a variety of digital applications, including frequency division, LED sequencing, and event counting. Its low power consumption, wide operating voltage range, and high noise immunity make it an excellent choice for both educational projects and professional designs. Whether you need to create a simple LED chaser or a more complex digital counter, the IC 4022 provides reliable performance and ease of use.

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