7406 (Hex Inverter with Open-Collector Outputs)

Description

The 7406 is a Hex Inverter with Open-Collector Outputs. It is part of the 7400 series of logic ICs, which are widely used in digital electronics for a variety of logic operations. The 7406 contains six independent inverters (NOT gates), each with an open-collector output. The open-collector output allows the output to be either low (logic 0) or high impedance (no output), and the output will be pulled high by an external pull-up resistor.

7406 IC Description:

The 7406 is specifically a Hex Inverter with open-collector outputs, meaning it inverts the input signal (NOT operation) and provides an open-collector output for each of its six gates. This IC is commonly used in digital systems where the inverted signal is required or when a high-current sink is needed for output devices like LEDs or interfacing with other TTL or CMOS logic.

Key Features:

• Hex Inverter: Contains six independent inverters (NOT gates) in a single IC package.
• Open-Collector Outputs: Each output is an open-collector type, meaning the output can either be low (0V) or high impedance (not driving any voltage). This allows you to interface with different voltage levels or drive high-current loads with the help of an external pull-up resistor.
• High-Speed Operation: The 7406 is designed to provide fast switching times, making it suitable for high-speed digital logic applications.
• Low Power Consumption: As a CMOS IC, it features low power consumption while maintaining the necessary speed for most logic operations.
• Single Supply Operation: The IC typically operates at 5V, but can also function over a voltage range of 4.5V to 5.5V.

Pin Configuration (14-pin package):

Here is the pinout for the 7406:

1. Pin 1 (Output 1): Open-collector output for Inverter 1.
2. Pin 2 (Input 1): Input for Inverter 1.
3. Pin 3 (Output 2): Open-collector output for Inverter 2.
4. Pin 4 (Input 2): Input for Inverter 2.
5. Pin 5 (Output 3): Open-collector output for Inverter 3.
6. Pin 6 (Input 3): Input for Inverter 3.
7. Pin 7 (Ground): Ground (0V).
8. Pin 8 (Output 4): Open-collector output for Inverter 4.
9. Pin 9 (Input 4): Input for Inverter 4.
10. Pin 10 (Output 5): Open-collector output for Inverter 5.
11. Pin 11 (Input 5): Input for Inverter 5.
12. Pin 12 (Output 6): Open-collector output for Inverter 6.
13. Pin 13 (Input 6): Input for Inverter 6.
14. Pin 14 (Vcc): Supply voltage (typically 5V).

How It Works:

1. Inversion:
   • The 7406 provides six inverters (NOT gates). It inverts the input signal: if the input is 0, the output will be 1, and if the input is 1, the output will be 0.
2. Open-Collector Outputs:
   • Each inverter in the 7406 has an open-collector output. This means the output is either low (logic 0) or high-impedance (not actively driving the output).
   • To make use of the high output state, an external pull-up resistor must be connected between the output pin and the supply voltage (typically 5V). When the inverter output is not actively pulling the output low, the pull-up resistor pulls the output high.
3. Interfacing with Other Logic Levels:
   • The open-collector output of the 7406 is particularly useful when interfacing with different logic families (e.g., TTL to CMOS) or when you need to sink current to control output devices like LEDs, motors, or other components.
4. Multiple Inverters:
   • The 7406 provides six independent inverters in a single IC package, meaning it can invert up to six signals. These inverters can be used independently or in combination, depending on the application.

Applications:

1. Driving LEDs:
   • The open-collector output makes the 7406 useful for driving LEDs. The IC can sink current through the LED, and an external pull-up resistor can be used to pull the output high when the transistor inside the IC is not actively pulling it low.
2. Level Shifting:
   • The open-collector outputs allow the 7406 to interface with different voltage levels. It can be used for level shifting between TTL (Transistor-Transistor Logic) and CMOS logic families or other voltage-level logic families.
3. Interfacing with Buses:
   • In open-collector bus systems, multiple devices can share a bus without conflict, as each device can only pull the bus low but cannot drive it high. The bus is pulled high via an external pull-up resistor.
4. Signal Inversion:
   • As with all inverters, the 7406 is useful in digital logic circuits where signal inversion is required. It is often used in timing circuits, clock generation, pulse shaping, or state machine design.
5. Sinking High Current:
   • Because of its open-collector output, the 7406 is capable of sinking relatively high currents compared to standard logic gates, making it useful for controlling high-current devices.
6. Pulse Generation and Timing:
   • The 7406 can be used to create timing circuits or pulse generation circuits, where the inverters generate square waves or act as building blocks in larger timing networks.
7. Logic Interfacing:
   • It is commonly used in logic interfacing between different devices that may not be directly compatible with each other. The open-collector output makes it possible to interface various logic families in a system.

Truth Table:

Electrical Characteristics:

• Supply Voltage (Vcc): Typically 5V (can operate from 4.5V to 5.5V).
• Input Voltage (Vih): Typically 2V for a logical high level.
• Output Voltage (Vol): When the output is low, it typically pulls to 0V.
• High Impedance Output: When the output is not actively driving a low state, it enters a high-impedance state.
• Low Power Consumption: The 7406 features low power consumption due to its CMOS technology, making it suitable for battery-powered applications or low-power systems.