CD4028 (Binary Decoder/Demultiplexer)

Description

The CD4028 is a BINARY DECODER/DEMULTIPLEXER integrated circuit (IC) from Texas Instruments. It is part of the 4000 series of CMOS (Complementary Metal-Oxide-Semiconductor) logic ICs, which are commonly used in digital electronics due to their low power consumption and wide voltage range.

Key Features of the CD4028:

1. Function:
   • The CD4028 is a BINARY DECODER with Demultiplexer functionality. It converts a 4-bit binary input into a one-out-of-sixteen output.
   • It takes a 4-bit input and selects one of 16 possible output lines to be “active” or “high” based on the binary value at the input.
2. Input/Output:
   • The IC has 4 binary input lines (A, B, C, D) which take a 4-bit binary value.
   • It has 16 output lines (Y0 to Y15), and only one of them will be active (high) at a time, depending on the binary input value.
   • The active output is determined by the binary value applied to the inputs.
   • The output lines are typically active low (i.e., they go to a low voltage when selected).
3. Control Pins:
   • Enable (E): The enable pin (E) allows you to enable or disable the outputs. When the enable pin is low, all outputs are disabled (inactive), and no output is selected.
   • Inhibit (I): This pin is used to inhibit or disable certain outputs selectively when needed.
4. Voltage Range:
   • The CD4028 operates over a wide voltage range of 3V to 15V, which makes it compatible with many logic systems, including TTL (Transistor-Transistor Logic) and CMOS systems.
5. Low Power Consumption:
   • As part of the CMOS family, the CD4028 has low power consumption, which is one of the key benefits of CMOS technology.
6. Package Options:
   • The CD4028 is available in various package types, including DIP (Dual In-Line Package) and SMD (Surface-Mount Device) packages.
7. Temperature Range:
   • The CD4028 is designed to work in a wide temperature range, typically from -55°C to +125°C, making it suitable for industrial and automotive applications.

Pin Configuration of the CD4028 (DIP-16 Package):

Control Pins:

Applications of the CD4028:

1. Digital Decoding:
   • The CD4028 can be used as a binary decoder in digital systems, such as converting 4-bit binary input to a one-hot output that could be used to activate specific components or devices.
2. Multiplexing and Demultiplexing:
   • The CD4028 can also function as a demultiplexer, where it takes a single input signal and directs it to one of many outputs based on the binary value of the input.
3. Memory Addressing:
   • It can be used in memory addressing systems, where the decoder helps select specific memory locations based on the address provided as a 4-bit input.
4. Control Systems:
   • In systems where multiple outputs need to be controlled by a 4-bit input signal (like a microcontroller), the CD4028 can be used to control several devices with a single input.
5. LED Drivers:
   • The decoder functionality can be used to drive LED displays or LED arrays where the 4-bit input represents the address or position of the LED to light up.
6. Digital Circuits:
   • It can be used in digital logic circuits, control systems, and peripheral interface applications, providing a simple way to activate one of many outputs with a small number of input signals.

Example of Operation:

Let’s say you connect the 4-bit binary inputs (A, B, C, D) to a microcontroller that outputs binary numbers from 0000 (0) to 1111 (15). The CD4028 will decode these inputs and activate the corresponding output pin (Y0 to Y15) that matches the binary input.

For example:

• If the binary input is 0001, output Y1 will be active (low).
• If the binary input is 1010, output Y10 will be active (low).

Advantages of the CD4028:

• Low Power Consumption: As a CMOS IC, the CD4028 is designed for low power usage, which is ideal for battery-powered and energy-efficient systems.
• Wide Voltage Range: It operates over a broad voltage range (3V to 15V), making it suitable for many different types of logic circuits.
• Versatility: The IC is useful in a variety of applications, from simple binary decoding to more complex digital signal routing.
• Availability: It is widely available in different package types, making it easy to integrate into your projects.