The CD4051B is a widely used analog multiplexer and demultiplexer IC designed to simplify signal routing in electronic circuits. It allows multiple input signals to be managed efficiently by selecting one channel at a time using digital control. This article will discuss the CD4051B’s basic overview, pin configuration, functional operation, specifications, features, working principle, and comparison with other models.

Catalog

CD4051B Basic

The CD4051B is an 8-channel analog multiplexer and demultiplexer IC designed to switch one of eight input signals to a single output using digital control. It supports both analog and digital signals, offering low ON resistance and very low OFF leakage current for stable performance. With three address pins, it selects channels in a simple binary manner, allowing precise signal routing in compact circuit designs.

This device is an improved and upgraded version of the CD4051, featuring better electrical performance, wider operating voltage range, and enhanced reliability. It operates typically from 3V to 15V and supports bidirectional signal flow, making it more flexible and efficient compared to earlier versions.

If you are interested in purchasing the CD4051B, feel free to contact us for pricing and availability.

Pinout Details of CD4051B

CAD Models of CD4051B

Texas Instrument CD4051BE symbol, footprint and 3d model.

Symbol of CD4051B

Footprint of CD4051B

3D Model of CD4051B

Alternatives & Equivalent Model

• MC14051B

• HCF4051

• CD4051BE

• CD4051BM

• 74HC4051

• SN74LV4051A

• ADG408

• CD4052

• CD4053

• CD4067

CD4051B Functional Block Diagram

The CD4051B functional block diagram shows how the IC selects one signal from eight channels and connects it to a single common output. On the left side, the logic level conversion block adjusts the input control signals (A, B, C, and INH) so they match the internal operating voltage levels. This ensures stable switching even when different voltage levels are used in the system.

At the center, the binary-to-1-of-8 decoder interprets the three address inputs (A, B, and C). Based on their binary combination, it activates only one of the eight internal switches at a time. The INH (inhibit) pin can disable all channels, preventing any signal from passing through.

On the right side, the diagram shows multiple transmission gates (TG) connected to channels 0 to 7. These switches control the signal flow. When a channel is selected, its transmission gate turns ON and connects that channel directly to the common output (COM), while all other channels remain OFF.

Specifications of CD4051B

Features of CD4051B

Wide Signal Range Support

The CD4051B supports a wide range of both digital and analog signal levels, making it flexible for different voltage conditions. It can handle digital signals from 3 V up to 20 V and analog signals up to 20 V peak-to-peak. This wide range allows the device to operate reliably across various system requirements without needing additional level-shifting components.

Low ON Resistance Performance

The device offers low ON resistance, typically around 125 Ω at higher supply voltages. This helps reduce signal loss when a channel is selected, allowing signals to pass through with minimal distortion. As a result, it maintains better signal quality, especially in analog switching conditions.

High OFF Resistance and Low Leakage

When a channel is not selected, the CD4051B provides high OFF resistance with very low leakage current. This prevents unwanted signal flow between channels, ensuring accurate signal isolation. It is especially useful in systems where signal integrity is important.

Logic-Level Conversion Capability

The IC includes built-in logic-level conversion, allowing control signals to operate across a wide voltage range from 3 V to 20 V. This means it can interface easily with different logic families while still controlling higher-voltage analog signals effectively.

Binary Address Decoding

The CD4051B uses an internal binary decoder to select one of the eight channels. With three address inputs, the device can quickly determine which channel to connect to the common output. This simplifies circuit design and reduces the need for external decoding components.

Low Power Consumption

The device has very low quiescent power dissipation, typically around 0.2 µW under standard conditions. This makes it energy-efficient and suitable for systems where power consumption needs to be minimized.

Stable Performance Across Voltages

The CD4051B is tested and characterized at common supply voltages such as 5 V, 10 V, and 15 V. This ensures consistent performance across different operating conditions, giving designers confidence in its reliability.

Low Input Current

The IC features very low input current, typically around 1 µA at higher voltages and even lower at room temperature. This helps reduce loading on the control signals and improves overall efficiency.

Break-Before-Make Switching

The CD4051B uses a break-before-make switching method, which ensures that the current channel is disconnected before a new one is connected. This prevents channel overlap and avoids short circuits or signal interference during switching.

CD4051B Working in Circuit

How the CD4051B is used with a microcontroller to select and read multiple input signals through a single line. The microcontroller provides three control signals (A, B, and C) that act as channel selectors. These signals are sent to the CD4051B, which uses them to choose one of the eight input channels (Ch0 to Ch7). The INH pin is also connected to the microcontroller, allowing it to enable or disable the switching function when needed.

Each channel is connected to a switch input (k0 to k7) with pull-down resistors. These resistors ensure that the inputs remain at a stable LOW level when the switches are open. When a switch is pressed, the corresponding channel receives a HIGH signal from the 3.3 V supply. This creates a clear and stable signal for the CD4051B to process.

Inside the CD4051B, the selected channel is connected to the COM (common) pin through an internal switch. Only one channel is active at a time, based on the binary combination of A, B, and C. The selected signal is then passed to the microcontroller input, allowing it to read multiple signals using a single input pin.

The power connections (VDD, VSS, and VEE) define the operating range of the device. In this circuit, the CD4051B operates with a 3.3 V supply, making it compatible with the microcontroller logic levels. Overall, this setup simplifies wiring and reduces the number of input pins required by allowing multiple signals to be scanned sequentially.

Applications of CD4051B

• Signal multiplexing

• Data acquisition systems

• Sensor signal selection

• Audio signal switching

• Analog signal routing

• Channel selection in measurement systems

• Microcontroller input expansion

• Test and measurement equipment

• Communication signal switching

• Voltage signal selection