CD4066 Quad Bilateral Switch : Pin Configuration & Its Working

CD4066 Quad Bilateral Switch is a CMOS logic integrated circuit that belongs to the CD4000 IC family. This IC includes four analog or digital switches. As the name suggests, these switches are mainly designed to conduct in two directions & they can be controlled separately through their particular control switch.

This type of CMOS IC includes separate control inputs which are available with diode protection. In addition, this IC provides some features like both analog & digital signal transmission and multiplexing. This article discusses an overview of a CD4066 IC and its working with applications.

What is a CD4066 Quad Bilateral Switch?

The CD4066 Quad Bilateral Switch is mainly designed for the multiplexing or transmission of analog otherwise digital signals. This kind of integrated circuit includes four switches where each switch can be controlled separately.

The main benefits of this IC over other switches based on a single channel mainly comprise peak input-signal voltage swings equivalent to the complete voltage supply & more stable on-state impedance on the input-signal range.

As compared to CD406 IC, this IC provides low on-state resistance where the resistance is stable for a complete input signal range. The internal resistance of this IC is 5ohms which is used when you need high efficiency and where weak signals are used.

Pin Configuration

The pin configuration of the CD4066 Quad Bilateral Switch is shown below. This IC mainly includes 14-pins where each pin & its functionality is discussed below.

• Pins 1, 3, 8 & 11 (Input Pins): These are input pins for 4-bilateral switches
• Pins 2, 4, 9 &10 (Output Pins): These are output pins for 4-bilateral switches
• Pins 5, 6, 12 &13 (Control Pins): These are control pins for 4-bilateral switches
• Pin 7 (Ground): This is the GND pin of the integrated circuit
• Pin 14 (Vcc): This pin provides power to the IC

Features & Specifications

The features & specifications of the CD4066 Quad Bilateral Switch include the following.

Quad Bilateral type Switch

• Internal resistance is low
• Operating voltage ranges from 3V to 18V
• Voltage for switching (Max) is 20V
• On-state resistance is 5Ω
• The high output current is -0.4mA
• Control pin maximum voltage at low level is 0.9V
• Control pin min voltage at a high level is 11V
• Available packages are 14-pin GDIP, PDIP & PDSO
• High ON/OFF o/p voltage ratio
• High Linearity
• Very low off-state switch leakage
• Very high control i/p impedance
• Crosstalk is less in between four switches
• 1:1 SPST Configuration
• Four channels
• Bandwidth is 40 MHz
• The range of operating temperature is -55 to 125

The equivalent CD4066 Quad Bilateral Switch is CD4016, CD4068 and an alternative multiplexer IC is 74HC157.

Both the switch ICs like CD4066 & CD4016 are extremely similar because they have the same pin configurations. However, the major difference between these two ICs is; the internal resistance of CD4066 IC is very low like 5Ω as compared to CD4016 IC like 200Ω. So the CD4066 Quad Bilateral Switch is applicable where weak signals are involved otherwise where high efficiency of switching is required.

How to use CD4066 Quad Bilateral Switch/Circuit Diagram?

The working principle of a CD4066 Quad Bilateral Switch is very simple as it includes four switches that are used for switching analog signals with digital control. Once the input-like analog signal is applied to the switch then the input is transmitted to the control input. So this analog signal will be transmitted in the switch from input to output.

This IC is a bilateral switch, so it works in both directions like forward & reverses. In this IC, each switch contains two pins, used as input & output for voltage switching. The Pin-14 of this IC is connected to the positive terminal whereas pin-7 is connected to the GND terminal of the circuit. Once the control input is 1, then the switch terminals will have less impedance in between them so the switch will be in ON condition. Similarly, once the switch input is 0, then it will be in OIFF condition and the terminal will have a High impedance.

The single switch circuit diagram using a CD4066 Quad Bilateral Switch is shown below. This circuit can be built with a switch IC, motor, a battery. In the above example circuit, we connect a dc motor in series with the CD4066 Quad Bilateral Switch. This circuit uses a 12 volts supply from the battery to operate the motor. Here, the voltage ranges from 5V to 18V based on the switch IC range.

When we notice the above circuit diagram, the motor will be turned off once there is no control signal. If we provide high logic control signal toward a control pin in the switch, the motor is turned ON and starts rotating. So, the main function of using this switch is to change the control signal through the power signal. This IC can be used as the 4×1 multiplexer.

Where to use CD4066 Quad Bilateral Switch/Applications?

The applications of CD4066 Quad Bilateral Switch include the following.

• The Bi-directional switch like CD4066 is similar to CD4016 IC, generally used in the applications of multiplexing
• This switch can also be used in signal isolation
• This is a bilateral switch, so used for both analog & digital signals.
• This IC operates from 3V to 18V, however commonly operated at nominal voltages like 5V/10V/15V and can switch up to 20V.
• This IC is used for multiplexing & switching analog and digital signals
• Sample & Hold (S&H) circuits
• Used in Modulators, Demodulators, Choppers, Commutating Switches, Signal Gating, etc
• Used in the dead-band filter
• Transmission gates logic implementation
• Networks switching
• A/D and D/A signals conversion
• Implementation of CMOS logic
• Phase impedance, Gain of analog signal & Digital control of frequency

Please refer to this link to know more about the CD4066 Quad Bilateral Switch Datasheet.

Thus, this IC is a Quad Bilateral Switch, inbuilt with four switches that are controlled separately through a control pin. These types of multiplexer switches will conduct in both the directions like forward and backward to make this IC bilateral. This IC is mainly used for multiplexing different signals which have extremely little internal resistance so used in audio-based applications. Here is a question for you, what are the different multiplexer ICs available?