How to Use 4066: Examples, Pinouts, and Specs

The CD4066 is a quad bilateral switch integrated circuit, capable of controlling analog and digital signals. This IC is widely used in signal routing, multiplexing, and as an effective method for gaining analog control over digital signals. It is particularly useful in applications where signal paths need to be opened or closed.

• Analog and digital signal switching
• Signal modulation/demodulation
• Multiplexing for data acquisition systems
• Audio signal routing
• Function generator output switching
• Communication circuits

The CD4066 consists of four independent bilateral switches. Each switch is a single-pole, single-throw (SPST) device that can conduct current in either direction when closed.

• Supply Voltage (V_DD): 3V to 18V
• Control Voltage (V_CTL): V_SS to V_DD
• Peak-to-Peak Analog Signal (V_PP): V_SS to V_DD
• On-State Resistance (R_ON): 100 Ohms typical at V_DD = 10V, V_CTL = 5V
• Off-State Leakage Current (I_OFF): ±100nA at V_DD = 10V
• Switching Time (t_ON / t_OFF): 100ns typical at V_DD = 10V

1. Power Supply: Connect V_DD (pin 8) to your positive supply voltage and V_SS (pin 4) to ground.
2. Signal Routing: Connect the analog or digital signal you wish to switch to the IN/OUT pins of the respective switch.
3. Control Signal: Apply a digital control voltage (V_CTL) to the control pin of the switch you want to activate. The switch conducts when V_CTL is high and is non-conducting when V_CTL is low.

• Ensure that the control voltage (V_CTL) is within the specified range to prevent damage.
• The analog signal voltage should not exceed the supply voltage range.
• Minimize the length of the control lines to reduce noise pickup.
• Decouple the power supply with a 0.1µF capacitor close to the V_DD pin to reduce noise.

// Example code to control CD4066 switch with Arduino UNO

const int controlPin1 = 2; // Connect to Control 1 of CD4066

void setup() {
  pinMode(controlPin1, OUTPUT);
}

void switchOn() {
  digitalWrite(controlPin1, HIGH); // Turns on switch 1
}

void switchOff() {
  digitalWrite(controlPin1, LOW); // Turns off switch 1
}

void loop() {
  switchOn();  // Activate the switch
  delay(1000); // Wait for 1 second
  switchOff(); // Deactivate the switch
  delay(1000); // Wait for 1 second
}

• Switch not operating: Ensure that the control voltage is applied correctly and within the specified range.
• Signal distortion: Check if the analog signal voltage exceeds the supply voltage or if there is a high on-state resistance due to a low supply voltage.
• Unexpected signal paths: Verify that no pins are shorted and that the control pins are not floating.

• If the switch does not operate, check the connections and measure the control voltage.
• For signal distortion, ensure that the supply voltage is adequate and that the signal voltage is within the allowed range.
• Prevent unexpected signal paths by ensuring that all control pins are either driven high or low, not left floating.

Q: Can the CD4066 be used with digital signals? A: Yes, the CD4066 can switch digital signals as well as analog signals.

Q: What is the maximum frequency the CD4066 can handle? A: The maximum frequency depends on the signal characteristics and the supply voltage but is typically in the MHz range.

Q: Can I use a single control voltage for all switches? A: Yes, a single control voltage can be used to control multiple switches if they need to be switched simultaneously.

Q: Is there a power-on sequence required for the CD4066? A: No specific power-on sequence is required, but it is good practice to ensure that the control pins are in a known state before the supply voltage is applied.