How to Use CD74HC4067: Examples, Pinouts, and Specs

The CD74HC4067 is a versatile 16-channel analog multiplexer/demultiplexer. It features a digital control interface that allows one of 16 inputs to be connected to a single output. This component is widely used in applications requiring multiple analog or digital signals to be routed to a single point, such as in data acquisition systems, signal routing, and sensor multiplexing.

• Data acquisition systems
• Signal routing
• Sensor multiplexing
• Audio signal switching
• Test equipment

1. Power Supply: Connect the Vcc pin to a power supply (2V to 6V) and the GND pin to ground.
2. Control Inputs: Connect the control inputs (S0, S1, S2, S3) to a microcontroller or other digital control circuit to select the desired channel.
3. Enable Input: Connect the EN pin to ground to enable the multiplexer. If the EN pin is high, the multiplexer is disabled.
4. Signal Connections: Connect the desired input signals to the Y0-Y15 pins. The selected input will be routed to the Z pin.

• Ensure that the input voltage on the Y0-Y15 pins does not exceed the supply voltage (Vcc).
• Use decoupling capacitors close to the Vcc pin to reduce noise and improve stability.
• When switching between channels, allow a small delay to ensure the signal has settled before reading the output.

// Example code to use CD74HC4067 with Arduino UNO

const int S0 = 2; // Control pin S0 connected to Arduino pin 2
const int S1 = 3; // Control pin S1 connected to Arduino pin 3
const int S2 = 4; // Control pin S2 connected to Arduino pin 4
const int S3 = 5; // Control pin S3 connected to Arduino pin 5
const int EN = 6; // Enable pin connected to Arduino pin 6
const int Z = A0; // Common output connected to Arduino analog pin A0

void setup() {
  pinMode(S0, OUTPUT);
  pinMode(S1, OUTPUT);
  pinMode(S2, OUTPUT);
  pinMode(S3, OUTPUT);
  pinMode(EN, OUTPUT);
  digitalWrite(EN, LOW); // Enable the multiplexer
  Serial.begin(9600);
}

void loop() {
  for (int channel = 0; channel < 16; channel++) {
    selectChannel(channel);
    int value = analogRead(Z); // Read the value from the selected channel
    Serial.print("Channel ");
    Serial.print(channel);
    Serial.print(": ");
    Serial.println(value);
    delay(500); // Wait for 500ms before reading the next channel
  }
}

void selectChannel(int channel) {
  digitalWrite(S0, channel & 0x01);
  digitalWrite(S1, (channel >> 1) & 0x01);
  digitalWrite(S2, (channel >> 2) & 0x01);
  digitalWrite(S3, (channel >> 3) & 0x01);
}

1. No Signal Output:

   • Ensure the EN pin is connected to ground to enable the multiplexer.
   • Verify that the control inputs (S0, S1, S2, S3) are correctly set to select the desired channel.

2. Incorrect Channel Selection:

   • Check the connections of the control inputs to the microcontroller.
   • Ensure the control signals are correctly set according to the desired channel.

3. Signal Distortion or Noise:

   • Use decoupling capacitors close to the Vcc pin.
   • Ensure the input signals do not exceed the supply voltage (Vcc).

• Verify Connections: Double-check all connections to ensure they are correct and secure.
• Check Power Supply: Ensure the power supply voltage is within the specified range (2V to 6V).
• Use Proper Grounding: Ensure a good ground connection to minimize noise and signal distortion.
• Delay Between Channel Switching: Allow a small delay when switching between channels to ensure the signal has settled before reading the output.

By following these guidelines and best practices, you can effectively use the CD74HC4067 in your projects and applications.