How to Use 4046: Examples, Pinouts, and Specs

The CD4046 is a versatile Phase-Locked Loop (PLL) integrated circuit that is widely used in electronic applications requiring frequency control. It consists of a low-power, linear voltage-controlled oscillator (VCO) and two different phase comparators with a common signal input amplifier and a common comparator input. The CD4046 is commonly used for frequency synthesis, modulation, demodulation, and signal conditioning.

• Frequency synthesis and clock generation
• Frequency modulation and demodulation
• Signal conditioning and filtering
• Motor speed control
• Wireless communication systems

• Supply Voltage (Vdd): 3V to 15V
• Input Frequency Range: 1Hz to 10MHz (typical, varies with Vdd)
• Operating Temperature: -55°C to +125°C
• Package: Available in DIP and SOIC packages

1. Power Supply: Connect the Vdd pin to a positive supply voltage within the range of 3V to 15V and the GND pin to the ground.

2. VCO Configuration: Connect an external resistor to the VCO Res pin and an external capacitor to the VCO Cap pin to set the VCO frequency range.

3. Signal Input: Apply the input signal to the SIGin pin. The signal can be buffered by connecting the SIGin pin to the SIGin buffer output pin.

4. Phase Comparator: Choose the appropriate phase comparator (PC1 or PC2) for your application and connect the output of the VCO to the corresponding comparator input pin.

5. Output: The output of the phase comparator can be used to control other parts of your circuit or for further processing.

• Ensure that the power supply voltage does not exceed the maximum rating of 15V.
• Use decoupling capacitors close to the power supply pins to minimize noise.
• Select the VCO components (resistor and capacitor) according to the desired frequency range.
• Avoid placing noise-generating components near the PLL to prevent interference.

• Unstable Output: This can be caused by incorrect VCO component values or insufficient power supply decoupling.
• No Output Signal: Ensure that the INH (Inhibit) pin is not active (low) and that the power supply and ground connections are secure.

• Double-check the VCO component values and replace them if necessary.
• Add or improve decoupling on the power supply lines.
• Verify that the INH pin is not inadvertently being driven high.

Q: Can the CD4046 be used for amplitude modulation (AM)? A: While the CD4046 is primarily designed for frequency modulation (FM), it can be used in AM applications with additional circuitry.

Q: What is the difference between PC1 and PC2? A: PC1 is an exclusive OR (XOR) phase comparator, while PC2 is a more complex phase comparator that provides a zero crossing detector output.

Q: How do I set the VCO frequency? A: The VCO frequency is set by choosing the correct values for the external resistor and capacitor connected to the VCO Res and VCO Cap pins, respectively.

Q: Can the CD4046 be used with an Arduino? A: Yes, the CD4046 can be interfaced with an Arduino for various applications, such as generating clock signals or reading the phase comparator outputs.

// Example code to read the phase comparator output of CD4046 with an Arduino UNO

const int phaseComparatorPin = 2; // Connect to PC1 or PC2 output of CD4046

void setup() {
  pinMode(phaseComparatorPin, INPUT);
  Serial.begin(9600);
}

void loop() {
  int phaseValue = digitalRead(phaseComparatorPin);
  Serial.println(phaseValue); // Print the phase comparator output value
  delay(100); // Simple delay for readability
}

Note: This example assumes that the CD4046 is properly configured and that the phase comparator output is connected to digital pin 2 of the Arduino UNO. The code reads the output of the phase comparator and prints the value to the Serial Monitor.