How to Use x9c104: Examples, Pinouts, and Specs

The X9C104 is a digital potentiometer manufactured in China, designed to provide variable resistance control through a digital interface. With a resistance range of 100kΩ, it is a versatile component suitable for a variety of applications. The X9C104 allows precise adjustment of resistance values, making it ideal for use in volume control, signal conditioning, sensor calibration, and other applications requiring fine-tuned resistance settings.

• Audio volume control
• Signal conditioning in analog circuits
• Sensor calibration and tuning
• Adjustable gain in amplifiers
• Programmable resistor networks

The X9C104 is a 100kΩ digital potentiometer with 100 wiper positions, allowing for fine-grained resistance adjustments. It operates via a simple digital interface, making it easy to integrate into microcontroller-based systems.

The X9C104 is an 8-pin device. The table below describes each pin:

The X9C104 is straightforward to use in a circuit. It requires a digital control signal to adjust the resistance between its terminals. Below are the steps and considerations for using the X9C104:

1. Power Supply: Connect the Vcc pin to a 2.7V to 5.5V power source and the Vss pin to ground.
2. Resistor Terminals: Connect Vh to the high end of the resistor network, Vl to the low end, and Vw to the adjustable wiper output.
3. Control Pins:
   • Connect the CS pin to a digital output pin of a microcontroller.
   • Connect the INC pin to another digital output pin for toggling the wiper position.
   • Connect the U/D pin to a digital output pin to set the direction of wiper movement.

• The CS pin must be pulled low to enable the device. When CS is high, the device is inactive.
• The INC pin must be toggled (high to low) to adjust the wiper position. The U/D pin determines whether the wiper moves up or down.
• The wiper position is non-volatile, meaning it retains its position even after power is removed.

Below is an example of how to control the X9C104 using an Arduino UNO:

// Define pin connections for the X9C104
const int CS_PIN = 10;  // Chip Select pin
const int INC_PIN = 9;  // Increment pin
const int UD_PIN = 8;   // Up/Down pin

void setup() {
  // Set pin modes
  pinMode(CS_PIN, OUTPUT);
  pinMode(INC_PIN, OUTPUT);
  pinMode(UD_PIN, OUTPUT);

  // Initialize pins
  digitalWrite(CS_PIN, HIGH);  // Disable the device initially
  digitalWrite(INC_PIN, HIGH); // Set INC to high
  digitalWrite(UD_PIN, LOW);   // Set direction to down
}

void loop() {
  // Example: Increase resistance by 10 steps
  digitalWrite(CS_PIN, LOW);  // Enable the device
  digitalWrite(UD_PIN, HIGH); // Set direction to up

  for (int i = 0; i < 10; i++) {
    digitalWrite(INC_PIN, LOW);  // Toggle INC pin
    delay(1);                    // Short delay
    digitalWrite(INC_PIN, HIGH); // Complete the toggle
    delay(1);                    // Short delay
  }

  digitalWrite(CS_PIN, HIGH); // Disable the device
  delay(1000);                // Wait for 1 second

  // Example: Decrease resistance by 5 steps
  digitalWrite(CS_PIN, LOW);  // Enable the device
  digitalWrite(UD_PIN, LOW);  // Set direction to down

  for (int i = 0; i < 5; i++) {
    digitalWrite(INC_PIN, LOW);  // Toggle INC pin
    delay(1);                    // Short delay
    digitalWrite(INC_PIN, HIGH); // Complete the toggle
    delay(1);                    // Short delay
  }

  digitalWrite(CS_PIN, HIGH); // Disable the device
  delay(1000);                // Wait for 1 second
}

• Use decoupling capacitors (e.g., 0.1µF) near the Vcc pin to stabilize the power supply.
• Avoid toggling the INC pin too quickly; ensure a minimum pulse width of 1µs.
• Ensure the CS pin is high when not adjusting the wiper to prevent unintended changes.

1. Wiper Position Not Changing:

   • Ensure the CS pin is pulled low during adjustments.
   • Verify that the INC pin is toggled correctly with sufficient delay.

2. Incorrect Resistance Output:

   • Check the connections to Vh, Vl, and Vw.
   • Ensure the U/D pin is set to the correct direction.

3. Device Not Responding:

   • Verify the power supply voltage is within the specified range (2.7V to 5.5V).
   • Check for loose or incorrect connections.

Q: Can the X9C104 retain its wiper position after power is removed?
A: Yes, the X9C104 has non-volatile memory and retains its wiper position even after power is disconnected.

Q: What is the maximum current the wiper can handle?
A: The wiper can handle a maximum current of 1mA. Exceeding this limit may damage the device.

Q: Can I use the X9C104 with a 3.3V microcontroller?
A: Yes, the X9C104 operates within a supply voltage range of 2.7V to 5.5V, making it compatible with 3.3V systems.

Q: How precise is the resistance adjustment?
A: The X9C104 provides 100 discrete wiper positions, allowing for fine-grained resistance adjustments.