CJMCU-5351 Si5351A Programmable Clock Generator Module 8 kHz–160 MHz Arduino I2C

The CJMCU-5351 Clock Generator Module uses the Si5351A chip from Silicon Labs, providing a highly flexible and stable clock source for your electronics projects. Perfect for Arduino, ESP32, Raspberry Pi, and radio applications such as SDR (Software-Defined Radio), test equipment, or frequency synthesis.

1. Generate precise RF and clock signals with the CJMCU-5351 Si5351A module — programmable 8 kHz–160 MHz via I²C, ideal for Arduino, ESP32, and SDR projects.

2. CJMCU-5351 Si5351A programmable clock generator with 3 outputs, 25 MHz crystal, and I2C control for Arduino, Raspberry Pi, and RF applications.

3. Compact Si5351A clock generator board for Arduino, ESP32, and STM32 — generate stable frequencies up to 160 MHz for SDR, RF, and test equipment.

4. CJMCU-5351 module with Si5351A chip provides precise multi-output clock generation — ideal for microcontroller, radio, and frequency synthesis projects.

5. Versatile Si5351A clock generator by CJMCU — programmable 3-output I²C module for Arduino, ESP8266, Raspberry Pi, SDR, and RF signal projects.

🔧 Features

• Si5351A programmable clock generator IC with 25 MHz crystal reference.
• Three independent clock outputs (CLK0, CLK1, CLK2).
• Wide frequency range: 8 kHz – 160 MHz.
• I²C interface compatible with Arduino, ESP8266, ESP32, STM32, and Raspberry Pi.
• Selectable 3.3V / 5V operation.
• Compact CJMCU PCB design with clearly labeled pins.

📊 Specifications

Parameter	Specification
IC	Si5351A (Silicon Labs)
Frequency Range	8 kHz – 160 MHz
Outputs	3 (CLK0, CLK1, CLK2)
Interface	I²C (SDA, SCL)
Supply Voltage	3.3V – 5V DC
Reference Crystal	25 MHz
Board Size	25 × 25 × 4 mm

💡 Applications

• RF signal generation and frequency synthesis
• Software-defined radio (SDR) projects
• Test and measurement equipment
• Clock reference for microcontrollers and ADC/DAC systems
• Frequency generation for communication systems

🧩 Compatibility

Fully compatible with Arduino, ESP8266, ESP32, STM32, Raspberry Pi, Teensy, and other I²C microcontrollers. Works seamlessly with the Adafruit Si5351 Arduino library.

🧱 Example Wiring

Arduino 5V  →  VCC
Arduino GND →  GND
Arduino A4  →  SDA
Arduino A5  →  SCL

⚙️ Example Arduino Code

#include <Wire.h>
#include <Adafruit_Si5351.h>

// Create Si5351 object
Adafruit_Si5351 clockgen = Adafruit_Si5351();

void setup() {
  Serial.begin(9600);
  Serial.println("Initializing Si5351...");

  // Initialize the clock generator
  if (clockgen.begin() == false) {
    Serial.println("Si5351 not found!");
    while (1);
  }

  // Example 1: Set output 0 to 10 MHz
  clockgen.setupPLLInt(SI5351_PLL_A, 32); // Configure PLL A multiplier
  clockgen.setupMultisynth(0, SI5351_PLL_A, 40, 0, 1); // 25MHz * (32/40) = 20 MHz
  clockgen.setupMultisynth(1, SI5351_PLL_A, 80, 0, 1); // 10 MHz
  clockgen.setupMultisynth(2, SI5351_PLL_A, 125, 0, 1); // 6.4 MHz
  clockgen.enableOutputs(true);

  Serial.println("Clock outputs enabled:");
  Serial.println("CLK0: 20 MHz, CLK1: 10 MHz, CLK2: 6.4 MHz");
}

void loop() {
  // Your code here
}

Notes

• Install Adafruit_Si5351 library via Arduino Library Manager.

• Each of the three outputs (CLK0, CLK1, CLK2) can be set to a different frequency.

• Supply voltage can be 3.3 V or 5 V, depending on your board.

• The I²C address is 0x60 by default.

📦 Package Includes

• 1 × CJMCU-5351 Si5351A Clock Generator Module

🚚 Shipping & Support

• Fast dispatch within 1–2 business days.
• Worldwide shipping with tracking available.

🧾 Warranty

Returns and replacements accepted 

© 2025 — CJMCU-5351 Clock Generator Module Listing. All specifications are for reference only.