DC 3V-5V CJMCU-5351 Si5351A Si5351 I2C Clock Signal Generator Breakout Board

Si5351A I2C Clock Signal Generator Module — DC 3V to 5V (CJMCU-5351)

The Si5351A is a programmable clock generator that produces up to three independent square-wave outputs simultaneously, each configurable from 8kHz to 160MHz over I2C. A single 25MHz crystal reference generates all outputs through fractional PLL synthesis, and frequency resolution reaches below 1 Hz at lower frequencies. This makes it the standard choice for software-defined radio (SDR) VFO generators, function generator modules, and multi-clock test setups where a fixed crystal oscillator is too inflexible.

• 3 independent clock outputs — CLK0, CLK1, CLK2
• 8kHz to 160MHz output range — per channel
• Sub-Hz frequency resolution — fractional PLL synthesis
• I2C control — address 0x60, programmed with Si5351 library
• 3V–5V supply — direct Arduino and ESP32 connection

How do you control the Si5351A from Arduino?

The Etherkit Si5351 Arduino library (available in Library Manager) handles all register programming. Calling si5351.set_freq(14074000ULL * 100ULL, SI5351_CLK0) sets CLK0 to 14.074MHz (the 20m FT8 frequency) in one line. Frequency is specified in hundredths of Hz for maximum resolution.

Best for

Software-defined radio VFO generators, QRP amateur radio transceivers, function generator builds, clock distribution for multi-ADC systems, audio test oscillators, and anywhere three programmable clock sources are needed without multiple discrete oscillators.

Why Kunkune

Shipped from UK stock. 60-day returns, no minimum order. Fast Royal Mail delivery.

Buying in bulk? For orders of 10+ units, contact us for trade pricing.