Features With the breakthrough for Adafruit's Si5351A clock generator, you will never look for another crystal! The chip has an accurate 25MHz crystal reference voltage source and internal for PLL and frequency divider, so it can generate almost any frequency, fr Si5351A clock generator is an I2C controller clock generator. It uses the onboard precision clock to drive multiple PLLs and clock dividers through I2C instructions. By setting for PLL and divider, you can make precise arbitrary frequencies. There are three independent outputs, and each output can have a different frequency. Through a breadboard friendly plug or optional SMA connector, the output is 3Vpp. Such convenient small chip is put on its own breakout board PCB, with 3.3V LDO regulator, so it can be powered by 3-5VDC. We also placed a level shift circuit on the I2C line, so you can safely use the chip under 3V or 5V logic. Most importantly, we even provide excellent tutorials and libraries to help you get started! Our code is designed to work for microcontrollers and IDEs, but it can be easily ported to your favorite platform through I2C support. Specification: Item Type: Signal generator  Package List: 1 x Signal Generator  Package List 1 x Signal Generator