SI5351 Signal Square Wave Generator

Never hunt around for another crystal again, with the Si5351A clock generator breakout This chip has a precision 25MHz crystal reference and internal PLL and dividers so it can generate just about any frequency, from <8KHz up to 150+ MHz.

The Si5351A clock generator is an I2C controller clock generator. It uses the onboard precision clock to drive multiple PLL's and clock dividers using I2C instructions. By setting up the PLL and dividers you can create precise and arbitrary frequencies. There are three independent outputs, and each one can have a different frequency. Outputs are 3Vpp, either through a breadboard-friendly header or, for RF work, an optional SMA connector.

We put this handy little chip onto it's own breakout board PCB, with a 3.3V LDO regulator so it can be powered from 3-5VDC. We also put level shifting circuitry on the I2C lines so you can use this chip safely with 3V or 5V logic.

Specification of SI5351 Signal Square Wave Generator:

• The Si5351 is an I2C configurable clock generator that is ideally suited for replacing crystals, crystal oscillators, VCXOs, phase-locked loops (PLLs), and fanout buffers in cost-sensitive applications.
• Based on a PLL/VCXO + high resolution Multisite fractional divider architecture, the Si5351 can generate any frequency up to 160 MHz on each of its outputs with 0 ppm error.
• Three versions of the Si5351 are available to meet a wide variety of applications. The Si5351A generates up to 8 free-running clocks using an internal oscillator for replacing crystals and crystal oscillators.
• The Si5351B adds an internal VCXO and provides the flexibility to replace both free-running clocks and synchronous clocks.
• The Si5351B eliminates the need for higher cost, custom crystals while providing reliable operation over a wide tuning range. The Si5351C offers the same flexibility but synchronizes to an external reference clock (CLKIN)

Features of SI5351 Signal Square Wave Generator:

• Generates up to 8 non-integer-related
• frequencies from 8 kHz to 160 MHz
• I2C user definable configuration
• Exact frequency synthesis at each output (0 ppm error)
• Highly linear VCXO
• Optional clock input (CLKIN)
• Low output period jitter: 100 ps pp
• Configurable spread spectrum selectable at each output
• Operates from a fixed frequency
• crystal: 25 or 27 MHz
• Supports static phase offset
• Programmable rise/fall time control
• Glitch less frequency changes Separate voltage supply pins: Core VDD: 2.5 or 3.3 V Output VDDO: 1.8, 2.5, or 3.3 V

Applications of SI5351 Signal Square Wave Generator:

•  HDTV, DVD/Blu-ray, set-top box
•  Printers, scanners, projectors
• Audio/video equipment, gaming
•  Residential gateways