Si5351A/B/C

5.2. Si5351 Application Examples

The Si5351 is a versatile clock generator which serves a wide variety of applications. The following examples show how it can be used to replace crystals, crystal oscillators, VCXOs, and PLLs.

5.3. Replacing Crystals and Crystal Oscillators

Using an inexpensive external crystal, the Si5351A can generate up to 8 different free-running clock frequencies for replacing crystals and crystal oscillators. A 3-output version packaged in a small 10-MSOP is also available for applications that require fewer clocks. An example is shown in Figure 13.

27 MHz

XA

 

Multi

CLK0

125 MHz

Ethernet

 

 

Synth

 

 

PHY

OSC

PLL

0

 

 

CLK1

 

 

Multi

 

 

XB

 

48 MHz

USB

 

 

Synth

 

 

Controller

 

 

1

 

 

 

 

 

 

 

 

 

Multi

CLK2

28.322 MHz

HDMI

 

 

Synth

 

 

 

 

 

Port

 

 

2

CLK3

 

 

 

Multi

74.25 MHz

 

 

 

Synth

 

 

 

 

 

3

CLK4

 

 

 

 

Multi

74.25/1.001 MHz

 

 

 

Synth

 

 

 

 

 

4

CLK5

 

Video/Audio

 

 

Multi

24.576 MHz

Processor

 

 

Synth

 

 

 

 

 

5

 

 

 

 

 

Multi

CLK6

22.5792 MHz

 

 

 

Synth

 

 

 

 

 

6

 

 

 

 

 

Multi

CLK7

33.3333 MHz

CPU

Si5351A

 

Synth

 

 

 

7

 

 

 

 

 

 

 

 

Note: Si5351A replaces crystals, XOs, and PLLs.

Figure 13. Using the Si5351A to Replace Multiple Crystals, Crystal Oscillators, and PLLs

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Silicon Laboratories SI5351A/B/C specifications Si5351 Application Examples, Replacing Crystals and Crystal Oscillators

SI5351A/B/C specifications

Silicon Laboratories SI5351A/B/C is a versatile, low-power clock generator and frequency synthesizer that has gained widespread popularity in various applications, including telecommunications, consumer electronics, and industrial control systems. These devices are primarily designed to provide precise clock frequency generation with low phase noise and jitter, making them ideal for high-performance applications.

One of the standout features of the SI5351 is its ability to generate multiple output frequencies simultaneously. Capable of producing up to three independent programmable outputs, the SI5351A/B/C can generate frequencies ranging from 8 kHz to 160 MHz. With its integrated phase-locked loop (PLL) technology, it achieves excellent frequency stability and accuracy, simplifying the design of frequency-dependent systems.

The device operates under a supply voltage range of 1.8V to 3.6V, allowing it to be used in battery-powered applications without excessive power consumption. The SI5351’s low current draw, typically as low as 25 mA, is especially beneficial in portable devices, extending battery life and enhancing overall efficiency. Furthermore, it features a programmable output driver, which can be set to various drive strengths, ensuring compatibility with a wide array of load requirements.

Configuration and control of the SI5351 are user-friendly, implemented via an I2C interface. This allows for straightforward integration into microcontroller-based designs. Moreover, the device includes an on-chip memory that stores settings, which streamlines the reconfiguration process when power cycling, minimizing setup time for developers.

Another significant advantage of the SI5351A/B/C is its output jitter performance, which is typically below 1 ps, resulting in clean output signals essential for high-speed data communications and precise timing applications. The SI5351’s integration of multiple synthesizer stages contributes to its impressive phase noise characteristics, making it suitable for demanding RF applications.

Additionally, the SI5351 devices offer programmable frequency stepping, allowing users to define custom frequency increments, which is particularly useful in applications requiring precise tuning or modulation. This flexibility, combined with its compact size and simple interface, makes the SI5351A/B/C an ideal choice for engineers seeking a reliable, cost-effective solution for generating clock signals in a myriad of electronic systems.

In summary, Silicon Laboratories SI5351A/B/C provides a robust, low-power solution for high-precision clock generation, characterized by its programmable outputs, low jitter, easy configurability, and broad frequency range, making it an excellent choice for both commercial and industrial applications across various sectors.