Part Number: SI5351A-B-GMR

Manufacturer: Skyworks Solutions Inc


Shipped from: Shenzhen/HK Warehouse

Stock Available: Check with us

Technical Specifications of SI5351A-B-GMR

Datasheet  SI5351A-B-GMR datasheet
Category Integrated Circuits (ICs)
Family Clock/Timing – Clock Generators, PLLs, Frequency Synthesizers
Manufacturer Silicon Labs
Series MultiSynth?
Packaging Tape & Reel (TR)
Part Status Active
Type Clock Generator
Input Crystal
Number of Circuits 1
Ratio – Input:Output 1:8
Differential – Input:Output No/No
Frequency – Max 200MHz
Divider/Multiplier Yes/No
Voltage – Supply 1.71 V ~ 3.6 V
Operating Temperature -40°C ~ 85°C
Mounting Type Surface Mount
Package / Case 20-VFQFN Exposed Pad
Supplier Device Package 20-QFN (4×4)


Unlocking Configurable Clock Generation with Si5351A-B-GMR

Clock generation is revolutionized by the Si5351A-B-GMR series, which provides a flexible and affordable option. These devices take the place of crystals, crystal oscillators, VCXOs, PLLs, and fanout buffers because precise timing is essential in electronic systems.

Si5351A-B-GMR produces precise clock signals up to 200 MHz with 0 ppm error by utilizing cutting-edge PLL/VCXO and MultiSynth fractional divider architecture. By providing flexibility through internal oscillator or VCXO options, it does not require pricey specialized components.

The quicker time-to-market and simplified design processes are advantageous to engineers, enthusiasts, and amateurs. Numerous applications, including those involving microcontrollers, communication systems, test apparatus, industrial automation, and more, are catered for by Si5351A-B-GMR.

This detailed article explains the Si5351A-B-GMR’s characteristics, specifications, uses, and programming. Elevate your electronic projects by utilizing the Si5351A-B-GMR’s customizable clock generation power. Let’s get going!

Understanding the Si5351A-B-GMR Series

Overview of Si5351A, Si5351B, and Si5351C

The Si5351A, Si5351B, and Si5351C models make up the Si5351A-B-GMR series. Due to their performance and adaptability, these devices are frequently utilized in clock generation applications.

The Si5351A model uses an internal oscillator to produce up to eight independent clocks. It is mainly intended to replace crystals and crystal oscillators, providing a practical answer for uses requiring numerous clock outputs.

Si5351B: Adding an inbuilt VCXO (Voltage-Controlled Crystal Oscillator) to Si5351A’s features. By allowing the replacement of both synchronous and free-running clocks, it offers more flexibility. Si5351B ensures dependable operation across a broad tuning range while doing away with the requirement for pricey specialized pullable crystals.

Si5351C: Si5351C has the same degree of flexibility as Si5351B but adds the capacity to synchronize with an external reference clock (CLKIN). Si5351C permits clock synchronization by using an external reference, making it appropriate for applications where accurate timing alignment is required.

Differences and Features of Si5351A, Si5351B, and Si5351C

Si5351A, Si5351B, and Si5351C have distinct features and capabilities tailored to different requirements:


  • Generates up to eight free-running clocks using an internal oscillator.
  • Ideal for replacing crystals and crystal oscillators in cost-sensitive applications.
  • Offers reliable operation and cost savings.


  • Incorporates an internal VCXO for enhanced clock generation capabilities.
  • Replaces both free-running and synchronous clocks.
  • Eliminates the need for custom pullable crystals, ensuring reliable operation over a wide tuning range.


  • Synchronizes to an external reference clock (CLKIN) for precise clock alignment.
  • Provides flexibility in applications where synchronization is critical.
  • Offers the same capabilities as Si5351B but with external reference compatibility.

Architecture of the Si5351 Series and Configurable Clock Generation

With a PLL/VCXO and MultiSynth fractional divider as part of its complex architecture, the Si5351 series uses these features. With this architecture, clock creation is precise and customizable.

While the VCXO (Voltage-Controlled Crystal Oscillator) fine-tunes the output frequency, the PLL (Phase-Locked Loop) latches onto the target frequency. The MultiSynth fractional divider divides the frequency even further, enabling flexible generation of different clock frequencies with fine-grained control.

The Si5351 series’ architecture provides several benefits:

  • Flexibility: Users can configure the clock generation parameters to meet specific requirements.
  • Precision: The PLL/VCXO and MultiSynth fractional divider architecture ensures accurate frequency generation with minimal error.
  • Ease of Use: The devices offer straightforward programming interfaces for easy configuration and control.

By understanding the Si5351A-B-GMR series and its architecture, users can harness the full potential of these devices in various applications requiring configurable and precise clock signals.

Key Features and Specifications of the Si5351A-B-GMR Series

Advanced Architecture

The PLL/VCXO architecture and MultiSynth fractional divider used by the Si5351A-B-GMR series provide precise and programmable clock generation. This architecture guarantees flexible generation of different clock signals and precise frequency control.

High-Frequency Generation: The Si5351A-B-GMR devices have a remarkable 0 ppm (parts per million) error rate and can generate frequencies up to 200 MHz. They are excellent for a variety of applications that call for precision timing thanks to their high-frequency capacity.

Internal Oscillator, VCXO, and External Reference Clock Options

The Si5351A-B-GMR series offers different options for clock sources.

  • Si5351A: It utilizes an internal oscillator to generate free-running clocks. This eliminates the need for external crystals or oscillators, reducing costs and simplifying designs.
  • Si5351B: In addition to the internal oscillator, it features an internal VCXO. This provides greater flexibility by allowing the replacement of both free-running and synchronous clocks, while still eliminating the need for custom pullable crystals.
  • Si5351C: It can synchronize to an external reference clock (CLKIN). This option enables precise clock alignment and synchronization, which is crucial in applications requiring timing coherence.

Cost-Effectiveness and Versatility

The Si5351A-B-GMR series offers significant cost savings by replacing multiple components like crystals, crystal oscillators, VCXOs, PLLs, and fanout buffers. This cost-effectiveness, coupled with their versatility and programmability, makes them an ideal choice for cost-sensitive projects and applications with diverse timing requirements.

The Si5351A-B-GMR series combines advanced architecture, high-frequency generation, multiple clock source options, and cost-effectiveness. These key features make them a powerful and flexible solution for clock generation, catering to a wide range of applications in the electronics industry.

Replacing Crystals and Crystal Oscillators

Generating Free-Running Clocks with the Internal Oscillator

Si5351A can generate free-running clocks using its internal oscillator. It offers up to eight configurable clock outputs, eliminating the need for external crystals or oscillators.

Advantages of Replacing Crystals and Crystal Oscillators with Si5351A:

  1. Cost-Effective: Si5351A reduces costs by eliminating the need for individual crystals or crystal oscillators.
  2. Simplified Design: Integration into a single IC simplifies PCB layout and reduces component count.
  3. Frequency Flexibility: MultiSynth fractional divider enables precise frequency configuration for various system requirements.
  4. Easy Integration: Si5351A’s I2C interface allows seamless communication with microcontrollers and other components.

Use Case Examples for Si5351A

  1. Microcontroller Projects: Suitable for Arduino-based systems, IoT devices, and digital communication systems.
  2. DIY Electronics: Enables projects like digital clocks, frequency synthesizers, and audio/video systems.
  3. Prototyping: Simplifies the prototyping process by providing an integrated clock generation solution.
  4. Education and Learning: Ideal for teaching clock generation concepts and hands-on learning experiences.

Si5351A offers a cost-effective and flexible alternative to crystals and crystal oscillators. It finds applications in various electronic projects, simplifying design and providing accurate clock signals.


In conclusion, the Si5351A-B-GMR series empowers users to replace crystals and crystal oscillators, simplify designs, and achieve precise timing. It provides a cost-effective and versatile approach to configurable clock generation. So, why wait? Contact us at ICRFQ for sourcing and further assistance. And dive into the world of Si5351A-B-GMR and discover the possibilities it holds for your electronic ventures.

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Kevin Chen