SI5351A-B06855-GMR

Clock Generators, PLLs, Frequency Synthesizers Overview

The SI5351A-B06855-GMR is a factory preprogrammed I2C programmable clock generator from Skyworks Solutions. It utilizes an internal oscillator with a 25 or 27 MHz crystal reference to generate up to eight independent, non-integer-related CMOS clock frequencies ranging from 2.5 kHz to 200 MHz. The device features 0 ppm frequency synthesis error and supports glitchless frequency changes. It operates on a core supply voltage (VDD) of 2.25 V to 3.6 V and output buffer voltages (VDDO) of 1.71 V to 3.6 V. The component is housed in a 20-QFN package and functions within an ambient temperature range of -40 °C to +85 °C.

Clock Generators, PLLs, Frequency Synthesizers Feature Summary

• Generates multiple free-running clocks using an internal oscillator without requiring external VCXOs.
• Provides exact frequency synthesis at each output with zero parts-per-million error.
• Supports configurable spread spectrum modulation selectable at each individual output.
• Features separate voltage supply pins for core and outputs to facilitate level translation.

Clock Generators, PLLs, Frequency Synthesizers Applications

• Replacing discrete crystals, crystal oscillators, and PLLs in cost-sensitive designs
• Clock generation for networking and communication equipment
• Timing solutions for servers and storage systems
• Clock distribution in audio/video equipment and gaming consoles

Clock Generators, PLLs, Frequency Synthesizers Procurement Notes

Verify the specific factory preprogrammed configuration code associated with the suffix B06855 against the system requirements before integration. Confirm that the 20-QFN footprint matches the PCB layout specifications. Ensure the I2C address settings align with the existing bus topology. Validate that the power supply sequencing meets the startup requirements defined in the datasheet.

Clock Generators, PLLs, Frequency Synthesizers Selection Notes

Select this variant when a fixed, factory-defined clock tree is required rather than field-programmable flexibility. The Si5351A version specifically lacks the VCXO input found in the Si5351B, making it suitable only for free-running applications. Verify that the maximum output frequency and number of active channels meet the design constraints. Consider the thermal resistance characteristics if operating near the upper temperature limits.

Clock Generators, PLLs, Frequency Synthesizers Part Context

This component belongs to the Si5351 family of I2C programmable clock generators. The 'A' designation indicates it uses an internal oscillator for free-running clocks, distinguishing it from the 'B' (VCXO) and 'C' (CLKIN) variants. The 'GMR' suffix denotes tape and reel packaging. This series is designed to replace multiple discrete timing components, simplifying board space and reducing overall bill of materials costs.

Clock Generators, PLLs, Frequency Synthesizers Replacement Considerations

Direct functional replacements include other Si5351 variants such as SI5351A-B-GMR for blank configurations. For applications requiring VCXO support, the SI5351B series is the appropriate alternative. If pin-compatible replacement is needed with different programming, verify register map compatibility. No other manufacturer part numbers are confirmed as direct substitutes in the provided documentation.

Clock Generators, PLLs, Frequency Synthesizers FAQ

What is the difference between the Si5351A and Si5351B versions?

The Si5351A generates free-running clocks using an internal oscillator, while the Si5351B includes an integrated VCXO that allows for synchronous clock generation and frequency pulling via a control voltage input.

Can the SI5351A-B06855-GMR be reprogrammed after purchase?

No, the 'xxxxx' suffix in the part number indicates that this specific device is factory preprogrammed with a custom configuration. Reprogramming requires ordering a blank device (e.g., SI5351A-B-GMR) and configuring it using ClockBuilder Pro software.

What is the maximum output frequency supported by this device?

The device can generate output frequencies up to 200 MHz. However, only two unique frequencies above 112.5 MHz can be simultaneously output on different pins.