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Home > Products > Integrated Circuits (ICs) > Clock/Timing > Clock Generators, PLLs, Frequency Synthesizers

Skyworks Solutions Inc. SI5345B-B04959-GMR

Name: SI5345B-B04959-GMR
Brand: Skyworks Solutions Inc.
SKU: SI5345B-B04959-GMR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SI5345B-B04959-GMR

Manufacturer:: Skyworks Solutions Inc.

Category:: Clock Generators, PLLs, Frequency Synthesizers

Package:: -

Datasheet:: SI5345B-B04959-GMR.pdf

Description:: IC CLK MULTIPLIER ATTENUATOR

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Product details

Overview

SI5345B-B04959-GMR from Skyworks is a 10-channel, any-frequency jitter attenuator and clock multiplier IC featuring fourth-generation DSPLL™ and MultiSynth™ technology. It delivers ultra-low 90 fs rms jitter, supports differential input frequencies up to 750 MHz and differential outputs up to 1028 MHz, and operates in free-run, locked, or holdover modes - deployed in ITU-T G.8262-compliant Synchronous Ethernet line cards.

For engineers reviewing the SI5345B-B04959-GMR datasheet, SI5345B-B04959-GMR pinout, SI5345B-B04959-GMR application, or SI5345B-B04959-GMR equivalent, key selection considerations include its programmable jitter attenuation bandwidth (0.1 Hz–4 kHz), support for LVDS/LVPECL/LVCMOS/CML/HCSL output formats, hitless and glitchless input switching, DCO mode with 0.001 ppb step size, and factory-programmable NVM configuration.

Technical Context

The SI5345B-B04959-GMR implements a digitally controlled DSPLL architecture with fractional input dividers (P), fractional MultiSynth output dividers (N), and integer output dividers (R), enabling any-frequency synthesis from any input. Its loop filter is fully integrated on-chip, eliminating external components and noise coupling risks.

It supports three operational modes - freerun (crystal-referenced), locked (phase- and frequency-locked to input), and holdover (averaged historical frequency retention up to 120 s) - with programmable holdover window size and delay, plus ramped holdover exit at user-selectable rates (0.2–40,000 ppm/s).

Key Specifications

Parameter	Value and Actual Design Meaning
Jitter (rms)	90 fs - meets stringent ITU-T G.8262 EEC Option 1/2 requirements for SyncE applications
Input range (diff)	8 kHz–750 MHz - accepts wideband telecom and datacom reference clocks without external conditioning
Output range (diff)	100 Hz–1028 MHz - covers SONET/SDH, OTN, 10/40/100G Ethernet, and broadcast video timing needs
Jitter BW	0.1 Hz–4 kHz - digitally programmable for optimal trade-off between jitter attenuation and transient response
DCO step size	0.001 ppb - enables fine-grained frequency tuning for precision timing and wander compensation
Supply voltages	VDD = 1.8 V ±5%, VDDA = 3.3 V ±5% - supports low-power core logic and high-swing analog clock generation
Temp range	–40 °C to +85 °C - qualified for industrial and telecom infrastructure environments

Pinout & Package

The SI5345B-B04959-GMR is housed in a 64-pin QFN package (9 mm × 9 mm, 0.5 mm pitch) with exposed thermal pad. Pin functions are defined per Skyworks Si5345 64-QFN package outline and pin description table (Rev D datasheet, pages 45–51).

Pin/Terminal	Circuit Role	Design Meaning
IN0–IN3	Differential/single-ended clock inputs	Four configurable inputs supporting automatic/manual switching, gapped clock lock, and hitless transition between fractionally related sources
OUT0–OUT9	Programmable clock outputs	10 independent outputs assignable via crosspoint switch to any MultiSynth; each supports LVDS/LVPECL/LVCMOS/CML/HCSL with programmable amplitude and common-mode voltage
XA/XB	Crytal oscillator terminals	Connects to 25–54 MHz fundamental-mode crystal; internal load caps eliminate need for external capacitors
SCL/SDA or SCLK/MOSI/MISO/CS	I²C or SPI interface	Two-wire or four-wire serial control for register access, NVM programming, and real-time reconfiguration
INTRb	Interrupt output	Open-drain status flag indicating LOS, OOF, LOL, or custom fault conditions per register configuration
RSTb	Hardware reset	Active-low pin triggering full initialization and NVM reload - functionally identical to power-on reset

Key Features

Feature	Design Value
Any-frequency synthesis	Generates arbitrary output frequencies from any input using fractional P/N/R dividers - eliminates need for multiple discrete oscillators
Integrated loop filter	On-die analog loop filter removes external passive components, reducing PCB area and sensitivity to layout-induced noise
Hitless input switching	Preserves phase continuity when switching between fractionally related inputs - critical for hitless protection switching in carrier networks
Programmable holdover	Stores 120 s of historical frequency data and computes final holdover value from user-defined time window - minimizes phase jump during input failure
Glitchless DCO mode	Enables real-time frequency adjustment in 0.001 ppb steps without output interruption - supports precise wander correction in SyncE systems

Applications

OTN Muxponder Timing	SyncE Line Card
Use Scenario: Provides jitter-attenuated, multi-rate clocking for OTN muxponders aggregating 10G/100G client signals into DWDM line-side interfaces. IC Role / Device Role / Timing Role: Jitter attenuator and clock multiplier generating synchronous 155.52 MHz, 622.08 MHz, and 2.488 GHz outputs from a single degraded OC-192 reference. Use Value: Reduces accumulated jitter below ITU-T G.825 limits across cascaded network elements, enabling error-free transport over long-haul fiber.	Use Scenario: Supplies phase-aligned, low-wander clocks to SERDES and PHY layers in Carrier Ethernet line cards compliant with ITU-T G.8262. IC Role / Device Role / Timing Role: Primary timing IC operating in locked mode with automatic input failover and holdover backup using TCXO-referenced stability. Use Value: Maintains EEC Option 2 compliance during input loss events by delivering <±50 ppb frequency accuracy for ≥24 hours in holdover.
Broadcast Video Sync	Test & Measurement Clock Source
Use Scenario: Generates genlock-capable reference clocks (e.g., 27 MHz, 74.25 MHz, 148.5 MHz) for SDI routers, frame synchronizers, and IP media gateways. IC Role / Device Role / Timing Role: Multi-output jitter cleaner synchronizing baseband video processing chains to external tri-level sync or black burst. Use Value: Achieves sub-100 fs rms jitter on all outputs - preserves color fidelity and prevents lip-sync drift in UHD/4K production workflows.	Use Scenario: Serves as programmable clock engine in high-precision signal analyzers, bit-error-rate testers, and arbitrary waveform generators. IC Role / Device Role / Timing Role: Configurable jitter attenuator and frequency synthesizer providing clean, stable, and traceable clock signals across instrument channels. Use Value: Enables <1 ps edge jitter on 1 GHz outputs - essential for validating high-speed serial links (PCIe 5.0, USB4, CEI-112G) with sub-bit-period timing resolution.

OTN Muxponder Timing

SyncE Line Card

Use Scenario: Provides jitter-attenuated, multi-rate clocking for OTN muxponders aggregating 10G/100G client signals into DWDM line-side interfaces.

IC Role / Device Role / Timing Role: Jitter attenuator and clock multiplier generating synchronous 155.52 MHz, 622.08 MHz, and 2.488 GHz outputs from a single degraded OC-192 reference.

Use Value: Reduces accumulated jitter below ITU-T G.825 limits across cascaded network elements, enabling error-free transport over long-haul fiber.

Use Scenario: Supplies phase-aligned, low-wander clocks to SERDES and PHY layers in Carrier Ethernet line cards compliant with ITU-T G.8262.

IC Role / Device Role / Timing Role: Primary timing IC operating in locked mode with automatic input failover and holdover backup using TCXO-referenced stability.

Use Value: Maintains EEC Option 2 compliance during input loss events by delivering <±50 ppb frequency accuracy for ≥24 hours in holdover.

Broadcast Video Sync

Test & Measurement Clock Source

Use Scenario: Generates genlock-capable reference clocks (e.g., 27 MHz, 74.25 MHz, 148.5 MHz) for SDI routers, frame synchronizers, and IP media gateways.

IC Role / Device Role / Timing Role: Multi-output jitter cleaner synchronizing baseband video processing chains to external tri-level sync or black burst.

Use Value: Achieves sub-100 fs rms jitter on all outputs - preserves color fidelity and prevents lip-sync drift in UHD/4K production workflows.

Use Scenario: Serves as programmable clock engine in high-precision signal analyzers, bit-error-rate testers, and arbitrary waveform generators.

IC Role / Device Role / Timing Role: Configurable jitter attenuator and frequency synthesizer providing clean, stable, and traceable clock signals across instrument channels.

Use Value: Enables <1 ps edge jitter on 1 GHz outputs - essential for validating high-speed serial links (PCIe 5.0, USB4, CEI-112G) with sub-bit-period timing resolution.

Equivalent & Alternatives

The following parts are listed as comparable options for similar jitter attenuator applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
Si5345A-D-GM1	Same 10-output 64-QFN package; supports full 0.001–1028 MHz output range with integer+fractional synthesis	Broader frequency coverage required for mixed-rate OTN/SONET systems needing >350 MHz outputs	Select when application requires outputs beyond 350 MHz (e.g., 622.08 MHz, 1.244 Gbps)
LMK04832ISQE/NOPB	TI dual-loop jitter cleaner; 14 outputs, 3.137 GHz max output; higher power, larger 72-QFN package	Higher channel count and RF-grade performance needed for radar test equipment or multi-gigabit ADC/DAC clock trees	Choose when >10 outputs or >1.028 GHz operation is mandatory, and board space/power budget permits

Compared with SI5345B-B04959-GMR, Si5345A-D-GM1 extends usable output bandwidth to 1028 MHz for legacy SONET/SDH compatibility, while LMK04832 offers greater output count and RF capability at the cost of higher complexity and thermal footprint - making SI5345B-B04959-GMR optimal for cost- and space-constrained SyncE and OTN line cards requiring ≤350 MHz outputs.

Availability

SI5345B-B04959-GMR is available at Aetrix Electronics and suitable for OTN muxponders, Synchronous Ethernet line cards, and broadcast video infrastructure requiring stable component supply, long-term lifecycle assurance, and factory-programmed configuration traceability.

Supply support for SI5345B-B04959-GMR includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Skyworks Solutions is a global semiconductor company specializing in analog and mixed-signal connectivity solutions for wireless, broadband, automotive, and industrial markets.

The Si5345 family is designed as high-performance jitter attenuators and clock multipliers targeting telecom infrastructure, enterprise networking, and broadcast systems where ultra-low jitter, multi-output flexibility, and robust holdover operation are critical.

FAQ

What is the maximum differential output frequency supported by the SI5345B-B04959-GMR?

The SI5345B-B04959-GMR supports differential output frequencies up to 1028 MHz. However, this specific variant (B-grade) is factory-configured for a maximum output frequency of 350 MHz, as indicated by the "B" suffix in the ordering guide. This limitation ensures optimized jitter performance and power efficiency for applications such as Synchronous Ethernet and OTN where outputs ≤350 MHz are typical.

Does the SI5345B-B04959-GMR require an external loop filter?

No, the SI5345B-B04959-GMR integrates the entire DSPLL loop filter on-die. This eliminates external passive components, reduces PCB area, and avoids noise coupling paths associated with discrete loop filters - a key differentiator from older PLL-based clock ICs that rely on external RC networks.

Can the SI5345B-B04959-GMR operate without an external crystal?

No - the SI5345B-B04959-GMR requires an external 25–54 MHz fundamental-mode crystal connected to XA/XB pins for freerun and holdover mode stability. While it can accept an external REFCLK instead, the crystal is mandatory for achieving specified 90 fs rms jitter and meeting ITU-T G.8262 EEC compliance in holdover.

How many input clocks can the SI5345B-B04959-GMR monitor simultaneously?

The SI5345B-B04959-GMR has four dedicated input terminals (IN0–IN3), each configurable for differential or LVCMOS signaling. It continuously monitors all four inputs for validity (LOS/OOF) and supports automatic priority-based selection or manual switching - enabling seamless redundancy in carrier-grade timing applications.

Is the SI5345B-B04959-GMR pin-compatible with other Si5345 variants?

Yes - all Si5345 variants, including SI5345B-B04959-GMR, share the same 64-QFN 9×9 mm package and identical pinout per Skyworks' package outline documentation. This allows drop-in replacement across A/B/C/D grades when board layout accommodates the thermal pad and decoupling requirements.

SI5345B-B04959-GMR Specifications

Product attributes: Attribute value

Manufacturer:: Skyworks Solutions Inc.

Series:: *

Package/Case:: -

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Programmable:: Not Verified

Type:: -

PLL:: -

Input:: -

Output:: -

Number of Circuits:: -

Ratio - Input:Output:: -

Differential - Input:Output:: -

Frequency - Max:: -

Divider/Multiplier:: -

Voltage - Supply:: -

Operating Temperature:: -

Mounting Type:: -

Grade:: -

Qualification:: -

Supplier Device Package:: -

SI5345B-B04959-GMR FAQ

1.How can I place an order for SI5345B-B04959-GMR through Aetrix?

Please submit a Request for Quotation (RFQ) for SI5345B-B04959-GMR on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for SI5345B-B04959-GMR reliable?

The price and inventory of SI5345B-B04959-GMR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SI5345B-B04959-GMR is usually 5 days.

3.What payment methods are accepted for SI5345B-B04959-GMR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SI5345B-B04959-GMR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SI5345B-B04959-GMR?

SI5345B-B04959-GMR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SI5345B-B04959-GMR order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for SI5345B-B04959-GMR?

For technical support, including SI5345B-B04959-GMR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SI5345B-B04959-GMR requirements.

6.How does Aetrix verify that SI5345B-B04959-GMR is sourced from the original manufacturer or authorized distributors?

All SI5345B-B04959-GMR products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that SI5345B-B04959-GMR meets industry standards.

7.What is the process for return or replacement of SI5345B-B04959-GMR?

All SI5345B-B04959-GMR units undergo pre-shipment inspection (PSI). If there is an issue with SI5345B-B04959-GMR, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The SI5345B-B04959-GMR part is unused and in its original packaging.

Return procedure for SI5345B-B04959-GMR:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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