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

Skyworks Solutions Inc. SI5351A-B04891-GTR

Name: SI5351A-B04891-GTR
Brand: Skyworks Solutions Inc.
SKU: SI5351A-B04891-GTR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SI5351A-B04891-GTR

Manufacturer:: Skyworks Solutions Inc.

Category:: Clock Generators, PLLs, Frequency Synthesizers

Package:: -

Datasheet:: SI5351A-B04891-GTR.pdf

Description:: I2C PROG, ANY FREQUENCY, ANY OUT

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Product details

Overview

SI5351A-B04891-GTR from Skyworks Solutions is an I²C-programmable, 8-output CMOS clock generator with integrated VCXO, generating free-running and synchronous clocks from 2.5 kHz to 200 MHz per output with 0 ppm frequency error. It operates from a 25 or 27 MHz crystal, supports independent 1.8/2.5/3.3 V output supplies, and delivers <70 ps pk-pk period jitter (typ) in the 20-QFN package. It replaces crystals, XO, VCXO, and PLL-based clock trees in compact embedded timing systems.

For engineers reviewing the SI5351A-B04891-GTR datasheet, SI5351A-B04891-GTR pinout, SI5351A-B04891-GTR application, or SI5351A-B04891-GTR equivalent, this device enables precise multi-domain clock synthesis with I²C reconfiguration, spread-spectrum control per output, static phase offset, and glitchless frequency transitions-critical for audio/video equipment, networking hardware, and residential gateways requiring stable, low-jitter timing.

Technical Context

The SI5351A-B04891-GTR implements a dual-PLL architecture: PLL A accepts the internal 25/27 MHz crystal oscillator, while PLL B (VCXO-enabled) allows voltage-controlled tuning across ±240 ppm (configurable). Each PLL feeds eight independent MultiSynth fractional dividers, enabling non-integer-related frequencies on all outputs simultaneously.

Its input stage supports crystal-only reference (no CLKIN or VC), and its output stage provides per-pin drive strength, rise/fall time control, and HCSL-compatible swing. The device uses separate VDD (2.5/3.3 V) and VDDO (1.8/2.5/3.3 V) rails, with excellent PSRR eliminating external filtering, and supports power-up times as low as 0.5 ms in PLL bypass mode.

Key Specifications

Parameter	Value and Actual Design Meaning
Output count	8 independent CMOS clock outputs (CLK0–CLK7)
Frequency range	2.5 kHz to 200 MHz per output; only two unique frequencies >112.5 MHz allowed simultaneously
Frequency accuracy	0 ppm error at each output via fractional MultiSynth synthesis
Period jitter	<70 ps pk-pk (typ), measured over 10K cycles at default high drive strength
Supply configuration	Core VDD: 2.25–3.6 V; per-output VDDO: 1.71–3.6 V (independent rail selection)
Control interface	I²C (Standard/Fast Mode: 100/400 kbps); no pin-strapping; register-based configuration
Crystal reference	25 or 27 MHz AT-cut crystal only; internal load capacitance selectable (0/6/8/10 pF)

Pinout & Package

SI5351A-B04891-GTR is housed in a 20-pin QFN (4 mm × 4 mm, 0.5 mm pitch) with exposed thermal pad. Pin functions are validated per Skyworks Si5351A 20-pin QFN specification (Rev. 1.3, Section 10.1).

Pin/Terminal	Circuit Role	Design Meaning
XA, XB	Crystal oscillator inputs	Accept 25/27 MHz fundamental-mode AT-cut crystal; internal load caps configurable
SCL, SDA	I²C serial interface	Standard-mode (100 kbps) or fast-mode (400 kbps) bidirectional control bus
OEB	Output enable bar	Active-low global output disable; asynchronous, glitch-free assertion
VDD, VDDOA–VDDOD	Power supply pins	VDD = core logic (2.25–3.6 V); VDDOA–D = independent output buffer rails (1.71–3.6 V each)
CLK0–CLK7	Differential-capable CMOS outputs	Configurable drive strength, rise/fall time, and spread spectrum per output
GND, EPAD	Ground and thermal pad	EPAD must be soldered to PCB ground plane for thermal performance (θJA = 41°C/W on 4-layer board)

Key Features

Feature	Design Value
8-output I²C-programmable clock generation	Enables single-chip replacement of multiple discrete XOs, VCXOs, and fanout buffers in space-constrained designs
0 ppm frequency error per output	Eliminates cumulative timing drift across domains; avoids manual calibration or trimming
Per-output spread spectrum control	Reduces EMI peak emissions by up to –2.5% down-spread or ±1.5% center-spread without affecting system timing margins
Glitchless frequency transitions	Ensures uninterrupted clock delivery during dynamic reconfiguration-critical for live audio/video and network packet timing
Static phase offset programmability	Allows precise inter-output skew alignment (333 ps/step resolution) for DDR, SerDes, or ADC/DAC synchronization
Independent VDDO rails	Supports mixed-voltage SoC interfaces (e.g., 1.8 V FPGA I/O + 3.3 V MCU) without level shifters or external regulators

Applications

Audio/Video Timing	Networking Hardware
Use Scenario: Generating synchronized pixel clocks (74.25 MHz), audio sample clocks (24.576 MHz), and HDMI TMDS clocks (125 MHz) in a single-board media processor. IC Role / Device Role / Timing Role: Centralized, multi-frequency clock source replacing four discrete oscillators and reducing board area by >60%. Use Value: Eliminates inter-clock skew-induced video artifacts and ensures frame-accurate audio-video lip sync via programmable phase offsets.	Use Scenario: Providing PCIe Gen1 reference (100 MHz), Ethernet PHY clocks (25/125 MHz), and management controller clocks (33.333 MHz) in a residential gateway. IC Role / Device Role / Timing Role: Single-chip timing solution meeting PCIe Gen1 jitter compliance (<1.5 ps RMS) and IEEE 802.3 requirements. Use Value: Reduces bill-of-materials cost and layout complexity while maintaining <70 ps pk-pk jitter across all outputs under full load.
Industrial Instrumentation	Laser Range Finder
Use Scenario: Delivering precise trigger clocks (10–50 MHz), ADC sampling clocks (48 MHz), and display refresh clocks (60 Hz) in handheld test equipment. IC Role / Device Role / Timing Role: Low-power, reconfigurable clock engine supporting battery-operated operation and firmware-upgradable timing profiles. Use Value: Enables field-upgradable clock plans without hardware change; 27 mA typical current draw with 8 outputs active at 3.3 V.	Use Scenario: Generating high-stability time-of-flight measurement clocks (125 MHz) and analog front-end sampling clocks (28.322 MHz) in pulsed laser distance sensors. IC Role / Device Role / Timing Role: Ultra-low-jitter clock source ensuring sub-nanosecond timing resolution for cm-level distance accuracy. Use Value: Achieves <40 ps pk-pk period jitter (typ) at 125 MHz-directly improving time-of-flight measurement precision.

Audio/Video Timing

Networking Hardware

Use Scenario: Generating synchronized pixel clocks (74.25 MHz), audio sample clocks (24.576 MHz), and HDMI TMDS clocks (125 MHz) in a single-board media processor.

IC Role / Device Role / Timing Role: Centralized, multi-frequency clock source replacing four discrete oscillators and reducing board area by >60%.

Use Value: Eliminates inter-clock skew-induced video artifacts and ensures frame-accurate audio-video lip sync via programmable phase offsets.

Use Scenario: Providing PCIe Gen1 reference (100 MHz), Ethernet PHY clocks (25/125 MHz), and management controller clocks (33.333 MHz) in a residential gateway.

IC Role / Device Role / Timing Role: Single-chip timing solution meeting PCIe Gen1 jitter compliance (<1.5 ps RMS) and IEEE 802.3 requirements.

Use Value: Reduces bill-of-materials cost and layout complexity while maintaining <70 ps pk-pk jitter across all outputs under full load.

Industrial Instrumentation

Laser Range Finder

Use Scenario: Delivering precise trigger clocks (10–50 MHz), ADC sampling clocks (48 MHz), and display refresh clocks (60 Hz) in handheld test equipment.

IC Role / Device Role / Timing Role: Low-power, reconfigurable clock engine supporting battery-operated operation and firmware-upgradable timing profiles.

Use Value: Enables field-upgradable clock plans without hardware change; 27 mA typical current draw with 8 outputs active at 3.3 V.

Use Scenario: Generating high-stability time-of-flight measurement clocks (125 MHz) and analog front-end sampling clocks (28.322 MHz) in pulsed laser distance sensors.

IC Role / Device Role / Timing Role: Ultra-low-jitter clock source ensuring sub-nanosecond timing resolution for cm-level distance accuracy.

Use Value: Achieves <40 ps pk-pk period jitter (typ) at 125 MHz-directly improving time-of-flight measurement precision.

Equivalent & Alternatives

The following parts are listed as comparable options for similar clock generator applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
Si5351B-B-GM	Includes VCXO with ±240 ppm tuning range; requires VC control voltage input	Required where system-level frequency pulling or jitter reduction via VCXO is needed	Select SI5351A-B04891-GTR when only crystal-referenced free-running clocks are required; choose Si5351B-B-GM if voltage-controlled synchronization is mandatory
Si5351C-B-GM	Supports external CLKIN (10–100 MHz) for synchronous clock generation; no VC pin	Used when design includes a master reference clock (e.g., GPSDO, atomic clock) that must be distributed	Choose SI5351A-B04891-GTR for standalone crystal-based timing; select Si5351C-B-GM only when external reference locking is architecturally required

Compared with Si5351B-B-GM and Si5351C-B-GM, SI5351A-B04891-GTR offers lowest system cost and simplest layout (no VC filter or CLKIN termination), optimized for fixed-frequency, multi-output clock distribution without external references or tuning-ideal for consumer audio/video and embedded gateway applications.

Availability

SI5351A-B04891-GTR is available at Aetrix Electronics and suitable for audio/video equipment, residential gateways, and industrial instrumentation requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for SI5351A-B04891-GTR 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 leader in analog and mixed-signal semiconductors, specializing in RF, timing, and connectivity solutions for wireless infrastructure, automotive, and industrial markets.

The Si5351 family was designed to replace discrete timing components-including crystals, XOs, VCXOs, and PLLs-with a single, software-configurable IC delivering high-frequency flexibility, ultra-low jitter, and minimal board footprint for cost-sensitive embedded systems.

FAQ

What is the maximum number of unique frequencies above 112.5 MHz supported by SI5351A-B04891-GTR?

The SI5351A-B04891-GTR supports only two unique frequencies above 112.5 MHz simultaneously-for example, 125 MHz on CLK0 and 130 MHz on CLK1. Additional outputs above 112.5 MHz must duplicate one of those two frequencies. This limitation arises from internal PLL bandwidth constraints and is explicitly specified in Table 7 of the Skyworks datasheet Rev. 1.3. SI5351A-B04891-GTR does not support three or more distinct high-frequency outputs above 112.5 MHz.

Does SI5351A-B04891-GTR require external load capacitors for the 25/27 MHz crystal?

No, SI5351A-B04891-GTR includes programmable internal load capacitance (0, 6, 8, or 10 pF) and eliminates the need for external crystal load capacitors in most cases. External capacitors ≤2 pF may be added only if using a crystal requiring 12 pF total load-e.g., two 4 pF caps on XA/XB to supplement the internal 10 pF setting. This configuration is validated in Skyworks AN551 and Section 4.1.1 of the SI5351A-B04891-GTR datasheet.

Can SI5351A-B04891-GTR generate spread spectrum clocking on individual outputs?

Yes, SI5351A-B04891-GTR supports per-output spread spectrum control with selectable down-spread (–0.1% to –2.5%) or center-spread (±0.1% to ±1.5%) modulation at 31.5 kHz nominal rate. This feature is configured independently for each CLK0–CLK7 via dedicated registers and requires no external components. Spread spectrum reduces EMI peaks without altering average frequency-verified in Table 5 of the SI5351A-B04891-GTR datasheet.

What is the minimum supply voltage for core logic (VDD) in SI5351A-B04891-GTR?

The minimum core supply voltage (VDD) for SI5351A-B04891-GTR is 2.25 V, with guaranteed operation across –40°C to +85°C ambient temperature. At 2.25 V, the device draws ≤35 mA with all 8 outputs enabled (Table 4). Operation below 2.25 V is outside specification and may result in undefined behavior or failure to lock PLLs. VDD must be stable within ±10% of nominal value during configuration and runtime.

Is SI5351A-B04891-GTR pin-compatible with other Si5351 variants like Si5351B or Si5351C in the 20-QFN package?

Yes, SI5351A-B04891-GTR shares identical 20-QFN pinout and footprint with Si5351B and Si5351C variants (per Section 10.1–10.3 of the datasheet), including matching XA/XB, SCL/SDA, OEB, VDD, VDDOA–D, CLK0–CLK7, and GND/EPAD assignments. However, functional differences exist: SI5351A lacks VC and CLKIN pins (they are NC), while Si5351B and Si5351C expose those pins for VCXO or external reference use. PCBs designed for SI5351A-B04891-GTR can accept Si5351B/C with firmware updates but not vice versa without signal routing changes.

SI5351A-B04891-GTR Specifications

Product attributes: Attribute value

Manufacturer:: Skyworks Solutions Inc.

Series:: *

Package/Case:: -

Packaging:: Tape & Reel (TR)

Product Status:: Active

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:: -

SI5351A-B04891-GTR FAQ

1.How can I place an order for SI5351A-B04891-GTR through Aetrix?

Please submit a Request for Quotation (RFQ) for SI5351A-B04891-GTR 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 SI5351A-B04891-GTR reliable?

The price and inventory of SI5351A-B04891-GTR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SI5351A-B04891-GTR is usually 5 days.

3.What payment methods are accepted for SI5351A-B04891-GTR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SI5351A-B04891-GTR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SI5351A-B04891-GTR?

SI5351A-B04891-GTR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SI5351A-B04891-GTR 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 SI5351A-B04891-GTR?

For technical support, including SI5351A-B04891-GTR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SI5351A-B04891-GTR requirements.

6.How does Aetrix verify that SI5351A-B04891-GTR is sourced from the original manufacturer or authorized distributors?

All SI5351A-B04891-GTR 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 SI5351A-B04891-GTR meets industry standards.

7.What is the process for return or replacement of SI5351A-B04891-GTR?

All SI5351A-B04891-GTR units undergo pre-shipment inspection (PSI). If there is an issue with SI5351A-B04891-GTR, 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 SI5351A-B04891-GTR part is unused and in its original packaging.

Return procedure for SI5351A-B04891-GTR:

1.Submit a request within 90 days.

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

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