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Home > Products > Integrated Circuits (ICs) > Clock/Timing > Application Specific Clock/Timing

Skyworks Solutions Inc. SI5338A-B04974-GM

Name: SI5338A-B04974-GM
Brand: Skyworks Solutions Inc.
SKU: SI5338A-B04974-GM
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SI5338A-B04974-GM

Manufacturer:: Skyworks Solutions Inc.

Category:: Application Specific Clock/Timing

Package:: 24-VFQFN Exposed Pad

Datasheet:: SI5338A-B04974-GM.pdf

Description:: I2C CONTROL, 4-OUTPUT, ANY FREQU

Quantity:: RFQ Add To RFQ list

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Product details

Overview

SI5338A-B04974-GM from Skyworks Solutions is an I²C-programmable quad clock generator with four independently configurable differential or single-ended outputs, 0.7 ps RMS typical phase jitter, PCIe Gen 1–4 Common Clock and Gen 3 SRNS compliance, and operation from 1.8/2.5/3.3 V core supply in a 4 × 4 mm 24-QFN package. It replaces up to four crystal oscillators in high-speed serial interface timing applications.

For engineers reviewing the SI5338A-B04974-GM datasheet, SI5338A-B04974-GM pinout, SI5338A-B04974-GM application, or SI5338A-B04974-GM equivalent, key selection criteria include PCIe Gen 4 jitter compliance (0.15–0.45 ps RMS), independent output voltage per driver (1.5/1.8/2.5/3.3 V), MultiSynth™ frequency synthesis resolution (1 ppb), spread-spectrum control (0.5–5.0% down-spread), and I²C/SMBus programmability with ClockBuilder Pro support.

Technical Context

The SI5338A-B04974-GM implements a two-stage PLL architecture: a high-stability reference stage (Phase Frequency Detector + Loop Filter + VCO) feeding four independent MultiSynth™ fractional-N synthesis blocks, each driving a configurable output buffer. It supports external crystal (8–30 MHz), CMOS (5–200 MHz), SSTL/HSTL (5–350 MHz), or differential (5–710 MHz) inputs.

Each of the four output drivers supports LVPECL/LVDS/HCSL/CMOS/SSTL/HSTL formats with independent voltage selection (1.5–3.3 V), programmable phase offset (±45 ns, <20 ps step), and glitchless frequency increment/decrement (1 ppm steps). The device includes loss-of-lock and loss-of-signal alarms, external feedback for zero-delay mode, and I²C-based OTP NVM configuration.

Key Specifications

Parameter	Value and Actual Design Meaning
Phase Jitter (RMS)	0.7 ps typical (12 kHz–20 MHz); meets PCIe Gen 4 common clock jitter spec (≤0.45 ps RMS)
Output Count & Flexibility	4 independent outputs: up to 4 differential, 8 single-ended, or mixed; each configurable for format and voltage
Frequency Range	LVPECL/LVDS: 0.16–710 MHz; HCSL: 0.16–250 MHz; CMOS: 0.16–200 MHz; SSTL/HSTL: 0.16–350 MHz
Input Reference Support	Crystal (8–30 MHz), CMOS (5–200 MHz), SSTL/HSTL (5–350 MHz), differential (5–710 MHz)
Supply Voltages	Core: 1.8/2.5/3.3 V ±10%; Output buffers: independently selectable 1.5/1.8/2.5/3.3 V
Package	24-pin QFN, 4 × 4 mm, 0.5 mm pitch, exposed thermal pad
Operating Temperature	–40 °C to +85 °C ambient; qualified for industrial and telecom line card environments

Pinout & Package

The SI5338A-B04974-GM is housed in a 24-lead QFN package (4 × 4 mm, 0.5 mm pitch) with exposed thermal pad. Pin assignments are fixed per Skyworks' Si5338 family layout and validated for this variant.

Pin/Terminal	Circuit Role	Design Meaning
IN1, IN2	Differential input pair #1	Accepts AC-coupled differential reference (5–710 MHz); internal 100 Ω termination enabled
IN3, IN4	Single-ended input pair	Supports CMOS/SSTL/HSTL (5–350 MHz); 20 kΩ pull-up/pull-down configurable via register
CLK0A, CLK0B – CLK3A, CLK3B	Differential output pairs	Four independent LVPECL/LVDS/HCSL/CML outputs; each with dedicated VDDOx supply pin
VDDO0–VDDO3	Output buffer supplies	Independent 1.5/1.8/2.5/3.3 V rails per output driver; enables mixed-voltage system interfacing
SCL, SDA	I²C/SMBus interface	Standard 100/400 kHz operation; supports ClockBuilder Pro programming and runtime reconfiguration
INTR	Interrupt output	Open-drain status flag for loss-of-lock, loss-of-signal, or PLL unlock events
VDD	Core supply	Single 1.8/2.5/3.3 V rail powers PLL, synthesizers, and logic; PSRR optimized for noisy environments
GND / RSVD_GND	Ground terminals	Multiple GND pins and reserved ground pad ensure low-impedance return path and thermal dissipation

Key Features

Feature	Design Value
MultiSynth™ synthesis	Four independent fractional-N synthesizers enabling true zero-ppm accuracy on all outputs simultaneously
PCIe Gen 4 compliance	Validated 0.15–0.45 ps RMS jitter in Common Clock mode; supports SRNS for Gen 3 and CDR lock for Gen 4
Glitchless frequency tuning	Pin- or I²C-controlled frequency increment/decrement in 1 ppm steps without output interruption
Programmable phase alignment	±45 ns phase offset per output with <20 ps resolution; enables precise skew management across multi-lane interfaces
Spread-spectrum clocking	Configurable down-spread (0.5–5.0%) and modulation rate (33–63 kHz) on any output to reduce EMI
Flexible input handling	Five input options (IN1–IN6) supporting crystal, single-ended, and differential references with automatic detection

Applications

PCIe Gen 4 Switch Timing	Ethernet Switch/Routing
Use Scenario: Providing synchronized 100 MHz reference clocks to multiple PCIe Gen 4 switch ASICs in a data center fabric card. IC Role / Device Role / Timing Role: Quad-output clock generator delivering four independent, low-jitter PCIe-compliant clocks with matched phase alignment. Use Value: Enables deterministic lane-to-lane skew control (<100 ps) and meets PCIe Gen 4 total jitter limit (≤33.6 ps pk-pk) without external jitter cleaners.	Use Scenario: Generating 125 MHz, 156.25 MHz, and 312.5 MHz clocks for 1/10/25 GbE PHYs and packet processors in a modular router line card. IC Role / Device Role / Timing Role: Any-frequency clock synthesizer replacing discrete oscillators and translating between Ethernet line rates. Use Value: Reduces BOM count by 4× vs. discrete XO solution while maintaining <0.7 ps RMS jitter required for 25G KR compliance.
Broadcast Video Timing	FPGA/Processor Clocking
Use Scenario: Delivering SMPTE ST 2082 (28.63636 MHz) and ST 2081 (74.25 MHz) reference clocks to video encoder/decoder FPGAs in a 4K/8K broadcast encoder. IC Role / Device Role / Timing Role: Precision frequency translator generating exact broadcast-standard frequencies from a single 25 MHz crystal. Use Value: Achieves true zero-ppm accuracy across all outputs using MultiSynth™ integer-mode synthesis, eliminating frame sync drift.	Use Scenario: Supplying core, DDR, and peripheral clocks (e.g., 100 MHz, 200 MHz, 300 MHz) to Xilinx Versal and Intel Agilex FPGAs in AI inference accelerators. IC Role / Device Role / Timing Role: Configurable quad clock source with independent voltage per output to match FPGA bank requirements. Use Value: Supports mixed-voltage FPGA designs (1.0 V core, 1.2 V DDR, 1.8 V peripherals) with single-device power domain isolation and <10 ps inter-output skew.

PCIe Gen 4 Switch Timing

Ethernet Switch/Routing

Use Scenario: Providing synchronized 100 MHz reference clocks to multiple PCIe Gen 4 switch ASICs in a data center fabric card.

IC Role / Device Role / Timing Role: Quad-output clock generator delivering four independent, low-jitter PCIe-compliant clocks with matched phase alignment.

Use Value: Enables deterministic lane-to-lane skew control (<100 ps) and meets PCIe Gen 4 total jitter limit (≤33.6 ps pk-pk) without external jitter cleaners.

Use Scenario: Generating 125 MHz, 156.25 MHz, and 312.5 MHz clocks for 1/10/25 GbE PHYs and packet processors in a modular router line card.

IC Role / Device Role / Timing Role: Any-frequency clock synthesizer replacing discrete oscillators and translating between Ethernet line rates.

Use Value: Reduces BOM count by 4× vs. discrete XO solution while maintaining <0.7 ps RMS jitter required for 25G KR compliance.

Broadcast Video Timing

FPGA/Processor Clocking

Use Scenario: Delivering SMPTE ST 2082 (28.63636 MHz) and ST 2081 (74.25 MHz) reference clocks to video encoder/decoder FPGAs in a 4K/8K broadcast encoder.

IC Role / Device Role / Timing Role: Precision frequency translator generating exact broadcast-standard frequencies from a single 25 MHz crystal.

Use Value: Achieves true zero-ppm accuracy across all outputs using MultiSynth™ integer-mode synthesis, eliminating frame sync drift.

Use Scenario: Supplying core, DDR, and peripheral clocks (e.g., 100 MHz, 200 MHz, 300 MHz) to Xilinx Versal and Intel Agilex FPGAs in AI inference accelerators.

IC Role / Device Role / Timing Role: Configurable quad clock source with independent voltage per output to match FPGA bank requirements.

Use Value: Supports mixed-voltage FPGA designs (1.0 V core, 1.2 V DDR, 1.8 V peripherals) with single-device power domain isolation and <10 ps inter-output skew.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
Si5338A-B05081-GM	Same Si5338A die; factory-programmed for PCIe Gen 4 SRNS + 100/125/156.25/312.5 MHz outputs	Fixed-frequency variant; no field reprogramming required for standard Ethernet/PCIe use cases	Select when pre-configured outputs eliminate need for I²C initialization in production boot flow
LMK04832RHAR	Two PLLs (jitter cleaner + synthesizer); higher integration (integrated LDOs, SPI interface); 0.18 ps RMS jitter	Requires external 100 MHz reference; better suited for ultra-low-jitter RF/data converter clocking than PCIe switching	Select when sub-0.2 ps RMS jitter and dual-loop cleaning are mandatory, and SPI is preferred over I²C

Compared with SI5338A-B04974-GM, Si5338A-B05081-GM trades field programmability for faster time-to-operate in fixed-frequency systems, while LMK04832RHAR offers superior jitter performance at the cost of higher power (125 mA vs. 45 mA) and no crystal oscillator support.

Availability

SI5338A-B04974-GM is available at Aetrix Electronics and suitable for PCIe Gen 4 switch timing, Ethernet routing infrastructure, broadcast video synchronization, and FPGA-based AI accelerator clocking requiring stable component supply across extended product lifecycles.

Supply support for SI5338A-B04974-GM 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, with leadership in RF, timing, and power management ICs for infrastructure, automotive, and mobile markets.

The Si5338 family was designed as a programmable, low-jitter clock generator platform targeting high-speed serial interface timing in networking, computing, and broadcast equipment-emphasizing flexibility, PCIe compliance, and space-constrained board layouts.

FAQ

What is the primary function of the SI5338A-B04974-GM in a PCIe Gen 4 system?

The SI5338A-B04974-GM serves as a quad-output clock generator delivering four independent, low-jitter reference clocks compliant with PCIe Gen 4 Common Clock specifications (≤0.45 ps RMS jitter). It replaces multiple discrete oscillators while enabling precise phase alignment across lanes-critical for maintaining signal integrity in high-speed switch and endpoint designs. SI5338A-B04974-GM achieves this using its patented MultiSynth™ architecture and validated PLL loop bandwidth settings.

Does the SI5338A-B04974-GM support crystal oscillator input, and what frequency range is supported?

Yes, the SI5338A-B04974-GM supports external crystal input on dedicated pins with a frequency range of 8 to 30 MHz. It includes on-chip load capacitance options (11–13 pF supported, 17–19 pF recommended) and accommodates crystals with ESR ≤300 Ω and drive level ≤100 µW. This capability allows SI5338A-B04974-GM to operate as a self-contained timing solution without requiring external clock sources.

Can the SI5338A-B04974-GM generate different output voltages on each channel, and which levels are supported?

Yes, the SI5338A-B04974-GM provides independent output buffer supply pins (VDDO0–VDDO3) enabling distinct voltage levels per output driver. Supported levels are 1.5 V, 1.8 V, 2.5 V, and 3.3 V-allowing direct interface with mixed-voltage devices such as FPGAs with separate I/O banks. This feature is implemented in hardware and configured via I²C registers, making SI5338A-B04974-GM suitable for complex heterogeneous system timing.

How is the SI5338A-B04974-GM programmed, and is external hardware required?

The SI5338A-B04974-GM is programmed via an I²C/SMBus-compatible serial interface using standard 100/400 kHz protocols. No external hardware programmer is required-configuration is performed using Skyworks' ClockBuilder Pro software running on a PC connected via USB-to-I²C adapter. SI5338A-B04974-GM stores settings in one-time-programmable (OTP) memory, enabling autonomous operation after initial setup.

What thermal and power characteristics define the SI5338A-B04974-GM's suitability for dense PCB layouts?

The SI5338A-B04974-GM operates with 45 mA typical core supply current at 100 MHz output and features a 4 × 4 mm QFN package with exposed thermal pad. Its junction-to-ambient thermal resistance (θJA) is 37 °C/W under still-air conditions, and it supports industrial temperature range (–40 °C to +85 °C). These characteristics allow SI5338A-B04974-GM to maintain stable timing performance in thermally constrained networking and telecom modules without forced airflow.

SI5338A-B04974-GM Specifications

Product attributes: Attribute value

Manufacturer:: Skyworks Solutions Inc.

Series:: MultiSynth™

Package/Case:: 24-VFQFN Exposed Pad

Packaging:: Tray

Product Status:: Active

Programmable:: Not Verified

PLL:: -

Main Purpose:: -

Input:: -

Output:: -

Number of Circuits:: -

Ratio - Input:Output:: -

Differential - Input:Output:: -

Frequency - Max:: -

Voltage - Supply:: -

Operating Temperature:: -

Mounting Type:: Surface Mount

Grade:: -

Qualification:: -

Supplier Device Package:: 24-QFN (4x4)

SI5338A-B04974-GM FAQ

1.How can I place an order for SI5338A-B04974-GM through Aetrix?

Please submit a Request for Quotation (RFQ) for SI5338A-B04974-GM 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 SI5338A-B04974-GM reliable?

The price and inventory of SI5338A-B04974-GM are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SI5338A-B04974-GM is usually 5 days.

3.What payment methods are accepted for SI5338A-B04974-GM?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SI5338A-B04974-GM transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SI5338A-B04974-GM?

SI5338A-B04974-GM orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SI5338A-B04974-GM 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 SI5338A-B04974-GM?

For technical support, including SI5338A-B04974-GM datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SI5338A-B04974-GM requirements.

6.How does Aetrix verify that SI5338A-B04974-GM is sourced from the original manufacturer or authorized distributors?

All SI5338A-B04974-GM 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 SI5338A-B04974-GM meets industry standards.

7.What is the process for return or replacement of SI5338A-B04974-GM?

All SI5338A-B04974-GM units undergo pre-shipment inspection (PSI). If there is an issue with SI5338A-B04974-GM, 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 SI5338A-B04974-GM part is unused and in its original packaging.

Return procedure for SI5338A-B04974-GM:

1.Submit a request within 90 days.

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

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