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

Skyworks Solutions Inc. SI5338H-B04521-GMR

Name: SI5338H-B04521-GMR
Brand: Skyworks Solutions Inc.
SKU: SI5338H-B04521-GMR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SI5338H-B04521-GMR

Manufacturer:: Skyworks Solutions Inc.

Category:: Application Specific Clock/Timing

Package:: 24-VFQFN Exposed Pad

Datasheet:: SI5338H-B04521-GMR.pdf

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

Quantity:: RFQ Add To RFQ list

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Product details

Overview

SI5338H-B04521-GMR from Skyworks Solutions is a quad-output, I²C-programmable clock generator with MultiSynth™ frequency synthesis, delivering four independent low-jitter clocks (0.7 ps RMS typ) across LVPECL/LVDS/HCSL/CMOS/SSTL formats, supporting PCIe Gen 1–4 and Ethernet timing in telecom line cards and FPGA clocking systems.

For engineers reviewing the SI5338H-B04521-GMR datasheet, SI5338H-B04521-GMR pinout, SI5338H-B04521-GMR application, or SI5338H-B04521-GMR equivalent, this device offers zero-ppm precision synthesis, independent output voltage per driver (1.5–3.3 V), spread-spectrum control, and phase/frequency increment/decrement features for dynamic system-level timing calibration.

Technical Context

The SI5338H-B04521-GMR integrates a high-stability PLL-based synthesis stage followed by four independent MultiSynth™ fractional-N dividers, each feeding configurable output drivers. Its architecture supports both free-running generation and synchronous frequency translation using up to six input references (differential, CMOS, SSTL/HSTL).

It implements dual-stage synthesis: first-stage PLL locks to an input reference (5–710 MHz), then second-stage MultiSynth™ blocks generate outputs with sub-ppb resolution. Each output supports independent format selection, voltage supply (VDDOx), phase offset (±45 ns), and spread-spectrum modulation (0.5–5.0%, 33–63 kHz).

Key Specifications

Parameter	Value and Actual Design Meaning
Output Count	Four differential clock outputs (CLK0A/B through CLK3A/B), configurable as eight single-ended or mixed-mode signals
Phase Jitter (RMS)	0.7 ps typical over 12 kHz–20 MHz - meets PCIe Gen 3 SRNS and GbE jitter requirements
Frequency Range	0.16–710 MHz per output, with support for >350 MHz on two outputs simultaneously (Fvco/4 and Fvco/6)
Input Reference Support	External 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; Output buffers: independently selectable 1.5/1.8/2.5/3.3 V per driver
Package	24-pin QFN, 4 × 4 mm, 0.5 mm pitch - space-efficient for high-density timing applications
Operating Temperature	–40 °C to +85 °C - qualified for industrial and telecom infrastructure environments

Pinout & Package

SI5338H-B04521-GMR is housed in a 24-lead, 4 × 4 mm QFN package with exposed thermal pad. Pin assignments are fixed per Skyworks' Si5338 family layout and validated for signal integrity and thermal performance in high-speed clock distribution.

Pin/Terminal	Circuit Role	Design Meaning
IN1/IN2, IN5/IN6	Differential input pairs	Accept 5–710 MHz AC-coupled differential clocks; require external 100 Ω termination
IN3/IN4	Single-ended input pins	Support CMOS/SSTL/HSTL inputs (5–350 MHz); internally biased, no external pull-up needed
CLK0A/CLK0B – CLK3A/CLK3B	Differential output pairs	Four independent outputs; each pair supports LVPECL/LVDS/HCSL/CML/SSTL with programmable VDDOx
VDDO0–VDDO3	Output buffer supplies	Independent 1.5–3.3 V supplies per output bank - enables mixed-voltage system interfacing
SCL/SDA	I²C interface	Standard SMBus-compatible serial bus (up to 400 kHz) for configuration and status monitoring
INTR	Interrupt output	Open-drain alarm signal indicating loss-of-lock or loss-of-signal events
VDD	Core supply	Single 1.8/2.5/3.3 V supply powering PLL, logic, and memory; PSRR optimized for noise immunity
GND / RSVD_GND	Ground terminals	Eight dedicated ground pins including thermal pad connection - critical for jitter and EMI performance

Key Features

Feature	Design Value
MultiSynth™ synthesis	Enables true zero-ppm frequency accuracy on all four outputs - eliminates need for multiple crystals or oscillators
Independent output voltage per driver	Permits direct interface to mixed-voltage SoCs, FPGAs, and SerDes without level-shifting components
Programmable phase adjustment	±45 ns range in <20 ps steps - supports precise skew compensation across multi-lane interfaces like PCIe or DDR
Glitchless frequency increment/decrement	1 ppm step size with hardware pin control - enables real-time clock tuning during operation without interrupting system timing
Spread-spectrum modulation	Configurable 0.5–5.0% down-spread at 33–63 kHz - reduces EMI peak emissions in dense PCB layouts
PCIe Gen 1–4 compliance	Validated total jitter ≤33.6 ps pk-pk (Gen 2) and ≤0.45 ps RMS (Gen 3/4) - meets common-clock and SRNS specifications

Applications

PCIe Gen 3/4 Switch Timing	Ethernet Switch/Routing
Use Scenario: Providing synchronized reference clocks to PCIe Gen 3/4 switches and endpoint devices in server backplanes and accelerators. IC Role / Device Role / Timing Role: Quad-output clock generator delivering 100 MHz HCSL clocks with SRNS-compliant jitter (<0.32 ps RMS) and independent phase alignment. Use Value: Eliminates multiple discrete oscillators while meeting Intel's PCIe jitter mask and enabling deterministic lane-to-lane skew control.	Use Scenario: Generating 125 MHz and 156.25 MHz clocks for 1/10 GbE PHYs and switch fabric interfaces in enterprise routers. IC Role / Device Role / Timing Role: Frequency translator converting a 25 MHz crystal into multiple Ethernet-compliant rates with low additive jitter (0.7 ps RMS). Use Value: Supports IEEE 802.3 clause 49 compliance and reduces BOM count by replacing separate synthesizers for MAC, PHY, and SerDes layers.
Broadcast Video Timing	FPGA & Processor Clocking
Use Scenario: Delivering SMPTE ST 2082 (12G-SDI) and ST 2081 (6G-SDI) reference clocks in broadcast video encoders and IP media gateways. IC Role / Device Role / Timing Role: Low-jitter clock source generating 74.25 MHz, 148.5 MHz, and 297 MHz outputs with <10 ps cycle-cycle jitter. Use Value: Ensures bit-error-free transmission over long coaxial or fiber links by maintaining strict eye diagram integrity per SMPTE standards.	Use Scenario: Supplying core, I/O, and transceiver clocks to Xilinx Versal and Intel Agilex FPGAs in adaptive compute platforms. IC Role / Device Role / Timing Role: Configurable quad generator providing 100–500 MHz clocks with independent voltage domains (1.8 V I/O, 1.0 V core). Use Value: Enables full utilization of FPGA transceiver PMA lanes and memory controllers without external clock trees or fanout buffers.

PCIe Gen 3/4 Switch Timing

Ethernet Switch/Routing

Use Scenario: Providing synchronized reference clocks to PCIe Gen 3/4 switches and endpoint devices in server backplanes and accelerators.

IC Role / Device Role / Timing Role: Quad-output clock generator delivering 100 MHz HCSL clocks with SRNS-compliant jitter (<0.32 ps RMS) and independent phase alignment.

Use Value: Eliminates multiple discrete oscillators while meeting Intel's PCIe jitter mask and enabling deterministic lane-to-lane skew control.

Use Scenario: Generating 125 MHz and 156.25 MHz clocks for 1/10 GbE PHYs and switch fabric interfaces in enterprise routers.

IC Role / Device Role / Timing Role: Frequency translator converting a 25 MHz crystal into multiple Ethernet-compliant rates with low additive jitter (0.7 ps RMS).

Use Value: Supports IEEE 802.3 clause 49 compliance and reduces BOM count by replacing separate synthesizers for MAC, PHY, and SerDes layers.

Broadcast Video Timing

FPGA & Processor Clocking

Use Scenario: Delivering SMPTE ST 2082 (12G-SDI) and ST 2081 (6G-SDI) reference clocks in broadcast video encoders and IP media gateways.

IC Role / Device Role / Timing Role: Low-jitter clock source generating 74.25 MHz, 148.5 MHz, and 297 MHz outputs with <10 ps cycle-cycle jitter.

Use Value: Ensures bit-error-free transmission over long coaxial or fiber links by maintaining strict eye diagram integrity per SMPTE standards.

Use Scenario: Supplying core, I/O, and transceiver clocks to Xilinx Versal and Intel Agilex FPGAs in adaptive compute platforms.

IC Role / Device Role / Timing Role: Configurable quad generator providing 100–500 MHz clocks with independent voltage domains (1.8 V I/O, 1.0 V core).

Use Value: Enables full utilization of FPGA transceiver PMA lanes and memory controllers without external clock trees or fanout buffers.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
Si5338H-B04522-GMR	Same silicon, different factory-programmed NVM configuration - preloaded with alternate default frequencies and output formats	Requires no I²C reprogramming for specific legacy board revisions; identical pinout and electrical behavior	Select when matching existing hardware initialization without firmware update
Si5332A-D06189-GM	Higher integration: includes integrated crystal, smaller 3 × 3 mm package, lower power (32 mA typ), but limited to three outputs and narrower frequency range (≤350 MHz)	Better suited for compact edge devices; lacks fourth output and >350 MHz capability required for 710 MHz SerDes clocks	Choose for space-constrained designs where fourth output or ultra-high-frequency support is not needed

Compared with Si5338H-B04522-GMR, the SI5338H-B04521-GMR provides distinct factory configuration for new designs requiring custom startup behavior; versus Si5332A-D06189-GM, it delivers full quad-output flexibility and 710 MHz capability essential for high-speed SerDes and PCIe Gen 4 applications.

Availability

SI5338H-B04521-GMR is available at Aetrix Electronics and suitable for telecom line cards, PCIe Gen 4 switch designs, and broadcast video equipment requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for SI5338H-B04521-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 leader in analog and mixed-signal semiconductors, specializing in RF, timing, and connectivity solutions for infrastructure, automotive, and mobile markets.

The Si5338 product line was engineered to replace multiple discrete clock sources with a single programmable IC, targeting high-reliability applications in data center switching, optical transport, and broadcast video where jitter, flexibility, and footprint matter.

FAQ

What is the default factory configuration of the SI5338H-B04521-GMR?

The SI5338H-B04521-GMR ships with non-volatile memory (NVM) preprogrammed for a specific set of output frequencies, formats, and voltage settings defined by Skyworks' B04521 variant. This configuration enables immediate operation upon power-up without I²C initialization, though full customization remains possible via ClockBuilder Pro software and the SI5338H-B04521-GMR I²C interface.

Does the SI5338H-B04521-GMR support PCIe Gen 4 Common Clock mode?

Yes, the SI5338H-B04521-GMR is validated for PCIe Gen 4 Common Clock operation with ≤0.45 ps RMS jitter (10 kHz–50 MHz) when configured per Skyworks' recommended settings - including PLL bandwidth of 2–4 MHz and CDR frequency of 10 MHz. This meets PCI-SIG Base Specification 4.0 requirements for host and endpoint timing.

Can the SI5338H-B04521-GMR generate four different frequencies above 350 MHz simultaneously?

No. The SI5338H-B04521-GMR can output only two unique frequencies above 350 MHz at once - specifically Fvco/4 and Fvco/6 - due to internal VCO and divider architecture constraints. Other outputs must be ≤350 MHz or integer-related to those high-frequency outputs to maintain synthesis integrity.

How is spread-spectrum modulation configured on the SI5338H-B04521-GMR?

Spread-spectrum modulation on the SI5338H-B04521-GMR is configured per-output via I²C registers controlling deviation (0.5–5.0%), modulation rate (33–63 kHz), and direction (down-spread only). It operates exclusively on MultiSynth™ outputs below ~Fvco/8 and requires no external components - enabling EMI reduction without altering system clock topology.

What is the maximum output current per VDDO supply on the SI5338H-B04521-GMR?

The SI5338H-B04521-GMR supports up to 30 mA per VDDO supply (VDDO0–VDDO3) when driving LVPECL outputs at 710 MHz. Current draw varies by format and frequency: LVDS draws ≤8 mA, HCSL ≤20 mA, and CMOS ≤18 mA (at 200 MHz, 3.3 V), as specified in Table 3 of the official datasheet.

SI5338H-B04521-GMR Specifications

Product attributes: Attribute value

Manufacturer:: Skyworks Solutions Inc.

Series:: MultiSynth™

Package/Case:: 24-VFQFN Exposed Pad

Packaging:: Tape & Reel (TR)

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)

SI5338H-B04521-GMR FAQ

1.How can I place an order for SI5338H-B04521-GMR through Aetrix?

Please submit a Request for Quotation (RFQ) for SI5338H-B04521-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 SI5338H-B04521-GMR reliable?

The price and inventory of SI5338H-B04521-GMR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SI5338H-B04521-GMR is usually 5 days.

3.What payment methods are accepted for SI5338H-B04521-GMR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SI5338H-B04521-GMR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SI5338H-B04521-GMR?

SI5338H-B04521-GMR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SI5338H-B04521-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 SI5338H-B04521-GMR?

For technical support, including SI5338H-B04521-GMR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SI5338H-B04521-GMR requirements.

6.How does Aetrix verify that SI5338H-B04521-GMR is sourced from the original manufacturer or authorized distributors?

All SI5338H-B04521-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 SI5338H-B04521-GMR meets industry standards.

7.What is the process for return or replacement of SI5338H-B04521-GMR?

All SI5338H-B04521-GMR units undergo pre-shipment inspection (PSI). If there is an issue with SI5338H-B04521-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 SI5338H-B04521-GMR part is unused and in its original packaging.

Return procedure for SI5338H-B04521-GMR:

1.Submit a request within 90 days.

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

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