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

Skyworks Solutions Inc. SI5338A-B04974-GMR

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

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Part No.:: SI5338A-B04974-GMR

Manufacturer:: Skyworks Solutions Inc.

Category:: Application Specific Clock/Timing

Package:: 24-VFQFN Exposed Pad

Datasheet:: SI5338A-B04974-GMR.pdf

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

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Product details

Overview

SI5338A-B04974-GMR from Skyworks Solutions is an I²C-programmable quad clock generator IC 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-GMR datasheet, SI5338A-B04974-GMR pinout, SI5338A-B04974-GMR application, or SI5338A-B04974-GMR equivalent, key selection considerations include its MultiSynth™-based any-frequency synthesis (0.16–710 MHz per output), independent output voltage per driver (1.5/1.8/2.5/3.3 V), spread-spectrum capability (0.5–5.0% down-spread), and PCIe-compliant jitter performance.

Technical Context

The SI5338A-B04974-GMR implements a two-stage PLL architecture: a high-stability reference stage followed by four independent MultiSynth™ fractional-N synthesizers, each driving one output channel. Its input flexibility supports external crystals (8–30 MHz), CMOS (5–200 MHz), SSTL/HSTL (5–350 MHz), and differential clocks (5–710 MHz).

Each output driver supports LVPECL/LVDS/HCSL/CMOS/SSTL/HSTL formats with independent voltage selection (1.5–3.3 V), programmable phase offset (±45 ns), and glitchless frequency increment/decrement in 1 ppm steps. Loss-of-lock and loss-of-signal alarms provide real-time status monitoring via the INTR pin.

Key Specifications

Parameter	Value and Actual Design Meaning
Phase Jitter (RMS)	0.7 ps - meets PCIe Gen 3 SRNS and Gen 4 common clock jitter requirements for high-reliability serial links.
Output Frequency Range	0.16–710 MHz - covers Ethernet (125/156.25 MHz), PCIe (100 MHz), Fibre Channel (1.0625 GHz ÷ 2 = 531.25 MHz), and broadcast video (27/74.25/148.5 MHz) without external dividers.
Input Reference Support	Crystal (8–30 MHz), CMOS (5–200 MHz), differential (5–710 MHz) - enables direct replacement of multiple fixed-frequency sources with one programmable device.
Supply Voltages	VDD = 1.8/2.5/3.3 V ±10%; VDDOx = 1.4–3.63 V - allows mixed-voltage system integration and level translation between FPGA I/O banks and PHYs.
Package	24-QFN, 4 × 4 mm - provides compact footprint and thermal resistance (θJA = 37 °C/W) suitable for dense PCB layouts in telecom line cards and switch/router modules.
Operating Temperature	–40 to +85 °C - qualified for industrial and networking equipment deployed in uncontrolled ambient environments.

Pinout & Package

SI5338A-B04974-GMR is housed in a 24-lead QFN package (4 × 4 mm, 0.5 mm pitch) with exposed thermal pad. Pin assignments are standardized across the Si5338 family and validated per Skyworks Rev. 1.6 datasheet Figure 1 (Top View).

Pin/Terminal	Circuit Role	Design Meaning
IN1, IN2, IN5, IN6	Differential clock inputs	Accept AC-coupled LVDS/LVPECL/CML references up to 710 MHz; require external 100 Ω termination for optimal jitter.
IN3, IN4	Single-ended clock inputs	Support CMOS/SSTL/HSTL references (5–350 MHz); slew rate >1 V/ns recommended for low additive jitter.
CLK0A–CLK3B	Differential output pairs	Four independent output channels; each pair (e.g., CLK0A/CLK0B) delivers complementary signals with user-selectable format and voltage.
VDDO0–VDDO3	Output buffer supplies	Independent 1.5/1.8/2.5/3.3 V rails per output bank - enables simultaneous drive of mixed-voltage receivers (e.g., 1.8 V FPGA + 3.3 V legacy PHY).
SCL, SDA	I²C/SMBus interface	Standard 2-wire serial bus (up to 400 kHz) for configuration, status readback, and dynamic frequency adjustment.
INTR	Interrupt output	Open-drain alarm signal asserting on loss-of-lock or loss-of-signal events; simplifies system-level fault detection without polling.

Key Features

Feature	Design Value
MultiSynth™ synthesis	Enables true zero-ppm frequency accuracy on all four outputs simultaneously - eliminates need for custom crystal sourcing and reduces BOM count.
Independent output voltage per driver	Permits coexistence of 1.8 V FPGA I/O, 2.5 V SerDes, and 3.3 V legacy peripherals on a single timing device - avoids discrete level shifters.
Glitchless frequency adjustment	1 ppm step size with <667 ns update time via PINC/FDEC pins - supports dynamic clock scaling in adaptive systems without disrupting data streams.
Programmable phase offset	±45 ns resolution in <20 ps steps - enables precise skew alignment across multi-lane interfaces like PCIe x16 or 10 GbE XAUI.
Spread spectrum modulation	Configurable 0.5–5.0% down-spread at 33–63 kHz - reduces EMI peak emissions in FCC/CE-constrained embedded systems without affecting timing margin.

Applications

Ethernet Switch Timing	PCIe Gen 4 Clocking
Use Scenario: 10 GbE/25 GbE switch fabric requiring synchronous 156.25 MHz and 312.5 MHz clocks for MAC and PHY layers with sub-1 ps jitter. IC Role / Device Role / Timing Role: Quad-output clock generator providing independent, low-jitter clocks to switch ASIC, packet processor, and SerDes PHYs while maintaining inter-channel skew <100 ps. Use Value: Replaces three discrete oscillators and one jitter cleaner; achieves PCIe Gen 4-compliant 0.15–0.45 ps RMS jitter at 100 MHz HCSL outputs.	Use Scenario: Server motherboard with dual CPU sockets and multiple PCIe Gen 4 x16 slots needing common-reference clock distribution with strict jitter budget. IC Role / Device Role / Timing Role: PCIe Gen 4 Common Clock generator delivering four synchronized 100 MHz HCSL outputs meeting SRNS and total jitter ≤33.6 ps pk-pk. Use Value: Eliminates layout-sensitive fanout buffers; built-in spread spectrum reduces EMI without compromising link training reliability.
Broadcast Video Sync	FPGA-Based Protocol Converter
Use Scenario: SMPTE ST 2082-1 (12G-SDI) video processing board requiring exact 297 MHz, 148.5 MHz, and 74.25 MHz clocks with frame-accurate phase alignment. IC Role / Device Role / Timing Role: Any-frequency clock synthesizer generating integer-related video rates from a single 27 MHz crystal reference using MultiSynth™ integer mode. Use Value: Achieves <10 ps cycle-cycle jitter and ±45 ns programmable phase offset - ensures stable genlock across multi-channel video pipelines.	Use Scenario: Industrial protocol gateway converting Modbus TCP to CAN FD, requiring isolated clocks for ARM MCU, Ethernet PHY, and CAN transceiver with different voltage domains. IC Role / Device Role / Timing Role: Configurable clock buffer and level translator supplying 50 MHz (1.8 V) to MCU, 25 MHz (2.5 V) to Ethernet PHY, and 8 MHz (3.3 V) to CAN controller. Use Value: Single-device solution replaces three discrete oscillators and two level shifters; reduces board area by >40% and power by 35 mA vs. discrete alternatives.

Ethernet Switch Timing

PCIe Gen 4 Clocking

Use Scenario: 10 GbE/25 GbE switch fabric requiring synchronous 156.25 MHz and 312.5 MHz clocks for MAC and PHY layers with sub-1 ps jitter.

IC Role / Device Role / Timing Role: Quad-output clock generator providing independent, low-jitter clocks to switch ASIC, packet processor, and SerDes PHYs while maintaining inter-channel skew <100 ps.

Use Value: Replaces three discrete oscillators and one jitter cleaner; achieves PCIe Gen 4-compliant 0.15–0.45 ps RMS jitter at 100 MHz HCSL outputs.

Use Scenario: Server motherboard with dual CPU sockets and multiple PCIe Gen 4 x16 slots needing common-reference clock distribution with strict jitter budget.

IC Role / Device Role / Timing Role: PCIe Gen 4 Common Clock generator delivering four synchronized 100 MHz HCSL outputs meeting SRNS and total jitter ≤33.6 ps pk-pk.

Use Value: Eliminates layout-sensitive fanout buffers; built-in spread spectrum reduces EMI without compromising link training reliability.

Broadcast Video Sync

FPGA-Based Protocol Converter

Use Scenario: SMPTE ST 2082-1 (12G-SDI) video processing board requiring exact 297 MHz, 148.5 MHz, and 74.25 MHz clocks with frame-accurate phase alignment.

IC Role / Device Role / Timing Role: Any-frequency clock synthesizer generating integer-related video rates from a single 27 MHz crystal reference using MultiSynth™ integer mode.

Use Value: Achieves <10 ps cycle-cycle jitter and ±45 ns programmable phase offset - ensures stable genlock across multi-channel video pipelines.

Use Scenario: Industrial protocol gateway converting Modbus TCP to CAN FD, requiring isolated clocks for ARM MCU, Ethernet PHY, and CAN transceiver with different voltage domains.

IC Role / Device Role / Timing Role: Configurable clock buffer and level translator supplying 50 MHz (1.8 V) to MCU, 25 MHz (2.5 V) to Ethernet PHY, and 8 MHz (3.3 V) to CAN controller.

Use Value: Single-device solution replaces three discrete oscillators and two level shifters; reduces board area by >40% and power by 35 mA vs. discrete alternatives.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
Si5338A-B05081-GM	Same Si5338A die, factory-programmed for 100/125/156.25/312.5 MHz outputs; no I²C reprogramming capability.	Fixed-frequency use cases only (e.g., pre-validated switch designs); lacks runtime frequency agility.	Select when production volume justifies OTP programming and design freeze is complete; avoid if field firmware updates or multi-config support are needed.
ICS8430I-01T	Three-output LVDS generator (not quad); max 700 MHz output; no spread spectrum; 1.2 ps RMS jitter at 156.25 MHz.	Limited to triple-clock systems; requires external oscillator for fourth clock; higher jitter limits PCIe Gen 4 adoption.	Consider only for cost-sensitive, non-PCIe Gen 4 applications where third-party validation is preferred over Skyworks' ClockBuilder Pro ecosystem.

Compared with SI5338A-B04974-GMR, Si5338A-B05081-GM trades programmability for lower unit cost in fixed configurations, while ICS8430I-01T lacks the fourth output, spread spectrum, and PCIe Gen 4 jitter compliance required for modern high-speed interconnects.

Availability

SI5338A-B04974-GMR is available at Aetrix Electronics and suitable for Ethernet switch/router, PCIe Gen 4 server boards, broadcast video timing, and FPGA-based protocol converter applications requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for SI5338A-B04974-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 Si5338 product line delivers programmable, low-jitter clock generation for high-speed serial interfaces including PCIe, Ethernet, Fibre Channel, and broadcast video - designed to replace multiple fixed-frequency oscillators with a single configurable IC.

FAQ

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

The SI5338A-B04974-GMR serves as a PCIe Gen 4 Common Clock generator, delivering four synchronized 100 MHz HCSL outputs with ≤0.45 ps RMS jitter (10 kHz–50 MHz) and total jitter ≤33.6 ps pk-pk. Its MultiSynth™ architecture ensures zero-ppm frequency accuracy and supports spread-spectrum modulation to reduce EMI, making it compliant with PCIe Base Specification 4.0 rev. 0.5 requirements. SI5338A-B04974-GMR integrates this functionality in a single 4 × 4 mm QFN package.

Does the SI5338A-B04974-GMR support both differential and single-ended output formats?

Yes, the SI5338A-B04974-GMR supports eight single-ended outputs (CMOS/SSTL/HSTL) or four differential outputs (LVPECL/LVDS/HCSL/CML), or any combination thereof. Each output driver is independently configurable for format and voltage (1.5/1.8/2.5/3.3 V). For example, CLK0A/CLK0B can be set to LVDS at 2.5 V while CLK1A/CLK1B operates as CMOS at 1.8 V - all simultaneously. SI5338A-B04974-GMR's pinout and register map enable this flexibility without hardware changes.

How is the SI5338A-B04974-GMR programmed, and what tools are required?

The SI5338A-B04974-GMR is programmed via its I²C/SMBus-compatible interface (SCL/SDA pins) using Skyworks' ClockBuilder Pro software, which generates configuration files and registers settings for any frequency/output format combination. The tool auto-calculates MultiSynth™ dividers and validates jitter performance. SI5338A-B04974-GMR also supports pin-controlled frequency increment/decrement (PINC/FDEC) for runtime adjustments without host processor intervention.

What is the maximum output frequency supported by the SI5338A-B04974-GMR, and under what conditions?

The SI5338A-B04974-GMR supports up to 710 MHz on LVPECL/LVDS/CML outputs and 350 MHz on SSTL/HSTL outputs. However, only two unique frequencies above 350 MHz can be generated simultaneously (Fvco/4 and Fvco/6), per the device's synthesis architecture. For full 710 MHz operation on all four outputs, they must be integer-related (e.g., 710 MHz, 355 MHz, 177.5 MHz, 88.75 MHz). SI5338A-B04974-GMR's datasheet Table 6 specifies these constraints explicitly.

Is the SI5338A-B04974-GMR suitable for industrial temperature range applications?

Yes, the SI5338A-B04974-GMR is rated for operation from –40 °C to +85 °C ambient temperature, meeting industrial-grade requirements. Its thermal resistance (θJA = 37 °C/W) and core supply current (45 mA typ at 100 MHz on all outputs) ensure stable performance in fanless enclosures and telecom line cards. SI5338A-B04974-GMR has been validated across this range for jitter, phase noise, and lock acquisition time per Skyworks Rev. 1.6 datasheet Section 1.

SI5338A-B04974-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)

SI5338A-B04974-GMR FAQ

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

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

The price and inventory of SI5338A-B04974-GMR 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-GMR is usually 5 days.

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

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

Note: Certain payment methods may incur a processing fee.

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

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

Once your SI5338A-B04974-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 SI5338A-B04974-GMR?

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

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

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

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

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

Return procedure for SI5338A-B04974-GMR:

1.Submit a request within 90 days.

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

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