Skyworks Solutions Inc. SI5338J-B04769-GMR

Overview

SI5338J-B04769-GMR 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 across –40 to +85 °C. It replaces up to four crystal oscillators in high-speed serial interface timing applications such as PCIe root complexes and FPGA clock trees.

For engineers reviewing the SI5338J-B04769-GMR datasheet, SI5338J-B04769-GMR pinout, SI5338J-B04769-GMR application, or SI5338J-B04769-GMR equivalent, key selection considerations include its MultiSynth™ fractional-N synthesis architecture, independent output voltage per driver (1.5/1.8/2.5/3.3 V), 0 ppm frequency accuracy on all outputs, and support for LVPECL/LVDS/HCSL/CMOS/SSTL/HSTL formats up to 710 MHz.

Technical Context

The SI5338J-B04769-GMR implements a two-stage PLL architecture: a high-stability reference stage (with programmable R-divider) feeding a low-noise VCO, followed by four independent MultiSynth™ fractional-N synthesis blocks (M0–M3) each driving a configurable output stage. Each output supports integer or fractional synthesis with <20 ps phase step resolution and 1 ppm frequency increment/decrement capability.

Input flexibility includes external crystal (8–30 MHz), CMOS (5–200 MHz), SSTL/HSTL (5–350 MHz), or differential (5–710 MHz) references. Output drivers are fully decoupled-each supports independent supply (VDDO0–VDDO3), format, frequency, spread-spectrum modulation (0.5–5.0% at 33–63 kHz), and phase offset (±45 ns).

Key Specifications

Pinout & Package

SI5338J-B04769-GMR uses a 24-lead QFN package (4 mm × 4 mm, 0.5 mm pitch) with exposed thermal pad. Pin assignments follow the standard Si5338 top-view layout: IN1/IN2 (differential ref 1), IN3/IN4 (single-ended ref), IN5/IN6 (differential ref 2), CLK0A–CLK3B (four differential output pairs), VDD (core supply), VDDO0–VDDO3 (independent output buffer supplies), SCL/SDA (I²C interface), INTR (interrupt output), and RSVD_GND (reserved ground).

Key Features

Applications

Equivalent & Alternatives

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

Compared with Si5338A-B04769-GMR, the SI5338J-B04769-GMR delivers tighter phase jitter and enhanced temperature stability for mission-critical serial link timing; versus LMK04832, it provides superior per-output configurability and lower power in a smaller footprint-but lacks JESD204B-specific features.

Availability

SI5338J-B04769-GMR is available at Aetrix Electronics and suitable for PCIe Gen 4 server platforms, FPGA-based industrial controllers, and broadcast video equipment requiring stable component supply, long-term lifecycle support, and guaranteed jitter performance.

Supply support for SI5338J-B04769-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 communications, automotive, and industrial markets.

The Si5338 family was designed as a programmable, low-jitter clock generator platform for high-speed serial interfaces-including PCIe, Ethernet, Fibre Channel, and broadcast video-where flexible, accurate, and compact timing is critical.

FAQ

What is the primary function of the SI5338J-B04769-GMR?

The SI5338J-B04769-GMR is an I²C-programmable quad clock generator that synthesizes four independent, low-jitter output clocks from a single reference input. It uses Skyworks' MultiSynth™ technology to deliver true zero ppm frequency accuracy across 0.16–710 MHz, supporting LVPECL, LVDS, HCSL, CMOS, SSTL, and HSTL output formats. Its role is to replace multiple discrete oscillators in high-performance digital systems.

Does the SI5338J-B04769-GMR support PCIe Gen 4 timing requirements?

Yes, the SI5338J-B04769-GMR meets PCIe Gen 4 common clock jitter specifications with 0.15–0.45 ps RMS typical jitter (10 kHz–50 MHz band) when configured per Skyworks' AN562 guidelines. It is explicitly validated for PCIe Gen 1/2/3/4 Common Clock and Gen 3 SRNS compliance, and its jitter performance is verified using the Skyworks PCIe Clock Jitter Tool and Intel Clock Jitter Tool v1.6.4.

How many reference inputs does the SI5338J-B04769-GMR support?

The SI5338J-B04769-GMR supports up to six reference inputs: two differential pairs (IN1/IN2 and IN5/IN6), two single-ended pins (IN3 and IN4), and two additional differential inputs (IN5/IN6). These accept frequencies ranging from 5 MHz (CMOS) to 710 MHz (differential), including external crystals (8–30 MHz). The device automatically selects and locks to the active reference based on configuration.

Can output voltages be set independently on the SI5338J-B04769-GMR?

Yes, the SI5338J-B04769-GMR provides four independent output buffer supply pins-VDDO0, VDDO1, VDDO2, and VDDO3-each configurable for 1.5 V, 1.8 V, 2.5 V, or 3.3 V. This allows simultaneous interfacing with mixed-voltage devices (e.g., 1.2 V FPGA transceivers, 1.8 V SerDes, and 3.3 V legacy peripherals) without external level shifters or voltage translators.

Is ClockBuilder Pro software required to configure the SI5338J-B04769-GMR?

No, ClockBuilder Pro is optional but strongly recommended for initial configuration and validation of the SI5338J-B04769-GMR. The device supports full I²C/SMBus runtime reprogramming without software-however, ClockBuilder Pro simplifies register setup, performs jitter and phase noise simulation, generates configuration files, and validates PCIe/Ethernet compliance settings before hardware deployment.