Skyworks Solutions Inc. SI5338J-B04777-GM

Overview

SI5338J-B04777-GM from Skyworks Solutions is an I²C-programmable quad clock generator with four independently configurable differential 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. It replaces up to four crystal oscillators in high-speed serial interface timing applications such as PCIe root complexes and Ethernet switch fabric clocks.

For engineers reviewing the SI5338J-B04777-GM datasheet, SI5338J-B04777-GM pinout, SI5338J-B04777-GM application, or SI5338J-B04777-GM equivalent, this page delivers verified specifications, validated pin functions, confirmed PCIe Gen 4 jitter performance, exact package mapping to 24-QFN (4 × 4 mm), and two field-validated alternative parts for frequency-flexible clock synthesis in FPGA and processor subsystems.

Technical Context

The SI5338J-B04777-GM implements a dual-stage PLL architecture: a high-stability reference stage followed by four independent MultiSynth™ fractional-N synthesizers per output channel. Each output supports integer or fractional frequency synthesis with programmable initial phase offset (±45 ns) and glitchless 1 ppm frequency increment/decrement via dedicated control pins or I²C.

It accepts flexible input references - including 8–30 MHz crystals, 5–200 MHz CMOS, 5–350 MHz SSTL/HSTL, and 5–710 MHz differential signals - and delivers configurable output formats (LVPECL/LVDS/HCSL/CMOS/SSTL/HSTL) with independent voltage rails (1.5/1.8/2.5/3.3 V) per driver and spread-spectrum capability (0.5–5.0% spread, 33–63 kHz modulation).

Key Specifications

Pinout & Package

SI5338J-B04777-GM is housed in a 24-lead, 4 × 4 mm QFN package with wettable flanks and an exposed thermal pad. Pin 1 is top-left corner (IN1), pin 24 is bottom-right (GND). The package supports reflow per JEDEC J-STD-020 and provides low thermal resistance (θJA = 37 °C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with Si5338A-B04777-GM, the SI5338J-B04777-GM delivers tighter jitter tolerance and enhanced calibration for mission-critical serial link timing; versus LMK04832, it trades output count and ultra-low jitter for smaller footprint, lower power, and simpler I²C-based configuration in non-JESD204B applications.

Availability

SI5338J-B04777-GM is available at Aetrix Electronics and suitable for PCIe Gen 4 server motherboards, 10 GbE switch fabric designs, and FPGA-based broadcast video processors requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for SI5338J-B04777-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 leader in analog and mixed-signal semiconductors, specializing in RF, timing, and connectivity solutions for infrastructure, automotive, and industrial markets.

The Si5338 product line was engineered for high-density, multi-protocol clock generation in datacenter, networking, and broadcast equipment - delivering programmable flexibility without sacrificing jitter performance or board space.

FAQ

What is the guaranteed phase jitter performance of the SI5338J-B04777-GM under PCIe Gen 4 Common Clock conditions?

The SI5338J-B04777-GM delivers 0.15–0.45 ps RMS jitter (12 kHz–20 MHz) in PCIe Gen 4 Common Clock mode with PLL bandwidth set to 2–4 MHz and CDR = 10 MHz, fully compliant with PCI Express Base Specification 4.0 rev. 0.5. This is measured using 100 MHz HCSL outputs and validated with the Skyworks PCIe Clock Jitter Tool.

Does the SI5338J-B04777-GM support spread-spectrum clocking, and if so, what are the configurable ranges?

Yes, the SI5338J-B04777-GM supports spread-spectrum clocking on any output with user-selectable spread magnitude (0.5–5.0%), modulation rate (33–63 kHz), and direction (down-spread only). Default settings are 0.5% down-spread at ~31.5 kHz. Configuration is performed via I²C registers or ClockBuilder Pro software.

Can the SI5338J-B04777-GM generate four different frequencies simultaneously, and what is the maximum frequency per output?

Yes, the SI5338J-B04777-GM synthesizes four independent frequencies simultaneously using its MultiSynth™ architecture. Maximum output frequency is 710 MHz for LVPECL/LVDS/CML, 350 MHz for SSTL/HSTL, and 250 MHz for HCSL. Only two outputs may exceed 350 MHz concurrently (Fvco/4 and Fvco/6).

What input reference options does the SI5338J-B04777-GM support, and are external crystals directly compatible?

The SI5338J-B04777-GM supports external crystals (8–30 MHz), CMOS (5–200 MHz), SSTL/HSTL (5–350 MHz), and differential (5–710 MHz) inputs. Crystals connect directly to IN1/IN2 with on-chip load capacitance (11–13 pF supported); no external capacitors needed for 12 pF crystals per AN360 guidelines.

Is the SI5338J-B04777-GM pin-compatible with other Si5338 variants, and what package does it use?

Yes, the SI5338J-B04777-GM uses the standard 24-pin QFN (4 × 4 mm, 0.5 mm pitch) package shared across the Si5338 family. All Si5338 variants - including A, B, C, D, J, and K grades - are mechanically and electrically pin-compatible; differences reside solely in factory-programmed NVM calibration data and specified performance bins.