Skyworks Solutions Inc. SI5338L-B04326-GM

Overview

SI5338L-B04326-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 and SRNS compliance, and support for input frequencies up to 710 MHz. It replaces multiple crystal oscillators in high-speed serial interface timing applications such as PCIe root complexes and FPGA-based communication systems.

For engineers reviewing the SI5338L-B04326-GM datasheet, SI5338L-B04326-GM pinout, SI5338L-B04326-GM application, or SI5338L-B04326-GM equivalent, key selection criteria include its MultiSynth™ fractional-N synthesis architecture, independent per-output voltage (1.5/1.8/2.5/3.3 V), programmable phase/frequency step resolution (<20 ps / 1 ppm), and 24-pin 4×4 mm QFN package with integrated loss-of-lock and loss-of-signal monitoring.

Technical Context

The SI5338L-B04326-GM implements a two-stage PLL architecture: a high-stability reference stage followed by four independent MultiSynth™ fractional-N synthesis blocks, each driving a configurable output buffer. Its core operates from a single 1.8/2.5/3.3 V supply with 45 mA typical current draw at 100 MHz on all outputs.

Input flexibility includes external crystal (8–30 MHz), CMOS (5–200 MHz), SSTL/HSTL (5–350 MHz), or differential (5–710 MHz) references. Output formats span LVPECL/LVDS/HCSL/CMOS/SSTL/HSTL/CML across 0.16–710 MHz, with independent voltage per driver and <100 ps output-to-output skew under matched conditions.

Key Specifications

Pinout & Package

SI5338L-B04326-GM uses a 24-pin 4 × 4 mm QFN package with exposed thermal pad. Pin assignments are fixed per the Si5338 family: six input pins (IN1–IN6), eight clock output pins (CLK0A/B through CLK3A/B), four VDDOx power pins (VDDO0–VDDO3), three supply pins (VDD, SCL, SDA), one interrupt pin (INTR), one reserved ground (RSVD_GND), and four ground pins (GND).

Key Features

Applications

Equivalent & Alternatives

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

Compared with Si5338A-B04326-GM, the SI5338L-B04326-GM offers identical silicon but factory-optimized configuration for PCIe Gen 4 and broadcast timing; versus LMK04832, it delivers lower power and smaller footprint at the expense of JESD204B-specific features and dual-loop jitter cleaning.

Availability

SI5338L-B04326-GM is available at Aetrix Electronics and suitable for PCIe Gen 4 server motherboards, FPGA-based 10GbE/25GbE switches, and broadcast video equipment requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for SI5338L-B04326-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 mobile markets.

The Si5338 product line was designed for high-performance, software-defined clock generation in data center, telecom, and broadcast systems-enabling flexible, low-jitter timing with minimal board space and no external loop filters.

FAQ

What is the primary function of the SI5338L-B04326-GM in a PCIe Gen 4 system?

The SI5338L-B04326-GM serves as a quad-output clock generator providing compliant 100 MHz REFCLK signals to PCIe Gen 4 root ports and endpoints. It meets SRNS jitter requirements (0.11–0.32 ps RMS) and supports independent output configuration, enabling simultaneous delivery of reference, PHY, and auxiliary clocks from a single device without external crystals or loop filters.

Does the SI5338L-B04326-GM support spread spectrum clocking (SSC)?

Yes, the SI5338L-B04326-GM supports fully programmable spread spectrum on any output: spread range 0.5–5.0%, modulation rate 33–63 kHz, and applicable to frequencies from 5 to 350 MHz. This feature reduces EMI in dense PCB layouts and is configurable per-output via I²C or ClockBuilder Pro software.

Can the SI5338L-B04326-GM operate without an external crystal?

Yes-the SI5338L-B04326-GM accepts multiple reference inputs including CMOS (5–200 MHz), SSTL/HSTL (5–350 MHz), and differential (5–710 MHz) clocks. An external crystal (8–30 MHz) is optional; if used, internal load capacitance is configurable for 11–13 pF crystals with recommended 17–19 pF external loading.

What is the maximum output frequency supported by the SI5338L-B04326-GM in LVDS mode?

The SI5338L-B04326-GM supports LVDS outputs up to 710 MHz, though only two unique frequencies above 350 MHz can be generated simultaneously (Fvco/4 and Fvco/6). For standard LVDS operation below 350 MHz, all four outputs may run at independent frequencies with full specification compliance.

How is the SI5338L-B04326-GM programmed and configured?

The SI5338L-B04326-GM is programmed via its I²C/SMBus-compatible serial interface using Skyworks' ClockBuilder Pro software. Configuration-including output frequencies, formats, voltages, SSC, and phase offsets-is stored in on-chip OTP memory. Factory-programmed settings in the SI5338L-B04326-GM enable immediate operation without host initialization.