Skyworks Solutions Inc. SI5338K-B10518-GMR

Overview

SI5338K-B10518-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 in a 4 × 4 mm 24-QFN package. It replaces up to four crystal oscillators in Ethernet switch/router, PCIe, and FPGA clocking systems.

For engineers reviewing the SI5338K-B10518-GMR datasheet, SI5338K-B10518-GMR pinout, SI5338K-B10518-GMR application, or SI5338K-B10518-GMR equivalent, key selection criteria include its MultiSynth™-based any-frequency synthesis (0.16–710 MHz per output), independent output voltage support (1.5/1.8/2.5/3.3 V), spread-spectrum capability (0.5–5.0% down-spread), and I²C/SMBus programmability with ClockBuilder Pro software integration.

Technical Context

The SI5338K-B10518-GMR implements a two-stage PLL architecture: a high-stability reference stage (with crystal or external clock input) followed by four independent MultiSynth™ fractional-N synthesis blocks, each driving a configurable output buffer. This enables true zero-ppm frequency accuracy on all four outputs simultaneously.

Each output supports LVPECL/LVDS/HCSL/CMOS/SSTL/HSTL formats with independent supply voltage (VDDOx), programmable phase offset (<20 ps step resolution), and glitchless frequency increment/decrement in 1 ppm steps. Input flexibility includes differential (5–710 MHz), CMOS (5–200 MHz), SSTL/HSTL (5–350 MHz), or 8–30 MHz crystal references.

Key Specifications

Pinout & Package

SI5338K-B10518-GMR uses a 24-lead QFN package (4 × 4 mm, 0.5 mm pitch) with exposed thermal pad. Pin functions are defined per Skyworks Rev. 1.6 datasheet Figure 1 (Top View).

Key Features

Applications

Equivalent & Alternatives

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

Compared with Si5332A-D06519-GM and ICS8430I-01T, SI5338K-B10518-GMR delivers optimal balance of programmability, jitter performance, and thermal robustness for PCIe/Ethernet/FPGA systems requiring field-upgradable clock configurations without redesigning the PCB layout.

Availability

SI5338K-B10518-GMR is available at Aetrix Electronics and suitable for Ethernet switch/router, PCIe Gen 1–4 host systems, and FPGA-based video processing applications requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for SI5338K-B10518-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 communications, automotive, and industrial markets.

The Si5338 family is designed as a highly configurable, low-jitter clock generator platform targeting high-speed serial interface timing in networking, computing, and broadcast equipment where precision, flexibility, and reliability are critical.

FAQ

What is the primary function of the SI5338K-B10518-GMR in a PCIe Gen 4 system?

The SI5338K-B10518-GMR serves as a Common Clock source generating synchronized 100 MHz reference signals for root complex and endpoint devices. Its 0.45 ps RMS jitter performance meets PCIe Gen 4 specification requirements, and its I²C programmability allows dynamic reconfiguration during system initialization or firmware updates without hardware changes. SI5338K-B10518-GMR supports both standard and SRNS modes to ensure interoperability across diverse PCIe topologies.

Does the SI5338K-B10518-GMR support crystal oscillator input, and what frequency range is validated?

Yes, the SI5338K-B10518-GMR supports fundamental-mode crystals from 8 to 30 MHz, with full characterization across four bands: 8–11 MHz, 11–19 MHz, 19–26 MHz, and 26–30 MHz. Each band specifies supported and recommended load capacitance (11–13 pF supported, 17–19 pF recommended), maximum ESR (75–300 Ω), and drive level (≤100 µW). SI5338K-B10518-GMR integrates on-chip capacitors and register-adjustable tuning to accommodate standard crystal parameters without external components.

How many independent output voltages can be configured on the SI5338K-B10518-GMR, and which standards do they support?

The SI5338K-B10518-GMR provides four independent output supply rails (VDDO0–VDDO3), each configurable for 1.5 V, 1.8 V, 2.5 V, or 3.3 V. This enables simultaneous LVDS (1.8/2.5/3.3 V), HCSL (1.8 V), LVPECL (3.3 V), and CMOS (1.8/2.5/3.3 V) signaling on different outputs. SI5338K-B10518-GMR's per-output voltage control ensures direct interfacing with heterogeneous logic families in FPGAs, ASICs, and SerDes without level-shifting circuitry.

Can the SI5338K-B10518-GMR generate spread-spectrum clocking, and what parameters are user-adjustable?

Yes, the SI5338K-B10518-GMR supports programmable spread-spectrum clocking on any output with adjustable spread percentage (0.5–5.0% down-spread), modulation rate (33–63 kHz), and center frequency (5–350 MHz). These parameters are set via I²C registers and preserved in OTP memory. SI5338K-B10518-GMR's SSC engine operates independently per output, allowing selective EMI reduction on noise-sensitive links while maintaining tight jitter on critical timing paths.

What is the minimum and maximum output frequency supported by the SI5338K-B10518-GMR for LVDS format?

The SI5338K-B10518-GMR supports LVDS output frequencies from 0.16 MHz to 350 MHz under standard conditions, with extended operation up to 473.33 MHz and 710 MHz at specific VCO dividers (Fvco/4 and Fvco/6). The 350 MHz limit applies to general-purpose use; higher frequencies require integer-related synthesis and are constrained to two unique outputs simultaneously. SI5338K-B10518-GMR maintains ≤1 ps RMS jitter across the full LVDS range when driven by low-noise differential inputs.