Skyworks Solutions Inc. SI5338C-B04266-GMR

Overview

SI5338C-B04266-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 high-speed serial interface timing applications.

For engineers reviewing the SI5338C-B04266-GMR datasheet, SI5338C-B04266-GMR pinout, SI5338C-B04266-GMR application, or SI5338C-B04266-GMR equivalent, this page delivers verified specifications, validated pin functions, confirmed PCIe/10GbE/Ethernet use cases, and two technically documented alternative parts for frequency synthesis and clock translation designs.

Technical Context

The SI5338C-B04266-GMR implements a dual-stage PLL architecture: a reference PLL (Stage 1) locks to one of six input sources (crystal, CMOS, SSTL/HSTL, or differential), followed by four independent MultiSynth™ fractional-N synthesizers (Stage 2) generating output clocks with 1 ppb frequency resolution. Each output supports programmable format (LVPECL/LVDS/HCSL/CMOS/SSTL/HSTL), voltage (1.5–3.3 V), phase offset (±45 ns), and spread-spectrum modulation (0.5–5.0%, 33–63 kHz).

It features loss-of-lock and loss-of-signal detection, independent frequency increment/decrement (1 ppm steps), glitchless output enable control via OEB pin, and I²C/SMBus interface with ClockBuilder Pro configuration support. The device operates from a single 1.8/2.5/3.3 V core supply and delivers 45 mA typical core current at 100 MHz on all outputs with 25 MHz reference.

Key Specifications

Pinout & Package

SI5338C-B04266-GMR uses a 24-lead, 4 × 4 mm QFN package with exposed thermal pad. Pin functions are defined per Skyworks Rev. 1.6 datasheet (pages 33–37) and validated for this variant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SI5338C-B04266-GMR, Si5332A-D06889-GM offers superior jitter and scalability but requires board redesign, while ICS8430I-01T provides lower cost and simpler layout at the expense of configurability and PCIe Gen 4 readiness.

Availability

SI5338C-B04266-GMR is available at Aetrix Electronics and suitable for PCIe Gen 4 server motherboards, 10/25 GbE switch fabrics, broadcast video timing systems, and FPGA-based signal processing platforms requiring stable component supply and long-term lifecycle support.

Supply support for SI5338C-B04266-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, with leadership in RF, timing, and precision analog ICs for communications, 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 discrete oscillators with a single configurable IC.

FAQ

What is the primary function of the SI5338C-B04266-GMR in a system design?

The SI5338C-B04266-GMR serves as an I²C-programmable quad clock generator that synthesizes up to four independent, low-jitter output frequencies from a single reference input. It replaces multiple crystal oscillators in applications such as PCIe root complexes, Ethernet switches, and FPGA clock trees-enabling flexible, software-defined timing with zero-ppm accuracy and sub-ps RMS jitter performance.

Does the SI5338C-B04266-GMR support PCIe Gen 4 Common Clock compliance?

Yes, the SI5338C-B04266-GMR is specified for PCIe Gen 4 Common Clock operation with ≤0.45 ps RMS jitter (10 kHz–50 MHz) under standard test conditions using HCSL outputs and appropriate PLL bandwidth settings. This compliance is explicitly documented in Table 12 of the Skyworks Rev. 1.6 datasheet and validated using the Skyworks PCIe Clock Jitter Tool.

Can the SI5338C-B04266-GMR generate both differential and single-ended outputs simultaneously?

Yes, the SI5338C-B04266-GMR supports a hybrid output configuration: up to four differential outputs (e.g., LVDS, LVPECL) and up to eight single-ended outputs (e.g., CMOS, SSTL), or any combination thereof. Each output driver is independently configurable for format, frequency, voltage, and termination-verified in the "Output Stage" section (page 21) and Table 6 of the datasheet.

What is the minimum and maximum input frequency supported by the SI5338C-B04266-GMR?

The SI5338C-B04266-GMR accepts input frequencies from 5 MHz to 710 MHz depending on source type: 8–30 MHz for crystals; 5–200 MHz for CMOS; 5–350 MHz for SSTL/HSTL; and 5–710 MHz for differential inputs. These ranges are guaranteed across –40 to +85 °C and are detailed in Table 6 of the Skyworks Rev. 1.6 datasheet.

How is the SI5338C-B04266-GMR programmed and configured in-system?

The SI5338C-B04266-GMR is programmed via its I²C/SMBus-compatible interface using Skyworks' ClockBuilder Pro software, which generates register maps and configuration files. Configuration can be stored in on-chip OTP memory for autonomous startup, or dynamically updated during operation-enabling field-upgradable timing profiles without hardware changes.