Skyworks Solutions Inc. SI5338B-B03799-GM

Overview

SI5338B-B03799-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 Common Clock and Gen 3 SRNS compliance, and operation from 1.8/2.5/3.3 V core supply 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 SI5338B-B03799-GM datasheet, SI5338B-B03799-GM pinout, SI5338B-B03799-GM application, or SI5338B-B03799-GM equivalent, key selection considerations include its MultiSynth™ any-frequency synthesis capability, independent output voltage per driver (1.5–3.3 V), ±20 ps phase step resolution, spread-spectrum support (0.5–5.0% down-spread), and loss-of-lock/loss-of-signal alarm functionality.

Technical Context

The SI5338B-B03799-GM implements a two-stage PLL architecture: a high-stability reference stage (VCO-based) followed by four independent MultiSynth™ fractional-N synthesis blocks, each driving a configurable output buffer. Input flexibility includes external crystal (8–30 MHz), CMOS (5–200 MHz), SSTL/HSTL (5–350 MHz), or differential (5–710 MHz) references.

Each output supports LVPECL/LVDS/HCSL/CMOS/SSTL/HSTL formats with independent voltage rails (VDDO0–VDDO3), programmable initial phase offset (±45 ns), and glitchless frequency increment/decrement in 1 ppm steps. The device operates across –40 to +85 °C and achieves PCIe Gen 4 common-clock jitter compliance (0.15–0.45 ps RMS).

Key Specifications

Pinout & Package

SI5338B-B03799-GM is housed in a 24-lead QFN package (4 mm × 4 mm, 0.5 mm pitch) with exposed thermal pad. Pin assignments are fixed per the Si5338 family and validated for this variant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with Si5338A-B03799-GM, the SI5338B-B03799-GM offers identical hardware but distinct factory OTP settings-enabling immediate operation without initial I²C programming. Versus LMK04832RHAT, it trades absolute jitter floor for smaller footprint, lower power, and greater per-output configurability in compact embedded systems.

Availability

SI5338B-B03799-GM is available at Aetrix Electronics and suitable for PCIe Gen 4 switch timing, Ethernet switching/routing, broadcast video synchronization, and FPGA/processor clocking requiring stable component supply across industrial temperature ranges and long product lifecycles.

Supply support for SI5338B-B03799-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 high-performance analog semiconductors, specializing in RF, timing, and connectivity solutions for infrastructure, automotive, and mobile markets.

The Si5338 product line delivers programmable, low-jitter clock generation for high-speed serial interfaces-including PCIe, Ethernet, Fibre Channel, and broadcast video-where precise frequency synthesis and flexible output formatting are critical.

FAQ

What is the primary function of the SI5338B-B03799-GM in a system?

The SI5338B-B03799-GM functions 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 discrete oscillators in applications like PCIe Gen 4 switches and Ethernet routers, providing configurable voltage, format, phase, and spread-spectrum control per output channel. Its MultiSynth™ architecture ensures zero-ppm frequency accuracy across all outputs.

Does the SI5338B-B03799-GM support PCIe Gen 4 timing requirements?

Yes, the SI5338B-B03799-GM is explicitly compliant with PCIe Gen 4 common-clock jitter specifications, delivering ≤0.45 ps RMS jitter (12 kHz–20 MHz) when configured per Skyworks' recommended settings. This compliance is verified using the Intel Clock Jitter Tool and documented in the official Si5338 datasheet Rev. 1.6. The device also meets PCIe Gen 1–3 and SRNS requirements for Gen 3.

Can the SI5338B-B03799-GM generate different output formats simultaneously?

Yes, the SI5338B-B03799-GM supports simultaneous mixed-format outputs: for example, CLK0A/B as LVDS, CLK1A/B as HCSL, CLK2A/B as LVPECL, and CLK3A/B as CMOS-all with independent voltage rails (VDDO0–VDDO3). Each output driver is fully configurable for signal standard, frequency, phase offset, and spread-spectrum parameters without cross-channel interference.

What is the minimum and maximum input frequency supported by the SI5338B-B03799-GM?

The SI5338B-B03799-GM accepts input frequencies ranging from 5 MHz to 710 MHz, depending on input type: 8–30 MHz for external crystal; 5–200 MHz for CMOS; 5–350 MHz for SSTL/HSTL; and 5–710 MHz for differential inputs. The device includes loss-of-signal detection with 2.6–5 µs response time and supports PLL bypass (buffer mode) for frequencies as low as 1 MHz.

How is the SI5338B-B03799-GM programmed and configured?

The SI5338B-B03799-GM is programmed via its I²C/SMBus-compatible serial interface using Skyworks' ClockBuilder Pro software, which generates custom configuration files and supports real-time register writes. Factory OTP memory stores default settings, and pin-controlled frequency increment/decrement (PINC/FDEC) enables dynamic tuning without host intervention. All configuration-including phase, spread-spectrum, and output format-is non-volatile and survives power cycles.