Skyworks Solutions Inc. SI5338B-B03799-GMR

Overview

SI5338B-B03799-GMR from Skyworks Solutions is an I²C-programmable quad clock generator IC 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. It replaces up to four crystal oscillators in Ethernet switch/router, PCIe, and FPGA clocking systems.

For engineers reviewing the SI5338B-B03799-GMR datasheet, SI5338B-B03799-GMR pinout, SI5338B-B03799-GMR application, or SI5338B-B03799-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 24-pin 4×4 mm QFN package with I²C/SMBus interface.

Technical Context

The SI5338B-B03799-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 paths. Each path supports integer or fractional mode, enabling true zero-ppm frequency accuracy on all outputs.

It features programmable initial phase offset (±45 ns), glitchless frequency increment/decrement in 1 ppm steps, and <20 ps phase step resolution. Input flexibility includes differential (5–710 MHz), CMOS (5–200 MHz), SSTL/HSTL (5–350 MHz), and 8–30 MHz crystal references - all supporting loss-of-signal and loss-of-lock detection.

Key Specifications

Pinout & Package

SI5338B-B03799-GMR is housed in a 24-pin, 4 × 4 mm QFN package with exposed thermal pad. Pin 1 is top-left (IN1), and pin numbering proceeds counterclockwise. The package supports reflow soldering per JEDEC J-STD-020 (peak 260 °C).

Key Features

Applications

Equivalent & Alternatives

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

Compared with Si5338A-B03799-GMR, SI5338B-B03799-GMR delivers immediate PCIe Gen 4 readiness; compared with LMK04832ISQE/NOPB, it offers lower power, smaller footprint, and finer-grained per-output configurability at the cost of absolute lowest jitter floor.

Availability

SI5338B-B03799-GMR is available at Aetrix Electronics and suitable for Ethernet switch/router, PCIe Gen 4 server platforms, and FPGA-based industrial control systems requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

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

The Si5338 family is designed as a programmable, low-jitter clock generator platform targeting high-speed serial interface timing - specifically PCIe, Ethernet, Fibre Channel, and broadcast video synchronization - where flexibility, integration, and jitter performance are critical.

FAQ

What is the primary function of the SI5338B-B03799-GMR?

The SI5338B-B03799-GMR is an I²C-programmable quad clock generator that synthesizes up to four independent, zero-ppm-accurate output frequencies from a single reference input. It serves as a drop-in replacement for multiple crystal oscillators in high-speed digital systems such as PCIe root complexes and Ethernet switches, leveraging Skyworks' MultiSynth™ technology for low-jitter, flexible timing generation.

Does the SI5338B-B03799-GMR support PCIe Gen 4 Common Clock compliance?

Yes, the SI5338B-B03799-GMR is explicitly validated for PCIe Gen 4 Common Clock compliance, delivering ≤0.45 ps RMS jitter (12 kHz–20 MHz) in HCSL format at 100 MHz. Its factory-programmed OTP image includes optimized PLL bandwidth and loop filter settings meeting PCI-SIG Base Specification 4.0 rev. 0.5 requirements without external tuning.

How many output formats does the SI5338B-B03799-GMR support per channel?

The SI5338B-B03799-GMR supports five output signal formats per channel: LVPECL, LVDS, HCSL, CMOS, and SSTL/HSTL. Each of the four output drivers can be independently configured for format, frequency, voltage (1.5/1.8/2.5/3.3 V), and termination - enabling mixed-signaling on a single device, e.g., LVDS for FPGA transceivers and CMOS for microcontroller peripherals.

What reference inputs are compatible with the SI5338B-B03799-GMR?

The SI5338B-B03799-GMR accepts four types of reference inputs: (1) 8–30 MHz fundamental-mode crystals, (2) single-ended CMOS clocks (5–200 MHz), (3) differential inputs (5–710 MHz via IN1/IN2 or IN5/IN6), and (4) SSTL/HSTL inputs (5–350 MHz). All support automatic loss-of-signal detection and seamless failover between references.

Is ClockBuilder Pro required to configure the SI5338B-B03799-GMR?

No - the SI5338B-B03799-GMR ships with factory-programmed OTP memory containing a default configuration, enabling immediate operation. ClockBuilder Pro is optional but recommended for advanced use cases: custom frequency plans, spread-spectrum tuning, phase alignment across outputs, or PCIe Gen 4 SRNS optimization. Configuration can also be performed via I²C using customer firmware.