Skyworks Solutions Inc. SI5338B-B04871-GMR

Overview

SI5338B-B04871-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. It replaces up to four crystal oscillators in Ethernet switch/router, processor/FPGA clocking, and broadcast video timing systems.

For engineers reviewing the SI5338B-B04871-GMR datasheet, SI5338B-B04871-GMR pinout, SI5338B-B04871-GMR application, or SI5338B-B04871-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), flexible reference inputs (crystal, CMOS, SSTL/HSTL, differential), and 24-QFN package with I²C/SMBus programming interface.

Technical Context

The SI5338B-B04871-GMR implements a two-stage PLL architecture: a high-stability synthesis stage (VCO + MultiSynth™ dividers) followed by an output stage with independent M/N/P dividers per channel. Each of the four output drivers supports programmable format (LVPECL/LVDS/HCSL/CMOS/SSTL/HSTL), voltage (1.5–3.3 V), phase offset (±45 ns, <20 ps step), and spread-spectrum modulation (0.5–5.0% spread, 33–63 kHz rate).

It accepts six input references (IN1–IN6): differential (5–710 MHz), CMOS (5–200 MHz), SSTL/HSTL (5–350 MHz), or external crystal (8–30 MHz). Loss-of-lock and loss-of-signal alarms, external feedback mode for zero-delay operation, and glitchless frequency increment/decrement (1 ppm steps) are integrated for robust system timing control.

Key Specifications

Pinout & Package

SI5338B-B04871-GMR is housed in a 24-lead QFN package (4 × 4 mm, 0.5 mm pitch) with exposed thermal pad. Pin functions are validated per Skyworks Si5338 datasheet Rev. 1.6 (August 2021), pages 33–37.

Key Features

Applications

Equivalent & Alternatives

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

Compared with Si5332A-D05880-GM and ICS8430I-01T, the SI5338B-B04871-GMR delivers optimal balance of programmability, jitter performance, and design flexibility for mid-complexity systems - supporting dynamic reconfiguration without over-engineering or sacrificing PCIe/ETH compliance.

Availability

SI5338B-B04871-GMR is available at Aetrix Electronics and suitable for Ethernet switch/router timing, PCIe Gen 3/4 clock distribution, and broadcast video/audio synchronization requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for SI5338B-B04871-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, mobile, infrastructure, and timing solutions with broad manufacturing scale and automotive-grade reliability.

The SI5338B-B04871-GMR belongs to Skyworks' Si5338 family of I²C-programmable quad clock generators, designed specifically for high-performance, multi-protocol timing in datacenter, telecom, and broadcast equipment where flexibility, low jitter, and compact footprint are critical.

FAQ

What is the primary function of the SI5338B-B04871-GMR in a timing architecture?

The SI5338B-B04871-GMR serves as a programmable quad clock generator that synthesizes up to four independent, zero-ppm-accuracy output frequencies from a single reference input. It replaces multiple discrete oscillators or clock buffers in systems like Ethernet switches and PCIe platforms, enabling flexible, low-jitter timing with I²C-based configuration. Its MultiSynth™ architecture allows true any-frequency generation across 0.16–710 MHz per output.

Does the SI5338B-B04871-GMR support PCIe Gen 4 timing requirements?

Yes, the SI5338B-B04871-GMR meets PCIe Gen 4 Common Clock jitter specifications with ≤0.45 ps RMS (12 kHz–20 MHz) when configured per Skyworks' recommended settings - including PLL bandwidth of 2–4 MHz and CDR = 10 MHz. It is explicitly validated for PCIe Gen 1/2/3/4 in the official datasheet Rev. 1.6 and supported by Skyworks' PCIe Clock Jitter Tool.

Can the SI5338B-B04871-GMR generate different output voltages simultaneously?

Yes, the SI5338B-B04871-GMR supports independent output supply voltages per bank: VDDO0 through VDDO3 can each be set to 1.5 V, 1.8 V, 2.5 V, or 3.3 V. This allows simultaneous LVDS (2.5 V), HCSL (1.8 V), and CMOS (3.3 V) outputs on the same device - eliminating external level shifters and simplifying mixed-I/O designs.

How is the SI5338B-B04871-GMR programmed and configured?

The SI5338B-B04871-GMR is programmed via its I²C/SMBus-compatible interface using Skyworks' ClockBuilder Pro software. This GUI tool generates custom configuration files (.cbs), validates timing constraints, and supports field updates. Configuration is stored in on-chip OTP memory, enabling pre-programmed startup behavior without external EEPROM.

What package type and thermal characteristics does the SI5338B-B04871-GMR have?

The SI5338B-B04871-GMR uses a 24-pin QFN package (4 × 4 mm, 0.5 mm pitch) with exposed thermal pad. Its thermal resistance is θJA = 37 °C/W (still air) and θJC = 10 °C/W, enabling reliable operation at full load across –40 to +85 °C. Proper PCB land pattern per Skyworks AN127 and thermal via placement under the pad are required for optimal performance.