Skyworks Solutions Inc. SI5344B-B03265-GM

Overview

SI5344B-B03265-GM from Skyworks is a 4-input, 4-output jitter attenuating clock multiplier with fourth-generation DSPLL™ and MultiSynth™ architecture. It delivers ultra-low 90 fs rms jitter, supports differential input frequencies up to 750 MHz and LVCMOS inputs up to 250 MHz, and generates outputs from 100 Hz to 1028 MHz (differential) or 250 MHz (LVCMOS). It is deployed in ITU-T G.8262-compliant Synchronous Ethernet line cards for precise timing recovery.

For engineers reviewing the SI5344B-B03265-GM datasheet, SI5344B-B03265-GM pinout, SI5344B-B03265-GM application, or SI5344B-B03265-GM equivalent, key selection criteria include its programmable jitter attenuation bandwidth (0.1 Hz–4 kHz), support for hitless/ramped/glitchless input switching, G.8262 EEC Option 1/2 compliance, and factory-programmable NVM configuration for deterministic power-up behavior.

Technical Context

The SI5344B-B03265-GM implements a digitally controlled DSPLL with fully integrated loop filter and programmable loop bandwidth (0.1 Hz–4 kHz), enabling application-tuned jitter filtering. Its MultiSynth output dividers support both integer and fractional synthesis, allowing any-output-frequency generation from any-input-frequency within specified ranges.

It operates across freerun, locked, holdover, and zero-delay modes, with automatic/manual input clock selection, status monitoring (LOS/OOF/LOL), and DCO mode offering 0.001 ppb step resolution. Input switching includes hitless (for phase-coherent sources), ramped (for plesiochronous sources), and glitchless (±500 ppm tolerance) variants - all configurable via I²C/SPI interface and stored in on-chip OTP memory.

Key Specifications

Pinout & Package

The SI5344B-B03265-GM is housed in a 44-pin QFN package (7 mm × 7 mm, 0.5 mm pitch) with exposed thermal pad. Pin functions are defined per Skyworks Si5344 Rev D datasheet Section 9 (Pin Descriptions).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar jitter attenuator applications.

Compared with Si5344A-D-GM, SI5344B-B03265-GM trades maximum output frequency for optimized cost and power in sub-350 MHz SyncE deployments; versus LMK04832ISQE/NOPB, it offers lower BOM count, smaller footprint, and deterministic NVM-based startup - critical for carrier-grade equipment with strict boot-time timing requirements.

Availability

SI5344B-B03265-GM is available at Aetrix Electronics and suitable for OTN muxponders, Carrier Ethernet switches, and broadcast video equipment requiring stable component supply, long-term lifecycle support, and G.8262-compliant timing performance.

Supply support for SI5344B-B03265-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 semiconductor company specializing in analog and mixed-signal connectivity solutions for communications infrastructure, automotive, and industrial markets.

The SI5344B-B03265-GM belongs to Skyworks' Si534x family of jitter-attenuating clock multipliers, designed specifically for high-reliability telecom and datacom timing applications demanding ultra-low jitter, flexible frequency synthesis, and robust holdover performance.

FAQ

What is the maximum differential input frequency supported by the SI5344B-B03265-GM?

The SI5344B-B03265-GM supports differential input frequencies up to 750 MHz, as specified in the Si5345/44/42 Rev D datasheet. This enables direct interfacing with high-speed SerDes reference clocks used in 100G and beyond networking applications. The device maintains full jitter attenuation capability across this entire input range when configured with appropriate loop bandwidth settings.

Does the SI5344B-B03265-GM require external loop filter components?

No, the SI5344B-B03265-GM integrates the entire DSPLL loop filter on-chip. This eliminates discrete passive components, reduces PCB area, and removes sensitivity to layout-induced noise coupling - a key reliability advantage over discrete PLL solutions. All loop dynamics are controlled digitally via register settings for bandwidth and damping.

Can the SI5344B-B03265-GM operate without an external crystal?

No - the SI5344B-B03265-GM requires an external 25–54 MHz crystal connected to XA/XB pins to provide the stable reference for freerun and holdover modes. While it accepts an external REFCLK instead of a crystal, doing so disables internal loading capacitors and requires careful signal integrity design. For optimal jitter performance, Skyworks recommends a 48–54 MHz fundamental-mode crystal.

How does the SI5344B-B03265-GM handle input clock failures in a redundant timing system?

Upon input failure, the SI5344B-B03265-GM automatically enters holdover mode using up to 120 seconds of stored historical frequency data to compute a stable averaged holdover frequency. This minimizes phase disturbance at outputs and ensures continuous, low-drift timing during reference outages - a critical feature for ITU-T G.8262-compliant SyncE systems.

Is the SI5344B-B03265-GM pin-compatible with other Si5344 variants?

Yes - all Si5344 variants (including SI5344A-D-GM, SI5344B-D-GM, SI5344C-D-GM, and SI5344D-D-GM) share identical 44-QFN 7×7 mm packaging and pinout. The SI5344B-B03265-GM is functionally compatible with these parts at the hardware level; differences lie solely in factory-programmed NVM configuration and specified output frequency range (≤350 MHz).