Skyworks Solutions Inc. SI5345A-B03278-GM

Overview

SI5345A-B03278-GM from Skyworks is a 10-channel, any-frequency jitter attenuator/clock multiplier featuring fourth-generation DSPLL™ and MultiSynth™ architectures. It delivers ultra-low 90 fs rms jitter, supports differential inputs up to 750 MHz and outputs up to 1028 MHz, and operates in free-run, locked, or holdover modes - enabling precise timing in SyncE-compliant 100 GbE line cards.

For engineers reviewing the SI5345A-B03278-GM datasheet, SI5345A-B03278-GM pinout, SI5345A-B03278-GM application, or SI5345A-B03278-GM equivalent, key selection considerations include its 64-QFN 9×9 mm package, programmable jitter attenuation bandwidth (0.1 Hz–4 kHz), G.8262 EEC Option 1/2 compliance, I²C/SPI configurability, and factory-programmable NVM for known-power-up state.

Technical Context

The SI5345A-B03278-GM implements a digitally controlled DSPLL with fractional input dividers (P) and MultiSynth output dividers (N) to enable hitless switching between fractionally related inputs and glitchless on-the-fly output frequency changes. Its integrated loop filter eliminates external component noise coupling risks.

It supports three operational modes - freerun (crystal-referenced), locked (phase- and frequency-locked to input), and holdover (averaged historical frequency retention up to 120 s) - with programmable ramped exit, Fastlock acquisition (100 Hz–4 kHz), and DCO mode offering 0.001 ppb step resolution.

Key Specifications

Pinout & Package

SI5345A-B03278-GM uses a 64-pin QFN package (9 mm × 9 mm, 0.5 mm pitch) with exposed thermal pad. Pin functions are defined per Skyworks Si5345 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 SI5345A-B03278-GM, the Si5345B variant trades output frequency range and synthesis mode flexibility for lower unit cost, while the LTC6957 offers superior analog jitter performance but lacks integrated NVM, multi-output configurability, and SyncE compliance features.

Availability

SI5345A-B03278-GM is available at Aetrix Electronics and suitable for 100GbE line cards, OTN transponders, and broadcast video infrastructure requiring stable component supply, long-lifecycle support, and guaranteed SyncE compliance.

Supply support for SI5345A-B03278-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, automotive, and industrial markets.

The Si5345 family is engineered for high-performance timing in carrier-class networking equipment, delivering jitter attenuation, multi-frequency synthesis, and holdover resilience required by OTN, SyncE, and 5G transport systems.

FAQ

What is the primary function of the SI5345A-B03278-GM in a timing architecture?

The SI5345A-B03278-GM serves as a jitter attenuating clock multiplier that cleans and regenerates high-frequency clock signals while supporting any-input-to-any-output frequency translation. Its DSPLL architecture locks to noisy or wandering references and produces ultra-low-jitter outputs - making it essential for maintaining signal integrity in 100GbE, OTN, and SyncE systems where jitter accumulation must stay below ITU-T G.8262 thresholds. The SI5345A-B03278-GM achieves this with integrated loop filtering and programmable bandwidth.

Does the SI5345A-B03278-GM support factory preprogramming, and how is it configured?

Yes, the SI5345A-B03278-GM includes in-circuit programmable non-volatile memory (NVM) and is available factory preprogrammed with custom frequency plans. Configuration is performed using Skyworks' ClockBuilder Pro™ software, which generates register maps and validates timing constraints. The SI5345A-B03278-GM powers up with the stored configuration immediately after reset - eliminating boot-time delays and ensuring deterministic behavior in mission-critical systems.

How does the SI5345A-B03278-GM handle input clock failures in carrier-grade networks?

The SI5345A-B03278-GM automatically enters holdover mode upon input failure, using up to 120 seconds of stored historical frequency data to compute a stable averaged holdover frequency. Its programmable holdover window and delay settings suppress transient disturbances, while ramped exit ensures smooth reacquisition when the input returns - all without glitches or phase jumps. This behavior makes the SI5345A-B03278-GM compliant with ITU-T G.8262 EEC Option 2 for carrier Ethernet resilience.

What output signaling standards does the SI5345A-B03278-GM support, and how are they configured?

The SI5345A-B03278-GM supports LVDS, LVPECL, LVCMOS, CML, and HCSL outputs with per-channel programmable amplitude, common-mode voltage (for differential), and slew rate. Each of the 10 outputs can be independently assigned a format and voltage supply rail (1.8 V, 2.5 V, or 3.3 V). Configuration is done via I²C or SPI registers - enabling dynamic reconfiguration in field-deployed systems without hardware changes. This flexibility allows the SI5345A-B03278-GM to drive diverse PHYs across a single board.

Is an external loop filter required for the SI5345A-B03278-GM's DSPLL operation?

No, the SI5345A-B03278-GM integrates the entire DSPLL loop filter on-chip - including charge pump, loop capacitor, and resistor emulation - eliminating discrete components and associated noise coupling paths. This integration improves jitter performance consistency across temperature and voltage variations while simplifying PCB layout. The loop bandwidth remains fully digitally programmable (0.1 Hz–4 kHz) without external tuning, and the SI5345A-B03278-GM maintains <0.1 dB peaking across the full range.