Skyworks Solutions Inc. SI5345B-B04706-GMR

Overview

SI5345B-B04706-GMR from Skyworks is a 10-channel, any-frequency jitter attenuator/clock multiplier with fourth-generation DSPLL™ and MultiSynth™ architecture. 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 - deployed in SyncE-compliant carrier Ethernet switches and OTN transponders.

For engineers reviewing the SI5345B-B04706-GMR datasheet, SI5345B-B04706-GMR pinout, SI5345B-B04706-GMR application, or SI5345B-B04706-GMR equivalent, key selection considerations include its G.8262 EEC Option 1/2 compliance, programmable jitter attenuation bandwidth (0.1 Hz–4 kHz), 64-QFN 9×9 mm package, I²C/SPI configurability, and factory-programmed frequency plan B04706.

Technical Context

The SI5345B-B04706-GMR implements a digitally controlled DSPLL with fractional input dividers (P), high-resolution MultiSynth output dividers (N), and integer R-dividers to generate precise output frequencies from any valid input. Its loop bandwidth is fully programmable (0.1 Hz–4 kHz) for application-specific jitter filtering without analog loop filter components.

It supports hitless switching between fractionally related inputs, glitchless transitions across ±500 ppm frequency offsets, and ramped holdover exit using user-defined slew rates (0.2–40,000 ppm/s). The device integrates on-chip crystal oscillator circuitry with internal 2×CL loading for 25–54 MHz XTALs and provides status monitoring (LOS/OOF/LOL) via dedicated flags and INTRb pin.

Key Specifications

Pinout & Package

SI5345B-B04706-GMR is housed in a 64-pin QFN package (9 mm × 9 mm, 0.5 mm pitch) with exposed thermal pad. Pin functions are defined per Skyworks Si5345 datasheet Rev D, 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-B04706-GMR, SI5345B-B04706-GMR trades maximum output frequency (350 MHz vs. 1028 MHz) for lower power and cost while retaining identical jitter, SyncE compliance, and feature set below 350 MHz; versus LMK04832RHAR, it offers integrated crystal, lower power, and simpler layout at the expense of maximum frequency and ultra-low offset phase noise.

Availability

SI5345B-B04706-GMR is available at Aetrix Electronics and suitable for carrier Ethernet switches, OTN transponders, broadcast video systems, and test equipment requiring stable component supply, long-term lifecycle support, and factory-programmed timing configurations.

Supply support for SI5345B-B04706-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 semiconductor company specializing in analog and mixed-signal connectivity solutions for communications, automotive, and industrial markets.

The Si5345 family is designed as a high-performance, software-configurable jitter attenuator/clock multiplier platform targeting telecom infrastructure, enterprise networking, and precision timing applications where ultra-low jitter and SyncE compliance are mandatory.

FAQ

What is the factory-programmed configuration for SI5345B-B04706-GMR?

The "B04706" suffix indicates a Skyworks factory-programmed configuration stored in on-chip OTP NVM. This specific variant is preconfigured for a defined set of input/output frequencies, loop bandwidth, and output formats - enabling immediate operation without external programming. SI5345B-B04706-GMR powers up with this exact configuration every time, eliminating boot-time initialization delays in mission-critical systems.

Does SI5345B-B04706-GMR support G.8262 Synchronous Ethernet compliance?

Yes, SI5345B-B04706-GMR meets ITU-T G.8262 EEC Option 1 and Option 2 specifications for Enhanced Equipment Clocks. Its 90 fs rms jitter, programmable loop bandwidth (0.1 Hz–4 kHz), and holdover stability with integrated crystal ensure full compliance in carrier Ethernet line cards and switches - verified per Skyworks Si5345/44/42 Rev D datasheet Section 1.1 and Table 5.1.

Can SI5345B-B04706-GMR operate without an external crystal?

No - SI5345B-B04706-GMR requires an external 25–54 MHz fundamental-mode crystal connected to XA/XB pins. The device integrates internal 2×CL loading capacitance, so no external load capacitors are needed. While an external REFCLK may be used instead, the SI5345B-B04706-GMR configuration relies on the crystal for free-run and holdover mode stability, and Skyworks validates jitter performance specifically with crystal reference.

What are the supported communication interfaces for configuring SI5345B-B04706-GMR?

SI5345B-B04706-GMR supports both I²C (SCL/SDA) and SPI (SCLK/SDIO/CSb) serial interfaces for register access, status monitoring, and in-circuit reprogramming. The interface mode is selected at power-up via hardware pin strapping or default configuration. ClockBuilder Pro software fully supports both interfaces, and SI5345B-B04706-GMR retains its factory-programmed state unless explicitly overwritten via either bus.

How does SI5345B-B04706-GMR handle input clock failures in telecom applications?

Upon input clock failure, SI5345B-B04706-GMR automatically enters holdover mode using up to 120 seconds of averaged historical frequency data to compute a stable output frequency. Its programmable holdover window and ramped exit (0.2–40,000 ppm/s) minimize phase disturbance during recovery. Status flags (LOL, OOF) and INTRb pin provide real-time fault indication - essential for meeting ITU-T G.8262 holdover stability requirements in carrier networks.