Skyworks Solutions Inc. SI5345B-B05608-GMR

Overview

SI5345B-B05608-GMR from Skyworks is a 10-channel, any-frequency jitter attenuator/clock multiplier IC 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 ITU-T G.8262 SyncE-compliant carrier Ethernet switches and OTN transponders.

For engineers reviewing the SI5345B-B05608-GMR datasheet, SI5345B-B05608-GMR pinout, SI5345B-B05608-GMR application, or SI5345B-B05608-GMR equivalent, key selection criteria include programmable jitter attenuation bandwidth (0.1 Hz–4 kHz), hitless input switching capability, DCO mode with 0.001 ppb step size, and support for LVDS/LVPECL/LVCMOS/CML/HCSL output formats with independent supply pins.

Technical Context

The SI5345B-B05608-GMR implements a digitally controlled DSPLL with fully integrated loop filter and programmable loop bandwidth (0.1 Hz–4 kHz), enabling precise jitter filtering without external components. Its MultiSynth™ dividers provide fractional and integer synthesis across all 10 outputs, each configurable for independent frequency, format, amplitude, and common-mode voltage.

It features automatic/manual input clock selection across four inputs (IN0–IN3), status monitoring (LOS/OOF/LOL), glitchless on-the-fly output frequency changes, and ramped holdover exit with user-selectable slew rates (0.2–40,000 ppm/s). The device uses in-circuit programmable OTP NVM and supports I²C/SPI configuration via ClockBuilder Pro™.

Key Specifications

Pinout & Package

SI5345B-B05608-GMR is housed in a 64-pin QFN package (9 × 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/clock multiplier applications.

Compared with SI5345A-B05608-GMR, SI5345B-B05608-GMR trades maximum output frequency (≤350 MHz) for identical jitter performance and feature set at lower cost - making it optimal for SyncE, OTN, and broadcast video where outputs stay below 350 MHz. Versus LMK04832RHAR, it integrates crystal oscillator and NVM but uses a single DSPLL instead of triple-loop architecture, reducing complexity and power for telecom timing applications.

Availability

SI5345B-B05608-GMR is available at Aetrix Electronics and suitable for carrier Ethernet switches, OTN transponders, broadcast video infrastructure, and test & measurement equipment requiring stable component supply, long-term lifecycle support, and G.8262-compliant timing performance.

Supply support for SI5345B-B05608-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 wireless, broadband, automotive, and industrial markets.

The Si5345 family is designed as a high-performance, software-configurable jitter attenuator and clock multiplier targeting ITU-T G.8262 SyncE, OTN, and broadcast video timing infrastructure - emphasizing ultra-low jitter, field-programmability, and robust holdover operation.

FAQ

What is the maximum output frequency supported by SI5345B-B05608-GMR?

The SI5345B-B05608-GMR supports differential output frequencies up to 350 MHz, as specified in the Skyworks Si5345 Ordering Guide for "B" variant devices. This is distinct from the "A" variant (e.g., SI5345A-B05608-GMR), which supports up to 1028 MHz. The 350 MHz limit applies regardless of output format (LVDS, LVPECL, etc.) and is enforced by internal synthesis constraints.

Does SI5345B-B05608-GMR require an external crystal, and what frequency range is supported?

Yes, SI5345B-B05608-GMR requires an external crystal connected to XA/XB pins, supporting 25–54 MHz fundamental-mode crystals. Skyworks recommends 48–54 MHz for optimal jitter performance. Internal load capacitors eliminate need for external C-L components, simplifying layout and improving noise immunity compared to discrete oscillator solutions.

How does SI5345B-B05608-GMR achieve 90 fs rms jitter performance?

SI5345B-B05608-GMR achieves 90 fs rms jitter through fourth-generation DSPLL™ architecture with fully integrated loop filter, low-noise VCO design, and optimized MultiSynth™ fractional dividers. Measured per IEEE 1149.1 at 12 kHz–20 MHz offset, this performance is maintained across all 10 outputs simultaneously when configured per datasheet guidelines and using recommended 48–54 MHz crystal.

Can SI5345B-B05608-GMR operate without an input clock, and what timing accuracy is maintained?

Yes, SI5345B-B05608-GMR operates in freerun or holdover mode without valid input clocks. In freerun mode, output accuracy matches the crystal's tolerance (e.g., ±100 ppm for standard XTAL); in holdover, it uses averaged historical frequency data stored over up to 120 seconds, with drift governed by crystal stability - TCXO recommended for <0.1 ppm/hour wander in extended holdover.

Is SI5345B-B05608-GMR pin-compatible with other Si5345 variants like SI5345A or SI5345C?

Yes, SI5345B-B05608-GMR is pin-compatible with all Si5345 variants (A/C/D) in the 64-QFN 9×9 mm package, including identical pinout, power sequencing, and thermal pad layout. Firmware and register maps are also compatible; only frequency synthesis limits and NVM programming differ - enabling drop-in replacement where 350 MHz output ceiling is acceptable.