Skyworks Solutions Inc. SI5345B-B04736-GMR

Overview

SI5345B-B04736-GMR 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 input frequencies up to 750 MHz and differential outputs up to 1028 MHz, and operates in free-run, locked, or holdover modes - deployed in Synchronous Ethernet line cards and OTN transponders.

For engineers reviewing the SI5345B-B04736-GMR datasheet, SI5345B-B04736-GMR pinout, SI5345B-B04736-GMR application, or SI5345B-B04736-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 NVM configuration for known-power-up behavior.

Technical Context

The SI5345B-B04736-GMR implements a digitally controlled DSPLL with fully integrated loop filter and programmable loop bandwidth (0.1 Hz–4 kHz), enabling precise jitter filtering and phase noise optimization. Its MultiSynth architecture supports fractional-N synthesis across all 10 outputs, with independent integer (R) and fractional (N) division per channel.

It features hitless and ramped input switching between four differential/LVCMOS inputs, status monitoring (LOS/OOF/LOL), and DCO mode with 0.001 ppb step resolution. Core supply is 1.8 V ±5% (VDD), analog supply 3.3 V ±5% (VDDA), and output supplies support 1.8 V/2.5 V/3.3 V independently.

Key Specifications

Pinout & Package

SI5345B-B04736-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 pinout documentation (Rev D, Section 9).

Key Features

Applications

Equivalent & Alternatives

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

Compared with Si5345A-B04736-GMR, SI5345B-B04736-GMR trades maximum output frequency (≤350 MHz vs. ≤1028 MHz) for cost efficiency while retaining identical jitter performance, package, and SyncE compliance - making it optimal for Synchronous Ethernet and OTN applications where outputs remain below 350 MHz. Against LMK04832, it offers certified holdover and EEC validation at higher integrated jitter but broader telecom applicability.

Availability

SI5345B-B04736-GMR is available at Aetrix Electronics and suitable for Synchronous Ethernet line cards, OTN transponders, broadcast video infrastructure, and test equipment requiring stable component supply, long-term lifecycle support, and G.8262-compliant timing solutions.

Supply support for SI5345B-B04736-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, with leadership in RF, timing, and precision analog ICs.

The Si5345 family is designed specifically for high-performance telecom and datacom timing applications - delivering jitter attenuation, multi-rate clock multiplication, and ITU-T G.8262 compliance in a single IC.

FAQ

What is the maximum differential output frequency supported by SI5345B-B04736-GMR?

The SI5345B-B04736-GMR supports differential output frequencies up to 350 MHz. This is defined by its "B" variant designation in the Si5345 ordering guide (Rev D), distinguishing it from the "A" variant (up to 1028 MHz). The 350 MHz limit applies regardless of output format (LVDS/LVPECL/CML) and is verified in the device's electrical specifications table.

Does SI5345B-B04736-GMR meet ITU-T G.8262 Synchronous Ethernet standards?

Yes, SI5345B-B04736-GMR meets ITU-T G.8262 EEC Option 1 and Option 2 requirements. This compliance is explicitly stated in the Si5345/44/42 Rev D Data Sheet Features List and validated through Skyworks' characterization across temperature and voltage ranges. It enables deployment in Carrier Ethernet switches and OTN systems requiring certified timing engines.

Can SI5345B-B04736-GMR operate without an external crystal?

No - SI5345B-B04736-GMR requires an external 25–54 MHz crystal connected to XA/XB pins for freerun and holdover mode stability. While it can accept an external REFCLK instead, the datasheet recommends a crystal for optimal jitter performance and BOM simplicity. The internal oscillator (OSC) depends on this reference for phase noise and holdover accuracy.

How many clock inputs and outputs does SI5345B-B04736-GMR provide?

SI5345B-B04736-GMR provides 4 clock inputs (IN0–IN3) and 10 clock outputs (OUT0–OUT9), consistent with the Si5345 product family definition. All inputs accept differential or LVCMOS signals; all outputs support LVDS, LVPECL, LVCMOS, CML, or HCSL formats with programmable amplitude and common-mode voltage.

Is SI5345B-B04736-GMR pin-compatible with other Si5345 variants like SI5345A?

Yes - SI5345B-B04736-GMR is pin-compatible with all Si5345 variants (A/C/D) in the 64-QFN 9×9 mm package. The "B" suffix denotes the 0.001–350 MHz output frequency range and integer+fractional synthesis capability, but shares identical pinout, power sequencing, and register map with SI5345A-B04736-GMR and SI5345C-B04736-GMR.