Skyworks Solutions Inc. SI5347B-B03716-GM

Overview

SI5347B-B03716-GM from Skyworks is a quad-DSPLL jitter-attenuating clock multiplier for high-speed telecom and SyncE line cards, delivering 95 fs RMS jitter (12 kHz–20 MHz), supporting differential input frequencies from 8 kHz to 750 MHz and differential output frequencies up to 350 MHz, with independent free-run, holdover, and hitless switching modes.

For engineers reviewing the SI5347B-B03716-GM datasheet, SI5347B-B03716-GM pinout, SI5347B-B03716-GM application, or SI5347B-B03716-GM equivalent, this device serves as a programmable, in-circuit configurable timing solution for OTN transponders, 100G Ethernet Synchronous Equipment Clocks (SEC), and carrier-grade switch fabric synchronization where ultra-low jitter and multi-input redundancy are critical.

Technical Context

The SI5347B-B03716-GM integrates four independent DSPLLs, each with fully configurable fractional-N synthesis (Pn/Pd, Mn/Md, Rn), programmable loop bandwidth (0.1 Hz–4 kHz), and Fastlock mode for accelerated lock acquisition. Each DSPLL accesses all four inputs (IN0–IN3) via a flexible crosspoint matrix and drives any of eight outputs (OUT0–OUT7).

It supports gapped-clock locking, ramped holdover exit (0.2–40,000 ppm/s), DCO mode with 0.01 ppb frequency steps, and status monitoring for LOS/OOF/LOL. Core supply is 1.8 V ±5% (VDD), analog supply 3.3 V ±5% (VDDA), with independent output voltage rails (1.8/2.5/3.3 V).

Key Specifications

Pinout & Package

SI5347B-B03716-GM uses a 64-pin QFN package (9×9 mm, 0.5 mm pitch) with exposed thermal pad. Pin functions align with Si5347B-D-GM family specification per Skyworks Rev D datasheet Section 9.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar jitter-attenuating clock generator applications.

Compared with SI5347A-B03716-GM, the SI5347B-B03716-GM trades maximum output frequency for lower power and cost in ≤350 MHz applications; versus LTC6957-3IDDD#PBF, it delivers four independent DSPLLs, sub-100 fs jitter, and telecom-grade fault recovery-making it uniquely suited for carrier-class infrastructure.

Availability

SI5347B-B03716-GM is available at Aetrix Electronics and suitable for OTN transponders, 100G Synchronous Ethernet line cards, and broadcast video timing systems requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for SI5347B-B03716-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 wireless, broadband, automotive, and industrial markets.

The SI5347B-B03716-GM belongs to Skyworks' Si5347 family of multi-DSPLL jitter attenuators, designed specifically for high-reliability telecom infrastructure requiring ultra-low jitter, multi-input redundancy, and seamless holdover operation in SyncE, OTN, and CPRI systems.

FAQ

What is the maximum differential output frequency supported by the SI5347B-B03716-GM?

The SI5347B-B03716-GM supports differential output frequencies up to 350 MHz, as defined in the Si5347 ordering guide (Table 2.1) for the "B" variant. This is distinct from the "A" variant (e.g., SI5347A-B03716-GM), which supports up to 720 MHz. The 350 MHz limit applies regardless of output format (LVDS/LVPECL/CML) and is verified in the Electrical Specifications section of the Rev D datasheet.

Does the SI5347B-B03716-GM support hitless switching between two input clocks?

Yes, the SI5347B-B03716-GM supports hitless input switching when both clocks are frequency-locked (identical or integer-related frequencies). The DSPLL absorbs phase differences during the switch, preventing output phase transients. This feature is configurable per DSPLL and operates down to 8 kHz input frequencies, as confirmed in Section 3.6.5 of the Rev D datasheet.

How is the SI5347B-B03716-GM configured and programmed?

The SI5347B-B03716-GM is configured via I²C or SPI serial interface and stores settings in on-chip non-volatile OTP memory. Configuration is typically performed using Skyworks' ClockBuilder Pro™ software, which generates register maps and validates frequency plans. Factory preprogrammed units (e.g., SI5347B-B03716-GM) ship with a fixed configuration, eliminating runtime initialization.

What crystal frequency is recommended for optimal jitter performance with the SI5347B-B03716-GM?

A 48–54 MHz fundamental-mode crystal is recommended for the XA/XB pins of the SI5347B-B03716-GM to achieve best jitter performance (<95 fs RMS). Crystals outside this range (e.g., 25–47.999 MHz) are supported but yield higher jitter. The device includes internal load capacitors, eliminating external components and reducing board-level noise coupling.

Can the SI5347B-B03716-GM operate in holdover mode without an external crystal?

No-the SI5347B-B03716-GM requires an external crystal (25–54 MHz) connected to XA/XB to function in holdover mode. The crystal provides the stable frequency reference that determines holdover accuracy and drift. Without it, the device cannot maintain timing during input reference loss, as explicitly stated in Section 3.3.5 and Figure 3.2 of the Rev D datasheet.