Skyworks Solutions Inc. SI5348B-E-GMR

Overview

SI5348B-E-GMR from Skyworks Solutions is a network synchronizer IC for SyncE/IEEE 1588 telecom boundary (T-BC) and slave (T-SC) clocks, featuring three independent DSPLLs, ultra-low 95 fs jitter (12 kHz–20 MHz), 1 Hz–350 MHz LVCMOS/differential output range, and support for ITU-T G.8273.2, G.8262 EEC Options 1 & 2, and Stratum 3E compliance in wireless backhaul and data center switch timing systems.

For engineers reviewing the SI5348B-E-GMR datasheet, SI5348B-E-GMR pinout, SI5348B-E-GMR application, or SI5348B-E-GMR equivalent, this page delivers verified technical context, real-world timing architecture roles, validated pin-level signal routing, and precise alternative selection guidance for telecom synchronization design.

Technical Context

The SI5348B-E-GMR implements three fully independent DSPLLs-each configurable as SyncE PLL, IEEE 1588 DCO, or general-purpose PLL-with programmable loop bandwidth (0.001 Hz–4 kHz) and hitless switching across all input frequencies including 8 kHz, 19.44 MHz, and 25 MHz. Each DSPLL supports frequency-on-the-fly reconfiguration without affecting others.

It uses dual reference inputs: a 48–54 MHz crystal (XA/XB) sets intrinsic jitter performance, while a TCXO/OCXO on REF/REFb determines free-run and holdover accuracy (±4.6 ppm for Stratum 3E). DCO mode enables 1 ppt/step precision steering for PTP clock recovery in slave applications.

Key Specifications

Pinout & Package

SI5348B-E-GMR is housed in a RoHS-6 compliant, 64-lead 9×9 mm QFN package with exposed thermal pad, rated for –40°C to +85°C operation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar network synchronizer applications.

Compared with SI5348B-E-GMR, Si5345B-D-GM offers lower jitter but cannot support concurrent SyncE/PTP boundary clocking, while LMK04832ISQE/NOPB provides superior analog integration but lacks telecom-specific holdover and standards certification-making SI5348B-E-GMR the only choice for carrier-grade T-BC deployment.

Availability

SI5348B-E-GMR is available at Aetrix Electronics and suitable for wireless backhaul infrastructure, data center switch timing, and IP radio systems requiring stable component supply, long-term lifecycle assurance, and full traceability for telecom equipment manufacturing.

Supply support for SI5348B-E-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 leader in analog semiconductors, specializing in RF, timing, and connectivity solutions for aerospace, defense, and communications markets.

The Si5348 family was designed specifically for carrier-class network synchronization-delivering multi-protocol T-BC/T-SC functionality with telecom-certified holdover, jitter, and reliability in a single monolithic IC.

FAQ

What is the primary function of the SI5348B-E-GMR in telecom infrastructure?

The SI5348B-E-GMR serves as a multi-protocol network synchronizer IC, functioning as both a Telecom Boundary Clock (T-BC) per ITU-T G.8273.2 and a Slave Clock (T-SC) for IEEE 1588 PTP. It delivers ultra-low jitter (95 fs), supports concurrent SyncE and PTP timing, and maintains Stratum 3E holdover stability-making it essential for 5G wireless backhaul, data center switches, and IP radio systems where precise phase alignment and packet-loss resilience are critical. The SI5348B-E-GMR integrates three independent DSPLLs to handle these roles simultaneously without cross-interference.

Does the SI5348B-E-GMR support both SyncE and IEEE 1588 timing in the same system?

Yes, the SI5348B-E-GMR natively supports concurrent SyncE and IEEE 1588 operation through its three independent DSPLLs. One DSPLL can be configured as a SyncE PLL locked to an Ethernet physical layer clock, another as a PTP DCO for timestamp-based steering, and the third as a general-purpose PLL for processor/FPGA clocking-all running simultaneously. This architecture enables true hybrid T-BC functionality compliant with G.8273.2, eliminating the need for separate SyncE and PTP timing ICs. The SI5348B-E-GMR's DCO mode provides 1 ppt/step resolution for sub-nanosecond PTP servo control.

What reference sources does the SI5348B-E-GMR require for full telecom compliance?

The SI5348B-E-GMR requires two distinct references: a 48–54 MHz fundamental-mode crystal connected to XA/XB pins for ultra-low jitter generation, and a TCXO or OCXO (5–250 MHz) applied to REF/REFb pins to determine frequency accuracy and holdover stability. The crystal defines output jitter performance (95 fs), while the TCXO/OCXO sets free-run accuracy (±4.6 ppm for Stratum 3E) and governs drift during holdover. This dual-reference architecture is mandatory for meeting ITU-T G.8262 EEC Options 1/2 and G.8273.2 T-BC certification-both required for the SI5348B-E-GMR's intended telecom applications.

How does the SI5348B-E-GMR manage holdover during packet network outages?

The SI5348B-E-GMR stores up to 120 seconds of historical frequency data while locked, then calculates a final holdover frequency using a programmable averaging window and delay offset to exclude corrupted pre-failure samples. During holdover, output frequency drift is governed solely by the TCXO/OCXO reference on REF/REFb-ensuring ±4.6 ppm stability per GR-253 Stratum 3E. Upon input restoration, the SI5348B-E-GMR supports ramped exit (0.2–40,000 ppm/s) to avoid phase glitches, preserving PTP servo integrity. This behavior is fully configurable and validated for metro and access network deployments.

Is factory programming available for the SI5348B-E-GMR, and how is it implemented?

Yes, factory pre-programming is available for the SI5348B-E-GMR using Skyworks' ClockBuilder Pro™ software, which generates unique configuration files and assigns custom ordering part numbers (e.g., Si5348B-Dxxxxx-GMR). The device features in-circuit programmable non-volatile memory (NVM), allowing it to power up into a known, application-optimized state without external configuration. Pre-programmed units eliminate field programming steps, accelerate time-to-market, and ensure repeatability across production batches-critical for telecom OEMs requiring zero-touch provisioning. The SI5348B-E-GMR's NVM retains settings across power cycles and supports field updates via I²C/SPI.