Skyworks Solutions Inc. SI5348A-C-GM

Overview

SI5348A-C-GM from Skyworks Solutions is a triple-DSPLL network synchronizer IC designed for telecom boundary (T-BC) and slave (T-TSC) clock applications in SyncE/IEEE 1588 PTP systems. It delivers 100 fs typical jitter (12 kHz–20 MHz), supports three independent DSPLLs, accepts 48–54 MHz crystal and 5–250 MHz REF inputs, and generates differential outputs up to 718.5 MHz - enabling precise timing in wireless backhaul and data center switches.

For engineers reviewing the SI5348A-C-GM datasheet, SI5348A-C-GM pinout, SI5348A-C-GM application, or SI5348A-C-GM equivalent, this page provides verified technical context, validated pin functions, confirmed compliance with ITU-T G.8262 EEC Options 1 & 2, G.8273.2 T-BC, and Stratum 3E requirements, and real-world selection guidance for telecom timing architectures.

Technical Context

The SI5348A-C-GM integrates three identical, independently configurable DSPLLs-each supporting SyncE PLL, IEEE 1588 DCO, or general-purpose clocking modes. Each DSPLL features programmable loop bandwidth (0.001 Hz–4 kHz), fastlock acquisition, and holdover with 120-second frequency history averaging.

It requires dual references: 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 frequency steering for PTP timestamp recovery.

Key Specifications

Pinout & Package

SI5348A-C-GM uses a 64-lead 9×9 mm QFN package with exposed thermal pad. Pin functions are validated per Skyworks Si5348 Rev D datasheet Section 9 (Pin Descriptions).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SI5348A-C-GM, Si5347A-D-GM reduces channel count but maintains identical jitter and compliance for dual-domain use, while LMK5B33216RGZT trades DCO precision and T-BC capability for integrated oscillator convenience in cost-constrained PTP slave roles.

Availability

SI5348A-C-GM is available at Aetrix Electronics and suitable for wireless backhaul, 5G macro cell base stations, and data center spine switches requiring stable component supply, long-term lifecycle assurance, and traceable sourcing for telecom infrastructure programs.

Supply support for SI5348A-C-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 communications infrastructure, automotive, and mobile markets.

The SI5348A-C-GM belongs to Skyworks' high-performance timing product family, engineered specifically for telecom-grade network synchronization in SyncE, IEEE 1588, and legacy SETS applications - emphasizing ultra-low jitter, multi-DSPLL flexibility, and standards-certified holdover stability.

FAQ

What is the primary function of the SI5348A-C-GM in telecom infrastructure?

The SI5348A-C-GM serves as a triple-DSPLL network synchronizer IC functioning as either a Telecom Boundary Clock (T-BC) per ITU-T G.8273.2 or a Telecom Time Stamp Clock (T-TSC) for IEEE 1588 PTP slave operation. It delivers ultra-low jitter (100 fs), supports hybrid SyncE/PTP architectures, and ensures Stratum 3E compliance using TCXO/OCXO holdover - making it essential for wireless backhaul and 5G base station timing. The SI5348A-C-GM integrates all required functions in a single 64-QFN package.

Does the SI5348A-C-GM support both SyncE and IEEE 1588 simultaneously?

Yes, the SI5348A-C-GM supports simultaneous SyncE and IEEE 1588 operation via its three independent DSPLLs. One DSPLL can lock to a SyncE line clock (IN0), another to a PTP-recovered timestamp reference (IN1), and the third to a local TCXO/OCXO (REF) for holdover - all while generating distinct output frequencies. This enables true hybrid T-BC functionality per ITU-T G.8273.2, with each DSPLL individually configurable for EEC Option 1/2 or PTP DCO mode. The SI5348A-C-GM's architecture eliminates need for discrete timing ICs in multi-standard systems.

What reference sources does the SI5348A-C-GM require to meet G.8273.2 Class C specifications?

To meet ITU-T G.8273.2 Class C (T-BC) specifications, the SI5348A-C-GM requires two references: a 48–54 MHz fundamental-mode crystal on XA/XB for ultra-low jitter generation, and a high-stability TCXO or OCXO (5–250 MHz) on REF/REFb to define free-run and holdover accuracy (±4.6 ppm for Stratum 3E). The crystal determines short-term jitter performance, while the REF input governs long-term frequency stability and wander - both mandatory for G.8273.2 compliance. The SI5348A-C-GM's dual-reference architecture is explicitly designed for this requirement.

How does the DCO mode of the SI5348A-C-GM enable precise PTP clock steering?

The SI5348A-C-GM's DCO mode provides 1 ppt/step frequency resolution per DSPLL, allowing sub-picosecond phase adjustments for IEEE 1588 PTP slave clock steering. Frequency increments/decrements are controlled either via dedicated FINC/FDEC pins for low-latency hardware updates or through the I²C/SPI interface for software-defined servo loops. This eliminates need for external DACs or analog tuning circuits. When used with recovered PTP timestamps, the SI5348A-C-GM's DCO enables closed-loop timing recovery with <1 ns residual time error - a key capability for T-TSC applications.

Can the SI5348A-C-GM replace legacy timing solutions in Stratum 3E systems?

Yes, the SI5348A-C-GM is certified for Telcordia GR-253 Stratum 3E and ITU-T G.813 Option 1, making it a direct upgrade path for legacy SETS timing modules. Its 64-pin QFN package matches common footprints, and its three DSPLLs support backward-compatible configurations (e.g., one DSPLL for Stratum 3E holdover, others for new SyncE/PTP features). Factory pre-programmed variants of SI5348A-C-GM are available to replicate legacy frequency plans and pin behaviors - ensuring seamless integration into existing hardware without layout changes.