Skyworks Solutions Inc. SI5344A-B05280-GMR

Overview

SI5344A-B05280-GMR from Skyworks is a 4-input, 4-output jitter attenuating clock multiplier with fourth-generation DSPLL™ and MultiSynth™ architecture. It delivers ultra-low 90 fs rms jitter, supports differential (8 kHz–750 MHz) and LVCMOS (8 kHz–250 MHz) inputs, and generates programmable outputs from 100 Hz to 1028 MHz across LVDS/LVPECL/LVCMOS/CML/HCSL formats - deployed in SyncE-compliant carrier Ethernet switches and OTN transponders.

For engineers reviewing the SI5344A-B05280-GMR datasheet, SI5344A-B05280-GMR pinout, SI5344A-B05280-GMR application, or SI5344A-B05280-GMR equivalent, key selection considerations include its G.8262 EEC Option 1/2 compliance, digitally programmable jitter attenuation bandwidth (0.1 Hz–4 kHz), integrated loop filter, hitless input switching capability, and factory-programmable NVM configuration for deterministic power-up behavior.

Technical Context

The SI5344A-B05280-GMR implements a fourth-generation DSPLL with fractional input dividers (P), high-resolution MultiSynth output dividers (N), and integer output dividers (R), enabling any-frequency synthesis from any input frequency. Its fully integrated loop filter eliminates external passive components and associated noise coupling risks.

It operates in freerun, locked, holdover, and zero-delay modes, with programmable holdover averaging over up to 120 seconds of historical frequency data and glitchless on-the-fly output frequency changes via DCO mode (0.001 ppb step size). Input switching supports automatic priority-based selection, hitless transitions between fractionally related clocks, and ramped switching for plesiochronous sources.

Key Specifications

Pinout & Package

The SI5344A-B05280-GMR is housed in a 44-pin QFN package (7 mm × 7 mm, 0.5 mm pitch) with exposed thermal pad. Pin functions are defined per Skyworks Si5344 Rev D datasheet Section 9 (Pin Descriptions).

Key Features

Applications

Equivalent & Alternatives

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

Compared with Si5344A-D-GM1, SI5344A-B05280-GMR provides guaranteed out-of-box functionality for defined SyncE use cases, eliminating configuration time; versus LMK04832ISQE/NOPB, it trades marginal jitter reduction for full integration, smaller footprint, and simplified qualification - making it preferred for volume carrier-grade deployments.

Availability

SI5344A-B05280-GMR is available at Aetrix Electronics and suitable for carrier Ethernet switches, OTN transponders, broadcast video routers, and test equipment requiring stable component supply, long-term lifecycle assurance, and G.8262-compliant timing performance.

Supply support for SI5344A-B05280-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 communications, industrial, and automotive markets.

The SI5344A-B05280-GMR belongs to Skyworks' Si534x family of jitter attenuators - engineered specifically for high-reliability telecom infrastructure where deterministic jitter performance, holdover stability, and seamless input switching are non-negotiable.

FAQ

What is the primary function of the SI5344A-B05280-GMR in a SyncE system?

The SI5344A-B05280-GMR serves as a jitter attenuating clock multiplier that cleans and multiplies incoming reference clocks to generate multiple low-jitter outputs compliant with ITU-T G.8262 EEC Option 1 and 2. In SyncE systems, it locks to a degraded network-derived reference, suppresses accumulated jitter, and delivers stable, phase-aligned clocks to Ethernet PHYs and MAC layers - ensuring packet timing integrity across metro networks. SI5344A-B05280-GMR achieves this using its fourth-generation DSPLL and integrated loop filter.

Does the SI5344A-B05280-GMR require an external crystal, and what frequency range is supported?

Yes, the SI5344A-B05280-GMR requires an external crystal connected to the XA/XB pins for freerun and holdover mode stability. It supports fundamental-mode crystals from 25 MHz to 54 MHz, with Skyworks recommending 48–54 MHz for optimal jitter performance. Internal load capacitors eliminate the need for external tuning capacitors, simplifying layout and improving noise immunity. The SI5344A-B05280-GMR also accepts LVCMOS reference clocks in the same frequency range if a TCXO or OCXO is preferred for enhanced holdover accuracy.

How many outputs does the SI5344A-B05280-GMR support, and what signaling formats are configurable?

The SI5344A-B05280-GMR supports four independent outputs (OUT0–OUT3), each configurable for LVDS, LVPECL, LVCMOS, CML, or HCSL signaling. Output amplitude, common-mode voltage (for differential formats), drive strength, and polarity are all programmable per channel via I²C or SPI. This flexibility allows a single SI5344A-B05280-GMR to simultaneously drive diverse interfaces - such as 1.8 V LVCMOS FPGA clocks, 3.3 V LVPECL SerDes references, and 2.5 V HCSL memory controllers - without external level-shifting circuitry.

What input switching modes does the SI5344A-B05280-GMR support, and how do they differ?

The SI5344A-B05280-GMR supports manual (via IN_SEL pins or registers), automatic priority-based, hitless, ramped, and glitchless input switching. Hitless switching preserves phase continuity between fractionally related inputs (e.g., 156.25 MHz and 311.04 MHz), while ramped switching smoothly transitions between plesiochronous sources (e.g., ±50 ppm offsets). Glitchless switching handles larger frequency jumps (±500 ppm) using DSPLL pull-in. All modes are configurable in SI5344A-B05280-GMR firmware and can be combined - for example, automatic selection with hitless fallback - to meet strict telecom switchover requirements.

Is the SI5344A-B05280-GMR pin-compatible with other devices in the Si534x family?

No, the SI5344A-B05280-GMR is not pin-compatible with Si5345 or Si5342 variants. It uses the 44-QFN 7×7 mm package shared with Si5344 and Si5342, but differs in pin assignment - particularly for output count and crosspoint routing. While Si5344A-B05280-GMR has four outputs mapped to OUT0–OUT3, Si5342 variants route only two outputs, and Si5345 variants use a different 64-QFN package. Board-level replacement requires layout revision; however, SI5344A-B05280-GMR is functionally and electrically compatible with other Si5344A-D-GM1/GM2 variants sharing the same 44-QFN footprint.