Skyworks Solutions Inc. SI5344H-D-GMR

Overview

SI5344H-D-GMR from Skyworks Solutions is a high-frequency, ultra-low jitter attenuator clock IC with integrated digitally controlled oscillator (DCO), designed for coherent optical transceiver timing. It delivers up to four outputs-two in High-Frequency Mode (2.75 GHz, <50 fs-rms jitter, 1–40 MHz offset) and two in MultiSynth Mode (717.5 MHz, <150 fs-rms jitter, 12 kHz–20 MHz)-with programmable loop bandwidth (10 Hz–4 kHz), I²C/SPI interface, and on-chip NVM. It powers critical clock synthesis in 100G/400G optical modules.

For engineers reviewing the SI5344H-D-GMR datasheet, SI5344H-D-GMR pinout, SI5344H-D-GMR application, or SI5344H-D-GMR equivalent, key selection criteria include jitter performance in both integer and fractional synthesis modes, gapped-clock input lock capability, hitless input switching, DCO step resolution (0.001 ppb), and support for LVDS/LVPECL/CML/HCSL/LVCMOS output standards with independent VDDO rails.

Technical Context

The SI5344H-D-GMR implements fourth-generation DSPLL architecture with dual-loop operation: a high-bandwidth jitter attenuation loop (10 Hz–4 kHz) and a low-noise fractional MultiSynth synthesizer. Its core integrates a 14 GHz VCO, fully on-chip loop filter, and independent output drivers configurable per-pin for voltage swing, common-mode, and format.

It supports automatic free-run and holdover modes, status monitoring (LOL, LOS, OOF), glitchless on-the-fly frequency changes, and locks to gapped reference clocks-enabling robust synchronization in packet-based networks and optical transport systems where reference integrity is intermittent.

Key Specifications

Pinout & Package

SI5344H-D-GMR is housed in a 7 mm × 7 mm, 44-pin QFN package with exposed thermal pad (RoHS-compliant, Pb-free). Pin assignments are defined for Si5344H variant per Rev D datasheet Figure 2 (Top View).

Key Features

Applications

Equivalent & Alternatives

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

Compared with Si5342H-D-GMR, SI5344H-D-GMR adds two extra outputs and higher total power dissipation but retains identical jitter, DCO, and reliability specs-making it optimal for full-featured 400G modules. Versus LMK5B33216RGZT, SI5344H-D-GMR offers superior jitter, telecom-grade DCO resolution, and robust reference switching-critical for optical infrastructure.

Availability

SI5344H-D-GMR is available at Aetrix Electronics and suitable for 100G/400G optical transceivers, wireless base station radios, and OTN line cards requiring stable component supply, long-term lifecycle support, and RoHS-6 compliance.

Supply support for SI5344H-D-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 and mixed-signal semiconductors, specializing in RF, timing, and connectivity solutions for infrastructure and mobility markets.

The Si534x family-including SI5344H-D-GMR-is engineered for ultra-low jitter clock generation in high-speed optical and wireless infrastructure, with emphasis on DSPLL stability, DCO precision, and system-level fault resilience.

FAQ

What is the maximum output frequency supported by SI5344H-D-GMR in High-Frequency Mode?

The SI5344H-D-GMR supports up to 2.75 GHz in High-Frequency Mode (integer synthesis), with typical phase jitter <50 fs-rms (1–40 MHz offset). This mode uses AC-coupled LVPECL outputs only and is optimized for direct SerDes clocking in 200G/400G optical interfaces. The 2.75 GHz limit is enforced by the internal VCO architecture and driver design-exceeding it is not supported.

Does SI5344H-D-GMR support gapped clock inputs, and how is this implemented?

Yes, SI5344H-D-GMR locks to gapped clock inputs-a key feature for packet-based timing recovery. It achieves this via adaptive input monitoring and extended PLL acquisition windows, allowing synchronization even when reference clocks contain periodic gaps (e.g., Ethernet PTP grandmaster outputs). This behavior is enabled by default and requires no special register configuration beyond standard input setup in ClockBuilder Pro.

How many independent output supply rails does SI5344H-D-GMR provide, and why is this important?

SI5344H-D-GMR provides four independent output supply pins (VDDO0–VDDO3), each configurable for 1.8 V, 2.5 V, or 3.3 V. This enables simultaneous delivery of LVDS, LVPECL, and LVCMOS clocks to heterogeneous downstream devices-eliminating level-shifting components and reducing board area in dense optical modules where multiple interface standards coexist.

Can SI5344H-D-GMR perform hitless clock switching between IN0 and IN1, and what conditions apply?

Yes, SI5344H-D-GMR supports automatic and manual hitless input clock switching between IN0 and IN1. Hitless operation requires both inputs to run at the same nominal frequency (±500 ppm pull-in range) and be phase-aligned within 2 ns transient window. The device maintains continuous output during switchover-verified per ITU-T G.8262 for telecom applications-and asserts LOL only if lock is lost on both inputs.

What software tool is used to configure SI5344H-D-GMR, and does it support factory preprogramming?

Skyworks ClockBuilder Pro software is used to configure SI5344H-D-GMR-supporting full register mapping, jitter simulation, and NVM programming. Factory preprogrammed SI5344H-D-GMR devices are available; these ship with user-defined frequency plans, output formats, and startup settings stored in OTP memory-reducing system initialization complexity and enabling plug-and-play deployment in optical modules.