Skyworks Solutions Inc. SI5345A-B04228-GM

Overview

SI5345A-B04228-GM from Skyworks is a 10-channel, any-frequency jitter attenuator/clock multiplier with fourth-generation DSPLL™ and MultiSynth™ architecture. It delivers 90 fs rms jitter, supports differential inputs up to 750 MHz and outputs up to 1028 MHz, and operates in free-run, locked, or holdover modes - enabling precise clock synthesis for SyncE-compliant 100 GbE line cards.

For engineers reviewing the SI5345A-B04228-GM datasheet, SI5345A-B04228-GM pinout, SI5345A-B04228-GM application, or SI5345A-B04228-GM equivalent, key selection criteria include programmable jitter attenuation bandwidth (0.1 Hz–4 kHz), G.8262 EEC Option 1/2 compliance, hitless input switching, DCO mode with 0.001 ppb step size, and independent output supply pins (1.8/2.5/3.3 V).

Technical Context

The SI5345A-B04228-GM implements a digitally controlled DSPLL with fully integrated loop filter and programmable loop bandwidth (0.1 Hz–4 kHz), enabling application-level jitter optimization. Its MultiSynth architecture uses fractional-N synthesis (Mn/Md) and integer-R division to generate any output frequency from any input frequency, with support for both integer and fractional synthesis modes.

It features four configurable inputs (IN0–IN3), ten independently programmable outputs (OUT0–OUT9), and dual reference paths: external crystal (25–54 MHz on XA/XB) or LVCMOS/LVDS/LVPECL reference clock. Status monitoring includes LOS, OOF, and LOL detection, with glitchless and ramped switching between plesiochronous inputs.

Key Specifications

Pinout & Package

The SI5345A-B04228-GM is housed in a 64-pin QFN package (9 × 9 mm, 0.5 mm pitch) with exposed thermal pad. Pin functions are defined per Skyworks Si5345 Rev D datasheet Section 9 (Pin Descriptions), including dedicated IN0–IN3, OUT0–OUT9, XA/XB, I²C/SPI, RSTb, INTRb, and multiple VDD/VDDA/VDDO supply domains.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SI5345A-B04228-GM, Si5345B-D-GM sacrifices frequency range and synthesis flexibility for cost reduction, while LMK04832ISQE/NOPB trades holdover intelligence and telecom-specific features for superior broadband jitter - making SI5345A-B04228-GM optimal for OTN, SyncE, and broadcast infrastructure demanding both precision and resilience.

Availability

SI5345A-B04228-GM is available at Aetrix Electronics and suitable for OTN muxponders, 100 GbE synchronous Ethernet line cards, and broadcast video timing systems requiring stable component supply, long-term lifecycle support, and factory preprogrammed configuration traceability.

Supply support for SI5345A-B04228-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 industrial markets.

The SI5345A-B04228-GM belongs to Skyworks' Si5345 family of jitter-attenuating clock multipliers, designed specifically for high-reliability telecom and datacom applications requiring G.8262 compliance, intelligent holdover, and any-frequency clock synthesis.

FAQ

What is the primary function of the SI5345A-B04228-GM in a 100 GbE line card?

The SI5345A-B04228-GM serves as the jitter-attenuating clock multiplier and timing engine in 100 GbE line cards, generating ultra-low-jitter (90 fs rms) output clocks from recovered or reference inputs while meeting ITU-T G.8262 EEC Option 1/2 requirements. It ensures deterministic phase alignment across SerDes lanes and maintains holdover stability during input failure - a critical capability for carrier Ethernet reliability. The SI5345A-B04228-GM achieves this via its DSPLL architecture and programmable loop bandwidth.

Does the SI5345A-B04228-GM support factory preprogramming, and how is it configured?

Yes, the SI5345A-B04228-GM supports in-circuit programmable non-volatile memory (NVM) and is available in factory preprogrammed configurations. Configuration is performed using Skyworks' ClockBuilder Pro™ software, which generates a unique OPN suffix (e.g., "-B04228") representing the stored frequency plan, input/output assignments, and operational modes. The SI5345A-B04228-GM retains this configuration across power cycles and requires no external boot ROM or configuration EEPROM.

How does the SI5345A-B04228-GM handle loss of input clock, and what is its holdover behavior?

Upon loss of all valid input clocks, the SI5345A-B04228-GM automatically enters holdover mode, using an averaged historical frequency value calculated from up to 120 seconds of prior locked data. The averaging window and delay are programmable to exclude corrupted data near failure time. During holdover, output frequency drift depends solely on the stability of the external 25–54 MHz crystal on XA/XB. The SI5345A-B04228-GM exits holdover glitchlessly when a valid input returns, optionally using ramped frequency transition.

What output signaling standards and voltage levels does the SI5345A-B04228-GM support?

The SI5345A-B04228-GM supports LVDS, LVPECL, LVCMOS, CML, and HCSL output formats across all ten outputs, with programmable amplitude and common-mode voltage. Each output has an independent supply pin (VDDO) supporting 1.8 V, 2.5 V, or 3.3 V logic levels - enabling direct interfacing with diverse FPGAs, ASICs, and SerDes without level-shifting. Output drivers can be individually enabled/disabled, and synchronous disable ensures zero-cycle glitches during power sequencing. This flexibility is integral to the SI5345A-B04228-GM's role in heterogeneous timing architectures.

Is the SI5345A-B04228-GM pin-compatible with other devices in the Si5345 family?

Yes, the SI5345A-B04228-GM shares the same 64-QFN 9×9 mm package and pinout as all Si5345 variants (e.g., Si5345B-D-GM, Si5345C-D-GM), including identical power, ground, I²C/SPI, IN/OUT, XA/XB, RSTb, and INTRb pin assignments. This allows drop-in replacement within the Si5345 family for design reuse and BOM simplification - provided the target variant supports the required frequency range and synthesis mode. The SI5345A-B04228-GM is fully compatible with existing PCB layouts designed for the Si5345 footprint.