Skyworks Solutions Inc. SI5345B-B04869-GMR

Overview

SI5345B-B04869-GMR from Skyworks is a 10-channel, any-frequency jitter attenuator/clock multiplier featuring fourth-generation DSPLL™ and MultiSynth™ technologies. It delivers ultra-low 90 fs rms jitter, supports differential input up to 750 MHz and differential output up to 1028 MHz, and operates in free-run, synchronous, or holdover modes with programmable jitter attenuation bandwidth (0.1 Hz–4 kHz). It is used in ITU-T G.8262-compliant Synchronous Ethernet line cards.

For engineers reviewing the SI5345B-B04869-GMR datasheet, SI5345B-B04869-GMR pinout, SI5345B-B04869-GMR application, or SI5345B-B04869-GMR equivalent, key selection considerations include its 4-input/10-output configuration, 64-QFN 9×9 mm package, G.8262 EEC Option 1/2 compliance, I²C/SPI programmability with on-chip NVM, and support for LVDS/LVPECL/LVCMOS/CML/HCSL output formats with programmable amplitude.

Technical Context

The SI5345B-B04869-GMR implements a digitally controlled DSPLL architecture with fractional input dividers (P), integer/fractional MultiSynth output dividers (N), and configurable R-divider stages. Its loop bandwidth is fully programmable from 0.1 Hz to 4 kHz, enabling precise jitter filtering tailored to SyncE or OTN applications.

It integrates hitless and glitchless input switching, ramped holdover exit, DCO mode with 0.001 ppb step size, and status monitoring (LOS/OOF/LOL). Input clock qualification, automatic priority-based selection, and gapped-clock locking are implemented via on-chip state machines - all configurable via I²C or SPI interface with factory-programmable NVM.

Key Specifications

Pinout & Package

SI5345B-B04869-GMR is housed in a 64-pin QFN package measuring 9×9 mm with 0.5 mm pitch and exposed thermal pad. The package supports standard reflow profiles and provides low-inductance ground paths critical for sub-100-fs jitter performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with Si5345A-D-GM1, SI5345B-B04869-GMR trades maximum output frequency (≤350 MHz vs. ≤1028 MHz) for optimized cost and power in SyncE/OTN edge applications; versus LTC6955IUF#PBF, it adds telecom-grade reliability features - holdover, G.8262 compliance, and embedded NVM - at the expense of wider input bandwidth.

Availability

SI5345B-B04869-GMR is available at Aetrix Electronics and suitable for OTN muxponders, Synchronous Ethernet line cards, and broadcast video infrastructure requiring stable component supply, long-term lifecycle support, and G.8262-certified timing performance.

Supply support for SI5345B-B04869-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 wireless, broadband, automotive, and industrial markets.

The Si5345 family is designed specifically for high-reliability telecom and datacom timing applications, delivering ultra-low jitter, G.8262 compliance, and autonomous holdover/failover - targeting carrier-grade network equipment manufacturers.

FAQ

What is the maximum output frequency supported by SI5345B-B04869-GMR?

The SI5345B-B04869-GMR supports a maximum differential output frequency of 350 MHz. This is defined by its "B" variant designation in the Si5345 ordering guide, distinguishing it from the "A" variant (up to 1028 MHz). The 350 MHz limit applies to all 10 outputs and is verified in the official Skyworks Si5345/44/42 Rev D Data Sheet, Table 2 - Ordering Guide. Applications requiring higher frequencies must use SI5345A-D-GM1 or equivalent.

Does SI5345B-B04869-GMR meet ITU-T G.8262 requirements?

Yes, SI5345B-B04869-GMR meets both EEC Option 1 and EEC Option 2 of ITU-T G.8262 for Synchronous Ethernet. This compliance is achieved through its ultra-low 90 fs rms jitter, programmable DSPLL loop bandwidth (0.1 Hz–4 kHz), and integrated holdover algorithm - all validated in Skyworks' characterization reports and explicitly stated in the Si5345/44/42 Rev D Data Sheet, Section 1 - Features List. It is certified for Stratum-3E timing applications.

How is SI5345B-B04869-GMR programmed, and does it retain settings after power cycle?

SI5345B-B04869-GMR is programmed via I²C or SPI interface using Skyworks' ClockBuilder Pro™ software and stores configuration in on-chip non-volatile OTP memory. This ensures SI5345B-B04869-GMR always powers up with its last programmed frequency plan and operational settings - no external EEPROM or boot firmware required. Factory preprogrammed variants (e.g., SI5345B-B04869-GMR) ship with configuration fused into NVM.

What package type and footprint does SI5345B-B04869-GMR use?

SI5345B-B04869-GMR uses a 64-pin QFN package with 9×9 mm body size and 0.5 mm pin pitch, including an exposed thermal pad. This matches the standard Si5345 mechanical outline documented in Skyworks' Si5345/44/42 Rev D Data Sheet, Section 10.1. The footprint complies with IPC-7351B density level B and supports standard lead-free reflow profiles.

Can SI5345B-B04869-GMR operate without an external crystal?

No - SI5345B-B04869-GMR requires an external 25–54 MHz fundamental-mode crystal connected to XA/XB pins for stable free-run and holdover operation. While it can accept an external REFCLK instead of a crystal, the datasheet recommends a crystal for optimal jitter performance. The internal oscillator (OSC) relies on this reference; omitting it prevents valid clock generation in freerun or holdover modes, though locked operation may still function if a valid input clock is present.