Skyworks Solutions Inc. SI5345A-B05771-GM

Overview

SI5345A-B05771-GM from Skyworks is a 10-channel, any-frequency jitter attenuator/clock multiplier IC featuring fourth-generation DSPLL™ and MultiSynth™ technologies. It delivers ultra-low 90 fs rms jitter, supports 4 differential or LVCMOS inputs and 10 programmable outputs (LVDS/LVPECL/LVCMOS/CML/HCSL), and operates across –40 to +85 °C. It powers up with factory-programmed configuration and serves as the primary clock synthesis and jitter cleaning engine in SyncE-compliant line cards.

For engineers reviewing the SI5345A-B05771-GM datasheet, SI5345A-B05771-GM pinout, SI5345A-B05771-GM application, or SI5345A-B05771-GM equivalent, key selection considerations include its G.8262 EEC Option 1/2 compliance, digitally programmable jitter attenuation bandwidth (0.1 Hz–4 kHz), hitless/ramped/glitchless input switching, DCO mode with 0.001 ppb step size, and support for gapped clock locking - all critical for carrier-grade timing integrity.

Technical Context

The SI5345A-B05771-GM implements a fourth-generation DSPLL architecture with fractional input dividers (P), fractional MultiSynth output dividers (N), and integer output dividers (R), enabling any-frequency synthesis from any input. Its loop filter is fully integrated on-chip, eliminating external components and noise coupling risks.

It supports three operational modes - freerun (crystal-referenced), locked (input-synchronized), and holdover (averaged historical frequency storage up to 120 s) - with automatic/manual input selection, status monitoring (LOS/OOF/LOL), and I²C/SPI control of non-volatile OTP memory for deterministic power-up behavior.

Key Specifications

Pinout & Package

SI5345A-B05771-GM uses a 64-pin QFN package (9 × 9 mm, 0.5 mm pitch) with exposed thermal pad. Pin functions are defined per Skyworks Si5345 64-QFN pinout specification, supporting four clock inputs (IN0–IN3), ten outputs (OUT0–OUT9), crystal interface (XA/XB), serial control (SDA/SCL/MOSI/MISO/SCLK/CSB), and dedicated status/enable pins.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SI5345B-D-GM and LTC6957-3, the SI5345A-B05771-GM uniquely combines 10 outputs, full 1028 MHz range, fractional synthesis, 120-second holdover history, and G.8262 EEC Option 1/2 certification - making it the only option for carrier-class multi-terabit line cards requiring deterministic timing recovery and multi-standard interoperability.

Availability

SI5345A-B05771-GM 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 assurance, and guaranteed traceable sourcing.

Supply support for SI5345A-B05771-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 wireless, broadband, automotive, and industrial markets.

The Si5345 family is engineered for carrier-grade timing applications, delivering ultra-low jitter, multi-input redundancy, and SyncE/ITU-T compliance in telecom, datacom, and broadcast infrastructure equipment.

FAQ

What is the primary function of the SI5345A-B05771-GM in a telecom timing architecture?

The SI5345A-B05771-GM serves as a jitter-attenuating clock multiplier that cleans and regenerates timing signals from noisy or unstable references. In telecom systems, it provides G.8262-compliant outputs for Synchronous Ethernet line cards, enabling precise synchronization across 10G/100G interfaces while supporting holdover during input failures. The SI5345A-B05771-GM achieves this using its integrated DSPLL and MultiSynth architecture with factory-programmed NVM configuration.

Does the SI5345A-B05771-GM support automatic input clock switching with priority-based selection?

Yes, the SI5345A-B05771-GM includes an automatic input selection state machine that evaluates input qualification (LOS/OOF), user-defined priority order, and revertive/non-revertive behavior. It seamlessly switches among IN0–IN3 based on validity and priority, entering holdover only when no valid inputs remain. This capability is integral to the SI5345A-B05771-GM's role in redundant timing architectures for carrier Ethernet and OTN equipment.

Can the SI5345A-B05771-GM generate output frequencies not harmonically related to its input?

Yes, the SI5345A-B05771-GM uses fractional-N synthesis in both its DSPLL and MultiSynth stages to generate any output frequency from any input frequency - including non-harmonic, irrational, or widely disparate ratios (e.g., 125 MHz input → 156.25 MHz output). This "any-frequency" capability is enabled by programmable P, N, and R dividers and is a defining feature of the SI5345A-B05771-GM across its full 100 Hz–1028 MHz output range.

How does the SI5345A-B05771-GM handle loss of input clock during operation?

Upon input failure, the SI5345A-B05771-GM automatically enters holdover mode, using up to 120 seconds of stored historical frequency data to compute an averaged holdover frequency. Its output remains phase-continuous and drifts only according to the stability of the XA/XB crystal or TCXO. The SI5345A-B05771-GM exits holdover glitchlessly when a valid input returns, optionally using ramped frequency transition to avoid transients - a key reliability feature for the SI5345A-B05771-GM in mission-critical infrastructure.

Is the SI5345A-B05771-GM preprogrammed, and how is configuration managed?

Yes, SI5345A-B05771-GM is a factory preprogrammed part (denoted by "B05771" in the OPN), meaning its NVM contains a specific frequency plan and operational settings assigned by Skyworks and generated via ClockBuilder Pro™. Configuration can be updated in-circuit via I²C or SPI, but the SI5345A-B05771-GM powers up immediately with its programmed state - eliminating boot-time uncertainty and simplifying system integration.