Skyworks Solutions Inc. SI5351A-B04690-GMR

Overview

SI5351A-B04690-GMR from Skyworks Solutions is an I²C-programmable, 8-output CMOS clock generator with integrated VCXO architecture, generating precise non-integer-related frequencies from 2.5 kHz to 200 MHz per output with 0 ppm synthesis error. It operates from a 25 or 27 MHz crystal reference and supports independent 1.8/2.5/3.3 V output supply rails. It replaces crystals, crystal oscillators, and VCXOs in compact embedded timing systems.

For engineers reviewing the SI5351A-B04690-GMR datasheet, SI5351A-B04690-GMR pinout, SI5351A-B04690-GMR application, or SI5351A-B04690-GMR equivalent, key selection factors include its 8-output QFN-20 package, VCXO tuning capability (±240 ppm at 3.3 V), <70 ps pk-pk period jitter, I²C programmability, and support for HCSL-compatible swing and spread spectrum modulation.

Technical Context

The SI5351A-B04690-GMR implements a dual-PLL architecture with PLL A (SSC-capable) and PLL B (VCXO-enabled), each feeding eight independent MultiSynth fractional dividers. Its input stage accepts only a 25/27 MHz crystal (no CLKIN or VC pin functionality), distinguishing it from Si5351B/C variants.

All eight outputs are derived from the same crystal-referenced PLLs, enabling synchronous or free-running clocks with static phase offset control, glitchless frequency changes, and per-output rise/fall time programming - all configured via I²C register writes or ClockBuilder Pro.

Key Specifications

Pinout & Package

SI5351A-B04690-GMR is housed in a 20-pin QFN package (4 mm × 4 mm, 0.5 mm pitch) with exposed thermal pad. Pin functions are defined per Skyworks datasheet Rev. 1.3, Section 10.1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with Si5351B-B-GM and Si5351C-B-GM, SI5351A-B04690-GMR provides identical 8-output capability and jitter performance but omits VC and CLKIN pins-reducing complexity, cost, and PCB routing while retaining full programmability and 0 ppm synthesis accuracy for crystal-based timing.

Availability

SI5351A-B04690-GMR is available at Aetrix Electronics and suitable for audio/video timing, networking equipment, industrial instrumentation, and laser rangefinding requiring stable component supply and long-term production continuity.

Supply support for SI5351A-B04690-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, with leadership in RF, timing, and power management ICs.

The Si5351 family is designed for cost-sensitive, space-constrained applications requiring flexible, software-configurable clock generation - specifically targeting replacement of crystals, XOs, VCXOs, and discrete PLLs in consumer, industrial, and communications equipment.

FAQ

What is the reference clock requirement for SI5351A-B04690-GMR?

The SI5351A-B04690-GMR requires a 25 MHz or 27 MHz fundamental-mode AT-cut crystal connected to XA/XB pins. It does not accept external CLKIN or VC signals - this is a defining characteristic of the Si5351A variant. Internal load capacitance (0/6/8/10 pF) is programmable to match crystal specifications without external capacitors.

Does SI5351A-B04690-GMR support spread spectrum clocking?

Yes, SI5351A-B04690-GMR supports per-output spread spectrum clocking with selectable down-spread (–0.1% to –2.5%) or center-spread (±0.1% to ±1.5%) modulation at 31.5 kHz. This feature reduces electromagnetic interference (EMI) in noise-sensitive applications such as audio/video systems and medical instrumentation without affecting functional timing margins.

Can SI5351A-B04690-GMR generate frequencies above 112.5 MHz?

Yes, SI5351A-B04690-GMR can generate frequencies up to 200 MHz, but only two *unique* frequencies above 112.5 MHz may be active simultaneously (e.g., 125 MHz and 130 MHz). Multiple outputs may replicate the same high-frequency signal - for example, four outputs at 125 MHz and four at 130 MHz - satisfying PCIe and USB timing in a single device.

What is the output jitter performance of SI5351A-B04690-GMR?

SI5351A-B04690-GMR delivers <70 ps pk-pk period jitter when all eight outputs are active in the 20-QFN package, measured over 10,000 cycles at default high-drive strength. Cycle-to-cycle jitter is <150 ps pk. Performance is validated with real-world frequency plans including 33.333, 74.25, 27, 24.576, 22.5792, 28.322, 125, and 48 MHz outputs.

How is SI5351A-B04690-GMR configured in-system?

SI5351A-B04690-GMR is configured via its standard-mode or fast-mode I²C interface (SCL/SDA), supporting full register-level access for frequency, phase, drive strength, spread spectrum, and output enable settings. Configuration can be performed at power-up using firmware or dynamically during operation - enabling field-upgradable timing without hardware changes.