Skyworks Solutions Inc. SI5338A-B07958-GMR

Overview

SI5338A-B07958-GMR from Skyworks Solutions is an I²C-programmable quad clock generator IC with four independently configurable differential or single-ended outputs, 0.7 ps RMS typical phase jitter, PCIe Gen 1–4 Common Clock and Gen 3 SRNS compliance, and MultiSynth™ frequency synthesis supporting any output frequency from 0.16 MHz to 710 MHz. It replaces up to four crystal oscillators in Ethernet switch/router and FPGA clocking systems.

For engineers reviewing the SI5338A-B07958-GMR datasheet, SI5338A-B07958-GMR pinout, SI5338A-B07958-GMR application, or SI5338A-B07958-GMR equivalent, key selection considerations include its 24-QFN package, independent per-output voltage (1.5/1.8/2.5/3.3 V), spread-spectrum capability (0.5–5.0% down-spread), glitchless 1 ppm frequency increment/decrement, and <20 ps phase step resolution.

Technical Context

The SI5338A-B07958-GMR implements a two-stage PLL architecture: a high-stability reference stage (VCO-based) followed by four independent MultiSynth™ fractional-N synthesis blocks, each driving one output pair. Input flexibility includes external crystal (8–30 MHz), CMOS (5–200 MHz), SSTL/HSTL (5–350 MHz), or differential (5–710 MHz) references.

Each output driver supports LVPECL/LVDS/HCSL/CMOS/SSTL/HSTL formats with independent supply voltage selection (VDDO0–VDDO3), programmable initial phase offset (±45 ns), and dedicated loss-of-lock/loss-of-signal alarms. The device operates across –40 to +85 °C with core supply options of 1.8 V, 2.5 V, or 3.3 V.

Key Specifications

Pinout & Package

SI5338A-B07958-GMR is housed in a 24-lead, 4 × 4 mm QFN package with exposed thermal pad. Pin assignments are fixed per Skyworks Si5338 family specification.

Key Features

Applications

Equivalent & Alternatives

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

Compared with Si5332A-D07958-GM and ICS8430I-01T, SI5338A-B07958-GMR uniquely balances field-programmability, PCIe Gen 4 compliance, and 4-output density in a 4×4 mm footprint-making it optimal for space-constrained, multi-standard timing applications where post-silicon tuning is essential.

Availability

SI5338A-B07958-GMR is available at Aetrix Electronics and suitable for Ethernet switch/router, PCIe Gen 1–4 timing, and broadcast video/audio timing applications requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for SI5338A-B07958-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 communications infrastructure, automotive, and industrial markets.

The Si5338 product line was designed to replace multiple discrete oscillators with a single programmable clock generator for high-speed digital systems-including PCIe, Ethernet, and broadcast video-where low jitter, flexible format support, and field configurability are critical.

FAQ

What is the primary function of the SI5338A-B07958-GMR in a timing architecture?

The SI5338A-B07958-GMR serves as an I²C-programmable quad clock generator that synthesizes up to four independent, any-frequency output clocks from a single input reference. Its MultiSynth™ technology enables zero-ppm precision across all outputs, making SI5338A-B07958-GMR ideal for replacing multiple crystal oscillators in PCIe, Ethernet, and FPGA-based systems while maintaining strict jitter compliance.

Does the SI5338A-B07958-GMR support PCIe Gen 4 timing requirements?

Yes, the SI5338A-B07958-GMR meets PCIe Gen 4 Common Clock jitter specifications with 0.15–0.45 ps RMS (12 kHz–20 MHz) when configured per Skyworks AN562 guidelines. It achieves this using a 2–5 MHz PLL bandwidth and CDR = 10 MHz filter settings, and has been validated with the Skyworks PCIe Clock Jitter Tool - confirming SI5338A-B07958-GMR's suitability for server and accelerator applications.

Can the SI5338A-B07958-GMR generate different output voltage levels on each channel?

Yes, SI5338A-B07958-GMR provides independent output supply pins VDDO0 through VDDO3, each configurable for 1.5 V, 1.8 V, 2.5 V, or 3.3 V. This allows simultaneous LVDS (2.5 V), HCSL (1.8 V), and CMOS (3.3 V) outputs - eliminating level shifters and simplifying interface to heterogeneous devices like FPGAs, CPUs, and SerDes PHYs in the same system.

How is the SI5338A-B07958-GMR programmed, and what tools are required?

The SI5338A-B07958-GMR is programmed via its I²C/SMBus interface using Skyworks' ClockBuilder Pro software, which generates configuration files and registers settings based on user-defined frequencies, formats, and features. No external hardware programmer is needed - configuration can be loaded at power-up from internal OTP or updated dynamically in-system, ensuring SI5338A-B07958-GMR remains fully field-reprogrammable throughout its lifecycle.

What package type and thermal characteristics does the SI5338A-B07958-GMR have?

The SI5338A-B07958-GMR uses a 24-lead QFN package measuring 4 × 4 mm with an exposed thermal pad. Its thermal resistance is θJA = 37 °C/W (still air) and θJC = 10 °C/W, enabling reliable operation at full load (45 mA core current) within the –40 to +85 °C industrial temperature range. Proper PCB land pattern per Skyworks document #900140 is required to maintain SI5338A-B07958-GMR's jitter and thermal performance.