Skyworks Solutions Inc. SI5338C-B05291-GMR

Overview

SI5338C-B05291-GMR from Skyworks Solutions is a quad-output, I²C-programmable clock generator with MultiSynth™ frequency synthesis, delivering four independent low-jitter clocks (0.7 ps RMS typ) across LVPECL/LVDS/HCSL/CMOS/SSTL/HSTL formats, supporting PCIe Gen 1–4 and Ethernet timing in telecom line cards and FPGA systems.

For engineers reviewing the SI5338C-B05291-GMR datasheet, SI5338C-B05291-GMR pinout, SI5338C-B05291-GMR application, or SI5338C-B05291-GMR equivalent, key selection considerations include its 4× differential output capability, 0 ppm synthesis accuracy, 24-pin 4×4 mm QFN package, and PCIe Gen 4 SRNS compliance - all critical for high-speed serial interface clocking.

Technical Context

The SI5338C-B05291-GMR implements a two-stage PLL architecture: a high-stability reference stage (with crystal or external clock input up to 710 MHz) followed by four independent MultiSynth™ fractional-N synthesizers per output. Each synthesizer supports integer/fractional mode operation, enabling any-frequency generation from 0.16 MHz to 710 MHz with <20 ps phase step resolution.

It features configurable output drivers with independent voltage supplies (1.5/1.8/2.5/3.3 V), spread-spectrum control (0.5–5.0% deviation, 33–63 kHz modulation), loss-of-lock/loss-of-signal alarms, and glitchless frequency increment/decrement via dedicated pins or I²C - all managed through on-chip OTP NVM and RAM-based runtime configuration.

Key Specifications

Pinout & Package

SI5338C-B05291-GMR is housed in a 24-lead, 4 × 4 mm QFN package with exposed thermal pad (RoHS-compliant, halogen-free). Pin 1 is top-left corner (IN1), pin 24 is bottom-right (GND), and pin 13 (INTR) provides interrupt status signaling.

Key Features

Applications

Equivalent & Alternatives

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

Compared with Si5332A-D05289-GM and ICS8430I-01T, the SI5338C-B05291-GMR uniquely balances field-programmability, PCIe Gen 4 readiness, and compact 4×4 mm packaging - making it optimal for space-constrained, multi-standard timing designs where post-silicon frequency agility is mandatory.

Availability

SI5338C-B05291-GMR is available at Aetrix Electronics and suitable for PCIe Gen 4 switch fabrics, 10GbE line cards, and FPGA-based broadcast video routers requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for SI5338C-B05291-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 infrastructure, automotive, and mobile markets.

The Si5338 family was designed specifically for high-performance, multi-protocol clock generation in datacenter, telecom, and broadcast equipment - emphasizing low jitter, flexible I²C configuration, and robust industrial temperature operation.

FAQ

What is the primary function of the SI5338C-B05291-GMR in a PCIe Gen 4 system?

The SI5338C-B05291-GMR serves as the common clock source for PCIe Gen 4 endpoints and switches, generating four synchronized, low-jitter HCSL clocks (e.g., 100 MHz) that meet the SRNS specification of ≤0.32 ps RMS jitter. Its MultiSynth™ architecture ensures zero-ppm accuracy and deterministic phase relationships between outputs - critical for reliable 16 GT/s link training and error-free data transmission in the SI5338C-B05291-GMR-based design.

Does the SI5338C-B05291-GMR support spread-spectrum clocking (SSC), and how is it configured?

Yes, the SI5338C-B05291-GMR supports fully programmable spread-spectrum clocking on any output, with adjustable spread (0.5–5.0%), modulation rate (33–63 kHz), and direction (down-spread only by default). Configuration is performed via I²C registers or ClockBuilder Pro software - no external components required. The SI5338C-B05291-GMR applies SSC independently per output, allowing selective EMI reduction without impacting non-SSC-critical subsystems.

Can the SI5338C-B05291-GMR generate different output voltages simultaneously?

Yes, the SI5338C-B05291-GMR provides four independent VDDO supplies (VDDO0–VDDO3), each configurable from 1.4 V to 3.63 V. This allows simultaneous LVDS (2.5 V), HCSL (1.8 V), and CMOS (3.3 V) outputs on separate banks - essential for interfacing with heterogeneous logic families in FPGAs, ASICs, and SerDes PHYs within the same SI5338C-B05291-GMR-based timing architecture.

What is the minimum input reference frequency supported by the SI5338C-B05291-GMR?

The SI5338C-B05291-GMR supports a minimum input reference frequency of 5 MHz for all input types (differential, CMOS, SSTL, HSTL) in normal PLL mode. In clock buffer (PLL bypass) mode, operation down to 1 MHz is supported - though loss-of-signal detection is disabled below 5 MHz. This flexibility ensures compatibility with legacy timing sources while maintaining full SI5338C-B05291-GMR functionality across diverse system architectures.

How does the SI5338C-B05291-GMR handle loss-of-lock or loss-of-signal events?

The SI5338C-B05291-GMR monitors both PLL lock status and input clock presence continuously. Upon loss-of-lock (typically within 5–10 ms) or loss-of-signal (detected in 2.6–5 µs), it asserts the open-drain INTR pin low and updates internal status registers. These events can trigger system-level fault handling or automatic failover - all without disrupting ongoing SI5338C-B05291-GMR output operation unless explicitly configured to halt clocks.