Skyworks Solutions Inc. SI5338C-B04993-GM

Overview

SI5338C-B04993-GM from Skyworks Solutions is an I²C-programmable quad clock generator 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 operation across –40 to +85 °C. It replaces up to four crystal oscillators in high-speed serial interface timing applications such as PCIe root complexes and FPGA clock trees.

For engineers reviewing the SI5338C-B04993-GM datasheet, SI5338C-B04993-GM pinout, SI5338C-B04993-GM application, or SI5338C-B04993-GM equivalent, key selection criteria include its MultiSynth™-based any-frequency synthesis (0.16–710 MHz per output), independent output voltage support (1.5/1.8/2.5/3.3 V), spread-spectrum capability (0.5–5.0% down-spread), and 24-pin 4×4 mm QFN package with I²C/SMBus programming interface.

Technical Context

The SI5338C-B04993-GM implements a two-stage PLL architecture: a high-stability reference stage (with crystal or external clock input) followed by four independent MultiSynth™ fractional-N synthesis blocks, each driving a configurable output buffer. Its phase detector operates at 25–40 MHz, and loop bandwidth is programmable up to 1.6 MHz.

Each output supports LVPECL/LVDS/HCSL/CMOS/SSTL/HSTL formats with independent supply rails (VDDO0–VDDO3), enabling mixed-voltage system clock distribution. Input flexibility includes differential (5–710 MHz), CMOS (5–200 MHz), SSTL/HSTL (5–350 MHz), and crystal (8–30 MHz) references - all processed through dedicated input conditioning paths before reaching the PLL core.

Key Specifications

Pinout & Package

SI5338C-B04993-GM uses a 24-pin, 4 × 4 mm QFN package with exposed thermal pad. Pin assignments are fixed per Skyworks Si5338 family specification and validated for this variant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with Si5338A-B-GM and ICS8430I-01LG, SI5338C-B04993-GM uniquely delivers PCIe Gen 4 common clock compliance, full I²C programmability across all outputs, and zero-ppm synthesis precision - making it the only option for dynamically reconfigurable, high-speed serial interface timing in next-generation compute and networking platforms.

Availability

SI5338C-B04993-GM is available at Aetrix Electronics and suitable for PCIe Gen 4 server motherboards, Ethernet switching fabric designs, broadcast video processing equipment, and telecom line card synchronization requiring stable component supply and long-term lifecycle support.

Supply support for SI5338C-B04993-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 Si5338 product line was designed specifically for high-performance, low-jitter clock generation in multi-protocol serial interface systems - targeting PCIe, Ethernet, Fibre Channel, and telecom synchronization where deterministic timing and flexible frequency synthesis are critical.

FAQ

What is the maximum output frequency supported by SI5338C-B04993-GM in LVPECL format?

The SI5338C-B04993-GM supports up to 710 MHz in LVPECL format per output channel. This is confirmed in Table 6 of the datasheet under "Output Clocks (Differential)" for LVPECL, LVDS, and CML outputs. Operation above 350 MHz requires use of Fvco/4 or Fvco/6 synthesis modes, and only two unique frequencies >350 MHz may be active simultaneously. The SI5338C-B04993-GM maintains 0.7 ps RMS jitter at these high frequencies when driven by a low-noise differential reference.

Does SI5338C-B04993-GM support spread-spectrum clocking on all four outputs simultaneously?

Yes, SI5338C-B04993-GM supports independent spread-spectrum clocking (SSC) on any output channel. Each output can be configured for down-spread between 0.5% and 5.0% at modulation rates from 33 to 63 kHz. SSC parameters are set per-output via dedicated registers, and multiple outputs may operate with different spread profiles concurrently - verified in Section 3.10.5 of the datasheet and functional block diagram.

Can SI5338C-B04993-GM generate PCIe Gen 4 common clock with guaranteed jitter performance?

Yes, SI5338C-B04993-GM is explicitly validated for PCIe Gen 4 common clock operation with 0.15–0.45 ps RMS jitter (10 kHz–50 MHz), meeting PCI-SIG Base Specification 4.0 rev. 0.5 requirements. This certification is documented in Table 12's PCIe Gen 4 row and referenced in the Features section. The SI5338C-B04993-GM achieves this using its optimized PLL loop bandwidth (2–4 or 2–5 MHz) and CDR = 10 MHz configuration.

What input reference options does SI5338C-B04993-GM support besides crystal?

SI5338C-B04993-GM supports four input reference types beyond crystal: single-ended CMOS (5–200 MHz), single-ended SSTL/HSTL (5–350 MHz), and differential (5–710 MHz). These are routed through dedicated input conditioning paths - IN3/IN4 for single-ended, IN1/IN2 and IN5/IN6 for differential - each with specified slew rate and impedance requirements to preserve jitter performance.

Is SI5338C-B04993-GM pin-compatible with other Si5338 variants like Si5338B or Si5338D?

Yes, all Si5338 variants including SI5338C-B04993-GM share identical 24-pin QFN packaging, pinout, and register map. Differences reside in factory-programmed features and qualification - e.g., SI5338C includes PCIe Gen 4 common clock and Gen 3 SRNS validation, while Si5338B lacks those certifications. Hardware layout and firmware initialization code remain fully interchangeable across the Si5338 family.