Skyworks Solutions Inc. SI5338N-B05578-GMR

Overview

SI5338N-B05578-GMR 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 Ethernet switch fabric clocking.

For engineers reviewing the SI5338N-B05578-GMR datasheet, SI5338N-B05578-GMR pinout, SI5338N-B05578-GMR application, or SI5338N-B05578-GMR 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-QFN package with I²C/SMBus programming interface.

Technical Context

The SI5338N-B05578-GMR implements a two-stage PLL architecture: a high-stability input stage with programmable R-divider and a fractional-N MultiSynth™ synthesis stage per output path. Each of the four outputs features independent M/N/P dividers, enabling true zero-ppm frequency accuracy and glitchless frequency increment/decrement in 1 ppm steps.

It supports six input types - external crystal (8–30 MHz), CMOS (5–200 MHz), SSTL/HSTL (5–350 MHz), and differential (5–710 MHz) - and eight output formats including LVPECL, LVDS, HCSL, CML, CMOS, SSTL, and HSTL, with per-output supply voltage selection and <20 ps phase step resolution.

Key Specifications

Pinout & Package

SI5338N-B05578-GMR is housed in a 24-lead QFN package (4 mm × 4 mm, 0.5 mm pitch) with exposed thermal pad. Pin assignments follow the standard Si5338 pinout defined in Skyworks Rev. 1.6 datasheet, page 37.

Key Features

Applications

Equivalent & Alternatives

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

Compared with Si5332A-D05578-GM and ICS853S02AGT, SI5338N-B05578-GMR uniquely balances programmability, jitter performance, and compact 24-QFN packaging-making it optimal for PCIe Gen 4 add-in cards and multi-rate Ethernet platforms where field-upgradable timing and space constraints are critical.

Availability

SI5338N-B05578-GMR is available at Aetrix Electronics and suitable for PCIe Gen 4 add-in cards, carrier-class Ethernet switches, and broadcast video processing systems requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for SI5338N-B05578-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 industrial markets.

The Si5338 product line was designed to replace multiple fixed-frequency oscillators with a single programmable clock generator for high-speed serial interfaces-including PCIe, Ethernet, Fibre Channel, and broadcast video-while delivering ultra-low jitter and flexible output formatting.

FAQ

What is the primary function of the SI5338N-B05578-GMR in a PCIe Gen 4 system?

The SI5338N-B05578-GMR serves as a Common Clock source in PCIe Gen 4 systems, generating four low-jitter (≤0.45 ps RMS) 100 MHz reference clocks that meet the PCI-SIG Gen 4 Common Clock specification. Its MultiSynth™ engine ensures zero-ppm frequency accuracy across all outputs, and its 24-QFN package enables dense layout near root complex controllers. SI5338N-B05578-GMR supports both standard and spread-spectrum modes to pass EMI testing without external filtering.

Does the SI5338N-B05578-GMR support differential input references?

Yes, the SI5338N-B05578-GMR supports differential input references on pins IN1/IN2 and IN5/IN6, accepting frequencies from 5 MHz to 710 MHz with 0.4–2.4 V_PP swing. These inputs require external 100 Ω termination and deliver best jitter performance when slew rate exceeds 0.3 V/ns. The device also accepts single-ended CMOS, SSTL, and HSTL inputs on IN3/IN4, making SI5338N-B05578-GMR compatible with diverse reference sources including crystal oscillators, FPGA clocks, and SerDes recover clocks.

Can the SI5338N-B05578-GMR generate different output voltages simultaneously?

Yes, the SI5338N-B05578-GMR provides independent VDDO0–VDDO3 supplies, allowing each of its four output banks to operate at 1.5 V, 1.8 V, 2.5 V, or 3.3 V concurrently. This enables direct interfacing with mixed-voltage components-such as a 1.8 V FPGA I/O bank, 2.5 V memory controller, and 3.3 V legacy peripheral-without external level shifters. SI5338N-B05578-GMR's per-output voltage control is configured via I²C registers and persists after power-on reset when programmed into OTP memory.

How is the SI5338N-B05578-GMR programmed and configured?

The SI5338N-B05578-GMR is programmed via its I²C/SMBus-compatible interface (SCL/SDA pins) using Skyworks' ClockBuilder Pro software, which generates register maps and configuration files based on user-defined frequency, format, and jitter requirements. Configuration can be loaded at runtime or stored in on-chip OTP memory for autonomous startup. SI5338N-B05578-GMR also supports hardware pin control (PINC/FDEC) for real-time frequency adjustment without host intervention.

What thermal considerations apply to the SI5338N-B05578-GMR in continuous operation?

The SI5338N-B05578-GMR has a junction-to-ambient thermal resistance (θ_JA) of 37 °C/W in still air and requires proper PCB thermal design: the exposed thermal pad must be soldered to a minimum 100 mm² copper pour with ≥4 thermal vias to internal ground planes. At full load (45 mA core current), junction temperature rise is ~1.7 °C per watt dissipated. SI5338N-B05578-GMR operates reliably from –40 °C to +85 °C ambient, with derating recommended above 70 °C case temperature.