Skyworks Solutions Inc. SI5338N-A-GM

Overview

SI5338N-A-GM 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 operation from 1.8/2.5/3.3 V core supply in a 4 × 4 mm 24-QFN package. It replaces up to four crystal oscillators in high-speed serial interface timing applications.

For engineers reviewing the SI5338N-A-GM datasheet, SI5338N-A-GM pinout, SI5338N-A-GM application, or SI5338N-A-GM equivalent, key selection criteria include its MultiSynth™-based any-frequency synthesis (0.16–710 MHz per output), independent output voltage control (1.5–3.3 V), programmable phase/frequency adjustment (±45 ns / 1 ppm steps), spread-spectrum capability (0.5–5.0% down-spread), and loss-of-lock/loss-of-signal alarm support.

Technical Context

The SI5338N-A-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 paths, each feeding a configurable output driver stage. This enables true zero-ppm frequency accuracy across all outputs without requiring external loop filters.

Each output supports LVPECL/LVDS/HCSL/CMOS/SSTL/HSTL formats with independent VDDO supply (1.4–3.63 V), selectable slew rate, and programmable termination. Input flexibility includes differential (5–710 MHz), CMOS (5–200 MHz), SSTL/HSTL (5–350 MHz), or 8–30 MHz crystal reference - all routed through a shared input multiplexer with automatic detection.

Key Specifications

Pinout & Package

The SI5338N-A-GM is housed in a 24-lead, 4 × 4 mm QFN package with exposed thermal pad. Pin assignments are fixed per Skyworks' Si5338 family layout and include four differential clock outputs (CLK0A/B through CLK3A/B), six input pins (IN1–IN6), I²C interface (SCL/SDA), interrupt (INTR), power (VDD, VDDO0–VDDO3), ground (GND), and reserved ground (RSVD_GND).

Key Features

Applications

Equivalent & Alternatives

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

Compared with Si5338B-A-GM and LMK04832RHAR, the SI5338N-A-GM uniquely combines crystal-based self-contained synthesis, full I²C configurability, and compact 24-QFN packaging - making it optimal for space-constrained, multi-protocol systems needing field-updatable clock trees.

Availability

SI5338N-A-GM is available at Aetrix Electronics and suitable for PCIe Gen 4 server platforms, 10/25/100 GbE switch designs, and broadcast video equipment requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for SI5338N-A-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 leader in analog and mixed-signal semiconductors, specializing in RF, timing, and connectivity solutions for infrastructure, automotive, and mobile markets.

The SI5338N-A-GM belongs to Skyworks' Si5338 family of programmable clock generators, designed specifically for high-density, multi-protocol digital systems requiring precise, flexible, and low-jitter clock distribution without external components.

FAQ

What is the primary function of the SI5338N-A-GM in a system design?

The SI5338N-A-GM serves as a fully programmable quad-output clock generator that synthesizes up to four independent, precise clock frequencies from a single reference (crystal or external clock). Its MultiSynth™ architecture enables zero-ppm accuracy and supports protocols including PCIe Gen 1–4, Ethernet, and broadcast video - eliminating multiple discrete oscillators. The SI5338N-A-GM integrates PLL, synthesis, and configurable output drivers in one 4 × 4 mm QFN package.

Does the SI5338N-A-GM support crystal oscillator input, and what frequency range is valid?

Yes, the SI5338N-A-GM supports fundamental-mode parallel-resonant crystals from 8 MHz to 30 MHz. It includes on-chip load capacitance options (11–13 pF supported, 17–19 pF recommended) and automatic crystal drive level control (max 100 µW). The SI5338N-A-GM also accepts external CMOS, SSTL, HSTL, or differential clock inputs - providing full input flexibility beyond crystal-only operation.

How does the SI5338N-A-GM achieve PCIe Gen 4 compliance given its jitter specifications?

The SI5338N-A-GM achieves PCIe Gen 4 Common Clock compliance with ≤0.45 ps RMS jitter (1.5 MHz–50 MHz band) when configured per Skyworks' validated settings: PLL bandwidth 2–4 MHz, CDR = 10 MHz, and HCSL 100 MHz outputs. This performance is measured using the Skyworks PCIe Clock Jitter Tool and aligns with PCI-SIG Base Specification 4.0 rev. 0.5. The SI5338N-A-GM's low-noise VCO and optimized loop filter design ensure consistent results across temperature and voltage.

Can the SI5338N-A-GM generate different output formats simultaneously, such as LVDS and HCSL?

Yes, the SI5338N-A-GM supports mixed output formats across its four differential pairs: CLK0A/B may be configured as LVDS, CLK1A/B as HCSL, CLK2A/B as LVPECL, and CLK3A/B as CML - all simultaneously and independently. Each output has its own VDDO supply rail (1.4–3.63 V), allowing direct interface to devices with differing I/O standards without level-shifting circuitry. The SI5338N-A-GM's register map permits per-output format, voltage, and termination control via I²C.

Is ClockBuilder Pro software required to configure the SI5338N-A-GM, or can it be programmed in-system?

ClockBuilder Pro is optional for initial configuration and validation but not required for in-system programming. The SI5338N-A-GM features a standard I²C/SMBus interface (up to 400 kHz) that allows full register access, frequency updates, and feature control directly from host firmware. Factory-programmed configurations are stored in one-time-programmable (OTP) memory, while runtime changes persist until power cycle unless written to OTP. The SI5338N-A-GM supports both methods without hardware dependency on ClockBuilder Pro.