Skyworks Solutions Inc. SI5338J-A-GM

Overview

SI5338J-A-GM 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 0.16–710 MHz output frequencies and PCIe Gen 1–4 compliance in a 4×4 mm 24-QFN package for FPGA and processor clocking.

For engineers reviewing the SI5338J-A-GM datasheet, SI5338J-A-GM pinout, SI5338J-A-GM application, or SI5338J-A-GM equivalent, key selection considerations include its 4-output any-frequency synthesis capability, differential input support up to 710 MHz, independent per-output voltage control (1.5–3.3 V), spread-spectrum modulation, and phase/frequency adjustment in 20 ps / 1 ppm steps.

Technical Context

The SI5338J-A-GM implements a two-stage PLL architecture: a high-stability reference stage followed by four independent MultiSynth™ fractional-N synthesis blocks, each feeding a configurable output driver. Its core operates from a single 1.8/2.5/3.3 V supply with 45 mA typical current draw and supports external crystal (8–30 MHz), CMOS (5–200 MHz), SSTL/HSTL (5–350 MHz), or differential (5–710 MHz) references.

Each of the four differential output pairs (CLK0A/B through CLK3A/B) is independently programmable for format, frequency, output voltage, phase offset (±45 ns), and spread-spectrum parameters (0.5–5.0% spread, 33–63 kHz modulation). Loss-of-lock and loss-of-signal alarms are provided via the INTR pin, and configuration is performed over I²C/SMBus with ClockBuilder Pro software.

Key Specifications

Pinout & Package

SI5338J-A-GM uses a 24-lead QFN package (4 × 4 mm, 0.5 mm pitch) with an exposed thermal pad. Pin assignments follow standard Si5338 top-view layout: pins 1–24 include six input clocks (IN1–IN6), four differential output pairs (CLK0A/B–CLK3A/B), three VDDOx supplies (VDDO0–VDDO3), dual-core VDD, SCL/SDA/I²C interface, INTR alarm, and reserved ground.

Key Features

Applications

Equivalent & Alternatives

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

Compared with Si5332A-D-GM, SI5338J-A-GM offers broader input flexibility and lower cost but higher jitter; versus ICS853S01AGI-01LFT, it provides full programmability at the expense of increased design complexity and qualification effort.

Availability

SI5338J-A-GM is available at Aetrix Electronics and suitable for PCIe Gen 4 switch timing, Ethernet switch clocking, FPGA-based video processing, and telecom line card synchronization requiring stable component supply, long-term lifecycle assurance, and consistent parametric performance across production batches.

Supply support for SI5338J-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 semiconductor company specializing in analog and mixed-signal connectivity solutions, with leadership in RF, timing, and precision analog products for infrastructure, automotive, and industrial markets.

The Si5338 family is designed as a programmable, low-jitter clock generator platform targeting high-speed digital systems-especially those requiring multiple synchronized clocks with flexible format, voltage, and frequency options in compact form factors.

FAQ

What is the maximum output frequency supported by SI5338J-A-GM in LVPECL mode?

The SI5338J-A-GM supports LVPECL output frequencies up to 710 MHz, as confirmed in Table 6 of the datasheet. This applies when operating in differential LVPECL format with appropriate termination and load conditions. The device achieves this using its MultiSynth™ fractional-N synthesis engine, which maintains 0.7 ps RMS jitter even at high frequencies when driven by a low-noise reference.

Does SI5338J-A-GM support PCIe Gen 4 Common Clock compliance?

Yes, SI5338J-A-GM meets PCIe Gen 4 Common Clock jitter requirements with ≤0.45 ps RMS (12 kHz–20 MHz), as specified in Table 12 of the datasheet under "PCIe Gen 4, Common Clock" test condition. It achieves this using a 2–4 MHz PLL bandwidth and CDR = 10 MHz configuration, and is validated with the Skyworks PCIe Clock Jitter Tool.

Can SI5338J-A-GM generate different output voltages on each channel?

Yes, SI5338J-A-GM supports independent output supply rails: VDDO0 powers CLK0A/B, VDDO1 powers CLK1A/B, VDDO2 powers CLK2A/B, and VDDO3 powers CLK3A/B. Each can be set to 1.5 V, 1.8 V, 2.5 V, or 3.3 V, enabling direct interfacing with mixed-voltage FPGAs, ASICs, and SerDes blocks without external level shifters.

How is SI5338J-A-GM programmed, and is external non-volatile memory required?

SI5338J-A-GM is programmed via its I²C/SMBus interface using ClockBuilder Pro software. Configuration is stored in on-chip one-time-programmable (OTP) NVM, so no external memory is needed. Factory-programmed devices power up with valid clocks within 2 ms (tRDY), and field updates are supported without interrupting operation.

What input reference options does SI5338J-A-GM support besides crystals?

In addition to 8–30 MHz crystals, SI5338J-A-GM accepts CMOS (5–200 MHz), SSTL/HSTL (5–350 MHz), and differential (5–710 MHz) input clocks on dedicated pins (IN3/IN4 for single-ended, IN1/IN2 and IN5/IN6 for differential). All inputs support loss-of-signal detection with configurable thresholds and response times.