Skyworks Solutions Inc. SI5338J-B04983-GMR

Overview

SI5338J-B04983-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 FPGA/processor clocking, PCIe interconnects, and broadcast video timing systems.

For engineers reviewing the SI5338J-B04983-GMR datasheet, SI5338J-B04983-GMR pinout, SI5338J-B04983-GMR application, or SI5338J-B04983-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 SI5338J-B04983-GMR implements a two-stage PLL architecture: a high-stability reference PLL (Stage 1) locks to one of six input sources (crystal, CMOS, SSTL/HSTL, or differential), followed by four independent MultiSynth™ fractional-N synthesizers (Stage 2) generating outputs with true zero-ppm accuracy. Each output driver supports LVPECL/LVDS/HCSL/CMOS/SSTL/HSTL formats and configurable termination.

It features real-time frequency and phase adjustment via dedicated pins (FINC/FDEC, PINC/PDEC) with 1 ppm and <20 ps resolution respectively, plus loss-of-lock and loss-of-signal alarms. External feedback mode enables zero-delay operation, while programmable initial phase offset (±45 ns) supports deterministic skew control across multi-clock domains.

Key Specifications

Pinout & Package

SI5338J-B04983-GMR is housed in a 24-lead QFN package (4 × 4 mm, 0.5 mm pitch) with exposed thermal pad. Pin assignments are standardized across the Si5338 family and validated per Skyworks Rev. 1.6 datasheet, page 33 (Pin Descriptions) and page 37 (Device Pinout by Part Number).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SI5338A-B04983-GM, the SI5338J-B04983-GMR offers full field-programmability at the cost of initial configuration effort; versus LMK04832ISQE/NOPB, it delivers greater frequency agility and smaller footprint but trades off ultimate jitter cleaning performance.

Availability

SI5338J-B04983-GMR is available at Aetrix Electronics and suitable for PCIe interconnects, FPGA-based embedded vision systems, and telecom line cards requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for SI5338J-B04983-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 semiconductor company specializing in analog and mixed-signal connectivity solutions for wireless, broadband, automotive, and industrial markets.

The Si5338 product line delivers highly configurable, low-jitter clock generation for high-speed serial interfaces-including PCIe, Ethernet, and broadcast video-enabling compact, software-defined timing architectures.

FAQ

What is the default configuration state of SI5338J-B04983-GMR at power-up?

The SI5338J-B04983-GMR powers up in a known reset state with all outputs disabled and internal registers set to factory defaults. Unlike pre-programmed variants (e.g., SI5338A), it requires explicit I²C initialization via ClockBuilder Pro or custom firmware before generating valid clocks. This ensures full configurability but mandates host processor intervention during boot.

Does SI5338J-B04983-GMR support spread-spectrum clocking on all four outputs simultaneously?

Yes, SI5338J-B04983-GMR supports independent spread-spectrum modulation on any or all outputs. Each output can be configured with unique spread percentage (0.5–5.0%), modulation rate (33–63 kHz), and direction (down-spread only). Configuration is performed via I²C register writes and takes effect without interrupting ongoing clock outputs.

Can SI5338J-B04983-GMR generate frequencies above 350 MHz on more than two outputs?

No. Per Skyworks documentation (Rev. 1.6, Table 6 note 6), SI5338J-B04983-GMR supports only two unique frequencies above 350 MHz simultaneously-specifically Fvco/4 and Fvco/6. Higher-frequency outputs beyond this limit require integer-related frequencies or reduced channel count to maintain spectral purity and jitter performance.

What is the minimum input frequency supported in PLL bypass (buffer) mode for SI5338J-B04983-GMR?

In PLL bypass mode, SI5338J-B04983-GMR accepts input frequencies as low as 1 MHz on single-ended inputs (IN3/IN4) and 5 MHz on differential inputs (IN1/IN2, IN5/IN6). However, loss-of-signal detection is functional only above 5 MHz; below that threshold, the INTR pin will not assert LOS under signal loss conditions.

How does the thermal performance of SI5338J-B04983-GMR compare to earlier Si533x generations?

SI5338J-B04983-GMR exhibits θJA = 37 °C/W (still air), matching the thermal resistance of prior Si5332/Si5334 devices. Its 4 × 4 mm QFN package with exposed thermal pad enables efficient heat dissipation up to 60 mA core current. For continuous operation at maximum junction temperature (150 °C), ambient must remain ≤85 °C with adequate PCB copper area under the thermal pad.